MCAT Behavioral Sciences

Afferent Neurons

Sensory neurons that carry information from receptors to the spinal cord.

Efferent Neurons

Motor neurons that carry information from the CNS to muscles and glands.

Interneurons

Neurons found between other neurons, located mainly in the central nervous system (CNS).

Reflex Arcs

Nervous system pathways where interneurons in the spinal cord relay information to the source of stimuli while simultaneously routing it to the brain.

Autonomic Nervous System

Division of the PNS that regulates involuntary functions; includes the sympathetic (fight/flight) and parasympathetic (rest/digest) branches.

Phrenology

The study of the relationship between skull anatomy and personality, first proposed by Franz Gall ($1758 \rightarrow 1828$).

Functionalism

A psychological perspective studied by William James and John Dewey that examines how mental processes help individuals adapt to their environment.

Broca’s Area

Brain region responsible for speech production; damage results in difficulty generating speech.

Wernicke’s Area

Brain region responsible for language comprehension; damage results in a lack of comprehension despite being able to speak.

Synapses

The points of communication between neurons, first described by Sir Charles Sherrington ($1857 \rightarrow 1952$).

Thalamus

A forebrain structure that acts as a relay station for sensory information.

Hypothalamus

Brain structure that maintains homeostasis and integrates with the endocrine system through the hypophyseal portal to the anterior pituitary.

Basal Ganglia

Forebrain structures that smooth movements and help maintain postural stability.

Limbic System

A group of brain structures including the septal nuclei (pleasure), amygdala (fear/aggression), and hippocampus (memory/emotion).

Cerebral Cortex

The outer layer of the brain divided into four lobes: Frontal (executive), Parietal (touch/spatial), Occipital (visual), and Temporal (sound/memory).

Acetylcholine

A neurotransmitter used by the somatic nervous system to move muscles, as well as by the parasympathetic and central nervous systems.

Dopamine

Neurotransmitter that maintains smooth movements and steady posture; imbalances are linked to Parkinson's disease and schizophrenia.

$\gamma$-aminobutyric Acid (GABA)

An inhibitory neurotransmitter that acts as a brain stabilizer; glycine serves a similar function.

Glutamate

An excitatory neurotransmitter in the brain.

Neuro-developmental Stages

The process of neurulation where the notochord stimulates ectoderm to fold into a neural tube (becoming the CNS) topped with neural crest cells.

Primitive Reflexes

Reflexes in infants that should disappear with age, such as the Rooting, Moro, Babinski, and Grasping reflexes.

Absolute Threshold

The minimum stimulus energy required to activate a sensory system.

Difference Threshold

The minimum difference in magnitude between two stimuli before one can perceive the difference, also called the just noticeable difference ($JND$).

Weber’s Law

States that the $JND$ for a stimulus is proportional to the magnitude of the stimulus.

Signal Detection Theory

Concept that nonsensory factors like experiences, motives, and expectations affect the perception of stimuli.

Retina

The part of the eye containing rods (light/dark detection with rhodopsin) and cones (color detection).

Parallel Processing

The brain's ability to analyze color, form, and motion simultaneously.

Inner Ear Structure

Consists of the bony labyrinth (perilymph) and membranous labyrinth (endolymph), containing the cochlea, utricle, saccule, and semicircular canals.

Habituation

The process of becoming used to a stimulus; dishabituation is the resensitization to the original stimulus by an intervening second stimulus.

Operant Conditioning

A form of associative learning where behavior is changed through reinforcement (increasing likelihood) or punishment (decreasing likelihood).

Classical Conditioning

Associative learning where a neutral stimulus becomes a conditioned stimulus that produces a conditioned response via pairing with an unconditioned stimulus.

Shaping

In operant conditioning, the process of reinforcing behaviors that are closer and closer to the target behavior.

Explicit Memory

Also known as declarative memory; requires conscious recall and is divided into episodic (events) and semantic (facts) memory.

Implicit Memory

Also known as nondeclarative memory; accounts for acquired skills (procedural memory) and conditioned responses.

Korsakoff’s Syndrome

Memory loss caused by thiamine deficiency; symptoms include retrograde and anterograde amnesia and confabulation.

Deductive Reasoning

The process of forming conclusions from established rules.

Inductive Reasoning

The process of forming conclusions based on specific evidence.

Heuristics

Rules of thumb used in decision-making, such as the availability heuristic and the representativeness heuristic.

Piaget’s Stages of Development

Four stages of cognitive development: Sensorimotor ($0 \rightarrow 2$ yrs), Preoperational ($2 \rightarrow 7$ yrs), Concrete Operational ($7 \rightarrow 11$ yrs), and Formal Operational ($11+$ yrs).

Sleep Waves Mnemonic

$\text{BAT-D}$ for the sequential order of brain waves: Beta (alert), Alpha (awake/tired), Theta (Stage 1 and 2), and Delta (Stage 3 and 4).

REM Sleep

Rapid Eye Movement sleep where the mind appears awake on EEG but the person is asleep; characterized by eye movements and body paralysis.

Drive Reduction Theory

States that motivation arises from the desire to eliminate uncomfortable internal states of tension.

Maslow’s Hierarchy of Needs

A prioritization of needs ranging from physiological (lowest) up to self-actualization (highest).

Theories of Emotion

James-Lange (physical action leads to emotion), Cannon-Bard (simultaneous response), and Schacter-Singer (physiological arousal and cognitive label lead to emotion).

General Adaptation Syndrome

The concept that a body's physical stress response across three stages—alarm, resistance, and exhaustion—is the same regardless of the specific stressor.

Locus of Control

The perception of influence over one's life; can be internal (owning success/failure) or external (blaming outside factors).

Kohlberg’s Stages of Moral Development

Moral reasoning stages divided into three phases: pre-conventional (consequences), conventional (laws/rules), and post-conventional (ethics/human rights).

Schizophrenia Symptoms

Positive symptoms include added behaviors like delusions and hallucinations; negative symptoms involve the loss of affect or avolition.

Bipolar I Disorder

A mood disorder characterized by the presence of at least one manic episode.

Groupthink

The tendency for groups to reach decisions based on internal solutions without considering outside ideas, often to maintain harmony.

Ascribed Status

A social position involuntarily assigned to an individual based on characteristics like race, gender, or ethnicity.

Achieved Status

A social position voluntarily earned by an individual through efforts and merit.

Fundamental Attribution Error

The bias toward making dispositional (internal) attributions rather than situational (external) attributions regarding the actions of others.

Demographic Transition

A model representing drops in birth and death rates as a result of a country's industrialization.

Conflict Theory

Sociological theory based on Karl Marx's work that focuses on how power differentials maintain social order and resource competition.

Anomie

A state of lack of social norms or the breakdown of social bonds between individuals and society.

Social Mobility

The movement up or down the social ladder based on acquired credentials, experience, or achievement.

Absolute Poverty

A condition where an individual cannot acquire basic life necessities like food, water, and shelter.