MCAT Psych/ Soc

Jack Westin P/S Diagnostic

Electroreceptors 

Detect electric fields in the environment. Many animals use it to navigate, locate prey, or communicate in water.

Mechanoreceptors

Detect mechanical pressure and transmit a signal. Hair cells in the organ of Corti are considered mechanoreceptors as they transmit signal upon brushing against the tectorial membrane.

Chemoreceptors

Detect chemical stimuli in the environment especially responsible for smell and taste.

Interoceptors

Detect stimuli within the body.

Sensory Adaptation

occurs when an individual is subjected to a constant, unchanging stimulus for an extended period of time and eventually will develop decreased sensitivity to this stimulus, and may even fail to perceive it.

Sensory threshold

Minimum intensity of a stimulus required for it to be detectable 50% of the time.

Absolute threshold

minimum amount of stimuli required for it to be detected.

Just Noticeable Difference

smallest detectable change between two stimuli.

Weber’s law

Change in the stimulus required for it to be detectable is a ratio of the original stimulus.

sensory pathway for eyesight

cornea→ lens→ retina→ rods/cones→ Phototransduction cascade→ bipolar and ganglion cells→ optic nerve→ LGN in thalamus→ visual cortex in occipital lobe

Phototransduction cascade

light→ rhodopsin→ transducin→ PDE (phpsphodiesterase)→ low cGMP→ Na+ channels close

Rods

highly photosensitive and detect dim light

cones

weakly photosensitive and detect color

Nasal retina and temporal retina

color blindness

results from issues with cones in the retina

cataracts

occurs when lens becomes cloudy with age

difficulty seeing objects up close

when lens becomes less flexible with age

parallel processing

simultaneously process visual information such as shape, color and movement.

optic chiasma

crossing of the optic nerve

Outer ear

pinna (collect sound waves from air)→ auditory canal (channels sound waves inwards)→ Tympanic membrane (eardrum vibrates)

Middle ear

vibration in eardrum→ Malleus→ Incus→ Stapes→ pushes on the oval/ elliptical window
Middle ear components amplify and transmit mechanical vibrations to the inner ear.

Inner ear

Oval window (movement of stapes causes pressure waves in cochlear fluid)→ Cochlea (consists of fluid, basilar and tectorial membrane and organ of corti) → Cochlear fluid movement→ bend Cochlear hair cells → convert mechanical signals to electrical signals

Organ of Corti (more specific)

Cochlear fluid→ movement of hair cells → hair bundle is made of kinocilium→ kinocilium is connected by a tip link→ tip link is attached to gate of K channel→ movement of hair cells allow K+ to move in→ Ca+ cells get activated→ spiral ganglion cells activated→ auditory nerve is activated

Frequency of sounds we can hear

20-20k Hz

endolymph

fluid in the semicircular canal that allows us to detect which direction our head is moving.

otolithic organs

utricle and saccule (help in detecting linear acceleration and head positioning).

primary auditory pathway

sound waves→ mechanoreceptors→ auditory nerve→ thalamus→ auditory cortex

function of the round window

it bulges as fluid pushes against it after being compressed by the oval window

somatosensation

sensation felt throughout body such as pain and temperature (tactile stimuli)+ proprioception (sense of body in space)+ interoception (sense of internal state)

base tuning

base hair cells of cochlea= high frequency sound and apex hair cells= low frequenchy sound

olfaction pathway

odorant molecules→ binds to olfactory receptors in olfactory neurons → activation of GPCR→ AP generated→ passes through cribriform plate→ glomeruli→ olfactory cortex, amygdala, limbic system

gustatory pathway

food in saliva→ taste buds on tongue→ receptors (GPCRs for sweet, bitter and umami and Ion channels for sour and salty)→ AP generated→ brainstem→ thalamus→ gustatory cortex

kinesthetic sense

the body’s ability to perceive its own position and movement, allowing for coordination and control without relying on vision.

top-down processing

interpreting an event within the context of past knowledge/ experiences.

bottom-up processing

stimulus influences processing

Gestalt’s principle

arranging, categorizing, and organizing stimuli based on similarity, proximity, continuity, closure and pragnanz (create simple meaning from things like shapes from clouds etc).

monocular cues

relies on vision from a single eye eg. relattive size, interposition, motion parallax, shading

motion parallax

closer objects move faster and further objects move slower

binocular cues

relies on vision from both eyes, eg. retinal disparity and convergence

divided attention

doing two things at once and simultaneously.

selective attention

doing multiple things but switching between them.

types of cues

exogenous: naturally look for these cues (bright colors, loud noises etc)

endogenous: require internal knowledge to respond to these cues (cocktail party effect)

cocktail party effect

ability to concentrate on one voice amongst a crowd, like your name

inattentional blindness

not being aware of things in our visual field when our attention is directed elsewhere in the field.

change blindness

inability to notice change

executive attention

ability to focus attention on steps taken to achieve a goal

Piaget’s theory of cognitive development

sensorimotor→ pre operational→ concrete operational → formal operational

overestimate bias

overestimate your ability to produce correct answer

Belief perseverance bias

ignoring/ rationalizing disconfirming facts

confirmation bias

actively seeking out only confirming facts

selection/ sampling bias

selection of data/ groups that are not randomized or representative

actor-observer bias

attribute the behavior of others to internal problems but attribute our own behavior to external problems

self-serving bias

if we succeed it is due to internal qualities, if we fail it is due to external qualities

optimism bias

bad things happen to others but not us

primacy bias

first impression/ information is more important/ easier to remember

recency bias

most recent impression/ information is important/ easier to remember

similarity bias

befriend people who are similar to us

projection bias

assuming others share the same belief as us

hindsight bias

thinking you already knew something after being told it

normalcy bias

the situation will stay normal, nothing bad will happen

reconstructive bias

memory isn’t reliable, it has been reconstructed

attrition bias

when a participant drops out of a long term study or experiemnt

social desirability bias

related to how people respond to research questions. want to appear desirable to researcher.

subjective bias

self reported information is vulnerable to this. thinking subjectively not objectively

implicit bias

a bias that we are unaware of but unconsciously influences our decisions

cognitive bias

tendency to think certain ways. causes deviation from rational thinking and good judgement

egocentric bias

tendency to overstress changes between past and present in order to make oneself appear more worthy or competent than one actually is.

framing bias

occurs when people make a decision based on the way the information is presented, as opposed to just on the facts

automation bias

the tendency to excessively depend on automated systems

expectation bias

expectations influence attitudes or behaviors

causation bias

belief that one thing caused the other when they are actually unrelated or simply correlated

availability bias

base decisions on the most salient information- whatever comes to mind first when thinking about a topic

Gardner’s theory of intelligence

differentiates intelligence into different (8) modalities

Spearman’s idea of general intelligence

single g factor responsible for intelligence that underlies performance on all cognitive tasks

galton’s idea of hereditary genius

intelligence/ human ability is hereditary

Binet’s idea of mental age

how a child at a specific age performs intellectually compared to average intellectual performance for that physical age in yrs

consciousness

awareness of our self and environment

alertness

awake

daydreaming

feel more relaxed not as focused

drowsiness

just before falling asleep

sleep

not aware of the world around you. has 4 main types

beta waves

associated with awake/ concentration; increased stress, anxiety, restlessness; constant alertness

alpha waves

daydreaming, relaxation

theta waves

drowsiness, right after you fall asleep

delta waves

deep sleep or coma

order of sleep stage patterns

N1→ N2→ N3→ N2→ REM

N1

theta waves; seeing or hearing things; hypnic jerks

N2

deeper stage of sleep; more theta waves+ sleep spindles+ K-complexes

Sleep spindles

inhibit certain perceptions so we maintain a tranquil state of sleep (sleep through loud noises)

K complexes

suppress cortical arousal

N3

slow wave sleep, characterized by delta waves; walking/ talking in sleep happens

REM

rapid-eye movement;

most of the muscles are paralyzed;

most dreaming occurs;

memory consolidation;

combination of alpha, beta and desynchronous waves;

brain is active but body is not

circadian rhythms

regular body rhythms across 24-hr period. controlled by melatonin (produced in the pineal gland)

what are osmoreceptors and where are they located?

osmoreceptors are located in the hypothalamus and kidneys to regulate homeostasis and monitor osmotic pressure, water and electrolyte balance in the body

what are baroreceptors and where are they located?

baroreceptors detect blood pressure and are located in blood vessels.

what are interoceptors and where are they located?

located in the internal organs like stomach and intestines that detect internal changes in levels of hormones, gases, and nutrients in the bloodstream.

what are proprioceptors and where are they located?

proprioceptors detect position and movement of the body and maintain balance. they are located in muscles, tendons and joints.