Psychology: MCAT

Psychological, Social, and Biological Foundations of Behavior Section

List out the different types of Experimental Design

1. Descriptive Experiments

   • Aim to describe a phenomenon

   • Focus on detailing and characterizing observed phenomena without necessarily testing specific hypotheses

   • Provide comprehensive descriptions

2. Inferential Experiments

   • Seek to draw conclusions and make predictions based on collected data

   • Focus on testing hypotheses based on collected data, often manipulating variables to examine cause-and-effect relationships

   • Employ statistical analysis to determine significance of results and generalize findings

3. Observational Studies

   • Involve observing and analyzing existing data

   • Analyze existing data or observations WITHOUT directly intervening

   • Try and identify patterns as they are

4. Experimental studies

   • Involve actively manipulating variables and collecting new data

   • Try and identify cause-and-effect relationships under controlled conditions and the use of treatments

5. Cross-Sectional Studies

   • Collect data from a SINGLE point in time, providing a snapshot of a population or phenomenon at a specific instant

6. Longitudinal Studies

   • Extend over an extended period of time, repeatedly collecting data from the same individuals or subjects at multiple time points

7. Case-Control Studies

   • Compare individuals with a specific condition to a control group of individuals without it

   • Good for identifying risk factors

8. Cohort Studies

   • Follow a group of individuals over time that share a common characteristic to assess the development of a condition

   • Valuable for assessing the incidence and causation of diseases or conditions in a population

Confounding Variable

• Linked to independent and dependent variables, potentially distorting their genuine relationship

Experimenter Effect

• Influence that researchers’ expectations, behaviors, biases, and credentials may have on participants’ behavior in a study

Demand characteristics

• Involve cues or expectations from participants that can influence their behavior or responses in a study

• Demand characteristics are cues in a study that lead influence participants’ responses or behavior in order to fit or contradict the research purpose and change their behavior accordingly.

• For example, if participants in a memory study realize the researcher is testing the effects of caffeine, they might try harder on memory tasks, skewing the results.

Socialization

• The process thorugh which individuals learn and internalize the values, beliefs, and norms of their society or immediate surroundings

• Adopting and internalizing views of those around them

Cultural diffusion

• Spread of cultural items such as ideas, styles, religions, techonlogies, and languages between indiviudals whether within a single culture or from one culture to another

Role strain

• Arises when there’s tension due to conflicting demands within a single societal role, or between different roles one may occupy

Roles of different parts of the brain

Hypothalamus

• Homeostasis

• Regulation of body temp, thirst, hunger, sleep, circadian rhythm, autonomic regulation of heart rate & breathing

Cerebellum

• Coordination of different parts of the body

Pre-central gyrus:

• Primary motor cortex

Post-central gyrus:

• Somatosensory cortex

Posterior Pituitary Gland

• Vasopressin

• Oxytocin

Hippocampus

• Memory, learning, and emotion

• Hold on to short-term memories and then transfer them to long-term storage in the brain

What are the sensory receptors?

Where are receptors in the skin? Are there any in the epidermis?

Exteroceptors (Location)

-Sensitive to stimuli arising from outside the body located at or near body surfaces

1. Touch

2. Pressure

3. Pain

4. Temperature

Interoceptors (Location)

-Receive stimuli from internal viscera, located in digestive tube, tongue, bladder, and lungs to monitor

1. Changes in [chemical]

2. Taste stimuli

3. Tissue stretching

4. Temperature

Proprioceptors (Location)

-Monitor degree of stretch and send inputs on body movements to the CNS

-Located in skeletal muscles, tendons, ligaments, and joints

Mechanoreceptors (Type of Stimuli)

-Respond to mechanical forces

1. Touch

2. Pressure

3. Stretch

4. Vibration

5. Itch

Baroceptors (Type of Stimuli)

-Monitor blood pressure

Thermoreceptors (Type of Stimuli)

-Respond to temperature changes

Chemoreceptors(Type of Stimuli)

-Respond to chemicals in solution

Photoreceptors(Type of Stimuli)

-Respond to light, located in eye

Nociceptors(Type of Stimuli)

-Respond to harmful stimuli that result in pain

Where are receptors in the skin? Are there any in the epidermis?

• Yes, receptors do exist in the epidermis:

  • Free nerve endings penetrate the epidermis.

  • Merkel cells are literally in the basal layer of the epidermis.

• But most of the bigger mechanoreceptors (Meissner, Pacinian, Ruffini) live in the dermis or deeper.

What are the main types of Mechanoceptors to know about?

Receptor	Stimulus	Adaptation	Skin Layer	Fiber Type	Key Features
Meissner’s Corpuscle	Light touch, flutter	Fast-adapting	Papillary dermis	Aβ	Detects gentle, changing stimuli (e.g. brushing, putting on clothes)
Pacinian (Lamellar) Corpuscle	Deep pressure, vibration	Fast-adapting	Hypodermis	Aβ	Deepest mechanoreceptor, detects vibration & poke
Merkel’s Disc	Sustained light touch, texture	Slow-adapting	Stratum basale + papillary dermis	Aβ	Specialized epidermal cell, used for reading Braille, shape & edge detection
Ruffini Ending	Sustained deep stretch/touch	Slow-adapting	Reticular dermis	Aβ	Responds to skin stretch, collagen deformation, good for grip stability
Hair Follicle Receptor	Hair movement/light touch	Fast-adapting	Anchored in reticular dermis	Aβ	Detects hair displacement, great for sensing insects or breeze

Fast-Adapting (Detect Change):

• Meissner’s corpuscle

• Pacinian (Lamellar) corpuscle

• Hair follicle receptor

Slow-Adapting (Detect Sustained Pressure):

• Merkel’s disc

• Ruffini ending

• Adaptation matters: fast = change detection; slow = continuous pressure detection

• Location matters: deeper mechanoreceptors (e.g., Pacinian, Ruffini) respond to stronger stimuli

• All touch receptors use Aβ fibers, which are fast, myelinated afferent fibers

• Hair follicle receptors are superficially stimulated but anchored deep

• Meissner’s = light, changing touch → fast-adapting, superficial

• Pacinian = deep pressure/vibration → fast-adapting, deep

• Merkel’s = constant touch/pressure → slow-adapting, mid-layer

• All use Aβ fibers for touch; pain uses Aδ or C fibers

• Adaptation: fast-adapting = respond only to change; slow-adapting = respond continuously

Mechanism of Activation (for all of them):

• Mechanical pressure deforms receptor → Na⁺ channels open

• Sodium influx causes graded potential

• If strong enough → triggers action potential in afferent Aβ fiber

What are the types of afferent fibers to know for MCAT?

Types of Afferent Fibers:

Fiber Type	Speed	Function
Aβ fibers	Fastest	Touch, pressure, proprioception
Aδ fibers	Medium	Sharp pain, temperature
C fibers	Slow	Dull, lingering pain

What are the heat transfer mechanisms you shoudl know about?

Radiation

• Description: Transfer of heat through electromagnetic waves, without the need for direct contact.

• Example: The sun's heat warming your skin.

Conduction

• Description: Transfer of heat through direct contact between molecules in solids or liquids.

• Example: A metal spoon heating up in a hot cup of coffee.

Convection

• Description: Heat transfer through the MOVEMENT of FLUIDS (liquids or gases), where warm particles rise and cool particles sink.

• Example: Warm air rising and being replaced by cooler air near a fan.

• Example 2: In a pot, warm water at the bottom rises due to reduced density, while cooler water moves down to replace it

What are the three different types of inhibition in enzymatic kinetics and how does this affect Km and Vmax?

1. Competitive Inhibition: The inhibitor competes with the substrate for binding to the active site, increasing the apparent Km but leaving Vmax unchanged.

   • IN COMP you get “more Kills/Km”

     • Higher Km, same V_max
       

2. Uncompetitive Inhibition: The inhibitor binds only to the enzyme-substrate complex, lowering both Km and Vmax.

   • UNCOMP, trying new characters so you’re lower at everything

     • Lower Km, lower V_max

3. Non-competitive Inhibition: The inhibitor binds to an allosteric site, not affecting substrate binding (Km remains unchanged) but decreasing the enzyme's maximum activity (Vmax).

   • Non-Comp, non-Muslim dunya stays same but akhira decreases

     • Same Km, lower Vmax

• Competitive: Increases Km, Vmax unchanged.

• Uncompetitive: Decreases Km, Vmax decreases.

• Non-competitive: Km unchanged, Vmax decreases.

So, Vmax CAN increase, but not due to inhibition — only through activation or increased enzyme concentration.

Describe step by step how the contraction of muscle is initiated

ATP has three phosphates

• Alpha

• Beta

• Gamma

  • The gamma phosphate of ATP is the one that is terminal to the chain of triphosphates which, when RELEASED from ATP forms ADP

  • The release of the gamma phosphate from ATP promotes the cocking of the myosin head which allows for the myosin head to form a new cross-bridge

THe opening of voltage-gated calcium channels allows for the free passage of calcium into the sarcoplasm (passive)

During contraction, muscle tissue shortens due to the overlap of contracticle units within the muscle

• Depolarization of the sarcolemma would result in muscle SHORTENING

Describe Carl Rogers’ theory of personal development in a nutshell

Carl Rogers' Theory of Personal Development (Humanistic Perspective)

• Core Idea: Personal growth happens when an individual strives for self-actualization, aiming to align their actual self with their ideal self through positive experiences and personal insight.

Key Concepts for the MCAT:

• Ideal Self:

  • The person you aspire to be based on personal goals and societal expectations.

  • Example: Wanting to be a kind, successful doctor.

• Perceived Self:

  • How you see yourself based on experiences and feedback from others.

  • Example: Believing you are hardworking but struggling with confidence.

• Actual Self:

  • Your true characteristics and behaviors at any given moment.

  • Example: Your current abilities, emotions, and self-awareness.

• Self-Concept:

  • The overall image and understanding of yourself, shaped by experiences.

  • Includes self-esteem, self-worth, and identity.

• Congruency:

  • When the ideal self and actual self are aligned, leading to fulfillment and self-actualization.

  • Example: You see yourself as compassionate and actively engage in helping others.

• Incongruency:

  • When the ideal self and actual self do not align, leading to discomfort or dissatisfaction.

  • Example: Wanting to be confident but struggling with self-doubt.

• Self-Esteem:

  • Your overall evaluation of your self-worth.

  • Higher when congruency is present, lower when there is incongruency.

• Existential Self:

  • The understanding that you are a separate, distinct being with your own experiences.

  • Example: Recognizing “I am me” and separate from others.

• Categorical Self:

  • The understanding of yourself in relation to different categories, such as age, gender, or roles.

  • Example: Identifying as a student, daughter, or future doctor.

MCAT Relevance:

• Ties into self-concept, self-esteem, and identity theories.

• Important for understanding human motivation and personal growth.

• Contrasts with Freudian and behaviorist perspectives

What are the different selfs?

Self-worth

• Refers to one’s recognition that they are unique, valuable, and worthy of love

Self-concept

• Describes how one thinks about themself overall

Self-verification

• Refers to the idea that individuals want to be perceived as they see and express themselves

Self-efficacy

• Refers to one’s belief in their own COMPETENCE and ability to succeed in a given SITUATION

• NOT to be confused with self-esteem

Self-esteem

• Describes an individual’s thoughts, feelings, beliefs about themselves and their VALUE

You can have high self-efficacy and low self-esteem and vice versa

Key Theories of Identity & Self-Concept for the MCAT

1. Erikson’s Psychosocial Development (Lifespan Identity Formation)

• Identity develops through eight life stages, each with a key social conflict.

• Example: Adolescence (Identity vs. Role Confusion) is when individuals explore and form their personal identity.

8 Life Stages:

• Trust vs. Mistrust (0-1 yr)

  • If caregivers are reliable, the infant develops trust; if not, mistrust forms.

  • Virtue developed: Hope

• Autonomy vs. Shame & Doubt (1-3 yrs)

  • Developing independence (e.g., walking, making choices); over-control leads to shame/doubt.

  • Virtue developed: Will

• Initiative vs. Guilt (3-6 yrs)

  • Children begin planning activities and showing initiative; if discouraged, they feel guilt.

  • Virtue developed: Purpose

• Industry vs. Inferiority (6-12 yrs)

  • Success in school and social tasks leads to competence; failure results in inferiority.

  • Virtue developed: Competency

• Identity vs. Role Confusion (12-18 yrs)

  • Adolescents explore who they are; success leads to strong identity, failure to confusion.

  • Virtue developed: Fidelity

• Intimacy vs. Isolation (18-40 yrs)

  • Forming deep relationships leads to intimacy; avoiding connection results in isolation.

  • Virtue developed: Love

• Generativity vs. Stagnation (40-65 yrs)

  • Helping the next generation (career, family) leads to fulfillment; failing to contribute leads to stagnation.

  • Virtue developed: Care

• Integrity vs. Despair (65+ yrs)

  • Reflecting on life with satisfaction leads to integrity; regret leads to despair.

  • Virtue developed: Wisdom

2. Freud’s Psychosexual Development (Childhood Stages & Personality Formation)

• Identity and personality develop through five psychosexual stages, where libido (sexual energy) focuses on different body parts.

• Fixation at a stage can lead to personality issues.

• Example: A person fixated at the oral stage (0-1 yr) may develop habits like nail-biting or overeating.

5 Stages: (OLD AGED PEOPLE LOVE GRAPES)

1. Oral (0-1 yr) → Mouth (sucking, biting) → Dependency issues if fixated.

2. Anal (1-3 yrs) → Bowel control → Orderliness/messiness fixation.

3. Phallic (3-6 yrs) → Oedipus/Electra complex → Sexual identity formation.

4. Latency (6-12 yrs) → Dormant libido → Social & intellectual development.

5. Genital (12+ yrs) → Maturity & adult relationships.

3. Cooley’s Looking-Glass Self (Self-Concept from Social Perception)

• We see ourselves based on how we think others see us.

• Three Steps:

  1. Imagine how we appear to others.

  2. Imagine their judgment of us.

  3. Develop feelings about ourselves based on this perceived judgment.

• Example: If people treat you as smart, you start seeing yourself as intelligent.

4. Meltzoff’s Imitation Theory (Infants Learn by Copying Others)

• Even newborns imitate behaviors, showing early social learning.

• Key Idea: Imitation helps form self-concept and social identity.

• Example: A baby sticking out its tongue after seeing an adult do the same.

MCAT Takeaways:

• Erikson → Identity develops throughout life via social conflicts.

• Freud → Identity & personality form through childhood psychosexual stages.

• Cooley → Self-concept is shaped by how we think others perceive us.

• Meltzoff → Imitation plays a key role in early identity development.

Let me know if you need a mnemonic or deeper explanation!

Describe Kohlberg’s theory of moral development

Kohlberg’s Theory of Moral Development

Kohlberg proposed that moral reasoning develops through three levels, each containing two stages, resulting in six stages total.

1. Preconventional Level (Self-Interest, Young Children)

• Stage 1: Obedience & Punishment → Right and wrong are based on avoiding punishment.

  • Example: “I won’t steal because I don’t want to get in trouble.”

• Stage 2: Self-Interest (Instrumental Relativist) → Moral decisions are based on rewards and personal gain.

  • Example: “I’ll help if I get something in return.”

2. Conventional Level (Social Order, Adolescents & Adults)

• Stage 3: Interpersonal Accord (“Good Boy/Good Girl”) → Right and wrong are based on seeking approval and maintaining relationships.

  • Example: “I’ll be honest because I want people to like me.”

• Stage 4: Law & Order → Morality is based on following rules and maintaining social order.

  • Example: “Stealing is wrong because laws must be followed.”

3. Postconventional Level (Abstract Ethics, Some Adults)

• Stage 5: Social Contract → Laws should be followed, but can be questioned if they violate rights or justice.

  • Example: “Laws should protect people, but unfair laws should be changed.”

• Stage 6: Universal Ethical Principles → Morality is guided by internal ethical principles, even if they conflict with laws.

  • Example: “I would break an unjust law to uphold human rights.”

MCAT Takeaways:

• Preconventional → Self-focused (Avoid punishment, seek reward).

• Conventional → Society-focused (Follow rules, seek approval).

• Postconventional → Ethics-focused (Justice > Laws).

What are the six major PERSONALITY theories, their key proponents, assumptions, overall view, assessment methods, and an example of each?

1. Psychoanalytic Theory

• Key Proponent: Sigmund Freud

• Assumptions: Personality is shaped by unconscious conflicts and childhood experiences.

• View of Personality: The id (pleasure-driven), ego (rational), and superego (moral) interact to create behavior. Unresolved conflicts lead to defense mechanisms.

• Assessment Methods: Projective tests like the Rorschach inkblot test or Thematic Apperception Test (TAT) to uncover unconscious motives.

• Example: A person with repressed childhood trauma develops an anxious or avoidant personality.

Unconscious mental life and the results of the ID/ego/superego struggle = personality

2. Humanistic Theory

• Key Proponents: Carl Rogers, Abraham Maslow

• Assumptions: People have free will and an innate drive toward self-actualization.

• View of Personality: Personality is shaped by self-concept and the presence of unconditional positive regard.

• Assessment Methods: Self-report questionnaires and interviews focusing on self-perception.

• Example: A person raised with unconditional love and support develops high self-esteem and confidence.

Free will actions to improve self = personality

3. Trait Theory

• Key Proponents: Gordon Allport, Raymond Cattell, Hans Eysenck

• Assumptions: Personality is made up of stable traits that can be measured and categorized.

• View of Personality: Traits exist on a continuum and influence behavior across situations.

• Assessment Methods: Personality inventories like the Big Five (OCEAN) test or 16 Personality Factors (16PF).

• Example: A person high in extraversion enjoys social interactions and thrives in leadership roles.

Categorizable traits = personality

4. Social-Cognitive Theory

• Key Proponent: Albert Bandura

• Assumptions: Personality is shaped by observational learning, cognitive processes, and environment (reciprocal determinism).

• View of Personality: Personality develops through interactions between personal factors, behavior, and social influences.

• Assessment Methods: Observation-based assessments and self-efficacy tests.

• Example: A child who watches their parent handle stress calmly learns to do the same.
  
  4 Stages of Observational Learning According to Albert Bandura

  1. Attention: Observer must pay attention to behavior in environment

  2. Memory: Observer must REMEMBER how to perform observed behavior

  3. Motor Capability: Observer must be physically capable of performing action

  4. Motivation: Observer must be motivated to perform the learned behavior

Interplay between personal choice and environment influences behavior = personality

5. Behavioral Theory

• Key Proponents: B.F. Skinner, John Watson

• Assumptions: Personality is learned through conditioning (rewards, punishments, and reinforcement).

• View of Personality: There is no innate personality—it is shaped by environmental stimuli.

• Assessment Methods: Behavioral observation and controlled experiments (e.g., Skinner boxes, operant conditioning studies).

• Example: A child praised for politeness develops a kind and considerate personality.

CONDITIONED behavior = personality

6. Biological Theory

• Key Proponents: Hans Eysenck, Jeffrey Gray

• Assumptions: Personality is influenced by genetics and neurobiology.

• View of Personality: Certain traits (e.g., extraversion, neuroticism) are heritable and linked to brain structures and neurotransmitters.

• Assessment Methods: Twin studies, genetic research, neuroimaging (fMRI, PET scans).

• Example: A person with a naturally low dopamine response may seek excitement and be highly extraverted.

GENES = Personality

MCAT Takeaways:

• Psychoanalytic → Unconscious conflicts (Freud).

• Humanistic → Free will, self-actualization (Rogers, Maslow).

• Trait → Stable personality traits (Allport, Cattell, Eysenck).

• Social-Cognitive → Learned behavior & environment (Bandura).

• Behavioral → Personality is shaped by rewards/punishments (Skinner, Watson).

• Biological → Genetics & brain chemistry influence personality (Eysenck, Gray).

What is attachment theory as proposed by Mary Ainsworth?

Attachment Theory (Mary Ainsworth)

Mary Ainsworth expanded on John Bowlby’s attachment theory by studying how infants form emotional bonds with caregivers. She identified four attachment styles based on the "Strange Situation" experiment, where a child’s reaction to separation and reunion with their caregiver was observed.

A CHILD REQUIRES ATTACHMENT TO AT LEAST ONE CAREGIVER FOR SUCCESSFUL SOCIAL AND EMOTIONAL DEVELOPMENT

Strange Situation Experiment

Ainsworth’s experiment involved a mother, an infant (12-18 months), and a stranger in a controlled setting with eight episodes of separation and reunion. The child’s responses were used to classify their attachment style.

1. Secure Attachment → The child is distressed when the caregiver leaves but is quickly comforted upon return.

   • Example: A baby cries when their mom leaves but calms down when she returns and seeks comfort.

2. Insecure-Avoidant Attachment → The child is indifferent to both the caregiver's departure and return, avoiding contact.

   • Example: A baby shows little reaction when their mother leaves or returns, avoiding eye contact.

3. Insecure-Ambivalent (Resistant) Attachment → The child is extremely distressed when the caregiver leaves and remains upset, even when comfort is offered.

   • Example: A baby cries when their mom leaves, but when she returns, they resist being comforted.

4. Disorganized Attachment → The child exhibits confused, fearful, or erratic behavior, often due to inconsistent caregiving (e.g., neglect or trauma).

   • Example: A baby seems fearful of their caregiver and shows mixed signals (approaching but then pulling away).

MCAT Takeaways:

• Secure attachment → Healthy emotional bonds; confident in caregiver’s return.

• Insecure attachments → Can lead to anxiety, avoidance, or disorganized behavior in relationships.

• Strange Situation → Used to assess attachment styles in infants

What is fertility rate, population momentum, and fecundity?

Key Population Terms for the MCAT

• Fertility Rate → TOTAL NUMBER OF CHILDREN BORN DIVIDED BY POPULATION SIZE OF WOMEN IN THEIR REPRODUCTIVE YEARS OVER A GIVEN TIME PERIOD

  • Example: A fertility rate of 2.1 (replacement level) is needed to keep a population stable without immigration.

  • THUS, population momentum can be attributed to increases in the number of women of reproductive age because as they increase in number the population still grows but if they don’t give birth then that is lowering fertility rate

• Population Momentum → The tendency of a population to continue growing despite a drop in fertility rates due to a large proportion of young individuals who will still have children.

  • Example: Even if a country lowers its birth rate, its population may still grow for decades due to many young people entering reproductive age.

• Fecundity → The biological potential to reproduce, referring to the maximum possible number of children a woman could have under ideal conditions.

  • Example: A woman’s fecundity may decline with age, even if fertility rates remain high in a population.

What is dependency ratio?

Dependency Ratio (MCAT Definition)

The dependency ratio of a population is the ratio of unemployed individuals to employed individuals within a population

• INCREASES in ratio when:

  • Size of population outpaces # of available jobs

  • # of available jobs decreases

  • # of working age individuals decreases

In population momentum, population size is INCREASING meaning more children are being born that are not yet old enough to work meaning that fraction of population who is part of labor force will DECREASE thus causing dependency ratio to further INCREASE

Formula:

Dependency Ratio= # of dependents (minors and seniors)/ # of working age individuals

MCAT Relevance:

• High dependency ratio → Greater strain on workers due to increased social and healthcare costs.

• Low dependency ratio → More workers supporting fewer dependents, which can boost economic productivity.

What are some prominent populational trends and theories?

1. Preventative Check (Malthusian Theory)

• Definition: A factor that prevents overpopulation by limiting birth rates, such as moral restraint, delayed marriage, or family planning.

• Example: In societies with access to contraception or cultural norms favoring smaller families, birth rates decrease, thus preventing population explosion.

2. Positive Check (Malthusian Theory)

• Definition: A factor that increases death rates when population growth exceeds resources, such as famine, disease, or war.

• Example: In history, the Black Death in Europe (14th century) dramatically decreased the population due to the spread of plague, which acted as a positive check on population growth.

3. Demographic Transition

• Definition: The shift from high birth and death rates to low birth and death rates as a country industrializes and develops economically.

• Example: Japan and South Korea went through a demographic transition, where initially high birth and death rates were replaced by lower rates due to urbanization, healthcare improvements, and women's empowerment.

4. Malthusian Theory

• Definition: The idea that population growth will outstrip food and resource production, leading to starvation and death, unless controlled by preventative or positive checks.

• Example: Malthus predicted that unchecked population growth would lead to widespread poverty and famine, though modern technological advancements (e.g., agricultural innovations) have prevented this to some extent.

MCAT Takeaways:

• Preventative Check → Limits birth rates (family planning).

• Positive Check → Increases death rates (famine, disease).

• Demographic Transition → Population shifts from high birth/death rates to low ones with development.

• Malthusian Theory → Population grows faster than resources, leading to crises unless checks occur.

List out Jean PIaget’s Stages of his Theory of Cognitive Development

1. Sensorimotor Stage

Age: 0–2 years
Key Concepts:

• Learning through senses and movement

• No mental representation yet (early on)

• Object permanence develops (things still exist even if not seen)

• Stranger anxiety may begin

MCAT Tip:
Object permanence is the hallmark milestone.

2. Preoperational Stage

Age: 2–7 years
Key Concepts:

• Development of symbolic thinking (use of words, images)

• Pretend play

• Egocentrism (can’t take another’s point of view)

• Centration (focus on one aspect of a situation)

MCAT Tip:
No understanding of conservation (e.g., pouring water into different shaped glasses — they think amount changes)

3. Concrete Operational Stage

Age: 7–11 years
Key Concepts:

• Can think logically about concrete events

• Conservation develops (understands quantity doesn’t change with shape)

• Mathematical operations understood

• Loss of egocentrism

MCAT Tip:
Conservation is the hallmark milestone. Kids can do basic logic, but only with concrete (real) objects.

4. Formal Operational Stage

Age: 12+ years
Key Concepts:

• Abstract reasoning

• Hypothetical thinking (what if...?)

• Moral reasoning emerges

MCAT Tip:
Teens in this stage can use logic without concrete objects.

What is kinesthetic sense?

What does totipotent refer to?

What Is Kinesthetic Sense?

• Definition: The ability to sense the position and movement of your body parts through receptors in muscles, tendons, and joints.

• It tells you where your limbs are without looking at them.

• Also called proprioception (though some sources use “proprioception” more broadly to include balance and spatial awareness).

Totipotent

• Referring to stem cells capable of giving rise to any cell type or a complete embryo

Compare and contrast vision as it pertains to rods and cones

Rods:

• Highly photosensitive and densely clustered around the PERIPHERY of the retina outside the fovea

• Achromatic: Black and White

• ONE TYPE: All contain Rhodopsin

• MORE rods than cones

Cones:

• Concentrated in the FOVEA in the CENTER of the retina and are lowly photosensitive

• There are THREE different iodopsin pgiments, each responsible for detecting one of three frequency bands or colors of light:

  1. Red

  2. Green

  3. Blue

How is visual data collected?

Visual information is collected from the left-and-right visual fields in a CONTRALATERAL MANNER

• Both eyes can pick up visual information from BOTH the L+ R visual fields, PROCESSING however is contralateral

• Data from the RIGHT visual field will be processed by the LEFT temporal retina which will be processed by LEFT hemisphere and vice versa

Light that hits Nasal Retina is Processed CONTRALATERALLY

1. Light from RIGHT side of visual field strikes RIGHT nasal retina

2. Information from RIGHT nasal retina (same side of retina as nose) will cross at optic chiasm to opposite side

3. Will be processed by LEFT occipital lobe

Light that hits Temporal Retina is Processed IPSILATERALLY

1. Light from RIGHT side of visual field strikes LEFT temporal retina

2. Information from the LEFT temporal retina (same side of retina as ear) DOES NOT cross at optic chiasm

3. Will pass through optic nerve staying at same side through optic chiasm to the LEFT occipital lobe

THIS IS BECAUSE MEDIAL FIBERS (closer to center, like nasal) CROSS WHILE LATERAL FIBERS (further from center, like temporal) STAY ON THEIR SIDE THROUGH THE OPTIC CHIASM

What is Signal Detection Theory?

Signal Detection Theory

• Describes whether stimuli have been correctly perceived as present or absent

• Signal: Actual stimulus you’re trying to detect

• Noise: Background information or distractions that could interfere with distraction

  POSSIBILITIES:

  1. Hit: Signal is PRESENT and DETECTED (true positive)

  2. False Alarm: Signal is ABSENT but DETECTED (false positive)

  3. Miss: Signal is PRESENT but MISSED (false negative)

  4. Correct Rejection: Signal is ABSENT and MISSED (true negative)

PICTURED CURVE: Receiver Operating Characteristic (ROC) Curve

• Helps visualize sensitivity independent of criterion

• d’=sensitivity=how well you tell signal from noise

• Beta or c=decision criterion=your personal bias or threshold

What do insulin, glucagon, somatostatin, and aldosterone stimulate; respectively?

Insulin

• Decreases blood sugar levels by prompting cells to take up glucose

• Stimulates glycogenesis in liver and muscles

• Promotes conversion of excess glucose into fatty acids for storage as adipose tissue in the liver (lipogenesis)

• INHIBITS breakdown of stores glycogen (glycogenolysis) and gluconeogenesis

• PROMOTES protein synthesis

Glucagon

• Increases blood sugar levels by prompting glucose release

• Gluconeogenesis in liver where glucose is synthesized from non-carbohydrate biomolecules like amino acids and lactates

• Glycogenolysis, breaking down glycogen and liberating it into blood stream

• Prompts BETA-OXIDATION of fatty acids into acetyl-CoA primarily in liver

Somatostatin

• Secreted by delta cells of the pancreas concurrently with insulin and produces a predominantly INHIBITORY EFFECT across different systems

• Inhibits GI, endocrine, exocrine, pancreatic, and pituitary secretions

  • Such as GH, TSH, prolactin, gastrin, secretin, insulin, and glucagon

Aldosterone

• Released from adrenal gland in response to low blood volume, blood pressure, or sodium levels.

• Activates mineralocorticoid receptors in various tissues

• In the KIDNEY, aldosterone acts on the cells of the distal tubules and collecting ducts triggering a signal that causes sodium REABSORPTION and potassium EXCRETION

• Promotes WATER REABSORPTION increasing blood volume and pressure

What is the importance of phosphoenolpyruvate carboxykinase (PEPCK)?

It is an important enzyme for GLUCONEOGENESIS

• In low blood glucose levels, glucagon stimulates glucose production from NON-CARB substrates like LACTATE

• The steps for gluconeogenesis are essentially the same as those for glycolysis EXCEPT for the three irreversible steps of

  1. Hexokinase

  2. PFK-1

  3. Pyruvate Kinase

If PEPCK is nonfunctioning, gluconeogenesis will NOT occur leading to the build-up of gluconeogenic substrates like lactate in the blood thus RAISING the acidity of the blood

What is the blood-testis barrier?

Blood-Testes Barrier

• Physical barrier between blood vessels and the seminiferous tubules of the testes where sperm production occurs

• This barrier prevents antibodies and immune cells from entering the testes in the blood since because sperm are unlike any other cells in the body the immune system could MISTAKENLY TARGET them as foreign cells

Leydic Cells

• Produce and release testosterone in the interstitial tissue surrounding the seminiferous tubules

What are the differences between displacement, projection, reaction formation

Projection

• Fault lies WITHIN you but is by you to avoid blame

• Defense mechanism in which a threatening urge or quality (e.g., affect, responsibility) is ascribed to others rather than to oneself.

• You are stupid so you call others stupid

Displacement

• The fault lies OUTSIDE of you but is shifted by you to DISPLACE blame

• Defense mechanism in which an individual discharges tensions by taking them out on a less threatening target.

• A student who is angry with her professor takes it out on her very understanding boyfriend because it avoids the anxiety that would arise from attacking her professor

Reaction Formation

• Defense mechanism where OPPOSITE of true feelings are expressed sometimes to exaggerated degree

• A man who feels overly gay may act overly MASCULINE

• A drug addicted woman may EXTOL reacthe virtues of ABSTINENCE

• Very stressed about the MCAT yet approach it CALMLY

Sublimation

• Channeling unwanted/unhealthy desires into something that is accepted by society

• Working out when you’re angry at someone

• Becoming a surgeon because you like to mutilate people

What are the two types of immunity that exist?

Active Immunity

• When our own immune system is responsible for a pathogen

Passive Immunity

• When we are protected from a pathogen by immunity gained from someone else

What are the different types of conditioning?

Operant Conditioning: Defined by CONSEQUENCES

• Punishment: Decrease undesirable behavior

  • POSITIVE: Introduces consequence to deter behavior

  • NEGATIVE: Takes something away to deter behavior

• Reinforcement: Increase desirable behavior

  • POSITIVE: Reward to encourage behavior

  • NEGATIVE: Take away negative to encourage behavior

Classical Conditioning: Defined by ASSOCIATION

• A neutral stimulus becomes associated with an unconditioned stimulus, eventually triggering a conditioned response.

What is Weber’s Ideal Bureaucracy? What are vertical and horizontal mobility?

Weber’s Ideal Bureaucracy

1. Formal Selection: Employment based on TECHNICAL qualifications

2. Formal Rules: Employees follow STANDARD operating protocol

3. Impersonality: Protocol is IMPERSONAL, same hierarchy same rulez

4. Career Orientation: Follow the rules, stay. Break them, ur FIRED

5. Division of Labor: Each position has a clear job description. Employees don’t take up a variety of tasks

6. Hierarchy: Only big dawgs at the top call the shots and make decisions; NO EMPLOYEE CONSENSUS

---

Horizontal Mobility

• Definition: A change in occupation or role without a change in social class or status.

• Key Idea: Lateral movement; same socioeconomic level, just a different position.

• Example: A schoolteacher becomes a police officer — different job, but same social class.

• MCAT Tip: Think of horizontal = sideways movement in society.

Vertical Mobility

• Definition: A change in a person's social class, either upward or downward.

• Key Idea: Movement up or down the socioeconomic ladder.

• Example (Upward): A factory worker earns a medical degree and becomes a doctor.

• Example (Downward): A corporate executive loses their job and becomes unemployed.

• MCAT Tip: Vertical = change in status or income level.

MCAT Takeaway:

Horizontal mobility = same class, different role
Vertical mobility = change in class (up or down)

What is the life course approach? What is the front stage self v. looking glass self?

Life Course Approach

• Definition: A perspective that considers how early life experiences (biological, psychological, social) influence health outcomes and behaviors across a person’s entire life.

• Focus: Long-term effects of childhood, family, education, socioeconomic status, trauma, etc.

• MCAT Angle: Health is shaped not just by current status, but by cumulative life experiences over time.

• Example: A child growing up in poverty may have poorer health in adulthood due to chronic stress and limited healthcare access.

• Life course approach = long-term, whole-life view of health/behavior

Front Stage Self (from Goffman’s dramaturgical theory)

• Definition: The persona you intentionally perform in social settings, where you're being watched and judged.

• Behavior: Polished, controlled, socially acceptable.

• Example: Acting professional during a job interview, even if you’re nervous or tired.

• Front stage self = your “performance” in public

Looking Glass Self (from Cooley)

• Definition: The idea that our self-concept develops through how we believe others perceive us.

• Process:

  1. We imagine how others see us

  2. We imagine how they judge us

  3. We develop feelings about ourselves based on that imagined judgment

• Example: A teen thinks others see them as awkward, so they start to view themselves as awkward.

Hawthorne Effect

• Definition: People change their behavior when they know they’re being observed.

• MCAT Relevance: Important in research design — can bias results.

• Example: Workers become more productive when they know a supervisor is watching, even if working conditions haven't changed.

Social Identity

• Definition: The part of your self-concept that comes from belonging to social groups (like race, gender, religion, nationality, occupation).

• You define who you are partially based on group membership.

• Comes from Social Identity Theory, which includes:

  • Social categorization (labeling groups),

  • Social identification (adopting group norms),

  • Social comparison (comparing in-group vs. out-group).

• Example: Someone sees themselves as a “Latina scientist” — blending ethnicity and profession into their identity.

Stereotype Threat

• Definition: When someone feels at risk of confirming a negative stereotype about their social group, and this pressure impairs performance.

• Often subconscious, and can create anxiety or self-doubt.

• Example: A woman underperforms on a math test after being reminded of the stereotype that “women are bad at math.”

Self-Fulfilling Prophecy

• Definition: A belief or expectation that influences behavior, causing it to become true.

• Can be based on others’ expectations or your own.

• Example: A teacher expects a student to fail, so they give them less attention → the student performs poorly → confirming the original expectation.

• Social identity = how you define yourself based on group membership.

• Stereotype threat = internalized fear of fulfilling a negative group stereotype.

• Self-fulfilling prophecy = expectations lead to behavior that makes the expectation come true.

What is the Elaboration Likelihood Model (ELM)?

Elaboration Likeihood Model (ELM)

• Explains how attitudes are formed and changed through persuasion.

• Focuses on how deeply a message is processed based on motivation and ability.

1. Central Route

   • Involves deep, careful thinking about the content of the message.

   • Used when a person is motivated and has the ability to focus.

   • Leads to stronger, more lasting attitude changes.

   • Example: A student changes their opinion on a health topic after reading well-reasoned scientific evidence.

2. Peripheral Route

   • Involves shallow processing of cues that aren't directly related to the message's content (like tone, appearance, or emotion).

   • Used when a person is not motivated or lacks the ability to pay close attention.

   • Leads to more temporary or superficial attitude change.

   • Example: Someone buys a product because a celebrity endorses it, not because they evaluated its benefits.

• Central route = logic, evidence, deep thinking

• Peripheral route = emotion, popularity, superficial cues

• The route taken depends on the listener's motivation and ability to process the message.

What is cortical activity?

Cortical Activity

• Cortical activity refers to the electrical and functional activity of the cerebral cortex — the outermost layer of the brain responsible for higher-level processing.

Cortical Lobes and Their Functions (Know These!):

• Frontal lobe: decision-making, planning, motor control, personality

• Parietal lobe: touch, spatial processing

• Temporal lobe: auditory processing, memory, language

• Occipital lobe: vision

Context Where MCAT Mentions Cortical Activity:

1. EEG & Sleep:

   • Different sleep stages show different patterns of cortical activity (e.g., beta waves = alertness, delta = deep sleep)

2. Consciousness:

   • Higher cortical activity = wakefulness or REM sleep

   • Lower cortical activity = deep sleep, coma

3. Sensory Processing:

   • Sensory info from eyes, ears, etc., is ultimately processed in specific cortical regions

4. Motor Function:

   • Primary motor cortex in frontal lobe controls voluntary movement

   • Somatosensory cortex in parietal lobe processes touch

Cortical activity refers to the brain's processing power for conscious awareness, perception, and voluntary behavior. It varies across sleep stages and is central to sensation, movement, and higher thinking.

What are the two types of deafness and how do they come about?

1. Conduction Deafness (Conductive Hearing Loss)

• Definition: A problem with conducting sound waves from the outer ear to the inner ear (cochlea).

• Cause: Physical blockage or damage to the outer or middle ear.

• Examples:

  • Earwax buildup (cerumen impaction)

  • Ruptured eardrum

  • Otitis media (middle ear infection)

  • Damage to ossicles (malleus, incus, stapes)

• Treatment: Often treatable with medication or surgery (e.g., hearing aids, ear tubes)

2. Sensorineural Deafness (Sensorineural Hearing Loss)

• Definition: A problem with the inner ear (cochlea) or the auditory nerve (cranial nerve VIII).

• Cause: Damage to hair cells in the cochlea or the auditory nerve itself.

• Examples:

  • Aging (presbycusis)

  • Loud noise exposure

  • Certain drugs (ototoxic)

  • Genetic conditions or congenital defects

• Treatment: Often permanent; cochlear implants may help in severe cases.

• Conduction = mechanical/outer or middle ear

• Sensorineural = nerve/inner ear

• Different causes, different treatments

• Rinne and Weber tests can help distinguish between them

Rinne Test:

Compares air conduction to bone conduction of sound using a tuning fork; in normal hearing, air conduction is greater than bone conduction (AC > BC).

Weber Test:

Places a tuning fork on the forehead to see if sound lateralizes (is heard more in one ear); helps distinguish between sensorineural and conductive hearing loss.

What are the big 5 OCEAN personality traits?

Big Five Personality Traits (OCEAN)

These are the five major dimensions of personality used in trait theory:

1. Openness to Experience

   • Imagination, creativity, willingness to try new things

   • High = curious, open-minded

   • Low = conventional, routine-loving

2. Conscientiousness

   • Organization, discipline, responsibility

   • High = dependable, careful

   • Low = careless, disorganized

3. Extraversion

   • Sociability, energy from social interaction

   • High = outgoing, talkative

   • Low = reserved, quiet

4. Agreeableness

   • Compassion, cooperation, kindness

   • High = warm, helpful

   • Low = antagonistic, suspicious, uncooperative

5. Neuroticism

   • Emotional stability vs. tendency toward negative emotions

   • High = anxious, moody

   • Low = emotionally stable, calm

What is the General Adaptation Syndrome?

General Adaptation Syndrome

• Hans Selye postulated the General Adaptation Syndrome, describing the body's UNIVERSAL response to stress in three stages: alarm, resistance, and exhaustion

• GAS describes how the body responds over time to sustained stress — initially rising to the challenge, adapting, and eventually breaking down if the stress continues too long.

Three Stages of GAS (BIOLOGICAL PERPECTIVE)

1. Alarm Stage

   • Initial reaction to the stressor

   • Fight-or-flight response: adrenaline and cortisol released

   • Increased heart rate, energy, alertness

2. Resistance Stage

   • Body tries to adapt to the stressor

   • Prolonged release of stress hormones (like cortisol)

   • Body remains alert but begins to wear down

3. Exhaustion Stage

   • Body’s resources become depleted

   • Increased risk of illness, fatigue, burnout, and other health issues

Example of GAS: College Student Facing Final Exams Alarm Stage:

The student finds out they have 3 final exams in 2 days.

1. ALARM REACTION (mobilize resources)
   → Immediate stress response kicks in: heart rate increases, adrenaline and cortisol are released.
   → Fight-or-flight mode: they feel alert, anxious, and jittery.

2. RESISTANCE STAGE (cope with stressor)

Over the next week, the student stays up late studying, drinks lots of coffee, and pushes through the stress.
→ The body adapts to the stress, but cortisol remains elevated.
→ They stay focused but start feeling irritable and tired.

3. EXHAUSTION STAGE (reserves depleted)

After finals are over, the student crashes.
→ Their immune system is weakened, and they catch a cold.
→ They feel mentally and physically drained — classic signs of burnout.

What is the difference between educational segregation and educational stratification?

Educational segregation is when different areas that are physically separated have UNEQUAL educational resources and facilities and that social stratification is when we group people in different hierarchical categories based on their education level and view and treat them differently based off how educated they are.

What are the three types of stress to know?

1. Eustress

   • Positive stress that enhances motivation, performance, and focus.

   • Helps with personal growth, resilience, and goal achievement.

   • Generally short-term and perceived as within one’s coping abilities.

   • EXAMPLE: Associated with beneficial challenges like exams, competitions, or public speaking.

2. Neustress

   • Neutral stress that does not directly affect the individual emotionally or physically.

   • Often results from information that is perceived as irrelevant or non-threatening.

   • Does not trigger a significant physiological stress response.

   • Example: hearing about a natural disaster in a distant country with no personal connection.

3. Distress

   • Negative stress that can impair functioning and well-being.

   • Can be acute (short-term crisis) or chronic (ongoing pressure or trauma).

   • Often leads to anxiety, decreased performance, and physical health issues.

   • Occurs when demands exceed coping resources.

   • Example: Failing an important exam despite weeks of studying, leading to feelings of hopelessness and anxiety.

Difference between moderating, mediating, confounding, and continuous variable with definition and example each:

1. Moderating Variable

   • Definition:
     A variable that affects the STRENGTH or direction of the RELATIONSHIP between an independent and a dependent variable.

   • Example:
     The effect of stress on depression depends on social support (moderator).

   • High support weakens the link; low support strengthens it.

2. Mediating Variable

   • Definition:
     A variable that EXPLAINS the MECHANISMS through which the independent variable affects the dependent variable.

     Example:
     Stress leads to poor sleep, which then leads to depression. The stress impacts depression through sleep.

3. Confounding Variable

   • Definition:
     A variable that is RELATED to BOTH the independent and dependent variables, potentially giving a FALSE IMPRESSION of their relationship.

     Example:
     People who carry lighters appear to have more lung disease.

   • But SMOKING is the CONFOUNDER—it causes both.

4. Continuous Variable

   • Definition:
     A continuous variable is a measurable variable that can take on an infinite number of values within a given range, including fractions and decimals.

     Example:
     Person's height is a continuous variable because it can be measured as 170 cm, 170.5 cm, or 170.532 cm—there's no fixed limit to how precisely you can measure it.

5. Discrete Variable

   • Definition: A variable that can only take on specific, separate values, usually whole numbers.
     Example: Number of siblings (you can have 2, not 2.4).

6. Ordinal Variable

   • Definition: A variable with ordered categories, but the intervals between them are not necessarily equal.

   • Example: Pain scale rating (1 = mild, 2 = moderate, 3 = severe).

     • COCOS SPICY RATING

7. Nominal Variable

   • Definition: A variable that consists of categories with no intrinsic order.

   • Example: Blood type (A, B, AB, O).

What is the synaptonemal complex?

Synaptonemal Complex

• A protein structure that forms between homologous chromosomes during prophase I of meiosis

• It physically holds homologs together to allow synapsis (alignment) and crossing over (genetic recombination).

• APPEARS specifically during zygotene stage of prophase I.

• Structure:

  • Two lateral elements (along each homolog)

  • One central element (connecting the homologs)

  • Resembles a zipper under electron microscopy—because of course chromosomes need formalwear for recombination.

• Importance:

  • Ensures accurate recombination and segregation of homologous chromosomes.

  • Failure to form properly can result in aneuploidy (like Down syndrome).

Difference between phosphorylase and phosphatase?

A “phosphatase” takes a phosphate OFF of a substrate, hydrolyzing it to yield phosphoric acid.

• ASE, get yer ass on back home chicken bone

A “phosphorylase” puts a phosphate ONTO a substrate, in a special way.

What is a p-value?

What is a p-value?

• The probability that the observed results (or more extreme) would occur by chance if the null hypothesis were true.

• In plain terms: "How likely is it that what I’m seeing is just a fluke?"

MCAT-Relevant Thresholds

• p < 0.05 → Statistically significant (the default threshold)

• p < 0.01 → Highly significant (stronger evidence against the null)

• p > 0.05 → Not statistically significant (you fail to reject the null)

What cancer genes to know for the MCAT?

p53 (TP53)

• Tumor suppressor known as the “guardian of the genome”; activates DNA repair, cell cycle arrest, and apoptosis in response to DNA damage.

• Mutated in over 50% of human cancers, leading to uncontrolled cell division.

p21 (CDKN1A)

• Activated by p53, inhibits cyclin-CDK complexes → causes G1 cell cycle arrest to allow DNA repair.

• Acts as a checkpoint regulator; loss removes brake on cell cycle progression.

BAX

• Pro-apoptotic protein from the BCL-2 family; promotes mitochondrial outer membrane permeabilization (MOMP) and cytochrome c release.

• Also regulated by p53, helps eliminate cells with irreparable DNA damage.

Retinoblastoma protein (Rb)

• Tumor suppressor that inhibits E2F, blocking G1 → S phase transition.

• Inactivated by phosphorylation (by CDKs); mutations → loss of cell cycle control, seen in retinoblastoma and other cancers.

BRCA1 / BRCA2

• Tumor suppressors involved in homologous recombination repair of double-stranded DNA breaks.

• Inherited mutations dramatically increase risk of breast, ovarian, and other cancers.

BCL-2

• Anti-apoptotic protein; prevents mitochondrial cytochrome c release and apoptosis.

• Overexpression seen in some B-cell lymphomas, helping cancer cells evade death.

MYC

• Proto-oncogene that encodes a transcription factor promoting cell growth and proliferation.

• Dysregulated in Burkitt lymphoma (t(8;14) translocation).

RAS

• Proto-oncogene coding for a GTPase involved in growth factor signaling.

• Mutations lock it in active (GTP-bound) form, promoting unchecked proliferation.

APC (Adenomatous Polyposis Coli)

• Tumor suppressor that regulates β-catenin in the WNT signaling pathway.

• Loss of APC function leads to colon cancer, especially familial adenomatous polyposis (FAP).

MCAT Takeaways

• Know p53, Rb, and BRCA for tumor suppression.

• Know BCL-2, MYC, RAS as common oncogenes.

• Understand their role in cell cycle control, apoptosis, and DNA repair.

What are the different VISUAL CUES to know for the MCAT?

Binocular Cues

Used for depth perception

• Retinal Disparity:

  • Each eye sees a slightly different image.

  • Eyes are 2.5 inches apart

  • The brain uses this difference to compute depth.

• Convergence:

  • Eyes turn inward more when looking at close objects.

  • The degree of inward movement helps estimate distance.

Monocular Cues (require one eye only)

Used for form, depth, motion, and constancy

Form & Depth:

• Relative Size:

  • Closer objects appear larger.

• Interposition (Overlap):

  • If object A blocks object B, then A is closer.

• Relative Height:

  • Objects higher in the visual field are seen as farther away.

• Shading & Contour:

  • Use of light and shadow to perceive depth and form.

  • MOTION PARALLAX

    • Things further away move SLOWER

Perceptual Constancy (brain corrections to maintain consistency) ; our perception of object doesn’t change even if it looks different on retina

• Size Constancy:

  • Even if an object moves closer or farther, we perceive its size as unchanging.

• Shape Constancy:

  • An object rotated at different angles is still perceived as having the same shape.

• Color Constancy:

  • We perceive colors as consistent even under different lighting.

What are the facts to know on SENSORY ADAPTATION for the MCAT?

Sensory Adaptation (MCAT Scope)

Definition:
A decrease in responsiveness of sensory receptors to a constant stimulus over time.

1. Hearing (CONTRACT WHEN LOUD)

• Inner ear muscle (stapedius) contracts in response to LOUD sounds.

  • Purpose: dampen vibrations to protect the inner ear.

  • Takes time to engage → can't protect from sudden sounds like a gunshot.

  • Works better for sustained loud noises (e.g., loud music).

2. Touch (DESENSITIZE OVER TIME)

• Continuous pressure (e.g., wearing clothes, holding a cup) becomes less noticeable over time.

• Mechanoreceptors fire less as stimulus continues → adaptation.

3. Smell (DESENSITIZE TO MOLECULES):

• Strong smells (e.g., perfume, garbage) become less intense after prolonged exposure.

• Olfactory receptors reduce firing → sensory adaptation.

4. Proprioception (YOUR MIND FLIPS)

• Your body's awareness of its position in space.

• Adaptation example: Being upside down for a prolonged time may adjust your internal sense of "upright."

5. Sight (UPREGULATION IN DARK, DESENS IN LIGHT):

• Light adaptation: In bright light, rods and cones desensitize to prevent overstimulation.

• Dark adaptation: In low light, rhodopsin regenerates in rods → increased sensitivity to light.

Key MCAT Takeaways

• Sensory adaptation = decreased receptor response over time

• Inner ear muscle contracts to protect from loud noise, but not sudden ones

• Touch and smell fade with constant exposure

• Vision adapts to light levels by up/down-regulating sensitivity

• Proprioception adjusts to unusual body positions

What is Weber’s Law in terms of what needs to be known for the MCAT?

Just Noticeable Difference (JND/ΔI)

• Definition: The smallest change in stimulus intensity that a person can detect 50% of the time.

• Example: If you’re holding a 100g weight, and you can only detect a difference when 5g is added, the JND is 5g.

Background Intensity (I)

• Definition: The initial stimulus level you're starting from (also called baseline or original intensity).

• Example: If you’re lifting a 100g weight, then 100g = background intensity.

Weber’s Law (K * Original Intensity = JND Amount)

• Definition: The ratio of the JND to the original stimulus is constant:

  Weber’s Constant/K = ΔI/I

  • ΔI: Just noticeable difference/JND

  • I: Original intensity

• Example:

  • If you can detect a 5g difference at 100g, what is the JND at 200g?

    1. K=5g/100g=0.05

    2. K x Original Intensity = JND, so

    3. 100 × 0.05 = 5 g

    4. 200 × 0.05 = 10 g

What is the difference between absolute threshold and Weber’s JND?

• Absolute threshold = intensity needed to detect a stimulus AT ALL 50% of the time

• JND = smallest CHANGE/DIFFERENCE in intensity you can notice between two stimuli

• Absolute threshold is about detection, JND is about discrimination

Absolute threshold can be influenced by a # of factors,

ex. Psychological states.

• Expectations'

• Experience (how familiar you are with it)

• Motivation

• Alertness

  Subliminal stimuli – stimuli below the absolute threshold.

What do you need to know about the vestibular system for the MCAT?

Vestibular System (MCAT Summary)

Overall Function

• Maintains balance and spatial orientation

• Located in the inner ear

Main Structures Involved (Inner Ear)

1. Semicircular Canals (for rotational motion)

• Three canals, each aligned to one orthogonal plane

  • X (lateral/horizontal)

  • Y (posterior)

  • Z (anterior)

• The canals are filled with endolymph (fluid):

  • When head rotates, endolymph lags behind → bends hair cells

  • SPEED and DIRECTION of ENDOLYMPH movement tells brain how SPEED and DIRECTION in which the head is turning

2. Otolithic Organs (for LINEAR acceleration & head position)

• Utricle = detects horizontal motion (e.g., walking forward)

• Saccule = detects vertical motion (e.g., jumping or falling)

• These organs contain:

  • Calcium carbonate crystals (CaCO3 otoliths) attached to hair cells embedded in gel

  • When you move, crystals shift → drag hair cells

  • Bending of hair cells triggers action potentials

Nerve Pathway:

• Signal from vestibular system is sent via:

  • Vestibulocochlear nerve (CN VIII) → brainstem → cerebellum, thalamus, and other regions

Common MCAT Clinical Tie-ins:

• Vertigo (DISPLACED CaCO3/OTOLITHS)

  • Caused by displaced otoliths or misfiring of hair cells → brain receives conflicting signals about motion

  • Results in dizziness, nausea, balance issues

• Motion Sickness ((ENDOLYMPH INERTIA, KEEPS MOVING AFTER YOU STOP ROTATING)

  • Caused when visual input doesn't match vestibular input (e.g., reading in a moving car)

  • Endolymph keeps moving even after you stop → lingering sense of motion → nausea

Key MCAT Takeaways

• Semicircular canals → detect rotational acceleration (endolymph movement)

• Utricle (horizontal) and saccule (vertical) → detect linear acceleration & head position

• Otoliths (CaCO₃ crystals) drag hair cells when you move → trigger action potentials

• Signal sent via vestibulocochlear nerve (CN VIII)

• Disorders like vertigo or motion sickness arise from otolith displacement or endolymph inertia

What is signal detection theory in as much detail as is needed for the MCAT but not more?

Signal Detection Theory (SDT)

SDT quantifies decision-making under uncertainty. It applies to perception (e.g., detecting faint signals), medicine (e.g., test results), and attention tasks.

FOUR POSSIBLE OUTCOMES

Actual Signal	You Respond “Yes”	You Respond “No”
Signal Present	Hit	Miss
No Signal	False Alarm	Correct Rejection

Two Key Variables in SDT:

1. d′ (d-prime) = Sensitivity (strength of signal)

• Measures how well you can distinguish signal from noise

• High d′= strong signal, EASY to detect

• Low d′ = weak signal, HARD to distinguish from background noise

Not “percent correctness”, but more like signal strength vs. noise overlap

2. C (Criterion) = Decision strategy/bias

• Determines how you choose to say yes or no

• Independent of d′ (you can be BIASED regardless of how clear the signal is)

• Greater C, more conservative, more misses, less false alarms

Strategy	Bias	Tendency
Liberal	C < 0	Say “yes” more often → more hits, more false alarms
Conserv	C > 0	Say “no” more often → fewer false alarms, more misses
Neutral	C ≈ 0	Balanced yes/no based on evidence

You think there's no car (no signal), but you go anyway without checking = Liberal strategy(C<0)→ risk of false alarm, less misses

You think there's no car, but stop and look again = Conservative strategy (C>0) → may miss opportunities, but safer

Signal Detection Theory (SDT) GRAPH

Larger d′ = less overlap = higher accuracy, fewer errors

Smaller d′ = more overlap = harder to tell signal from noise = more errors

• The LEFT blue curve = noise only

• The RIGHT red curve = signal

• d′ is the horizontal distance between the two peaks:

  • If d′ is large, you can separate hits from false alarms more easily.

  • If d′ is small, the curves overlap, and you’re more likely to make misses or false alarms.

• d′ = sensitivity (not precision, not error)

• Large d′ = better signal detection, fewer errors

• Small d′ = more overlap = more decision errors (false alarms/misses)

• VERTICAL LINE on graph= decision threshold (your response criterion) (C=STRATEGY)

• C>0 (further to right) is more conservative; MISS more of noise, less likely to make false alarm

• C<0 (further to left) is more liberal; more likely to hit but also more likely for false alarm

• C=0; IDEAL OBSERVER, BALANCED

Bottom-Up v. Top-Down: Dawn of Processing

Bottom-Up Processing

• Definition: Processing based entirely on incoming sensory input, without prior knowledge

• You start from the stimulus and build the perception

• Analogous to: Inductive reasoning (start with data → build a conclusion)

• Example: Seeing a strange fruit for the first time and using its features (color, texture) to figure out what it is

Top-Down Processing

• Definition: Processing that uses prior knowledge, expectations, or experiences to interpret sensory input

• You start with what you know and apply it to make sense of the stimulus

• Analogous to: Deductive reasoning (start with concept → apply it to details)

• Example: Reading messy handwriting more easily if you already know the sentence context

Feature	Bottom-Up	Top-Down
Driven by	Stimulus	Expectations/Knowledge
Speed	Slower (more data-driven)	Faster (uses shortcuts)
Flexibility	Good for novel info	Can be biased by assumptions
Reasoning Type	Inductive	Deductive

What are Gestalt’s Principles and what are the 7 types?

Gestalt’s Principles

• Describe how our brains tend to organize visual information into whole forms ("gestalts") rather than perceiving isolated parts.

• Based on the idea that "the WHOLE is GREATER than the SUM of its parts."

• Applies mostly to visual perception, but also to auditory and cognitive grouping

• Key figures: Max Wertheimer, Wolfgang Köhler, and Kurt Koffka; COGNITIVE APPROACH

Principle	Definition	Example
Similarity	We group similar elements together	Columns of circles vs triangles seen as groups, not rows
Proximity	We group objects that are close together	Dots that are near each other are perceived as one group
Continuity	We perceive lines and patterns as continuing smoothly	A curved line crossing a straight one is seen as two continuous paths
Closure	We fill in missing parts to perceive a complete, whole object	A triangle formed by broken lines is still seen as a triangle
Prägnanz (Simplicity) _____________ Common Fate ______________ Figure Ground	We perceive complex images in the simplest form possible _____________________________ Elements that move together are perceived as part of the same group. ____________________________ We tend to separate a visual scene into a figure (object of focus) and a background.	Five interlocking rings are seen as five circles (not complex shapes) ________________________________ A flock of birds flying in the same direction looks like one unit. ________________________________ In the Rubin vase illusion, you either see a vase (figure) or two faces (ground), depending on what you focus on.

Pathway of Light Through the Eye and Its Parts:

1. Cornea (part of outer tunic)

through the

2. Anterior chamber

• Contains aqueous humor for nourishment since cornea has no blood vessels

• Provides PRESSURE to maintain shape of eyeball

through the

3. Pupil (controlled and hole made by the iris)

through the

4. Posterior chamber (also aqueous humor)

through the

5. Biconvex Lens (bends/focuses light rays)

• Fine tunes light onto retina (ACCOMODATION)

  Suspensory Ligaments:

  -Thin, white fibers that attach the lens to the CILIARY MUSCLE, suspensory ligaments also adjust its shape for focusing by changing the TENSION

through the

6. Vitreous body/humor in the Posterior Segment/Cavity

• Gel that holds retina in place

through the

7. Retina (inner tunic of eye)

Within the retina, light waves pass

8. Ganglionic layer (outer layer of cells)

• Axons bundle to form CN II (Optic Nerve)

to the

9. Bipolar layer (middle layer of cells)

• Intermediate neurons that relay signal from photoreceptors

• Have axons coming along from both sides of the cell which makes snese since they are in the middle and receive signals to-and-fro, receiving from photoreceptor cells in particular POST-stimulation

to the

10. Photoreceptor layer (which transduces the light, before this step, brain does not understand light as it is not yet transduced into info)

• Contains rods and cones

Action Potentials then pass from the photoreceptor layer

to the

9. Bipolar cell layer

to the

10. Ganglionic cell layer, the axons of which form the

11. Optic Nerve CN II which has some of its fibers cross in the

12. Optic chiasm

• Nasal/Medial fibers CROSS to opposite side, temporal/lateral fibers STAY same side

to the

13. Optic tract

Then in a three-step pathway from

14a. Thalamus (Lateral Geniculate Nucleus/LGN)

14b. As optic radiation to the

14c. Visual Cortex (occipital lobe)

OR TO

15. Superior colliculi of the corpora quadrigemina of the mesencephalon (midbrain) for VISUAL REFLEXES

Key structures of eye to know for the MCAT

Choroid (eye) = rich in blood vessels, nourishes the retina (especially peripheral parts)

• A Black/dark-brown layer depending on concentration of melanin

Macula Lutea: Area of retina with most acute vision (broadly in center), upon macular degeneration a person will lose their sharp/acute vision

Fovea Centralis: Central pit of macula lutea; Ganglionic, bipolar, and even rods of photoreceptor layer are pushed aside

• ONLY MADE UP OF CONES, EXCLUSIVELY, NO RODS ALLOWEDDDD

Ciliary Body: Ciliary Muscle + Suspensory Ligaments

• Secretes the vitreous humor for the posterior chamber

Sclera

• Whites of the eye, thick fibrous tissue that covers posterior 5/6th of eyeball.

• Attachment point for muscles.

What are the 4 Key Visual Processes for Focus and Depth Perception?

Process	Definition	Function / Relevance
Accommodation	Lens shape changes via ciliary muscles and suspensory ligaments	Focuses light on the retina (near vs. far objects)
Convergence	Both eyes rotate inward when focusing on a near object	Binocular depth cue—helps determine object distance
Pupillary Constriction	Iris muscles constrict pupil to limit light entry and improve depth of field	Helps with sharpness and clarity of near vision
Lens Constriction / Refraction	Light bending by cornea and lens to direct image onto the fovea of retina	Critical for focusing light precisely on photoreceptors

Key MCAT Takeaways

• Accommodation = lens thickness adjustment

• Convergence = eye rotation inward for close objects

• Pupil constriction = sharper focus for near objects

• Refraction = bending of light via cornea & lens to focus on retina

How do we see? What is the phototransduction cascade?

1. Light comes in, goes through pupil, and hits rod.

2. Normally rod is turned on, but when light hits turns off.

3. When rod is off, it turns on a bipolar cell, which turns on a retinal ganglion cell, which goes into the optic nerve and enters the brain.

Phototransduction Cascade

• PURPOSE: Convert light into electrical signal in the retina (specifically in RODS)

1. In Darkness (Rhodopsin is by DEFAULT inactive due to high cGMP)

• Rhodopsin is inactive

• High [cGMP] keeps Na⁺ channels open

• Na⁺ flows into rod → rod is depolarized

• Rod releases glutamate continuously

  • Glutamate inhibits ON bipolar cells

  • Glutamate excites OFF bipolar cells

2. Light Enters the Eye (Light causes tautomerization of rhodopsin to ACTIVATE IT)

• Light hits the retina and reaches rods

• Retinal (inside rhodopsin) changes shape:

  • 11-cis-retinal → all-trans-retinal

• Rhodopsin changes shape and becomes activated

3. Signal Transduction Begins (Transducin/G ACTIVATED)

• Activated rhodopsin activates transducin (G-protein)

  • Transducin = α, β, γ subunits

• α-subunit of transducin binds and activates phosphodiesterase (PDE)

4. Activated PDE breaks cGMP down into GMP

• PDE breaks down cGMP → GMP

• [cGMP] drops, so Na⁺ channels close

• Rod becomes hyperpolarized (more negative inside) STOPPING glutamate release

5. Signal Sent to Brain

• ON bipolar cells disinhibited → they depolarize and fire

• ON bipolar cell ACTIVATES retinal ganglion cell

• Ganglion cell sends signal via optic nerve to brain (occipital lobe)

Rods N Cones Fun Facts

• A photoreceptor is a specialized nerve that can take light and convert to neural impulse.

• Inside rod/cones are thousands of OPTIC DISCS

• In membrane of each optic disc are proteins that fire APs to the brain.

• Rods: Rhodopsin, Cones: Photopsin

• Cones: 60% Red, 30% Green, 10% Blue

• Rods: SLOW recovery time, Cones: FAST recovery

Rods v. Cones: Dawn of Sight

Feature	Rods	Cones
Photopigment	Rhodopsin	Photopsin
Function	Night vision (scotopic), low light	Day vision (photopic), color vision
Number	~120 million	~6 million
Sensitivity	Very sensitive (work in dark)	Less sensitive (need more light)
Adaptation Speed	Slow to adapt to light	Fast adaptation to changes
Color Detection	No	Yes (RGB types: red, green, blue)
Location in retina	Periphery	Concentrated in fovea
Visual acuity	Low (blurrier)	High (sharp detail)
Saturation	Easily saturated (bleached in light)	Less easily saturated

How does visual field processing occur? Describe FEATURE DETECTION of visual stimuli:

Understanding the Diagram (MCAT Style)

• The yellow box on the left represents the left visual field.

• The green box on the right is the right visual field.

• The white circles are the retinas of each eye.

Light from the LEFT visual field hits the NASAL retina of the LEFT eye and the TEMPORAL retina of the RIGHT eye.

• Both are processed in RIGHT occipital lobe

• Nasal/medial retina CROSSES OVER

• Temporal retina STAYS SAME SIDE

The image is flipped and inverted on the retina, so field and retinal side are opposites

---

Feature Detection (MCAT Summary)

Your brain detects three key features of visual stimuli:
Color, Form, and Motion

1. Color

• Detected by cones

• Based on Trichromatic Theory:

  • Red cones (long wavelength) → most abundant (60%)

  • Green cones (medium wavelength, 30%)

  • Blue cones (short wavelength) → ~10% of cones

• Works best in bright light conditions

2. STILL Shape & Detail: PARVOCELLULAR PATHWAY

• Specializes in:

  • High SPATIAL resolution → clear detail, sharp edges

  • Low temporal resolution → does not work well with motion

• Activated by stationary objects

3. MOVING Shape & Detail: MAGNOCELLULAR PATHWAY

• Specializes in:

  • High temporal resolution → detects motion well

  • Low spatial resolution → blurry image, low detail

• Does NO detect color

Describe the pathway of sound along with the important structures of the ear to know for the MCAT

Sound Wave Entry

• Sound = pressurized wave (areas of high and low pressure)

1. Pinna (Auricle) → collects sound

2. External Auditory Canal → channels wave inward

3. Tympanic Membrane (Eardrum) → vibrates with sound

Middle Ear Ossicle Vibration (AMPLIFY vibrations)

4a. Malleus/Hammer

4b. Incus/Anvil

4c. Stapes/Stirrup: Attached to OVAL WINDOW

5. Oval window (membrane between middle and inner ear)

• Stapes pushing it creates waves in perilymph in SV

6. Scala vestibuli (perilymph-filled space in inner ear)

• Perilymph moves here vibrating the

7. Organ of Corti which contains the BM and TM

8. Basilar membrane (membrane in organ of corti)

• HIGH frequencies displace BASE of basilar membr

• LOW frequencies displace APEX of basilar membr

• Vibration here causes perilymph here to move and DISPLACE

9. Hair cells

• Contain stereocilia bundles made of kinocilia and are embedded in the

10. Tectorial membrane (stiff)

Movement of the stereocilia OPENS K+ channels, influx of K+ TRIGGERS Ca²⁺ influx GENERATING ACTION POTENTIAL

This transduces sound into action potentials transmitted through the vestibulocochlear nerve (CN VIII) to the

11. Inferior colliculi (of corpora quadrigemina of mesencephalon) for AUDITORY REFLEXES

to

12. Thalamus (relay station)

to

13. Auditory cortex of the temporal lobe (final destination in brain)

ALSO

Vibrations pass from the basilar membrane into the

14. Scala tympani (fluid-filled space/lower chamber of cochlea)

to

15. Round window (membrane between inner ear back to middle ear)

• Bulges outwards to RELEASE pressure

MCAT Takeaways

• Organ of Corti = functional unit of hearing

• K⁺ and Ca²⁺ ions initiate the neural signal

• Hair cells transduce mechanical → electrical energy

• Sound frequencies are separated via basilar membrane tuning

• Final destination = temporal lobe of the brain

So with basilar tuning, brain can distinguish dif frequencies – tonotypical mapping

How do we know where we are and feel ourselves (pause)?

Post-Central Gyrus/Somatosensory Cortex

• Somatosensory Homunculus (MCAT Scope)

  • It’s the brain’s map of the body’s sensory input.

  • Each body part sends touch, pressure, pain, and temperature info to a specific area of the brain.

  • Receives input mapped by body region (homunculus)

  • More sensitive areas (e.g. lips, hands) take up more cortical space

  • More sensitive areas (like lips and hands) have larger representation.

  Feature	Proprioception	Kinesthesia
  Definition	Sense of body position in space	Sense of body movement
  Focus	Static awareness (e.g., where your arm is)	Dynamic awareness (e.g., how your arm moves)
  Balance-related?	Yes—helps with balance and posture	No—not involved in balance
  Receptors	Muscle spindles, joint stretch receptors	Also muscle/joint receptors, but focus on motion
  Conscious?	Mostly subconscious	More conscious awareness of motion
  Example	Knowing your foot is behind you while standing	Adjusting your arm mid-throw

• Proprioception = position + BALANCE (e.g., standing on one leg with eyes closed)

• Kinesthesia = movement (e.g., learning to shoot a basketball), BEHAIVORAL, NO balance

• Proprioception is more about "where", kinesthesia is more about "how it moves"

How do we feel pain?

Pain and Temperature Sensation (MCAT Summary) TRPV1 Receptor

• TRPV1 = transient receptor potential vanilloid 1

• A membrane-bound receptor that responds to:

  • Heat

  • Tissue damage (pain)

  • Chemical signals (e.g., capsaicin from spicy food)

• Mechanism: Binding of stimulus → conformational change in receptor → activates sensory neuron → signal to brain

Capsaicin Example

• Capsaicin binds to TRPV1, mimicking heat damage.

• Results in a "burning" pain sensation, sweating, etc.

• Doesn’t convert pain—just triggers the same receptors that heat or injury would.

• Aβ fibers: FAST reflex—pull hand away

  • THICC, myelinated, high conductance

• Aδ fibers: MEDIUM sharp, localized pain

  • Med-diameter, less myelin

• C-fibers: SLOW, throbbing, lingering pain

  • SMOL-diameter, UNMYELINATED

Key MCAT Takeaways

• TRPV1 = ion channel involved in pain and heat sensing

• Capsaicin binds to TRPV1 → mimics pain/heat

• Aβ, Aδ, and C fibers transmit pain at different speeds

• Nociceptors ≠ thermoreceptors, but they can overlap

• TRPV1 = a receptor used by both nociceptors and thermoreceptors

What are the two olfactory pathways to know?

System	Used For	Detected Molecules	Bulb
Main olfactory system	General smell	Volatile odorants (e.g., perfume, food)	Olfactory bulb
Accessory olfactory system	Pheromone detection	Pheromones (social/sexual signals)	Accessory olfactory bulb

• Pheromones are usually non-volatile, detected via direct contact or close proximity.

• Humans may not have a functional accessory olfactory system like some animals do—this is still debated but fair game for MCAT-level conceptual understanding.

OLFACTION OVERVIEW

• Olfaction = sense of smell, involving detection of airborne chemicals.

• Closely linked to taste (why food tastes bland with a cold).

• Two main pathways:

  • Main olfactory system – general smells

  • Accessory olfactory system – pheromones (mostly functional in animals)

Main Olfactory Pathway (General Odors) 🔬 Structures Involved

1. Olfactory epithelium – in nasal cavity; contains receptors for different odor molecules

2. Cribriform plate – porous bone separating nasal cavity from brain

3. Olfactory bulb – brain structure sitting above the cribriform plate; receives input from receptors

Mechanism of Signal Transduction

1. Odor molecules bind to GPCRs on olfactory sensory neurons.

2. G-protein dissociates → activates cascade → opens ion channels → depolarization → action potential (AP)

3. AP travels through axons to olfactory bulb, where:

   • Neurons converge in glomeruli (each glomerulus = 1 odor type)

   • Synapse on mitral/tufted cells, which relay signals to:

     • Piriform cortex (odor identity)

     • Amygdala (emotional relevance)

     • Orbitofrontal cortex (conscious perception of smell)

Key Points

• Olfactory nerve (CN I) transmits signals.

• Each olfactory receptor responds to one type of molecule (e.g., benzene).

• Brain decodes smell by combinatorial receptor activation patterns.

Accessory Olfactory Pathway (Pheromones) – Animals Structures Involved

• Vomeronasal Organ (VNO) = accessory olfactory epithelium

  • Contains apical cells and basal cells, each with specific pheromone receptors

• Accessory Olfactory Bulb

  • Receives axons from VNO → sends signals to amygdala and hypothalamus

Mechanism of Detection

• Pheromone binds to apical/basal cell receptor

• AP travels through vomeronasal nerve → accessory olfactory bulb

• Synapse in glomerulus → amygdala → hypothalamus

  • Triggers innate behavioral and hormonal responses (e.g., mating, aggression)

Important Notes

• Humans have a vomeronasal organ, but no functional accessory olfactory bulb, making the pathway likely vestigial.

• Amygdala = major target for both general odors (emotional response) and pheromones (instinctual behavior)

MCAT Key Takeaways

• Main olfactory system detects general smells through GPCRs and glomerular mapping.

• Accessory system (in animals) detects pheromones through apical and basal cells in the VNO.

• Amygdala is a common target for emotional and behavioral response.

• Humans lack a functional accessory olfactory bulb, making our pheromone response minimal.

Describe GUSTATION in as much detail as is needed for the MCAT:

Taste	Receptor Type	Mechanism
Sweet	GPCR (T1R2 + T1R3)	G-protein → depolarization
Umami	GPCR (T1R1 + T1R3)	G-protein → depolarization
Bitter	GPCR (T2R family)	G-protein → depolarization
Sour	Ion channel (H⁺)	Protons enter cell → depolarization
Salty	Ion channel (Na⁺)	Sodium enters cell → depolarization

Key MCAT Takeaways

• Each taste bud contains receptors for all 5 basic tastes

• Papilla type ≠ taste type specialization

• Sweet, bitter, and umami use GPCRs

• Sour and salty use ion channels

• Taste info is carried via cranial nerves VII, IX, and X to the gustatory cortex

Where is the Gustatory Cortex?

• Located in the INSULA (deep within the cerebral cortex) and extends into the frontal operculum.

• It receives taste signals from the thalamus after synapsing from cranial nerves.

Labeled Lines Model

• Each taste bud has EVERY taste receptor cell

• Each taste receptor cell is specialized for only one taste (sweet, salty, sour, bitter, or umami).

• These cells send signals via dedicated axons to specific regions of the gustatory cortex.

• This is known as the labeled lines model:

  • Each taste is carried by its own “line” (pathway).

  • So stimulating a sweet receptor’s pathway, even with a salty stimulus, would make the brain perceive sweetness.

Brilliant Logic You Noted (MCAT-Backed)

• Salty and sour = ion channels:

  • Salty = Na⁺ influx

  • Sour = H⁺ (protons) enter and alter internal charge

• Sweet, bitter, and umami = GPCRs:

  • Signal via secondary messengers (slower but more sensitive)

Key MCAT Takeaways

• Gustatory cortex is in the insula and frontal operculum

• Labeled lines model: each taste cell → its own axon → brain interprets based on which pathway fires

• Salty & sour = ion channels

• Sweet, umami, bitter = GPCRs

• Swapping receptor mechanisms can trick the brain into misidentifying tastes

E.g. Glucose binds GPCR, conformational change, G-protein dissociates, opens ion channels, cause cell to depolarize and fire an AP

If a salty receptor is placed in a sweet cell, the brain will interpret the salty stimulus as SWEET because the axon pathway remains the same, causing the SAME action potential and perception.

What to know about sleep and conscoiusness for the MCAT

5 LEVELS OF CONSCIOUSNESS & EEG/BRAIN PATERNS

Level	Description	Associated Brain Waves
Alertness	Fully awake, aware of self and environment	Beta
Daydreaming	Relaxed, awake, lightly distracted (e.g., meditation)	Alpha
Drowsiness	On the verge of sleep or just waking	Alpha → Theta transition
Sleep	Unconscious but brain still active (non-REM & REM stages)	Theta, Delta, and Beta (in REM)
Coma	No awareness or responsiveness	Varies or flat EEG

4 STAGES OF SLEEP

Sleep Cycle Structure

• Each sleep cycle lasts ~90 minutes

• A full night includes 4–6 cycles, increasing in REM as the night goes on

• General progression:

  • N1 → N2 → N3 → N2 → REM → repeat

  • (Your “N-Woo before REM” mnemonic = gold)

1. NREM 1 SLEEP

Wave Type	Theta (4–7 Hz)
Features	Light sleep, drifting off, hypnic jerks, hypnagogic, hallucinations
Transition	From wakefulness (alpha) → sleep (theta)

2. NREM 2 SLEEP

Wave Type	Theta (4-7 Hz) + Sleep Spindles + K-Complexes
Features	Light sleep but harder to wake; memory consolidation begins
Sleep Spindles	Burst of high-frequency waves, keep you ASLEEP
K-complexes	Sharp, high-amplitude waves, SUPPRESS arousal to keep you asleep

3. NREM 3 / SLOW-WAVE SLEEP

Wave Type	Delta (0.5–4 Hz) (low frequency, high amplitude)
Features	Deepest sleep, difficult to wake, sleepwalking, night terrors
Functions	Physical recovery, GH/Pessiii release, immune function

4. REM SLEEP

Wave Type	Beta-like (similar to wakefulness) (13-30 hz)
Features	Rapid eye movements, dreaming, muscle atonia (sleep paralysis)
Also Called	Paradoxical sleep (brain active, body paralyzed)
Memory	Important for emotional processing, procedural memory

• Sleep cycle = NREM 1 → 2 → 3 → 2 → REM, ~90 minutes per cycle

• Stage 3 (Delta) = deep, restorative sleep

• REM = vivid dreams, brain active, body paralyzed

• Spindles/K-complexes = Stage 2

• Beta in wakefulness and REM

Sleep Cycle Structure

• Each sleep cycle lasts ~90 minutes

• A full night includes 4–6 cycles, increasing in REM as the night goes on

• General progression:

  • N1 → N2 → N3 → N2 → REM → repeat

  • (Your “N-Woo before REM” mnemonic = gold)

Circadian Rhythm

• ~24-hour biological cycle regulated by:

  • Light (especially sunlight)

  • Controlled by the suprachiasmatic nucleus (SCN) in the hypothalamus

• Regulates:

  • Sleep-wake cycle

  • Body temperature

  • Hormone release from MELATONIN produced in the PINEAL GLAND

  • Can change as you age; old heads go to bed early

Dreaming

• Everybody dreams during REM sleep.

• Can tell someone is dreaming because eyes are moving rapidly under eyelids, and brainwaves look like they are completely awake (BETA)

• Activity in prefrontal cortex during REM sleep is DECREASED– part responsible for logic. Why things in our things that defy logic don’t seem weird.

What are the different theories on dreams?

Freudian Theory

Component	Definition
Manifest content	What you literally see in the dream (e.g., being chased)
Latent content	Underlying meaning of dream (e.g., fear of failure)
Purpose	Freud believed dreams were a way to express unconscious desires and repressed urges safely

Other Theories

Theory	Main Idea
Activation-Synthesis Theory	Brainstem activation during REM = random neural firing → Cortex synthesizes it into a storyline (dreams are meaningless "noise" interpreted)
Problem-Solving Theory	Dreams allow you to work through real-life issues creatively or emotionally
Cognitive Development Theory	Dreams reflect your current level of cognitive maturity and development
Threat Simulation Theory	Dreams evolved as a safe space to rehearse survival-based threats (evolutionary psych)
Continuity Hypothesis / Day Residue	Dreams reflect waking life, no hidden meaning

DISORDERS LIKE SLEEP APNEA YOU DON’T GET ENOUGH N3 (Slow-wave/theta sleep)

• Sleep walking and talking ALSO occur during N3, more often in children (who have more N3 sleep)

Hypnosis and Meditation

• Hypnotism usually involves getting person to relax and focus on breathing, and they become more susceptible to suggestion in this state – but only if they want to.

• MORE ALPHA waves in this stage – an awake but relaxed state.

What are the 4 classes of drugs?

Drug Class	Primary Function	Key Examples	Mechanism	Distinguishing Features
Depressants	↓ CNS activity (sedation, slowed processing)	Alcohol, Barbiturates, Benzodiazepines	↑ GABA activity (Cl⁻ influx) ↓ neural firing	Reduces inhibition, does not counteract stimulants—effects stack
Stimulants	↑ CNS activity (alertness, energy)	Caffeine, Nicotine, Amphetamines, MDMA	↑ Dopamine, norepinephrine, serotonin	Alerting, ↑ heart rate & BP, nicotine = stimulant despite relaxing sensation
Hallucinogens	Alter perception, sensory distortion	LSD, PCP, Psilocybin (shrooms)	Varies (often serotonin pathway, esp. 5-HT₂A receptors)	Effects are not classified by energy, but by perceptual change despite increased CNS activity (like stimulant)
Opiates / Opioids	Pain relief, euphoria; CNS depressant too	Morphine, Heroin, Codeine, Fentanyl	Bind to endorphin (opioid) receptors, mimics endorphins in pain relief	Analgesic + euphoric, different from depressants, very addictive

MCAT Tips

• Depressants: GABA-based inhibition; think alcohol’s disinhibition.

• Stimulants: Enhance excitatory neurotransmitters; do not cancel depressants.

• Hallucinogens: Classified by sensory changes, not stimulation or sedation.

• Opiates vs. opioids: Natural vs. synthetic, but both act on endorphin receptors.

GABA and Depressants (MCAT Breakdown) What is GABA?

• Gamma-Aminobutyric Acid (GABA) = the brain’s primary inhibitory neurotransmitter

• Structure: Simple amino acid derivative (similar to glutamate but with an amine group instead of carboxyl)

• Normal Function:

  • Binds to GABA-A receptors (ligand-gated chloride channels)

  • Opens Cl⁻ channels → Cl⁻ flows into the neuron → hyperpolarization (makes the inside more negative)

  • Inhibits depolarization → decreases likelihood of firing an action potential

HOW DO DEPRESSANTS WORK?

Drug Class	Mechanism of Action
Benzodiazepines	Enhance the effect of GABA by increasing Cl⁻ influx (via GABA-A receptor modulation)
Barbiturates	Prolong GABA channel opening time
Alcohol	Also enhances GABA activity and reduces glutamate excitability

Key Concept:

• The more chloride influx, the harder it is to depolarize the neuron → reduced CNS activity

• Depressants = promote inhibition, sedation, anxiolysis (anti-anxiety), or sleep induction

Use	Type of Depressant
Insomnia, short-term sedation	Short-acting benzos/barbs
Anxiety, seizure control	Long-acting benzos/barbs

WHAT NEUROTRANSMITTERS DO STIMULANTS AFFECT?

Main Neurotransmitters Affected by Stimulants	Effect
Dopamine (DA)	↑ Dopamine = reward, motivation, euphoria
Norepinephrine (NE)	↑ Norepinephrine = alertness, focus, increased heart rate
Serotonin (5-HT) (to a lesser extent)	Can elevate mood slightly, but dopamine and norepinephrine are primary

Why Stimulants Make You "Hyper"

• Caffeine blocks adenosine receptors (adenosine promotes sleepiness)

• Amphetamines, cocaine, MDMA = increase dopamine and norepinephrine availability (by preventing reuptake or promoting release)

• Result = increased CNS activity, heightened alertness, mood elevation

HOW DO OPIATES WORK?

Drug Class	Mechanism of Action
Opiates/Opioids	Mimic endorphins (natural painkillers) by binding to opioid receptors (μ-opioid receptor is key)
Effect	Block pain signals, cause euphoria, sedation, slow breathing, high risk of addiction

WHAT NEUROTRANSMITTERS DO HALLUCINOGENS AFFECT?

Hallucinogen Type	Main Neurotransmitter Affected	Effect
LSD, Psilocybin, DMT	Serotonin (5-HT)	Distortions in perception, mood swings, hallucinations
PCP, Ketamine	Glutamate (NMDA receptor antagonists)	Dissociation, hallucination, altered reality

Serotonin and Hallucinations

• Hallucinogens stimulate serotonin receptors (especially 5-HT2A subtype).

• Leads to sensory distortions, emotional swings, and hallucinations.

• Schizophrenia is more classically associated with excess DOPAMINE, not serotonin.

  • Serotonin is central for mood and perception, but dopamine drives psychosis symptoms.

Describe Drug Homeostasis for the MCAT

What Is Tolerance?

• Tolerance = Needing increased amounts of a drug over time to achieve the same effect.

• Happens because the body either:

  • Downregulates receptors (receptor desensitization)

  • Increases metabolism of the drug (enzyme induction)

  • Or, as you mentioned, prepares in advance through environmental cues.

Conditioned (Learned) Tolerance

Concept	Definition
Conditioned tolerance	Body anticipates drug effects based on environmental cues (e.g., same room, same people, same ritual)
Example	Taking a stimulant like cocaine in the same room daily → body lowers heart rate ahead of time because it "knows" the drug is coming
Risk Factor	Taking the same dose in a new environment → body does not compensate → higher risk of overdose

• Your brain is always trying to maintain homeostasis.

• If a drug increases CNS activity, your body compensates by dampening that activity when it senses the drug is coming.

• If you suddenly remove the environmental cue, the body’s compensation doesn’t kick in → higher drug effect than expected → overdose risk.

Term	Definition (MCAT-Relevant)
Tolerance	Needing higher doses of a drug to achieve the same effect due to receptor desensitization or metabolic adaptation
Dependence (Physical)	Body physically adapts to drug → withdrawal symptoms when stopped (e.g., shaking, sweating)
Dependence (Psychological)	Emotional need or craving for the drug (e.g., needing it to relieve stress)
Withdrawal	Negative symptoms experienced when stopping a drug after dependence develops
Addiction (Substance Use Disorder)	Compulsive drug-seeking behavior despite negative consequences
Craving	Intense desire for the drug (can occur even after long abstinence)
Relapse	Return to drug use after a period of abstinence
Conditioned Tolerance	Environmental cues trigger the body to preemptively counteract drug effects (risk of overdose without cues)
Sensitization (Reverse Tolerance)	Opposite of tolerance → increased response to the drug after repeated use (less common)
Comorbidity	Having two or more disorders at the same time (e.g., depression and substance use disorder)
Extinction	Gradual weakening of a conditioned response when the stimulus is no longer reinforced (e.g., craving goes down if drug is unavailable repeatedly)
Reward Pathway	Dopamine pathway → VTA → nucleus accumbens → prefrontal cortex (key in addiction and reinforcement learning)
POSITIVE Reinforcement	Using the drug because it produces pleasurable effects (dopamine release)
NEGATIVE Reinforcement	Using the drug to remove unpleasant feelings (e.g., avoiding withdrawal symptoms)
Substance Use Disorder (SUD)	Clinical diagnosis of addiction → characterized by tolerance, withdrawal, cravings, inability to stop despite harm

Key MCAT Concepts to Focus On

• Reward Pathway = dopamine → reinforcement of behavior

• Addiction = compulsive use + tolerance + withdrawal/craving

• Positive reinforcement = drug feels good → repeat behavior

• Negative reinforcement = drug removes bad feelings (e.g., withdrawal relief)

• Extinction = when reinforcement stops → behavior decreases over time

• Comorbidity = overlapping mental health + substance use disorders

Why "CRASHES" Happen After Drug Use Stops (Compensatory Response)

• When you frequently use a stimulant (like cocaine, nicotine, caffeine), your body adapts to the drug’s effect (↑ CNS activity).

• The body, trying to maintain homeostasis, starts to counteract the drug:

  • Reduces natural stimulant neurotransmitters

  • Might lower heart rate, downregulate dopamine receptors, etc.

• If the drug suddenly isn’t there (because you stopped taking it):

  • Your body is still in "counteracting mode", expecting the drug’s presence.

  • Result = below-normal baseline activity → feelings of fatigue, depression, low energy = "crash"

• Taking amphetamines daily → body lowers baseline dopamine to compensate.

• Stop taking amphetamines → dopamine stays low, but no drug to boost it → depressed mood, lethargy, anhedonia (no pleasure).

Key MCAT Takeaway

• Crash = the result of compensatory downregulation combined with sudden drug absence.

• The body prepares to fight the drug effect, but if the drug isn’t there, the compensation overshoots = withdrawal or crash.

Describe the different routes of Drug Entry for the MCAT

Oral

• Ingesting something, one of slowest routes because goes through GI tract – half hour.

Inhalation

• Breathing or smoking, because once you inhale goes straight to brain – 10 seconds.

Injection

• Most direct, intravenous means goes right to vein. Takes effects within seconds. Can be very dangerous. 

Transdermal

• Drug is absorbed through skin, ex. Nicotine patch.

• Drug in patch has to be pretty potent, released into bloodstream over several hours.

Intramuscular

• Suck into muscle. Can deliver drugs to your system slowly or quickly.

• Quick for example is epipen. Or vaccines, slowly.

Faster route of entry = more addictive potential.

Describe the REWARD PATHWAY IN THE BRAIN

The Brain’s Reward Pathway

1. Triggering the Reward Pathway (Cake Example)

• You see the cake → Prefrontal cortex = decision-making (“I want it”)

• You taste the cake → Sensory cortex (e.g., postcentral gyrus) processes the flavor

• You feel pleasure:

  • Amygdala = emotion (“This is amazing!”)

  • Hippocampus = memory (“Remember this for next time”)

• Your brain is flooded with dopamine → you feel reward

2. Core Structure: MESOLIMBIC DOPAMINE PATHWAY

Region	Function in Reward
Ventral Tegmental Area (VTA)	Origin of dopamine release (in midbrain)
Nucleus Accumbens	Motivation, pleasure (“I want more”)
Prefrontal Cortex	Focus, planning (“Let’s get more cake”)
Amygdala	Emotional response (“Yum!”)
Hippocampus	Memory of the experience (“Remember the bakery”)

• All of these are part of or connected to the limbic system, which handles emotion, motivation, and memory.

3. Role of Dopamine (DA) and Serotonin (5-HT)

Neurotransmitter	Function	In Reward Context
Dopamine	Pleasure, motivation, reinforcement	Increases in reward pathway → craving
Serotonin	Mood, satiety, well-being	Decreases as dopamine rises → less satisfaction, more craving

High dopamine + low serotonin = “It feels good, but I can’t stop”

• HIGH DOPAMINE=HAPPY

• LOW SEROTONIN=INCREASED CRAVING

Key MCAT Takeaways

• Reward pathway = VTA → Nucleus Accumbens → Prefrontal Cortex (+ amygdala, hippocampus)

• Limbic system = emotion, memory, reward (includes amygdala, hippocampus, nucleus accumbens)

• Dopamine = drives reward and craving

• Serotonin = regulates satiety → low serotonin = keep seeking reward

What are the Neurobiological Responses to Addiction?

1. Medication-Assisted Treatment

   Approach	Explanation
   Substitution therapy	Prescribe a weaker, safer version of the addictive substance to reduce cravings and withdrawal symptoms
   Examples	- Nicotine patches/gum for smokers

Methadone or buprenorphine for opioid addiction |
| Goal | Prevent withdrawal, reduce relapse, and wean off dependence gradually

2. Cognitive Behavioral Therapy

Purpose	Cognitive re-training → patient learns to recognize, avoid, and cope with triggers for substance use
Effectiveness	- Helps maintain long-term abstinence

Especially useful for preventing relapse |
| MCAT Connection | CBT increases awareness of the underlying causes of substance use, not just treating symptoms |
| Common Pairing | Often combined with MAT for better outcomes |

3. 12-Step Programs: GROUP MEETINGS

   1. ADMIT the Problem

   2. SURRENDER to higher power or support system

   3. GIVE BACK to others (community support)

• Body compensates by downregulating receptors

• Fewer receptors = weaker response, even with same dose |

Key MCAT Takeaways

• Tolerance = fewer receptors or faster metabolism → more drug needed

• SUD = continued drug use despite negative consequences

• Not all addiction-like behavior qualifies as a substance use disorder

• Caffeine use shows tolerance and withdrawal, but not enough harm for clinical SUD diagnosis

What are the different things on attention we need to know for the MCAT?

Selective Attention

• Selective attention = flashlight → whatever you shine it on is what you consciously process most

Types of Cues That Guide Attention

Cue Type	Definition	Examples
Exogenous	External, automatic attention-grabbers	Loud noise, bright color, flash, sudden movement
Endogenous	Internal, based on meaning or goals	Arrow on a sign, your name in a convo (cocktail effect)

Cocktail party effect = endogenous cue (name = meaning), but if screamed, exogenous OVERRIDES endogenous due to intensity.

Types of Attention Failures

Type	Definition	Example
Inattentional blindness	Missing something in plain sight because attention is elsewhere	Missing a clown while texting
Change blindness	Not noticing a change between two visual scenes	Not seeing a haircut change

Theories of Selective Attention

Theory	Core Idea	Weakness/Note
Broadbent’s Early Selection	Sensory register → filter → perception → response	Can’t explain cocktail party effect
Deutsch & Deutsch (Late)	Sensory register → perception of all input → filter → response	All input assigned meaning, then filtered; TOO MUCH BRAIN POWER
Treisman’s Attenuation	Sensory register → attenuator → perception → response	Unattended info is weakened, not blocked (your name can still grab attention)

Key MCAT Takeaways

• Selective attention = limited processing capacity → prioritize based on cues

• Exogenous = automatic, Endogenous = learned/meaningful

• Treisman’s theory = best explains cocktail party effect

• Attention failures = inattentional blindness & change blindness

What is the spotlight model of attention and its associated quirks?

Attention Models & Priming

Priming

• Definition: Being more likely to detect or respond to a stimulus if you’ve recently encountered something related

• Can be conscious or subconscious

• Example: You're more likely to notice your name because it's been primed over your entire life

Spotlight Model of Attention

• Attention = a focus beam on one area of interest

• You process information more deeply when it falls within the spotlight

• Explains why relevant stimuli are noticed faster

Resource Model of Attention

• Brain has a limited pool of attention resources

• Can only distribute so much at once → limits multitasking ability

Multitasking LIMITATIONS and IDEALISM

Factor	Effect on Multitasking
Task SIMILARITY	Harder to multitask if tasks are too similar (e.g., writing + podcast)
Task DIFFICULTY	Harder to multitask when tasks are mentally demanding
Practice/familiarity	Easier to multitask if a task is well-practiced (e.g., folding laundry while talking)

Bottom line: Even with practice, multitasking is almost always less efficient than single-tasking

Key MCAT Takeaways

• Priming influences attention (especially to meaningful stimuli like your name)

• Spotlight model = focus-driven attention

• Resource model = attention is limited and shared

• Multitasking efficiency decreases with similarity, difficulty, and inattention

What are the main things that you should know about memory for the MCAT?

Information Processing Model: Sensory, Working, Long-Term Memory

• Proposes our brains are similar to computers.

• We get INPUT from environment, PROCESS it, and OUTPUT decisions.

• First stage is getting the input – occurs in sensory memory (sensory register).

• Temporary register of all senses you’re taking in.

Memory Systems

1. Sensory Memory

• Definition: Very short-lasting memory tied directly to your senses.

• Types:

  • Iconic memory = visual → lasts ~0.5 seconds

  • Echoic memory = auditory → lasts ~3–4 seconds

• Function: Longer sensory ECHOIC memory you to briefly retain sensory info (e.g., re-entering a conversation after zoning out).

2. Working Memory (Short-Term Memory)

• Definition: What you’re actively thinking about; limited capacity and duration.

• Capacity: 7 ± 2 items → known as Miller’s Law, proposed by George Miller

• Duration: About 20 seconds without rehearsal

• Components (from Baddeley & Hitch model):

  • Phonological loop: Handles verbal/auditory info (words, numbers)

  • Visuospatial sketchpad: Handles visual and spatial info (shapes, maps)

  • Episodic buffer: Integrates information from both systems and links it to long-term memory

• Brain region: Working memory and episodic buffer are coordinated by the CENTRAL EXECUTIVE

• located in the prefrontal cortex

3. Long-Term Memory

Explicit (Declarative) Memory

• Requires conscious RECALL

• Types:

  • SEMANTIC memory: Facts, vocabulary, general knowledge

  • EPISODIC memory: Personal experiences or life events (e.g., your 10th birthday)

• Stored mainly in: Medial temporal lobe, especially hippocampus

Implicit (Nondeclarative) Memory

• Does not require conscious recall

• Types:

  • PROCDURAL memory: Skills and habits (e.g., riding a bike, typing)

  • PRIMING : Prior exposure influences response (e.g., if you research rabbits all day, the word “hare” brings up the animal instead of hair)

• Stored in: Cerebellum (procedural) and basal ganglia

Key MCAT Takeaways

• Sensory memory is ultra-short and tied to specific senses

• Working memory = 7 ± 2 rule → George Miller

• Baddeley’s model: phonological loop, visuospatial sketchpad, episodic buffer, central executive

• Long-term memory splits into:

  • Explicit (semantic + episodic)

  • Implicit (procedural + priming)

• Different brain regions support each system (prefrontal cortex, hippocampus, cerebellum, basal ganglia

DUAL CODING HYPOTHESIS

• Says it’s easier to remember words ASSOCIATED with images than either one ALONE.

• Can use the method of LOCI – imagine moving through a familiar place and in each place leaving a visual representation of topic to be remembered.

What are the encoding strategies to know for the MCAT?

Encoding Strategies (Working → Long-Term Memory)

Strategy	Description	Effectiveness
Maintenance/ROTE Rehearsal	Repeating info (rote memorization) with no meaning attached	Least effective
Chunking	Grouping items into meaningful categories (e.g., FBI-NBC-CIA)	More effective
Mnemonics	Using images, acronyms, or funny associations (e.g., ligma = ligament = bone)	Strong tool
Self-referencing	Relating new info to yourself or personal experience; good for preparing to TEACH	Very effective
Spacing effect	Spreading out study sessions over time instead of cramming	Most effective long-term

Retrieval Cues

Type	Definition	Example
Free recall	Recall with no cues	“Name all 7 dwarfs”
Cued recall	Recall with a prompt or category hint	“Name the dwarf whose name starts with ‘D’”
Recognition	Choose the correct answer from a list	Multiple choice question

Free recall < Cued Recall < Recognition in ease of retrieval

For Free Recall, there is something called the SERIAL POSITION CURVE/EFFECT

• Best at remembering first (primacy) and last (recency), hardest in middle

Memory Distortion Concepts

Term	Definition
Memory reconstruction	Memory is not a perfect playback—we fill in gaps based on expectations
Source monitoring error	Forgetting where info came from (e.g., dream vs. real conversation); recognize someone but forget from where
Flashbulb memories	Highly EMOTIONAL events remembered with vivid detail—but not always accurate; susceptible to reconstruction

MCAT likes to test how emotions distort or strengthen memories.

Sometimes information we retrieve is based on a

SCHEMA

• Mental blueprint containing common aspects of world, instead of reality

Long-Term Potentiation vs. Synaptic Plasticity

Feature	Long-Term Potentiation (LTP)	Synaptic Plasticity
Definition	Strengthening of a synapse with repeated use	General ability of synapses to change strength
Mechanism	↑ neurotransmitter release & ↑ receptor sensitivity	Includes both LTP (strengthening) and LTD (weakening)
Role in learning	Key basis for learning and memory formation	Broader concept: learning, memory, and forgetting

• THIS IS LEARNING

Aging & Memory

Memory Type	Effect with Age
Semantic memory	Improves or remains stable (e.g., vocabulary)
Crystallized intelligence	Peaks in mid-adulthood (~30s), then slowly declines
Episodic memory	Declines (especially for recent events)
Processing speed & working memory	Declines with age
Procedural memory	Stays intact (e.g., riding a bike)
Prospective Memory	Ability to remember to do things in the future also decreases with age

DECAY

• When we don’t encode something well or don’t retrieve it for a while, we can’t at all anymore.

• Connections become weaker over time. Initial rate of forgetting is high but levels off over time

HERMANN EBBINGHAUS, first investigator of decay

• Found his rate of forgetting very fast, but if he remembered it after initial stage it levelled out

• Just because you can’t retrieve something doesn’t mean it’s completely gone – relearning.

• Even if Ebbinghaus couldn’t reproduce everything, took less time to learn list second time around.

• Called SAVINGS, like with relearning piano after it having been a minute

Key MCAT Takeaways

• Encoding improves with meaning and strategy (mnemonics, spacing, self-reference)

• Recognition is easier than recall; memory is reconstructive, not photographic

• LTP = biological basis for learning; synaptic plasticity = broader umbrella

• Interference + decay = forgetting; semantic memory is resilient with age

RETROGRADE AMNESIA is inability to recall info previously encoded,

ANTEROGRADE AMNESIA is inability to encode new memories.

Dementia is forgetting to point of interfering with normal life – results from excessive damage to brain tissue,

• Most common form is Alzheimer’s Disease.

  • Neurons die off over time.

  • Earliest symptoms are memory loss, attention, planning, semantic memory, and abstract thinking.

  • As it progresses, more severe language difficulties and greater memory loss, emotional stability and loss of bodily functions.

  • Cause is unknown – have buildup of AMYLOID PLAQUES

    • AGGREGATES OF MISFOLDED PROTEINS THAT FORM IN THE SPACES BETWEEN NERVE CELLS

Korsakoff’s Syndrome – caused by lack of vitamin B1 or thiamine. Caused by malnutrition, eating disorders, and especially alcoholism.

• Thiamine converts carbohydrates into glucose cells need for energy. Imp for neurons.

• Damage to certain areas causes poor balance, abnormal eye movements, confusion, and memory loss.

• At this stage called Wernicke’s encephalopathy – precursor to KS.

• If diagnosed in time can prevent further damage. If untreated, will progress to Korsakoff’s.

• Main symptom is severe memory loss, accompanied by confabulation (patients make up stories to fill in memories).

  • Treatment is healthy diet, abstain from alcohol, take vitamins, and relearn things

What is cognition and what did Piaget have to say about it

Piaget’s 4 Cognitive Development Stages**

Stage	Age Range	Key Characteristics	Milestones Achieved
Sensorimotor	0–2 years	Experience the world through senses and actions	Object permanence (understanding that objects still exist when out of sight); stranger anxiety
Preoperational	2–7 years	Use language, play, and imagination; thinking is symbolic but not logical	Pretend play, egocentrism, begin to understand symbols (e.g., words, images)
Concrete Operational	7–11 years	Begin logical thinking about concrete events	Conservation, water in different jugs is the same; mathematical transformations, reduced egocentrism
Formal Operational	12+ years	Abstract reasoning and hypothetical thinking	Abstract logic, moral reasoning, think about “what if” scenarios

MCAT Notes

• Object permanence = major milestone of sensorimotor stage.

• Egocentrism is most notable during the preoperational stage.

• Conservation and math skills solidify in the concrete operational stage.

• Formal operational stage introduces abstract thinking and forming independent moral frameworks.

What are the different ways that we interpret or problem solve by?

Assimilation v. Accomodation: Dawn of New Information

Term	Definition	Mnemonic	Example
Assimilation	Interpreting new information by fitting it into an existing schema	Two S's = Same Schema	A child sees a raccoon and says “dog!” because it fits their preexisting schema of a dog.
Accommodation	Changing an existing schema or creating a new one to incorporate new info	Two C's = Change/Create	After learning raccoons are different from dogs, the child forms a new schema for raccoons.

Key MCAT Takeaways

• Schemas = mental frameworks used to interpret information

• Assimilation = new info fits existing understanding

• Accommodation = new info modifies or creates schema

• Correctness doesn’t matter—it’s about what happens to the schema

Problem Solving Strategies

Method	Definition	Example
Trial and Error	Trying random solutions until one works	Typing random codes until one unlocks a phone
Algorithm	Step-by-step method that guarantees a solution, but may be slow	Trying every possible key on a keyboard
Heuristic	Mental shortcut that’s fast but can be error-prone	See below
Intuition	Relying on instinct, high chance of effort	Type I error = false positive Type II error = false negative

Heuristic Types

Type	Relies On	Definition	Example
Availability Heuristic	Specific examples from memory	Judging likelihood based on how easily examples come to mind	Thinking sharks are more common than plane crashes after seeing a news story
Representativeness Heuristic	Prototypes or general concepts	Judging likelihood based on how well something matches a prototype	Assuming someone is a librarian not a truck driver because they’re quiet and wear glasses

• Availability = Memory recall

• Representativeness = Mental stereotype

  • But can lead to a CONJUNCTION FALLACY, which means co-occurrence of two instances is more likely than a single one

Other Problem Solving Concepts

Term	Definition
Fixation	Getting stuck on a single approach that isn’t working
Functional fixedness	Inability to see alternative uses for an object (e.g., not using a shoe as a hammer)
Insight	Sudden realization of a solution (“Aha!” moment)
Incubation	Stepping away from a problem; solution often arises after a break
Confirmation bias	Favoring information that supports your preconceptions, ignoring contradicting evidence
Belief perseverance	Clinging to a belief despite contradictory evidence
Framing effects	The way a problem is presented can influence decisions (e.g., 90% survival vs. 10% death)

Key MCAT Takeaways

• Heuristics = mental shortcuts (Availability = ease of recall, Representativeness = match to prototype)

• Fixation and functional fixedness can block creative problem-solving

• Insight + incubation often lead to breakthroughs

• Confirmation bias, belief perseverance, and framing affect how we interpret information

What are Semantic Networks and Spreading Activation***

Theoretical Framework

• Cognitive Psychology: Collins & Loftus are part of this school, which emphasizes mental processes like memory, language, and perception.

• Their model REPLACED earlier, hierarchically structured semantic networks (like the one proposed by Collins & Quillian).

Collins & Loftus – Modified Semantic Network

Concept	Definition
Modified Semantic Network	Memory is organized based on individual EXPERIENCES, not strict hierarchies (like "animal → bird → canary")
Spreading Activation	Activating one concept in memory activates related concepts via neural links

• Example: Thinking of “fire truck” might also activate “red,” “sirens,” or “emergency.”

Key MCAT Takeaways

• Spreading activation = one idea triggers related ones; explains false memories

• Modified networks = memory structure is flexible and personal, not rigid

• Collins & Loftus = cognitive psychologists who challenged older hierarchical memory models

What are the different theories of intelligence?

Theories of Intelligence

Theory	Proponent	Key Idea
General Intelligence (g-factor)	Charles Spearman	Intelligence is a single general ability. High performance in one area predicts performance in others.
Triarchic Theory of Intelligence	Robert Sternberg	Intelligence has three components: Analytical (problem-solving) Creative (novel thinking), Practical (everyday tasks).
Primary Mental Abilities	L.L. Thurstone	Proposed 7 independent factors (e.g., verbal fluency, numerical ability, spatial reasoning) Challenged Spearman, but most factors still correlated
Multiple Intelligences	Howard Gardner	Intelligence is not unitary. Includes 7–9 independent intelligences like musical, spatial, kinesthetic, etc.
Emotional Intelligence	Daniel Goleman (popularized)	Ability to perceive, understand, and manage emotions in self and others.
Fluid vs. Crystallized	Raymond Cattell	Fluid = problem-solving (declines with age). Crystallized = acquired knowledge (increases with age).

MCAT Takeaways

• Spearman's g-factor: Intelligence is a single, general capacity

• Thurstone: Intelligence is made of several correlated abilities

• Gardner: Intelligence includes a wide range of human talents, not all academic

• Sternberg: Intelligence is what helps you succeed in real life

IQ Testing and Origins

Test	Creator	Purpose
Binet-Simon Test	Alfred Binet	Designed to measure mental age to predict school performance in children.
Stanford-Binet IQ Test	Lewis Terman	Adapted Binet's test for U.S.; used to quantify intelligence as a single score (IQ).

Mindset and Intelligence

Test	Creator	Purpose
Binet-Simon Test	Alfred Binet	Designed to measure mental age to predict school performance in children.
Stanford-Binet IQ Test	Lewis Terman	Adapted Binet's test for U.S.; used to quantify intelligence as a single score (IQ).

What is cognitive dissonance and what are some of the coping strategies we come up with to counter it?

4 Ways to Reduce Cognitive Dissonance

Strategy	Definition	Example
1. Modify Cognition	Change your belief to match your behavior	“I don’t really smoke that much” (downplaying frequency)
2. Trivialize	Make the conflict seem unimportant	“Smoking isn’t that bad for you anyway”
3. Add Cognitions	Introduce new justifications to outweigh the conflict	“I smoke, but I also work out, so it balances out”
4. Deny Conflict	Reject the facts that cause the dissonance	“There’s no conclusive evidence that smoking causes cancer”

MCAT Tip

• Dissonance creates mental discomfort, and people are motivated to reduce it—often irrationally.

• Most likely to occur when behavior conflicts with strongly held beliefs, especially when personal choice is involved.

What is language, where does it take place in the brain, and what are the different prevailing theories concerning it?

Language and the Brain (MCAT Summary)

Structure	Location	Function	Damage Results In
Broca’s Area	Left frontal lobe	Speech production	Broca’s (expressive) aphasia = broken, effortful speech but comprehension intact
Wernicke’s Area	Left temporal lobe	Language comprehension	Wernicke’s (receptive) aphasia = fluent but nonsensical speech
Arcuate Fasciculus	White matter tract between Broca & Wernicke	Connects comprehension & production	Conduction aphasia = fluent speech + comprehension, but inability to repeat words
Corpus Callosum	Between hemispheres	Communication between hemispheres	If severed: left visual field info (processed in right hemisphere) can't reach left-side language centers → inability to verbally describe left-field objects

MCAT Takeaways

• Left hemisphere dominance: Especially for language in right-handed people

• Broca = production, Wernicke = comprehension

• Damage to connecting structures (e.g., arcuate fasciculus or corpus callosum) leads to disconnection syndromes

• Use split-brain research to predict deficits in verbal reporting

Theories of Language and Thought (MCAT Summary)

Theory	Main Idea	Key Figure(s)	Example
Universalism	Thought DETERMINES language—we all have the same underlying cognition	Jerry Fodor	You think about colors, and your language creates words for them
Piaget’s Theory	Thought INFLUENCES language; Language develops as children’s cognition matures	Jean Piaget	Think first then develop language to describe those IDEAS
Vygotsky’s Interactionist	Thought and language are INDEPENDENT at first, then MERGE via social interaction	Lev Vygotsky	Children use language to develop inner speech and structure thinking
Linguistic Determinism (Weak)	Language influences thought—but does not determine it	—	Language direction (e.g., right-to-left) influences how we picture time flow
Linguistic Determinism (Strong)	Language determines thought—you CAN’T think BEYOND what your LANGUAGE allows	Sapir-Whorf (Whorfian Hypothesis)	No words for past/future = cannot conceive time in that way

MCAT Takeaways

• Universalism → cognition first, language second

• Piaget → cognitive development guides language development

• Vygotsky → language and thought start separately, then integrate through socialization

• Weak linguistic determinism = influence, strong = limitation of thought by language

Theories on Language DEVELOPMENT

Theory	Main Idea	Key Figure	Example
Nativist (INNATENESS OF LANGUAGE)	We are born with a Language Acquisition Device (LAD)—an innate ability to learn grammar; there’s a critical period (0–8/9 yrs)	Noam Chomsky	A child picks up language rapidly in early years without formal instruction
Learning (BEHAIVORIST)	Language is learned through reinforcement and imitation	B.F. Skinner	A baby says “mama,” mom smiles → positive reinforcement strengthens behavior
MATERIALIST	Look at what happens in brain EXCLUSIVELY when people think/speak/write
Interactionist	Language develops through a blend of biological capacity and social interaction	Lev Vygotsky	A child learns to speak through talking with caregivers and peers

MCAT Takeaways

• Nativist = innate grammar wiring + critical period

• Learning = reward-based behaviorism (criticized for oversimplicity)

• Interactionist = blend of biology + environment

What is the Limbic system and how does it regulate emotion?

HIPPO WEARING HAT (Structures of Limbic System)

Letter	Structure	Function	DAMAGED Effects
H	Hypothalamus	Regulates the autonomic nervous system, emotions, hunger, thirst, sex drive, body temp; links brain and endocrine system via pituitary	Hormonal imbalance, disrupted homeostasis (e.g. extreme hunger, rage, etc.)
A	Amygdala	Processes emotions, especially fear, aggression, arousal	Klüver–Bucy syndrome: hyperorality, hypersexuality, docility (tameness)
T	Thalamus	RELAY station for SENSORY info (except smell) to the cortex	Loss of sensory integration; can lead to sensory confusion or hallucinations
Hippo	Hippocampus	Converts short-term to long-term memory; involved in learning	Anterograde amnesia: inability to form new memories, old memories remain intact

MCAT Takeaways

• Amygdala = fear and anger: AMSITHDALA

• Hippocampus = memory (damage = anterograde amnesia)

• Hypothalamus = homeostasis and drives (Four Fs: fight, flight, feeding, fornication)

• Thalamus = relay of all senses except smell

Emotions and the Brain

Hemispheric Specialization

• Left Hemisphere: Associated with positive emotions (e.g., happiness, sociability).

• Right Hemisphere: Associated with negative emotions (e.g., fear, sadness, withdrawal).

Prefrontal Cortex

• Function: Regulates decision-making, social behavior, and impulse control.

• Damage leads to: Disinhibition, inappropriate behavior, poor judgment (e.g., Phineas Gage case).

Paul Ekman's 6 Universal Emotions

These are seen across all cultures—even in infants and individuals born blind:

1. Happiness

2. Sadness

3. Anger

4. Fear

5. Disgust

6. Surprise

3 Components of Emotion

1. Cognitive – What you think (e.g., "I’m in danger").

2. Physiological – What your body does (e.g., increased heart rate).

3. Behavioral – What you do (e.g., run away, smile, freeze).

Cultural Differences in Emotion

• While universal emotions are biologically innate, emotional expression can vary by culture. This is known as display rules.

• Display rules: Cultural norms that dictate how and when emotions are expressed.

MCAT Tip

• Know that blind individuals and infants express universal emotions despite no modeling, suggesting an innate biological basis.

• Be able to distinguish universal emotions from culturally modulated expressions (display rules).

What are the key theories of emotion to know for the MCAT?

Major Theories of Emotion (MCAT Summary Table)

Theory	Order of Events	Example	Mnemonic / Tip
James-Lange	Stimulus → Physiological response → Emotion	You cry → then feel sad	I am afraid because I have consciously assessed that I am trembling, thus I am experiencing FEAR.
Cannon-Bard	Stimulus → Physiological response + Emotion	You see a cat → heart races and feel happy at the same time	“Cannon fires both at once”
Schachter-Singer	Stimulus → Physiological response → Cognitive appraisal → Emotion	Heart races → you evaluate situation → if safe = happy, if danger = fear	“SCHACTERWATSKI: ANALYSIS”: Emotion comes from analysis
Lazarus	Stimulus → Cognitive appraisal → Emotion + Physiological response	You label situation as dangerous → then feel fear and heart starts racing	“Body is a Lazy Lazarus”: Mind acts before the body

MCAT Tips

• Be ready to differentiate theories by order.

• Know that James-Lange and Schachter-Singer both begin with physiological response but differ in the subconscious vs. conscious evaluation.

• Lazarus theory is the only one where cognitive appraisal comes BEFORE anything else.

YERES-DODSON LAW: PEOPLE PERFORM BEST WHEN MODERATELY AROUSED

What to know about stress for the MCAT?

Lazarus’s Appraisal Theory of Stress (MCAT Version)

• Same dude who said we cognitively label FIRST then have physiological response

Stage	Description	MCAT Example
Primary Appraisal	You evaluate the nature of the stressor:
	- Benign/Positive: No threat, or actually something good	Seeing your favorite wrestler return in the Royal Rumble = excitement!
	- Neutral: Unimportant or irrelevant	A stranger walks past you with no eye contact = no emotional reaction
	- Negative: Perceived as a threat	Seeing the Sigma Boy charging at you with a knife = stress trigger
Secondary Appraisal	You assess your resources and options to cope with the threat
	- Can I handle this? What are the consequences?	“Can I run away fast enough?” “Can I hide behind the table?”
	- Involves evaluating: harm, threat, and challenge	Harm = already injured; Threat = potential harm; Challenge = possible growth

MCAT Takeaways

• Stress is a two-stage process: Primary (what is it?) → Secondary (can I handle it?)

• The Lazarus theory places stress as the result of appraisal, not the stimulus itself.

• Use "Sigma Boy might stab me" as a vivid example of negative primary + urgent secondary appraisal.

4 MCAT Categories of Stressors

Category	Description	Example
1. Significant Life Changes	Major transitions or shifts that require adjustment	Moving to a new state (e.g., Ohio), starting college, getting divorced
2. Catastrophic Events	Large-scale, unpredictable disasters perceived as threatening by most people	Tornado, earthquake, or a sky-demon tearing through Ohioan infrastructure
3. Daily Hassles	Minor, frequent irritations or demands of daily life	Running late, traffic, yelling at a dealership, or an Ohio goblin kidnapping your child
4. Ambient Stressors	Global, background stressors that are chronic and often unnoticed	Noise, light pollution, smog in Beijing, or demons flying across the sky in Ohio

MCAT Key Points

• All four types can contribute to chronic stress and impact health.

• Daily hassles and ambient stressors are often underestimated but most impactful over time.

• Primary vs. secondary appraisal still applies to how each stressor is experienced.

Biological Responses to Stress Response

Neurotransmitters & Hormones of the Stress Response

Substance	Type	Released By	Function in Stress
Epinephrine (Adrenaline)	Hormone & Neurotransmitter	Adrenal medulla (inner adrenal gland)	Increases heart rate, blood pressure, dilates pupils, bronchodilation
Norepinephrine (Noradrenaline)	Hormone & Neurotransmitter	Adrenal medulla & sympathetic neurons	Vasoconstriction (especially in skin/GI), increases alertness, raises BP
Cortisol	Hormone	Adrenal cortex (outer adrenal gland)	Increases glucose metabolism, suppresses immune system, longer-term stress
Acetylcholine (ACh)	Neurotransmitter	Preganglionic neurons (both SNS & PNS)	Stimulates adrenal medulla to release epi/norepi (in sympathetic system)
CRH (Corticotropin-Releasing Hormone)	Hormone	Hypothalamus	Signals anterior pituitary to release ACTH
ACTH (Adrenocorticotropic Hormone)	Hormone	Anterior pituitary	Stimulates adrenal cortex to produce cortisol

MCAT-Style Pathways to Know

1. Sympathetic Nervous System (Fast/Short-Term Stress):

   • Hypothalamus → Sympathetic nerves → Adrenal medulla

   • Releases epinephrine & norepinephrine

2. HPA Axis (Slow/Long-Term Stress):

   • Hypothalamus (CRH) → Pituitary (ACTH) → Adrenal cortex (Cortisol)

MCAT Flashcard Takeaways

• Epinephrine = fight-or-flight; short-term

• Cortisol = longer-term stress, glucose regulation, immune suppression

• Adrenal medulla = catecholamines, adrenal cortex = cortisol

• CRH → ACTH → Cortisol = classic HPA axis

Everything you need to know about stress for the MCAT

Stress Response Overview

• Autonomic Nervous System (ANS) + Limbic System + Reticular Activating System (RAS) work together to process stress and emotions.

  • RAS (midbrain): Controls alertness and arousal.

  • Midbrain Structures: Cerebral peduncle, corpora quadrigemina, cerebral aqueduct.

• Sympathetic Nervous System (Fight or Flight):

  • ↑ Heart rate, ↑ respiration → more oxygen and energy

  • ↑ Peripheral vasoconstriction → prioritizes core organ perfusion

  • ↓ Digestion, ↓ immune activity

  • Adrenal Glands:

    • Adrenal medulla → Epinephrine & Norepinephrine (short-term stress)

    • Adrenal cortex → Cortisol (long-term stress)

• Tend-and-Befriend Response:

  • Promotes seeking social support

  • Driven by oxytocin, especially in females (linked to estrogen)

General Adaptation Syndrome (Hans Selye)

1. Alarm: Acute stress kicks in (↑ HR, adrenaline spike)

2. Resistance: Prolonged cortisol release, coping mechanisms engaged

3. Exhaustion: Immune suppression, tissue damage, ↑ risk of illness

Physical Effects of Chronic Stress

System	Effects
Cardiovascular	↑ BP → vessel damage → ↑ risk of CAD (esp. coronary arteries)
Metabolic	↑ Cortisol & glucagon → ↑ blood glucose → ↑ diabetes risk
Reproductive	↓ Fertility in women (energy conservation); impotence in men
Immune	Short-term = inflammation; long-term = suppressed immunity

Brain & Behavioral Effects

• Hippocampus: Memory → atrophies under chronic stress

• Prefrontal Cortex: Judgment & control → atrophies → poor decision-making

• Amygdala: Fear and anxiety → becomes hyperactive

Key emotional/behavioral consequences:

• Depression: Anhedonia (↓ pleasure); perceive more stress

• Learned Helplessness: Perceived loss of control → impaired coping

• Anger: Type A personalities → ↑ risk of heart disease

• Anxiety: Hyperactivation of amygdala

• Addiction: Substance abuse as maladaptive coping → worsens stress cycle

Stress Management (Coping)

Psychological Strategies:

• Perceived control → major factor in resilience

• Optimism → improves outcomes and motivation

• Social support → reduces cortisol, improves recovery

Behavioral Techniques:

• Exercise → physical outlet, ↑ endorphins

• Meditation → ↓ HR, ↓ BP, ↓ cholesterol

• Religious/Spiritual involvement → lifestyle structure + community

• Cognitive flexibility → reframing stressors; improved adaptability (CBT helps here)

Key MCAT Takeaways:

• Stress hormones: Epinephrine (short-term), Cortisol (long-term)

• Key brain areas: Hippocampus (memory), Amygdala (fear), PFC (judgment)

• Stress = systemic: cardiovascular, immune, reproductive, metabolic impacts

• General Adaptation Syndrome = alarm → resistance → exhaustion

• Coping = protective: exercise, social support, CBT, optimism, control

What to know about the biological basis of behavior for the MCAT?

Muscle Stretch Reflex:

• A monosynaptic reflex arc with:

  • Afferent neuron (stimulus): detects stretch via muscle spindle

  • Efferent neuron (response): causes same muscle to contract

• Example: Knee-jerk reflex:

  • Hammer taps tendon → stretches quadriceps

  • Stretch sensed by muscle spindles

  • Signal sent to spinal cord → LMN activates quads

  • Simultaneously, antagonist muscle (hamstring) is inhibited to allow proper movement (reciprocal inhibition)

Major Neurotransmitters & Their Origins

• Glutamate

  • Main excitatory NT in CNS

  • Involved in cortex activation via reticular activating system (RAS) → important for consciousness

• GABA (brain) & Glycine (spinal cord)

  • Main inhibitory NTs

• Acetylcholine (ACh)

  • Released by Basalis & septal nuclei to cerebral cortex

  • Used by lower motor neurons (LMNs) and autonomic nervous system (ANS)

• Histamine

  • Produced by hypothalamus

• Norepinephrine (NE)

  • Produced in locus coeruleus (pons)

  • Also involved in ANS, though less than ACh

• Serotonin (5-HT)

  • Released by raphe nuclei (midbrain, pons, medulla)

• Dopamine (DA)

  • Produced in ventral tegmental area (VTA) and substantia nigra

  • Involved in reward, motor control, and Parkinson’s pathology

Gene-Environment Interaction  Nature vs. nurture.  Ex. Attractive baby and hideous baby. As a result, attractive baby receives more attention and is more sociable and well-adjusted. But say both have genes that predispose for depression, that are triggered by environment. Beautiful baby’s genes are not activated, while ugly baby’s genes are making proteins all the time since his life is tougher.

What are the 5 theories of motivation?

Theory	Key Idea	Example
Evolutionary	Behavior is driven by instincts that promote survival and reproduction.	Babies crying, sleeping, feeding instinctively.
Drive-Reduction Theory	Needs cause drives (aroused states), which motivate behavior to restore homeostasis.	Thirst → drink water; Fatigue → sleep.
Optimum Arousal Theory	Motivation to reach an optimal level of arousal (not too low or too high).	Going to an amusement park for stimulation.
Cognitive Theory	Thoughts and expectations guide behavior (intrinsic/extrinsic motivation).	Studying because you enjoy learning.
Maslow’s Hierarchy of Needs	Motivation progresses through a pyramid of needs: physiological → safety → love → esteem → self-actualization.	Seeking food before self-esteem.

What is the ABC Model of Attitude?

What are the 4 theories on how our attitudes influence behavior?

Attitude = Affective + Behavioral + Cognitive

Component	Definition	Example
Affective	Emotional reaction or feeling toward an object/event	"I love yoga." / "I’m frightful of rollercoasters."
Behavioral	How you behave or act toward the object/event	"I go to class weekly." / "I will ride the carousel."
Cognitive	Thoughts, beliefs, or knowledge about the object/event	"I believe yoga relaxes me." / "Rollercoasters are stupid."

4 Theories on how our attitudes influence behavior

Theory	Core Idea	Key Components / Factors	Example
Theory of Planned Behavior	Behavior is determined by intentions, which come from attitude, social norms, and control.	- Attitude toward behavior - Subjective norms - Perceived behavioral control	"I like studying (attitude), my peers value it (norm), and I can manage my time (control)."
Attitude-to-Behavior Process Model	Event triggers attitude, which + knowledge = behavior	- Event → attitude - Attitude + stored knowledge → interpretation → behavior	Junk food seen as unhealthy → doesn’t eat chips due to past family health issues.
Prototype Willingness Model	Behavior shaped by intentions, willingness, and social modeling (prototype behavior)	- Past behavior - Attitudes - Subjective norms - Intentions - Willingness - Prototypes (social role models)	Peer pressure and willingness lead teen to try vaping even without intent.
Elaboration Likelihood Model	Persuasion route (central vs. peripheral) influences attitude and behavior change	Central route: QUALITY of arguments Peripheral route: cues like appearance, status	Convinced by a doctor's logical argument (central) or celebrity endorsement (peripheral).

Freud’s Iceberg Theory of Personality (Psychodynamic Perspective)

Component	Location	Function
Id	Unconscious	Primitive drives, pleasure principle, immediate gratification (e.g., hunger, libido)
Superego	Mostly unconscious	Internalized morals, guilt, societal values (“shoulds”)
Ego	Mostly conscious	Mediates between id & superego, based on the reality principle (what’s socially acceptable)

Comparison of the 5 Personality Theories

Comparison of the 5 Personality Theories

Theory	Key Figures	Core Beliefs	Conscious vs. Unconscious	Key Concepts / Tools	MCAT Notes
Humanistic	Abraham Maslow, Carl Rogers	People are inherently good and driven toward self-actualization	Conscious	Self-concept, genuineness, acceptance, hierarchy of needs	Emphasizes personal growth; contrasts with Freud's deterministic approach
Biological Theory	Hans Eysenck, Jeffrey Alan Gray, C Robert Cloninger	Personality is genetically determined; brain systems influence behavior	Biological basis	Temperament, dopamine, twin studies, fight-or-flight systems	Genetics + brain structures shape traits; includes evidence from twin studies
Behaviorist Theory	BF Skinner, Ivan Pavlov	Personality is learned from environment via conditioning	Neither (observable)	Operant (Skinner) and classical (Pavlov) conditioning	Deterministic and environment-based; focuses only on behavior, not thoughts
Trait Theory	Gordon Allport Raymond Cattel Hans Eysenck	Personality = patterns of stable traits	Descriptive only	Cardinal/Central/Secondary traits 16personality traits OCEAN, factor analysis	Trait categories describe but don't explain personality; Big Five often appears on MCAT
Social Cognitive Theory	Albert Bandura	Behavior is a mix of cognition, learning, and environment (reciprocal)	Cognitive + Social	Observational learning, Bobo Doll, AMIM (Attention, Memory, Imitation, Motivation)	Bridges behaviorist and cognitive models; learning ≠ performance; emphasizes modeling effects

Summarize the Three Clusters of Personality Disorders (A, B, and C)

MCAT Takeaways:

• Personality disorders are long-term patterns of thoughts and behaviors that deviate from social norms.

• Divided into three clusters (A, B, C) based on similar features.

• Know the descriptive patterns of each cluster—not the specific disorders—for the MCAT.

Cluster	Description	Key Traits	Example Disorders (for context only)
A	Odd or Eccentric	Social withdrawal, suspicion, peculiar thinking	Paranoid, Schizoid, Schizotypal
B	Dramatic, Emotional, Erratic	Intense emotions, unstable relationships	Antisocial, Borderline, Histrionic, Narcissistic
C	Anxious or Fearful	Anxiety, avoidance, obsessive behavior	Avoidant, Dependent, Obsessive-Compulsive

What are the biological basises of 3 Major Neurological Disorders?

Biological Basis of Major Neurological Disorders

Disorder	Affected Brain Regions	Key Features & Symptoms	Biological Markers / Causes	Treatment / Notes
Depression	↓ Frontal lobe activity, ↑ Limbic system activityInvolves hypothalamus, raphe nuclei, locus coeruleus, VTA	Hopelessness, loss of interest, fatigue, appetite/sleep changes	- ↓ Serotonin (raphe nuclei) ↓ Norepinephrine (locus coeruleus) ↓ Dopamine (VTA)- Hypothalamic stress hormone imbalance (↑ cortisol)- Neural plasticity changes	SSRIs, SNRIs, MAO inhibitors (↑ monoamines in synapse) Psychosocial factors also play a role
Alzheimer’s Disease	Atrophy of cerebrum, especially temporal → parietal/frontal lobesLoss of nucleus basalis (↓ ACh)	Memory loss, progressive cognitive declineLater loss of ADLs	- β-amyloid plaques (outside neurons)- Tau tangles (inside neurons)- ↓ Acetylcholine- ApoE4 mutation- High BP risk factor	No cure Higher education/mental stimulation protective Early synaptic dysfunction
Parkinson’s Disease	Substantia nigra (in brainstem, part of basal ganglia) → ↓ dopamine to striatum	Tremor, rigidity, shuffling gait, bradykinesia Later cognitive & behavioral symptoms	- Loss of dopaminergic neurons (especially in SN) - Lewy bodies with clumped α-synuclein- Genetic mutations, toxins (e.g., pesticides)	L-DOPA, dopamine agonists Stem cell therapy under study

Key MCAT Takeaways:

• Depression: Monoamine hypothesis (↓ serotonin, dopamine, norepinephrine); abnormal limbic-frontal activity.

• Alzheimer’s: Plaques (β-amyloid), tangles (tau), ↓ acetylcholine; starts in temporal lobe → spreads.

• Parkinson’s: Dopaminergic neuron loss in substantia nigra; presence of Lewy bodies (α-synuclein); affects basal ganglia motor circuit.

Group Polarization vs. Groupthink

Group Polarization vs. Groupthink

Concept	Definition	Key Feature	Example
Group Polarization	Tendency of a group to make decisions that are more extreme than the initial inclinations of its individual members.	Reinforces preexisting beliefs or attitudes → becomes stronger or more extreme.	A jury discusses a case where most members lean toward a light punishment. After discussion, they vote for a much harsher sentence than any initially proposed.
Groupthink	When group members suppress dissenting opinions in order to maintain harmony and consensus, often leading to poor decisions.	Desire for unity overrides critical evaluation.	A government team ignores warnings from an engineer and launches a faulty space shuttle to avoid disagreement—Challenger disaster is a real-life example.

MCAT Tip:

• Group polarization = ideas get more EXTREME after discussion.

• Groupthink = poor decisions made due to pressure to conform and avoid conflict.

Conformity v Obedience and different types of Conformity

Conformity vs. Obedience

Term	Definition	Example
Conformity	Adjusting behavior/thought to match a group	Dressing casually because your friends do
Obedience	Changing behavior in response to authority	Following a supervisor's instructions

Types of Conformity

Type	Description	Example
Compliance	Conforming to gain reward or avoid punishment; usually temporary	Paying taxes to avoid fines to COMPLY
Identification	Conforming to be like someone you admire; dependent on continued respect	Dressing like a celebrity because you want to BE LIKE THEM
Internalization	Integrating beliefs into your own value system; deepest and most lasting form of conformity	Adopting meditation because YOU BELIEVE IN IT

Social Influence Types

Type	Definition	Example
Normative Social Influence	Conforming to be LIKED/ACCEPTED even if you privately disagree	Laughing at a joke you don’t find funny
Informational Social Influence	Conforming because others seem more knowledgeable	Following crowd during a fire drill because you think THEY KNOW WHATS UP

ANOMIE= Breakdown of social bonds between individual and community (loss of norms → alienation)

Asch Conformity Study v. Milgram Obedience Experiment

Asch Conformity Study (1951)

Category	Details
Researcher	Solomon Asch
Purpose	To investigate the extent to which social pressure from a majority group could affect conformity
Participants	Male college students
Setup	Participants asked to match line lengths; confederates (actors) gave wrong answers intentionally
Key Concept	Conformity — adjusting behavior to align with a group
Findings	75% conformed at least once; 37% conformed consistently
Social Influence Types	- Normative Influence: desire to fit in - Informational Influence: assumption that the group is correct
Reasons for Non-conformity	Confidence in personal judgment or resistance to social pressure
Criticisms	- All male sample - Lab setting lacks ecological validity - Demand characteristics possible
MCAT Takeaways	Group pressure can strongly influence perception and decision-making even without formal authority

Milgram Obedience Experiment (1961)

Category	Details
Researcher	Stanley Milgram
Purpose	To test how far individuals would go in obeying an authority figure, even if it meant harming another person
Participants	Adult male volunteers
Setup	"Teacher" instructed to shock "learner" for wrong answers; shocks increased in voltage up to 450V
Key Concept	Obedience — compliance with authority, even when it conflicts with personal morals
Findings	65% of participants delivered the maximum shock; many showed visible distress
Mechanisms of Obedience	- Authority figure assumed responsibility - Gradual escalation - Lack of clear escape
Psychological Factors	- Just World Phenomenon -Fundamental Attribution Error -Self-serving Bias
Ethical Issues	Deception, emotional stress, questionable consent
MCAT Takeaways	Authority can override morality; situational pressure often trumps individual character

Zimbardo’s Stanford Prison Experiment

Category	Details
Researcher	Philip Zimbardo
Year	1971
Purpose	To investigate how situational roles and authority influence behavior, particularly in prisons
Participants	18 healthy, middle-class male college students; randomly assigned as guards or prisoners
Setup	Simulated prison in Stanford’s basement. Guards were told not to physically harm but could assert psychological control.
Key Events	Day 1 uneventful Day 2: Prisoner rebellion Day 3–5: Escalation of abuse, hunger strikes, solitary confinement, psychological collapse
Findings	-Guards quickly adopted authoritarian roles -Prisoners internalized submissive roles -Zimbardo lost objectivity by acting as warden
Key Psychological Concepts	- Situational attribution over dispositional -Deindividuation (prisoners as numbers) -Cognitive dissonance in guards -Internalization of roles
Ethical Issues	- Lack of informed withdrawal - Emotional trauma - Zimbardo’s dual role impaired objectivity - Poor operational definitions and controls
Criticisms	- Demand characteristics - Selection bias (who volunteers to simulate prison?) - Small sample size
MCAT Takeaway	Situations—not just personality traits—can powerfully influence human behavior, especially in authority-role dynamics and loss of personal identity.

What are the different group behaviors for the MCAT:

Bystander Effect & Deindividuation

Concept	Definition	Key Mechanism	Example
Bystander Effect	People are less likely to help when others are present	Diffusion of responsibility	Kitty Genovese case (38 witnesses, no help)
Diffusion of Responsibility	People feel less personally responsible when in a group	Group size increases this effect	More bystanders = less individual action
Deindividuation	Loss of self-awareness and restraint in groups, leading to deviant behavior	Anonymity within group	Black Friday riots, online trolling

Social Facilitation vs. Social Loafing

Concept	Definition	Effect of Group Presence	Example
Social Facilitation	Presence of others increases arousal, improving performance on easy tasks	Enhances DOMINANT RESPONSE	Practiced speech is delivered better in a crowd
Social Loafing	People put in less effort in a group if individual performance isn’t evaluated	Reduces accountability	SLACKING during group projects

Agents of Socialization

Agent	Role in Socialization	Example
Family	Primary agent; teaches norms, values, language, caregiving	Parental influence on behavior, socioeconomic differences
School	Teaches discipline, order, cooperation; includes hidden curriculum	Learning to obey authority, raise hand before speaking
Peers	Influence identity, social interaction, preferences	Peer pressure, exposure to music/media/fashion
Mass Media	Disseminates culture, norms, stereotypes; shapes expectations and beliefs	TV shows promoting gender roles, violence in media

MCAT Key Takeaways

• Bystander Effect is stronger with more people; reduced in smaller groups.

• Social Facilitation improves simple tasks but worsens complex ones if you're unprepared.

• Social Loafing is reduced when individual contributions are tracked.

• Deindividuation lowers personal accountability → riskier behavior.

• Socialization occurs across life stages and is shaped by family, school, peers, and media.

Types of Learning

Type	Definition	Examples
Nonassociative	Learning from repeated exposure to a single stimulus	Habituation, Sensitization
Associative	Learning from linking two stimuli or a behavior with consequence	Classical & Operant Conditioning

Classical Conditioning: Ivan Pavlov

Term	Definition	Example
Unconditioned Stimulus (US)	Naturally triggers a response	Carrot for a guinea pig
Unconditioned Response (UR)	Natural response to US	Excitement
Neutral Stimulus (NS)	Doesn’t trigger a response initially	Refrigerator door sound
Conditioned Stimulus (CS)	NS becomes CS when it triggers same response as US after pairing	Refrigerator door (after conditioning)
Conditioned Response (CR)	Response to CS	Excitement at door sound
Extinction	CS presented without US → response fades	Door opens with no carrot → less excitement
Spontaneous Recovery	CR returns after extinction	Suddenly excited again after hearing door
Generalization	Similar stimuli elicit same response	Desk drawer also excites guinea pig
Discrimination	Differentiation between similar stimuli	Doesn’t react to dresser drawer

Operant Conditioning: BF Skinner

Type	Definition	Example
Positive Reinforcement	Add something to increase behavior	Gas card for safe driving
Negative Reinforcement	Remove something to increase behavior	Buzzer stops when seatbelt fastened
Positive Punishment	Add something to decrease behavior	Speeding ticket
Negative Punishment	Remove something to decrease behavior	License taken away

Reinforcement Schedules

Schedule	Definition	Example
Fixed Ratio	Reinforce after fixed # of behaviors	Bonus every 5 cars sold
Variable Ratio	Reinforce after average # of behaviors	Slot machine
Fixed Interval	Reinforce after fixed time interval	Paycheck every 2 weeks
Variable Interval	Reinforce after varying time intervals	Surprise bonus

FIXED INTERVAL: LEAST EFFECTIVE

VARIABLE RATIO: MOST EFFECTIVE

Shaping, Insight, and Latent Learning

Concept	Definition	Example
Shaping	Reinforce successive approximations of a behavior	Teaching a headstand, rewarding steps
Insight Learning	Sudden realization using previous knowledge	Aha! moment solving a puzzle
Latent Learning	Learned behavior not demonstrated until needed	Knowing maze path but not showing it yet

Shaping, Insight, and Latent Learning

Concept	Definition	Example
Shaping	Reinforce successive approximations of a behavior	Teaching a headstand, rewarding steps
Insight Learning	Sudden realization using previous knowledge	Aha! moment solving a puzzle
Latent Learning	Learned behavior not demonstrated until needed	Knowing maze path but not showing it yet

Aversive Learning

Type	Definition	Example
Escape	Behavior eliminates EXISTING unpleasant stimulus	Fire alarm rings → run outside
Avoidance	Behavior PREVENTS stimulus from occurring in the FIRST PLACE	Leave building when you smell smoke

MCAT Takeaways

• Classical Conditioning = automatic associations (Pavlov)

• Operant Conditioning = behavior shaped by consequences (Skinner)

• Reinforcement = increases behavior; punishment = decreases behavior

• Variable ratio = most resistant to extinction

• Escape = get away from stimulus; avoidance = prevent it entirely

Theories of Attitude and Behavior Change for the MCAT

Persuasion and the Elaboration Likelihood Model (ELM)

Path	Processing Style	When Used	Result
Central	Deep, thoughtful, content-based	When topic is important or person is engaged	LASTING attitude change
Peripheral	Surface-level, superficial cues	When uninterested or distracted	Temporary attitude change

Persuasion Influencers:

1. Message Characteristics – clarity, logic, quality of arguments

2. Source Characteristics – credibility, trustworthiness, appearance

3. Target Characteristics – listener traits like mood, intelligence, self-esteem

Reciprocal Determinism (Bandura)

Key Idea: Behavior is shaped by a constant interaction between:

• Cognition (thoughts, motivations)

• Environment (social context)

• Behavior (actions)

Example:

• You like soccer → join a team → hang out with players

• OR: You hang out with players → grow interest → join team

Personal Control

Type	Definition	Effect
Internal Locus	You control your fate	Better stress coping, achievement, lower depression
External Locus	Outside forces control outcomes	Higher stress, worse outcomes
Learned Helplessness	Repeated failures → perceived loss of control	Passive, avoidant behavior
Tyranny of Choice	Too many options → decision paralysis, regret	Less satisfaction, reduced well-being

Self-Control

Definition: Ability to SUPPRESS short-term temptations for long-term goals.

• Famous Experiment: Marshmallow Test – kids who delayed gratification had better outcomes years later.

Ego Depletion:

• Self-control is a LIMITED RESOURCE (like a muscle).

• Overuse weakens short-term capacity.

• Training in one area can generalize.

Ways to Improve Self-Control:

1. Change Environment – e.g., remove temptations

2. Operant Conditioning – reinforce good behavior

3. Classical Conditioning – pair healthy substitutes

4. Avoid Total Deprivation – increases craving, risk of relapse

MCAT Key Takeaways:

• Central route: Lasting persuasion from thoughtful engagement.

• Reciprocal determinism: Tri-directional influence of behavior, thoughts, and environment.

• Internal control improves outcomes; external worsens them.

• Learned helplessness explains avoidance after uncontrollable events.

• Too much choice → anxiety and regret.

• Self-control can be trained but is exhaustible.

Self-Identity Concepts for the MCAT

Self-Concept and Development

Self-concept = How we perceive and evaluate ourselves (self-awareness)

• Two components of development:

  • Existential self – awareness of being separate, constant (develops early)

  • Categorical self – understanding that we exist in categories (age, gender, traits, careers)

Carl Rogers' 3 Components of Self-Concept:

Component	Description
Self-image	How we SEE ourselves (see an image)
Self-esteem	VALUE we place on ourselves (esteemed value)
Ideal self	Who we strive to become (what we IDEALLY will become)

• Congruence between REAL and IDEAL self → positive self-concept

• Incongruence → leads to dissatisfaction or confusion

Social Identity Theory (Tajfel & Turner)

Two parts of identity:

• Personal identity – traits unique to you (e.g., kind, funny)

• Social identity – group memberships (e.g., student, athlete)

3 Steps in Social Identity Formation:

1. Categorization – GROUPING ourselves and others (e.g., race, profession)

2. Identification – adopting group identity and norms

3. Comparison – boosting self-esteem by comparing our group to others
   → Basis for in-group bias and prejudice

Self-Esteem vs. Self-Efficacy

Concept	Definition	High Level Traits	Low Level Traits
Self-esteem	One's overall sense of self-WORTH	Self-accepting	Self-critical
Self-efficacy	Belief in ability to succeed at tasks	Persistent, confident (RISE)	Doubtful, avoids challenges (FALL)

Sources of Self-Efficacy (ALBERT BANDURA):

1. Mastery experiences (past success)

2. Social modeling (seeing others succeed)

3. Social persuasion (encouragement)

4. Psychological states (stress/mood management)

Key Insight: Self-esteem ≠ self-efficacy (e.g., a perfectionist may feel capable but not worthy)

MCAT Takeaways

• Self-concept forms early, shaped by both personal and social identities.

• Carl Rogers emphasized congruence between ideal and real self.

• Self-efficacy is situational and can be strengthened; it is not the same as self-esteem.

• Social Identity Theory explains how group affiliation contributes to self-concept and prejudice.

• Locus of control affects motivation and resilience; internal locus promotes autonomy.

What are the different theories of development to know for the MCAT

Theories of Development – Comparative Table

Theory & Theorist	Focus of Development	Key Idea	Stages	Age Range	MCAT Notes
Freud’s Psychosexual	Personality (unconscious)	Libido (sexual energy) focused on different body zones	5	0 – puberty	Fixation if conflict not resolved; based on pleasure and tension
Erikson’s Psychosocial	Personality (social conflicts)	Conflict between individual needs and societal demands	8	Entire lifespan	Successful resolution leads to virtue; failure leads to reduced functioning
Vygotsky’s Sociocultural	Cognitive development through social context	Learning via social interaction, language, and culture	Not staged	Continuous	Zone of Proximal Development (ZPD), MKO, and internal speech
Kohlberg’s Moral	Moral reasoning	Morality develops in stages through dilemmas and logic	3 levels (6 stages)	Pre-adolescence → adulthood	Based on Heinz Dilemma; only some reach post-conventional morality

Freud’s 5 Psychosexual Stages (Mnemonic: Old Age Parrots Love Grapes)

Stage	Age	Focus/Conflict	Fixation Outcome
Oral	0–1 yr	Mouth (feeding)	Dependency, aggression, nail-biting
Anal	1–2 yrs	Anus (toilet training)	Orderliness or messiness
Phallic	3–6 yrs	Genitals (Oedipus/Electra)	Sexual dysfunction, identification issues
Latent	6–12 yrs	None (social/exploration)	No adult fixation
Genital	12+ yrs	Genitals (mature sex)	Mentally healthy, other-focused

Erikson’s 8 Psychosocial Stages

Stage	Age	Conflict	Virtue	Negative Outcome
Trust vs. Mistrust	0–1 yr	Are needs reliably met?	Hope	Mistrust, suspicion
Autonomy vs. Shame/Doubt	1–3 yrs	Can I act independently?	Will	Shame, low self-esteem
Initiative vs. Guilt	3–6 yrs	Can I initiate activities?	Purpose	Guilt, inhibition
Industry vs. Inferiority	6–12 yrs	Can I be competent?	Competence	Inferiority, modesty
Identity vs. Role Confusion	12–18 yrs	Who am I?	Fidelity	Confusion, rebellion
Intimacy vs. Isolation	18–40 yrs	Can I form close relationships?	Love	Isolation, loneliness
Generativity vs. Stagnation	40–65 yrs	Am I contributing?	Care	Stagnation, unproductivity
Integrity vs. Despair	65+ yrs	Was my life meaningful?	Wisdom	Regret, dissatisfaction

Vygotsky’s Sociocultural Theory

Concept	Description
Elementary Mental Functions	Attention, sensation, perception, memory (natural)
Higher Mental Functions	Developed through social interaction with MKO
Zone of Proximal Development	Range between what a child can do alone and with help
Private Speech (Internal Speech)	Self-guidance through speech – vital for cognitive growth

Kohlberg’s Moral Development Theory

Level	Stage	Focus
Pre-Conventional	Obedience vs. Punishment	Avoid punishment
	Individualism & Exchange	Recognize different perspectives
Conventional	Good Boy/Good Girl	Conform to societal expectations
	Law and Order	Uphold law for social order
Post-Conventional	Social Contract	Laws may conflict with moral values
	Universal Ethical Principle	Follow internal moral principles (e.g., Gandhi)

MCAT Key Takeaways

• Freud & Erikson: Both emphasize early life stages, but Erikson extends into adulthood with social conflicts.

• Vygotsky: Emphasizes social interaction and language in developing higher cognition.

• Kohlberg: Focuses on how moral reasoning evolves, not behavior itself.

• Vygotsky and Kohlberg are cognitive development theories

• Freud and Erikson focus on personality development.

What to know on social influences for the MCAT?

Social Influences: Overview

Concept	Description	MCAT Key Examples/Associations
Imitation	Basic form of social behavior, even in infants (e.g., sticking tongue out)	Mirror neurons, early development of empathy
Roles	Social norms dictate expected behaviors by role (e.g., student, parent)	Zimbardo prison experiment, social scripts
Reference Groups	Groups we compare ourselves to when shaping beliefs/behaviors	Political parties, religious groups, peer groups
Culture & Socialization	Society/culture contributes to personal development through norms/values	Agents of socialization: family, school, media

• Social influences shape our identity, behaviors, and self-perception through:

Mead’s Theory of the Self (PPG)

George Herbert Mead proposed that the self develops through social interaction via 3 stages:

Stage	Description
Preparatory	Imitation only; no understanding of others' perspectives
Play	Role play; understands relationships and begins perspective-taking
Game	Understands generalized other (society); recognizes multiple roles

Mead’s “Me” v. “I” [How we’re perceived by society, our RESPONSE to society)

Component	Description	Analogy
Me	The social self – how we think society sees us	"Me" = what society expects
I	The response to the “Me” – our individual identity	"I" = my personal reaction

Cooley’s “Looking Glass Self”

Step	Description
1	How do I appear to others?
2	What do others think of me?
3	Revise self-image based on perceived judgments

Key Insight: We are shaped not by others' actual thoughts, but by what we imagine others think of us.

MCAT Key Takeaways

• Imitation is observable in early infancy and may be tied to mirror neurons.

• Roles and social expectations influence behavior (e.g., conformity in Zimbardo's study).

• Reference groups serve as benchmarks for evaluating our own actions or beliefs.

• Mead believed self-awareness develops through stages, culminating in the awareness of society’s views.

• Mead's “I” = individual agency, “Me” = societal expectation.

• Cooley’s Looking Glass Self emphasizes that self-image is socially constructed, but based on perceived, not actual, judgments.