MCAT psych sensation, learning, intelligence

Absolute threshold

minimum amount of stimulation needed to detect a stimulus and cause the neuron to fire 50% of the time

Gustav Fechner

founder of psychophysics (field that studies how physical stimuli impacts sensory response), found perceived strength of a stimulus is proportional to log of actual intensity

Signal detection theory

stimulus is either perceived or not

Weber’s law

the bigger a stimulus is, the bigger a difference must be to notice the difference (math= proportion)

Discrimination threshold

the point at which someone can distinguish the difference between 2 stimuli

Just noticeable difference/difference threshold

minimum amount of stimulus difference that can be detected as different stimuli

Priming

preconscious processing from rapid stimuli

Tip-of-the-tongue phenomenon

try to recall something that you know you know but cannot access through conscious awareness

Single cell recording

firing rate and pattern of a single receptor cell can give qualitative and quantitative info

Distal stimulus

visual stimulus IRL

Proximal stimulus

visual stimulus as it appears inverted on the retina

Rods

cells in retina that are sensitive in low light

Cones

cells in retina that are sensitive to bright light and colors

Hubel and Wiesal

determined that there is a critical period after birth in which visual problems must be corrected to allow for proper processing

Young-Helmholtz

cones in the eye see red, blue, and green waves and the brain combines to form all other colors

Opponent process theory

cells in the thalamus respond to opponent pairs of receptor sets like seeing either black or white, when one set is on the other is off

Place theory

sound waves generate activity at different places along the basilar membrane

Frequency theory

sense audio pitch bc rate of neural impulses is equal to frequency

Conductive deafness

deaf bc ear structures broke (hearing aids)

Sensorineural deafness

deaf bc nerves broke (cochlear implant)

Vestibular sense

sensation of balance based on semicircular canals of inner ear

Kinesthesis

joints and ligaments help brain sense location of limbs (proprioception)

Vision

processed in occipital lobe

Audio

processed in temporal lobe

Tactile

processed in somatosensory cortex

Olfaction

processed in olfactory bulb

gustation(taste)

processed in cerebral cortex

Selective attention

trying to focus on one thing while ignoring another- eg cocktail party phenomenon or paying attention to one conversation at busy party

Filter theory

stimuli must pass through some kind of filter to enter attention

Attentional resource theory

we have a certain amount of attention and the resource can only be divided a certain amount

Divided attention

trying to focus on multiple stimuli simultaneously is more difficult when using the same sense for both

Inattentional blindness

gorilla in basketball video

Bottom-up processing

sensation; recognition of an object by breaking it into parts

Top-down processing

perception; brain labels a particular stimulus or experience based on expectation

Texture gradient

things look smoother farther away

Motion parallax

difference in the apparent movement of objects at different distances when the observer is also moving (eg. close by things in a train move faster than further away)

Stereopsis

3D image of the world from binocular vision

Visual cliff experiment

proved that depth perception is innate by testing if infants would walk onto the glass part of a table (aka the cliff) and they wouldn’t

Gestalt approach

perceptual stimuli can be broken down into figure and ground relationships and can be switched

Proximity

tendency to see objects close to each other as forming groups

Similarity

tendency to prefer grouping like objects

Continuity

tendency to perceive fluid or continuous forms instead of jagged or irregular ones

Closure

tendency to see closed shapes

Law of Pragnanz

we tend to see objects in their most simple forms

Constancy

we know a stimulus has the same properties even when it appears not to

Phi phenomenon

blinking arrows give appearance of movement

Stroboscopic effect

pictures move fast enough to imply movement (think stop motion)

Autokinetic effect

still light appears to twinkle in the dark

Sensitization

learned increase in how strong a negative phenomenon is over time

Classical conditioning

neutral stimulus paired with a previously meaningful stimulus takes on its own meaning (Pavlov’s dogs)

Acquisition

when the neutral stimulus elicits the conditioned response

Spontaneous recovery

even if you ring the bell and give no treats, ringing the bell later will still cause drooling bc the brain remembers the relationship

Second-order conditioning

the old conditioned stimulus is paired with a new conditioned stimulus (light used to indicate bell ringing)

operant conditioning

organism learns to make a response in order to avoid a punishment or gain a reward, studied by BF Skinner and his rats

Primary reinforcement

innate pleasure that serves as a reward (food, sex, water)

Secondary reinforcement

thing that is a learned reward (paper money)

Positive reinforcement

rewarding a response to increase chance it happens again (treats)

negative reinforcement

removal of an adverse event to encourage behavior (pressing lever stops mild electric shock that is constant otherwise)

Positive punishment

adding an unpleasant stimulus to decrease/deter behavior (do 20 push-ups for speaking back)

Negative punishment

taking away a reward or freedom to decrease behavior after it has occurred (no TV for a week since you didn’t do hw)

Continuous reinforcement schedule

all correct responses get a reward, increases rate of learning but has rapid extinction of the behavior if not rewarded

Fixed-ratio

reward occurs after specific number of responses (pressing lever 10 times)

Variable-ratio

reward occurs after varying number of responses, used by slot-machines to make a behavior more resistant to extinction

Fixed-interval

reward occurs after fixed amount of time as long as it occurs

Variable-interval

reward occurs after varying amounts of time

Escape

behavior used to escape an aversive stimulus, can become reinforced if it works

Avoidance

behavior used to avoid the presentation of aversive stimulus (pretending to be sick)

Token economy

tokens used as secondary reinforcements that can be traded for a primary reinforcement, used a lot in controlled populations

Learned helplessness

consistent efforts lead to no rewards to the subject stops trying (dogs in shocked cage)

Bio coding of learning

neurons that fire together, wire together (creation of new connections or strengthening existing ones is learning)

Social learning

learning by observing the behavior of others and the consequences they face

Bobo Doll Experiment

Albert Bandura made kids watch a adult either beat up a blow up doll or do nothing and then tested how they respond to frustration, proved that modelling affects behavior

Cognitive learning

previously learned ideas and behaviors can be generalized to similar stimuli through cognitive processes (like the garcia effect where people avoid a food after 1 experience that causes sickness)

Latent learning

learning that is not outwardly expressed until the situation calls for it

Insight learning

solution to a problem seems to magically appear after struggling with it for a while

Sensory memory

lasts a few seconds and only a little bit enters short term memory

Iconic memory

short exposure to an image causes it to be retained for a little bit but accessing the memory is hard

Maintenance rehearsal

simple repetition to keep info in short term memory

Elaborative rehearsal

organizing and understanding info to transfer part of it to long-term memory

Dual-coding hypothesis

easier to remember words if associated with a visual

Self-reference effect

easier to remember things associated with the self

retroactive interference

old info gets pushed out of short term memory by new info

Serial positioning effect

easier to remember beginning and end of a list

semantic memory

facts, figures, general world info

procedural memory

skills and habits

explicit memory

can be recalled

implicit memory

learning and things beyond conscious awareness

Working memory

some psychologists believe in a type of memory between sensory and short term

Flashbulb memory

strong remembrance of some episodically in long term memory known for its emotional response (eg. 9/11)

Framing

suggestions and misleading questions can create false memories

Phonemes

smallest units in speech distinct in sound from each other

Morphemes

smallest units in speech with meaning different from each other

Prosody

rhythm, stress, intonation of speech

Overextension

not knowing enough words leads infant to represent many things with one word, called a holophrase

Telegraphic speech

at around 2 years, using bare minimum words (2-3) to express something

Noam Chomsky

believed that there is a critical period for kids to learn language to understand grammar and underlying meaning

Linguistic relativity

amount of words to represent something is based on its relative importance to a culture

Syllogisms

deductive conclusion from 2 premises

Availability heuristic

conclusion drawn from events that are remembered most easily

Representativeness heuristic

judgement of something based on how well it resembles a prototype (racism)