AP Psychology Unit 1: Biological Bases of Behavior

Biological Psychology

• the scientific study of the links between biological (genetic, neural, hormonal) and psychological processes

• some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists

Neurons

• a nerve cell; the basic building block of the nervous system

• neurons differ, but all are variations of the same theme

• each consists of a cell body and its branching fibers

Dendrites

• a neuron´s bushy, branching extensions that receive messages and conduct impulses toward the cell body

• short

• from there, cell’s lengthy axon fiber passes the message through its terminal branches to other neurons or to muscles or glands

• dendrites listen, Axons speak

Axon

• the neuron extension that passes messages through its branches to other neurons or to muscles or glands

• axons may be very long, projecting several feet through the body

• some axons are encased in a myelin sheath

• Dendrites listen, Axons speak

Soma

• body of a cell

• contains cell nucleus

Myelin Sheath

• a fatty tissue layer segmentally encasing the axons of some neurons

• enables vastly greater transmission speed as neural impulses hop from one sausage-like node to the next

• INSULATES AXONS

• laid down up to about age 25, neural efficiency, judgment, and self-control grow

Multiple Sclerosis

• if the myelin sheath degenerates, multiple sclerosis results

• the communication to muscles slows, with eventual loss of muscle control

Axon Terminals (Terminal Buttons)

• ends of an axon which transmits messages to other cells via use of neurotransmitters at synapses

Action Potential (depolarization)

• a brief electrical charge that travels down its axon; a neural impulse

• neurons transmit messages when stimulated by signals from our senses or when triggered by chemical signals from neighboring neurons

• in response, a neuron fires an impulse, called the action potential

Refractory Period

• a period of inactivity after a neuron has fired

• during a resting pause, called the refractory period, like a web page pausing to refresh, the neuron pumps hte positively charged sodium ions back outside

  • then, it can fire again

• electrochemical process repeats up to 100 or even 1000 times a second

Resting Potential

• neurons generate electricity from chemical events

• in the neuron’s chemistry-to-electricity process, ions (electrically charged atoms) are exchanged

• the fluid outside an axon’s membrane has mostly positively charged ions; a resting axon'‘s fluid interior has mostly negatively charged ions

• this positive-outside/negative-inside state is called the RESTING POTENTIAL

• the imbalance of electrical charge that exists between the interior of electrically excitable neurons and their surroundings

Threshold

• the level of stimulation required to trigger a neural impulse

• if excitatory signals exceed inhibitory signals by a minimum intensity, or threshold, the combined signals trigger an action potential

• ex) if excitatory people with hands up outvote the inhibitory people with their hands down, then the vote passes

• action potential then travels down the axon, which branches into junctions with hundreds or thousands of other neurons or with the body’s muscles and glands

Excitatory

• most signals are excitatory

• excitatory signals excite the neuron and cause it to fire off the message; somewhat like pushing a neuron’s accelerator

• each neuron is a miniature decision-making device performing complex calculations as it receives signals from hundreds, or even thousands, of other neurons

Inhibitory

• some signals are inhibitory

• chemical messengers that restrain or inhibit other neurons, making them less likely to fire messages of their own; pushing a brake

All or None Principle

• INCREASING THE LEVEL OF STIMULATION ABOVE THE THRESHOLD WILL NOT INCREASE THE NEURAL IMPULSE’S INTENSITY

• the neuron’s reaction is an all-or-nothing response —> a neuron’s reaction of either firing (with a full strength response) or not firing at all

• a strong stimulus can trigger MORE neurons to fire, and to fire more often

  • but it does not affect the action potential’s strength or speed

Synapse

• the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

• the tiny gap at this junction is called the synaptic gap or synaptic cleft

• axon terminal of one neuron is in fact separated from receiving neuron by a synaptic gap less than 1 millionth of an inch wide

Neurotransmitters

• when an action potential reaches the knob-like terminals at an axon’s end, it triggers the release of chemical messengers called neurotransmitters

• chemical messengers that cross the synaptic gaps between neurons

• when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse (key to lock)

• for an instant, the neurotransmitter unlocks tiny channels at the receiving site, and ions flow in, exciting or inhibiting the receiving neuron’s readiness to fire

• particular neurotransmitters may affect specific behaviors and emotions

Reuptake

• for an instant, the neurotransmitter unlocks tiny channels at the receiving site, and ions flow in, exciting or inhibiting the receiving neuron’s readiness to fire

• then, in a process called reuptake, the sending neuron reabsorbs the excess neurotransmitters

• an neurotransmitter’s reabsorption by the sending neuron

Nodes of Ranvier

• gaps in the myelin sheath of a neuron on the axon, between adjacent Schwann cells

• support the fast de- and repolarization process necessary for generation of action potentials

• ontain sodium and potassium ion channels, allowing the action potential to travel quickly down the axon by jumping from one node to the next

Acetylcholine (ACh)

• one of the best-understood neurotransmitters

• plays a role in learning and memory

• it is the messenger at every junction between neurons (which carry info from the brain and spinal cord to the body’s tissues) and skeletal muscles

• when ACh transmission is blocked (sometimes during anesthesia), the muscles can’t contract and we are paralyzed

• enables muscle action, learning, and memory

• Alzheimer’s disease —> ACH-producing neurons deteriorate

• think, focus, control muscles, calm

• low levels —> Alzheimer’s, Dementia

• high levels —> muscle twitching

Dopamine

• influences movement, learning, attention, and emotion

• oversupply linked to schizophrenia

• undersupply linked to tremors and decreased mobility in Parkinson’s

• “feel-good” neurotransmitter, key role in pleasure, reward, motivation

• what makes us addicted to social media

Serotonin

• affects mood, hunger, sleep, and arousal

• undersupply linked to depression

  • some antidepressant drugs raise serotonin levels

• helps heal wounds

Norepinephrine

• helps control alertness and arousal

• undersupply can depress mood

• hormone —> found in adrenal glands

• neurotransmitter —> made from dopamine

GABA

• a major inhibitory neurotransmitter

• helps with learning and memory

• lowers stress levels, calms you down, restrains neural stimulants and blocks signals in CNS

• undersupply linked to seizures, tremors, and insomnia

• oversupply linked to drowsiness and memory loss

Glutamate

• a major excitatory neurotransmitter

• involved in memory

• oversupply can overstimulate the brain, producing migraines or seizures (why some people avoid MSG in food)

• amino acid, excitates/stimulates nerves, helps with learning + memory

• can lead to epilepsy

Substance P

• neuropeptide that neurons use to send signals

• functions in CNS as a neurotransmitter

• transmits pain signals from body to brain

• REGULATES PAIN

• emotion regulation

Endorphins

• our body releases several types of neurotransmitter molecules similar to morphine in response to pain and vigorous exercises

• “morphin within” - natural, opiate-like neurotransmitters linked to pain control and to pleasure

• they help explain good feelings such as the “runner’s high”, painkilling effects of acupuncture, and indifference to pain to some severely injured people

• low levels lead to higher anxiety

Agonist

• a molecule that, by binding to a receptor site, stimulates a response

• agonist molecules may be similar enough to a neurotransmitter to bind to its receptor and mimic its effect

• some opiate drugs are agonists and produce a temporary “high” by amplifying normal sensations of arousal or pleasure

Antagonists

• a molecule, that by binding to a receptor site, inhibits or blocks a response

• blocks a specific neurotransmitter from activating a receptor

• also binds to receptors but blocks a neurotransmitter’s functioning

• these antagonists. are enough like the natural neurotransmitter to occupy its receptor site and block its effect, but are not similar enough to stimulate the receptor

• Botulin, a person that can form in improperly canned foods, causes paralysis by blocking ACh release

  • works as smoothing wrinkles by relaxing facial muscles (botox)

Reuptake Inhibitors

• drugs that stop a neurotransmitter from being absorbed into the axon terminal

• A reuptake inhibitor is a substance that increases the levels of neurotransmitter in the brain by preventing their absorption by nerve cells

• A type of drug that is used to treat depression and some other conditions. Selective serotonin reuptake inhibitors stop or delay the body from reabsorbing a substance called serotonin, which leaves more of it available for the body to use

Myasthenia Gravis

• chronic autoimmune disorder where antibodies attack the normal receptors on muscle

• This blocks a chemical needed in order to stimulate muscle contraction

  • Resulting in weakness of musclescauses muscles under your voluntary control to feel weak and get tired quickly

• A disease in which antibodies made by a person's immune system prevent certain nerve-muscle interactions

• mainly eyes

Nervous System

• the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

The Neural Chain

• a metaphorical highway from our brains to the rest of the body

• uses electrical and chemical charges to send and receive information

• Sensory receptors, afferent neurons, interneurons, efferent neurons, effectors

Sensory Neurons (afferent neurons)

• neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord for processing

• the nerve cells that are activated by sensory input from the environment

• ex) hand over a hot stove, it would say “I feel heat”

Interneurons

• neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

• between the sensory input and motor output, information is processed in the brain’s internal communication system via its interneurons

• the central nodes of neural circuits, enabling communication between sensory or motor neurons and the central nervous system (CNS)

• our complexity resides mostly in our interneuron systems

Motor Neurons (efferent neurons)

• neurons that carry outgoing information/instructions from the brain (CNS) and spinal cord to the muscles and glands

• cells in the brain and spinal cord that allow us to move, speak, swallow and breathe by sending commands from the brain to the muscles that carry out these functions

• ex) if hand over hot stove, motor neurons tells brain to move hand away

Spinal Reflex

• rapid, involuntary, and predictable responses to specific stimuli that are mediated by the spinal cord without requiring input from the brain

• a simple, automatic response to a sensory stimulus, such as the knee-jerk response

  • knee-jerk response could be done by a headless body

• it is composed of a single sensory neuron and a single motor neuron

Central Nervous System

• the brain and spinal cord; the body’s decision maker

• It is responsible for processing and coordinating sensory information from the body and controlling most bodily functions, including movement, thought, and emotions

Peripheral Nervous System

• the sensory and motor neurons that connect the central nervous system to the rest of the body

• responsible for gathering information and for transmitting CNS decisions to other body parts

• consists of all the nerves outside the central nervous system

• 2 components

  • somatic nervous system

  • automatic nervous system

Somatic Nervous System

• the division of the peripheral nervous system that controls the body’s skeletal muscles

• VOLUNTARY MOVEMENTS

• Controls conscious functions; responsible for all conscious influence of body parts where an individual consciously controls muscles and body part- moving legs, arms, head

• also called the skeletal nervous system

• ex) bell rings, somatic NS reports to brain current state of muscles, triggers the body to rise

Autonomic Nervous System

• part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart)

• Comprised of heart rate, blood pressure, digestion, and sexual desire

• 2 components - in everyday situations, the sympathetic and parasympathetic NS work together to keep us at a steady, internal state

  • sympathetic division

  • parasympathetic divisio

• SYSTEM MAY BE CONSCIOUSLY OVERRIDDEN, BUT USUALLY OPERATES ON ITS OWN

Sympathetic Nervous System

• the division of the ANS that arouses the body, mobilizing its energy in stressful situations

• if something alarms/challenges you, your sympathetic nervous system will accelerate heartbeat, raise blood pressure, slow digestion, raise blood sugar, making you alert and ready for action

Parasympathetic Nervous System

• the division of the ANS that calms the body, conserving its energy

• when stress subsides, PNS will decrease heart rate, lower blood sugar, etc

• FIGHT OR FLIGHT

Endocrine System

• the body’s “slow” chemical communication system

• a set of glands that secrete hormones into the bloodstream

  • secretes hormones which travel through the bloodstream and affect other tissues, including the brain

• includes: ovaries, testes, the pituitary gland, and the thyroid gland

• They impact the systems that cause changes in our behavior, like biological motivations

• endocrine system and nervous system are close relatives —> both produce molecules that act. noreceptors elsewhere

  • also differ —> speedy nervous system zips messages from eye to brain to hand in a fraction of a second

    • endocrine messa

Hormones

• chemical messengers that are manufactured by the endocrine glands that travel through the bloodstream and affect other tissues

• They control or regulate the activity of certain cells or organs

  • metabolism, growth, development, mood, sexual function, and reproduction

• when hormones act on the brain, they influence our interest in sex, food, and aggression

• some hormones are chemically identical to neurotransmitters

Pituitary Gland

• the endocrine system’s most influential gland

• under the influence of the hypothalamus, the pituitary gland regulates growth and controls other endocrine glands

  • pea-sized structure

• Releases certain hormones

  • Growth hormones: stimulates physical development

  • Oxytocin: enables contractions associated with birthing, milk flow, and orgasms

    • also promotes pair bonding, group cohesion, and social trust

    • “love hormone” or “cuddle hormone”, causes range of emotions

• pituitary secretions influence the release of hormones by other endocrine glands

• “master gland”

• It regulates metabolism, growth, and reproduction through the hormones it produces

Adrenaline

• increases heart rate, blood pressure, and blood sugar, providing us with a surge of energy known as the fight-or-flight reaction

• hormone secreted by the adrenal glands, especially in conditions of stress, increasing rates of blood circulation, breathing, and carbohydrate metabolism and preparing muscles for exertion

Leptin

• hormone that signals to brain that we are full

• junk food causes body to ignore leptin signals because of release of “feel good” hormones like dopamine and serotonin in insane amounts - contributes to obesity

• L —> lessens appetite

Ghrelin

• “hunger hormone” —> tells brain we’re hungry

• produced by stomach

• role is to promote appetite and increase food intake

• G —> Greatens appetite

Melatonin

• role in sleep

• production and release of melatonin in the brain is connected to the time of day, increasing during dark and decreasing during light

• available as a supplement

Oxytocin

• “love hormone” or “cuddle chemical” hormone that causes a range of emotions including

  • trust and building relationships

• Oxytocin: enables contractions associated with birthing, milk flow, and orgasms

  • also promotes pair bonding, group cohesion, and social trust

Lesion

Lesion

• tissue destruction

• a brain lesion is a naturally or experimentally caused destruction of brain tissue

EEG

• an amplified recording of the waves of electrical activity sweeping across the brain’s surface

• these waves are measured by electrodes placed on the scalp —> shower-cap-like hat filled with electrodes covered with a conductive gel

• with no direct access to brain, researchers present a stimulus repeatedly and have a computer filter our brain activity unrelated to the stimulus

  • what remains is the electrical wave evoked by the stimulus

fMRI (functional MRI)

• a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans

• fMRI scans show brain function as well as it’s stimulus

Brainstem

• the oldest part and central core (innermost region) of the brain, beginning where the spinal cord swells as it enters the skull

• the brainstem is responsible for automatic survival functions

• we need higher brain or conscious mind to orchestrate our heart’s pumping and lung’s breathing

  • brainstem handles these tasks

Medulla

• HEARTBEAT, BREATHING

• the base of the brainstem

• controls heartbeat and breathing, slight swelling of spinal cord

• like autopilot

Reticular Formation

• AROUSAL

• a nerve network that travels through the brainstem and thalamus and plays an important role in controlling arousal

• extends from spinal cord right through thalamus

• as the spinal cord’s sensory input flows up to the thalamus, some of it travels through the reticular formation, which filters incoming stimuli and relays important information to other brain areas

• damage to reticular formation can result in coma, sleep disorders, attention deficit disorders

Thalamus

• SENSES (except smell)

• the brain’s sensory control center, located on top of the brainstem

• it directs messages to the sensory cortex and transmits replies to the cerebellum and medulla

• receives information from all the senses (EXCEPT SMELL) and routes it to the higher brain regions that deal with seeing, hearing, tasting, and touching

• also receives some of higher brain’s replies, which it then directs to medulla and cerebellum

Cerebellum

• COORDINATION, BALANCE

• The “little brain” at the rear of the brainstem

• functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory

• also helps us judge time, modulate our emotions, and discriminate sounds and textures

• coordinates voluntary movement (with assistance from pons)

• if injured cerebellum, you would have difficulty walking, keeping balance, or shaking hands —> movements would be jerky and exaggerated

• UNDER ALCOHOL INFLUENCE ON CEREBELLUM, COORDINATION SUFFERS

Limbic System

• neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres

• associated with emotions and drives, memory, and behavior

Hypothalamus

• HUNGER

• a neural structure lying below (hypo) the thalamus, it directs several maintenance activities (eating, drinking, body temp), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward

• as hypothalamus monitors the state of your body, itunes into your blood chemistry and any incoming orders from other brain parts

Hippocampus

• MEMORY

• process conscious memories

• animals who lose hippocampus also lose ability to form new memories of facts and events

Amygdala

• EMOTIONS

• two lima-bean-sized neural clusters in the limbic system

• linked to emotions (aggressions and fear)

• 1939, psychologist Heinrich Kluver + Paul Bucy removed a rhesus monkey’s amygdala, turning normally ill-tempered monkey into most mellow creature

• Experiments have confirmed the amygdala’s role in rage and fear, including the perceptions of emotions and processing of emotional memories

• psychos have much smaller amygdala’s

  • lack of emotions —> don’t really care about other’s fears or distress

Glial Cells

• cells in the nervous system that support, nourish, and protect neurons

• “glue cells”

• maintenance of homeostasis, forms myelin sheath

• does not conduct nerves, protects and nourishes it

• they may also play a role in learning and thinking

• supporting billions of nerve cells, 9x as many glial cells

• neurons are like queen bees who cannot feed/sheathe themselves; glial cells are worker bees

• provide nutrients and insulating myelin, guide neural connections, and mop up ions and neurotransmitters

• may also play role in learning and memory

• by “chatting” with neurons, they may participate in information transmission and memory

Cerebral Cortex

• the intricate fabric of interconnected neural cells covering the cerebral hemispheres

• the body’s ultimate control and information-processing center

• largest part, grey matter, contains 4 lobes

• damage can lead to cognition, learning, memory issues, etc

• as we move up ladder of animal life, the cerebral cortex expands, tight genetic controls relax, an organism’s adaptability increases

  • frogs and small cortex amphibians operate extensively on preprogrammed genetic instructions

• the large cortex of mammals offer increased capacity for learning and thinking —> more adaptable

• WHAT MAKES US HUMAN ARISES FROM COMPLEX FUNCTIONS OF OUR CEREBRAL CORTEX

Frontal Lobes

• portion of the cerebral cortex lying just behind the forehead

• high cognitive functions, judgement, decision making, impulse control

• involved in speaking and muscle movements and in making plans and judgements

• frontal lobe damage can also alter personality and remove a person’s inhibitions

  • railroad worker Phineas Gage in 1848 (25 years old) was packing gunpowder into a rock with a tamping iron —> a spark ignited the gunpowder, shooting rod up through left cheek and out the top of the skull, leaving his frontal lobes massively damaged

  • he was, immediately able to sit up and speak, and returned to work after he healed

  • but the affable, soft-spoken man was now irritable, profane, and dishonest

  • hids friends said he was no longer Gage

  • although his mental abilities and memories were intact, his personality was not

Motor Cortex

• an area at the rear of the frontal lobes that controls voluntary movements

• sends messages out to the body

• 1870, German physicians Gustav Fritsch and Edward Hitzig discovered mild electrical stimulation to parts of an animal’s cortex made parts of its body move

  • effects were selective —> stimulation caused movement only when applied to an arch-shaped region at the back of frontal lobe, running roughly ear-to-ear across the top of the brain

  • stimulating parts of this region in the left or right hemispheres caused movement of specific body parts on the opposite side of the body —> they discovered the motor cortex

Parietal Lobes

• portion of the cerebral cortex lying at the top of the head and toward the rear

• receives sensory input for touch and body position

• processes sensory information, especially touch, pain and pressure

• helps with spacial awareness

Association Areas

• areas of the cerebral cortex that are not involved in primary motor or sensory functions

• rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking

• HIGH-ORDER FUNCTIONING —> DECISION MAKING, PLANNING, DIFFERENTIATES US FROM ANIMALS

• in these association areas, neurons are busy with higher mental functions - many of the tasks that make us human

• electrically probing an association area won’t trigger any observable responses

• unlike sensory and motor areas, association area functions cannot be neatly mapped

• their silence has been called “one of the hardest weeds in the garden of psychology”

• these areas interpret, integrate, and act on sensory information and link it with stores memories - a very important part of thinking

• ASSOCIATION AREAS ARE FOUND IN ALL 4 LOBES

Somatosensory Cortex

• area at the front of the parietal lobes that registers and processes body touch and movement sensations

• parallel to and just behind the motor cortex

• the more sensitive the body region, the larger the somatosensory cortex area devoted to it

Occipital Lobes

• portion of the cerebral cortex lying at the back of the head

• includes areas the receive information from the visual fields

• smallest lobe for vision

Temporal Lobes

• portion of the cerebral cortex lying roughly above the ears

• includes the auditory areas, each receiving information primarily from the opposite ear

• 2nd largest lobe

• contains auditory cortex

Phineas Gage - case study

• frontal lobe damage can also alter personality and remove a person’s inhibitions

  • railroad worker Phineas Gage in 1848 (25 years old) was packing gunpowder into a rock with a tamping iron —> a spark ignited the gunpowder, shooting rod up through left cheek and out the top of the skull, leaving his frontal lobes massively damaged

  • he was, immediately able to sit up and speak, and returned to work after he healed

  • but the affable, soft-spoken man was now irritable, profane, and dishonest

  • hids friends said he was no longer Gage

  • although his mental abilities and memories were intact, his personality was not

• highlights brain injury affects personality

• gage wanted to stay outside with animals, not inside

• temper tantrums

• PHYSICAL CHANGE IN BRAIN AFFECTS BEHAVIOR

Plasticity

• the brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience

• under surface of our awareness, the brain is constantly changing, building new pathways as it adjusts to little mishaps and new experiences

• may also occur after serious damage, especially in young children

• ex) plasticity helps explain why some studies find that deaf people have enhanced peripheral vision

  • in those people whose native language is sign, the temporal lobe area normally dedicated to hearing waits in vain for stimulation

  • finally, it looks for other signals to process, such as those from the visual system

• ex) if slow-growing left hemisphere tumor disrupts language, the right hemisphere may compensate

The Split Brain

• a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them

• split brain patients are surprisingly normal —> their personality and intellect are hardly affected

• information sharing between the two hemispheres in split brain patients does not occur

• In an experiment, Gazzaniga asked split brain patients to stare at a dot as he flashed HE•ART

  • HE appeared in the left visual field, which transmits to the right hemisphere

  • ART appeared in the right hemisphere, which transmits to the left hemisphere

  • When he asked them to SAY what they had seen, the patient reported they had seen ART

  • But when he asked to POINT to the word they had seen, they were startled when their left hand (controlled by the right) painted to HE

  • This happens because the left hemisphere is involved with language

    • When image flashed to the left, the right hemisphere can’t verbalize what it saw because it is not involved in language

    • Flashed to the right, left hemisphere can verbalize what they saw

Corpus Callosum

• axon fibers connecting the two cerebral hemispheres

• the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

• CONNECTS TWO HEMISPHERES

• when cut, it stops seizures and produces split-brain patients

Left Hemisphere

• associated with logic, math, language, reading, writing, and analysis

• very STRUCTURED

• takes in and controls the right side of the body

Right Hemisphere

• associated with personality, creativity, intervention, music, art, and spatial abilities (ex. architect)

• LAID BACK AND CREATIVE

• takes in and controls the left side of the body

Broca’s Area

• a region in the frontal lobe of the dominant hemisphere, usually the left, of the brain with functions linked to speech production

• SPEAKING

• damage to Broca’s area disrupts speaking

Wernicke’s Area

• an area of the brain that is located in the posterior left temporal lobe and is associated with comprehension of language

• UNDERSTANDING LANGUAGE

• damage to Wernicke’s area disrupts understanding of language

Aphasia

• a disorder that affects how you communicate

• It can impact your speech, as well as the way you write and understand both spoken and written language

• occurs after a stroke or head injury

Sensation

• the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

• PICKS UP ON SOMETHING, 1 OF 5 SENSES

• ex) if there is perfume in the room, you sensation would detect the perfume and smell it

  • I smell perfume

Perception

• the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

• INTERPRETS IT

• ex) when there is perfume in a room, perception allows us to recognize that the smell is perfume, what it reminds us of

  • it smells like medicine

Transduction

• conversion of one form of energy into another

• in sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brain can interpret

Absolute Threshold

• the minimum stimulation needed to detect a particular stimulus (light, sound, pressure, taste, or odor) 50% of the time

• when you FIRST pick up on stimuli

• ex) hearing test

  • “raise your hand when you first hear a tone”

Signal Detection Theory

• a theory predicting how and when we detect the presence of a fain stimulus (signal) and background stimulation (noise)

• assume that there is on single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and alertness

• predicts when we will detect weak signals (measured as our ration of “hits” to “false alarms”/”miss”)

• signal detection theorists seek to understand why people respond differently to the same stimuli and why the same person’s reactions vary as circumstances change

  • exhausted parents will notice the faintest whimper from a newborn’s cradle while failing to notice louder, unimportant sounds

• ex) scenario —> teacher suspects student has phone on them

  • student has phone (present), teacher responds yes (yes) —> hit

  • student has phone (present), teacher doesn’t notice (no) —> miss

  • phone is not there (absent), but teacher thinks it is (no) —> false alarm

  • phone is not there (absent, no accusation (no) —> correct rejection

Difference Threshold (just noticeable difference, JND)

• the minimum difference between two stimuli required for detection 50% of the time

• WHEN WE FIRST NOTICE A DIFFERENCE

• ex) hearing test

  • “tell me when the tone gets higher or lower”

• we experience the difference threshold as a just noticeable difference (or jnd)

• the difference threshold increases with the size of the stimulus

  • thus, if you add 1 ounce to a 10 ounce weight, you will detect the diffference

  • if you add 1 ounce to a 100 ounce weight, you will not

Weber’s Law

• the principle that, to be perceived as different, two stimuli must differ by a constant minimum PERCENTAGE (rather than a constant amount)

• the exact proportion varies, depending on the stimulus

  • two lights must differ in intensity by 8%

  • two objects must differ in weight by 2%

  • two tones must differ in frequency by only 0.3%

Sensory Adaptation

• diminished sensitivity as a consequence of constant stimulation

• when we are constantly exposed to a stimulus that does not chance, we become less aware of it because our nerve cells fire less frequently

Bottom-Up Processing

• analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information

• taking in everything thats NEW

• ex) freshmen in high school, taking in new environment

Top-Down Processing

• information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

• using PAST EXPERIENCES in lives

• ex) senior in high school using experiences

Perceptual Set

• a predisposition to perceive things in a certain way

• a mental predisposition or readiness to perceive stimuli in a particular way based on previous experiences, expectations, beliefs, and context

Selective Attention

• the focusing of conscious awareness on a particular stimulus

• the act of focusing on a particular object for some time while simultaneously ignoring distractions and irrelevant information

Cocktail Party Effect

• your ability to attend to only one voice among many (while also being able to detect your own name in an unattended voice)

• ex) in party, someone says your name and you tune in

Inattentional Blindness

• failing to see visible objects when our attention is directed elsewhere

• it is a byproduct of what we are really good at: focusing attention on some part of our environment

• failure to notice a fully-visible, but unexpected object because attention was engaged on another task, event, or object

Change Blindness

• a form of inattentional blindness

• failing to notice changes in the environment

• out of sight, out of mind

• significant changes in a visual scene are not noticed due to the lack of visual attention

Cornea

• protects the eye and bends light to provide focus

• transparent part of the eye that covers the iris and the pupil

Pupil

• the adjustable opening in the center of the eye through which light enters

• blakc, small adjustable opening

• light enters through here after cornea

Iris

• a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

• colored muscle that dilates or constricts in response to light intensity and even inner emotions

  • when we feel sexual desire, our dilated pupils and dark eyes subtly signal our interest

  • each iris is so distinctive, an iris-scanning machine can confirm your identity

• in high light, iris constricts pupil

• in low light, iris dilates pupil