MCAT Phsyc/Soc: Sensation and Perception

sensation

the encoding of physical stimuli from the environment without interpretation

perception

the decoding of sensation through selection, organization, and interpretation

types of stimuli you can detect

light, sound, touch, taste, and smell

Sensing Visual Stimuli

Light from objects hits the retina on the right or left side of the retina. This signal travels through the optic nerve to the optic chiasm, where left/right signals split to the right/left primary visual cortex, respectively.

optic chiasm

the point in the brain where the visual field information from each eye "crosses over" to the appropriate side of the brain for processing

auditory cortex

strip of cortex in the temporal lobe that is responsible for processing auditory information

auditory association area

stores memories of sounds and permits perception of sound stimulus

broca's area

Controls language expression - an area of the frontal lobe, usually in the left hemisphere, that directs the muscle movements involved in speech.

prefrontal cortex

part of frontal lobe responsible for thinking, planning, and language

somatic motor association area

responsible for coordinating learned movements

primary motor cortex

the section of the frontal lobe responsible for voluntary movement

primary sensory cortex

regions of the cerebral cortex that initially process information from the senses

somatic sensory association area

monitors activity in the primary sensory cortex; involved with special senses: hearing, smelling, sight...

visual association area

interprets information acquired through the primary visual cortex

visual cortex

The visual processing areas of cortex in the occipital and temporal lobes.

wernicke's area

controls language reception - a brain area involved in language comprehension and expression; usually in the left temporal lobe

agnosia

Inability to process sensory information, most likely caused by damage to the occipitotemporal border

visual agnosia

the inability to recognize a visual stimulus despite the ability to see and describe it

speech agnosia

Inability to comprehend spoken words despite intact hearing, speech production, and reading ability

frontal lobe

region of the brain associated with concentration, planning, problem-solving, voluntary movement, personality, speech, and smell

temporal lobe

A region of the cerebral cortex responsible for hearing and language.

parietal lobe

A region of the cerebral cortex whose functions include processing information about touch and taste

occipital lobe

A region of the cerebral cortex that processes visual information

cerebellum

A large structure of the hindbrain that controls fine motor skills like balance and corrdination

kinesthesis

The system for sensing the position and movement of individual body parts

Receptors involved in kinesthesis

mechanoreceptors (mechanical disturbances), proprioceptors (physical body disturbances), thermoreceptors (heat), nociceptors (pain)

brain lateralization

specialization of function in each hemisphere of the brain

functions of the left hemisphere

analytical thought, rational thought, verbal, math/science, logic, right side, visual/motor skills

functions of the right hemisphere

intuitive thought, emotional thought, creative writing, art, left vision, and motor skills

corpus callosum

a broad band of nerve fibers joining the two hemispheres of the brain.

absolute threshold

The minimum amount of a single stimulus that can be detected 50% of the time

difference threshold

The minimum difference that must occur between two stimuli for them to be perceived as different

Weber's law

The size of the just noticeable difference is a constant proportion of the original stimulus value. Different sensory stimuli have different threshold differences

signal detection theory

a method for quantifying a person's ability to detect a given stimulus (signal) amidst other, non-important stimuli (noise)

The accuracy of signal detection depends on

external noise (environmental obstructions) and internal noise (inner/mental obstructions

receiver operating characteristic curve

tracks hit rate (correct identification of signal) vs false alarm rate to represent a person's accuracy at a given task graphically.

modality

the type of stimulus that is being detected, communicated based on the type of receptor firing

Four stimulus properties

modality, location, intensity, and duration of the signal

tonic receptors

generate action potentials as long as the stimulus is present

phasic receptors

Fire only when the stimulus begins, and communicate changes in stimuli

feature detection theory

A theory of visual perception that proposes that certain neurons fire for individual and specific features of a visual stimulus, such as shape, color, line, movements, etc.

parallel processing

Many aspects of a visual stimulus are processed simultaneously rather than in a step-wise fashion

Three stages of perception

environmental stimulus (attended stimulus on receptors), electrochemical processes (transduction, transmission and processing), and experience/action (perception and recognition)

bottom up processing

starts with information from our sensory receptors and builds up to a final product in our brain. Assumes that we start with the details and end with a final representation in our mind

top down processing

starts with a larger concept or idea and works down to the details. Assumes we start with an idea about the final representation and work down to the sensory details

perceptual organization

In order to transform sensory information into useful perceptions, we must organize it

gestalt psychology

studies the predictable ways in which we organize sensory information into meaningful patterns that we perceive

Gestalt principle of emergence

When attempting to identify an object, we first identify its outline which then allows us to figure out what the object is

Gestalt principle of multistability

tendency of ambiguous images to pop back and forth unstably between alternative interpretations in our brains

law of proximity

Elements close to one another tend to be perceived as a unit

law of continuity

we perceive smooth, continuous lines and forms rather than disjointed ones

law of closure

when a space is enclosed by a group of lines, it is perceived as a complete or closed line

law of common fate

Things moving in the same direction appear to be grouped together

law of connectedness

predicts that things that are joined or linked or grouped are perceived as connected

law of simplicity

we perceive the simplest pattern possible

depth perception

ability to see objects in three dimensions despite the fact that images are imposed on the retina in only two dimensions.

retinal disparity

A binocular cue for perceiving depth by comparing images from the retinas in the two eyes, the brain computes distance—the greater the disparity (difference) between the two images, the closer the object.

convergence

A binocular cue for perceiving depth; the extent to which the eyes converge inward when looking at an object

monocular cues

depth cues that depend on information that is available to either eye alone

relative size

a monocular cue for perceiving depth; the smaller retinal image is farther away

interposition

monocular visual cue in which two objects are in the same line of vision and one partially conceals the other, indicating that the first object concealed is further away

relative clarity

a monocular cue for perceiving depth; hazy objects are farther away than sharp, clear objects

texture gradient

a monocular cue for perceiving depth; a gradual change from a coarse, distinct texture to a fine, indistinct texture signals increasing distance. Objects far away appear smaller and more densely packed

relative height

a monocular cue for perceiving depth; objects higher in our field of vision are perceived as farther away

linear perspective

A monocular cue for perceiving depth; the more parallel lines converge, the greater their perceived distance.

light and shadow

a monocular cue for perceiving depth; a dimmer object seems farther away

relative motion

As we move, stable objects appear to move as well. Objects that are near us appear to move faster than objects that are farther away

perceptual constancy

perceiving objects as unchanging even as illumination and retinal images change

shape constancy

the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina

size constancy

the tendency to interpret an object as always being the same actual size, regardless of its distance

lightness constancy

we perceive an object as having a constant lightness even while its illumination varies

Broadbent Filter Model of Selective Attention

Input enters the sensory store, the selective filter removes unattended input and allows it to decay, then the input goes to higher-level processing and working memory

Treisman attenuation model of selective attention

Input enters the sensory store and enters the attenuating filter. If an unattended message is then attended to, the signal moves through higher-level processing and working memory.

cocktail party effect

When you filter out other conversations until your name is mentioned, at which point your attention shifts to this other channel

successful multitasking depends upon

task similarity (if the tasks are similar, it is easier to multitask)

task difficulty (if the tasks are easier it is easier to multitask)

task practice (practiced tasks are easier to multitask)

cognitive schema

a mental framework that allows us to organize our experiences/stimuli and respond to new expereiences/stimuli

assimilation of new experiences

New information is interpreted based on our current schemas

accomodation of new experiences

as we interact with the world we accomadate our schemes to incorporate new information and expereinces

sensorimotor stage

In Piaget's theory, the stage (from birth to about 2 years of age) during which infants know the world mostly in terms of their sensory impressions and motor activities

Milestones of the sensorimotor stage

object permanence, stranger anxiety

preoperational stage

In Piaget's theory, the stage (from about 2 to 6 or 7 years of age) during which a child learns to use language but uses intuitive not logical reasoning

milestones of the preoperational stage

symbolic thinking, egocentrisim

concrete operational stage

in Piaget's theory, the stage of cognitive development (from about 6 or 7 to 11 years of age) during which children gain the mental operations that enable them to think logically about concrete events

milestones of concrete operational stage

conservation

formal operational stage

in Piaget's theory, the stage of cognitive development (normally beginning about age 12) during which people begin to think logically about abstract problems

milestones of the formal operational stage

abstract logic and moral reasoning

insight

occurs when we puzzle over a problem, and then the complete solution appears to come to us all at once

heuristic

a rule-of-thumb problem-solving strategy

confirmation bias

occurs when we seek evidence to support our conclusions or ideas more than we seek evidence that will refute them

fixation

occurs when we have structured a problem in our mind a certian way, even if that way is ineffective, and are unable to restructure it we are then unable to see the problem from a fresh perspective

mental set

our tendency to approach stiuations in a certain way becuase that method worked for us in the past

functional fixedness

mental bias that limits our view of how an object can be used, based on how that object is traditional used

availability heuristic

estimating the likelihood of events based on their availability in memory; if instances come readily to mind (perhaps because of their vividness), we presume such events are common

representativeness heuristic

Judging the likelihood of things in terms of how well they seem to represent, or match, particular prototypes (most relevant/typical example), may lead us to ignore other relevant information

social intelligence

ability to manage and understand people

emotional intelligence

the ability to monitor and discriminate emotions in order to guide thinking and action

fluid intelligence

reason abstractly, increased processing speed

crystallized intelligence

accumulated knowledge and verbal skills

fixed mindset

belief that intelligence and abilities are static

growth mindset

the belief that intelligence and abilities can be developed through effort