Ap psych unit 3 sensations and perception

sensation

the process by which we receive information from the environment - our peripheral nervous system detects physical stimuli from the environment and converts it into neural signals

transduction

refers to the process by which sensory information is converted into neural signals that the brain can interpret this process is crucial for how we perceive and interact with the world

Just - noticeable difference

the smallest amount 2 stimuli had to differ for us to be able to tell them apart

sensory adaptation

diminished sensitivity as a consequence of constant stimulation

Webers law

the amount of change needed to produce a constant just noticeable difference is a constant proportion of the original stimulus intensity

sensory interaction

occurs when one sense affects the perception of another

synesthesia

a neurological condition in which stimulation of one sensory pathway leads to automatic involuntary experiences in another sensory pathway

Retina

the light sensitive inner surface of the eye containing receptor rods and cones plus layers of other neurons (bipolar and ganglion cells) that process visual information

blind spot

the disc where the ganglion cells meet at the back of the eye is a hole in the retina where the visual nerve exits the eye - there are no photoreceptors

optic nerve

a bundle of nerve fibers that transmit visual information from the retina in the eye to the brain specifically to the visual cortex

lens

focuses light on the eye

accommodation

the process by which the eye adjusts its focus to maintain a clear image of objects at different distances this is primarily achieved through the lens

Nearsightedness

a condition in which nearby objects are seen more clearly than distant objects cause the eye is elongated in shape, so the image focuses before it hits the retina

farsightedness

a condition in which nearby faraway objects are seen more clearly than near objects cause the eye is shortened the image focuses after it hits the retina

photoreceptors

light receptor cells that transduce light energy into electrochemical energy (nerve impulses)

rods

photoreceptors that lie in the periphery of the eye and detect shapes and movement but not color

cones (blue, green, red)

photoreceptors that only function in bright light

trichromatic theory

it hypothesis that the 3 cone types in the retina each producing only red, green, or blue work together to let us perceive a range of colors

opponent - process theory

proposed that we process 4 primary colors opposed in pairs of red-green, blue-yellow, and black white

afterimages

a visual sensation that remains after the stimuli’s is removed

ganglion cells

neurons located in the retina that receive visual information from photoreceptors an whose axons make up the optic nerve to transmit signals to the brain

dichromatism

a specific type of color blindness in which an individual has only 2 types of functioning cone photoreceptors in the retina instead of the usual 3

monochromatism

people who only lack functional color photoreceptors in the retina

prosopagnosia

a neurological condition that impairs an individual’s ability to recognize familiar faces including those of friends and family

blindsight

a unique phenomenon where individuals with damage to the primary visual cortex can respond to visual stimuli without conscious awareness of seeing

wavelength

the distance from the peak of one wave to the peak of the next

pitch

dimension of frequency determined by wavelength of sound measured in hertz

amplitude

how high each wave is

loudness

amount of energy in a wave determined by amplitude related to perceived loudness

pitch perception

how the brain interprets the frequency of sound waves to determine weather a sound is high or low

place theory

suggests that sound frequences stimulate the basilar membrane at specific places resulting in perceived pitch

volley theory

helps explain how we can hear high pitched sounds by using the combined responses of many cells our brain figures out the pitch of the sound

frequency theory

states that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone thus enabling us to sense its pitch

sound localization

how we determine where sounds are coming from using our eyes and brain

conduction deafness

inability to hear due to damage to mechanical elements of the ear (parts other than the cochlea)

sensorineural deafness

inability to hear due to damage to the cochlea receptor cells or the auditory nerve

olfactory system

the sensory system used for smelling which starts with receptor cells in the nasal cavity detecting chemical odorants an transmitting signals to the olfactory bulb

thalamus

the brains sensory relay station located on top of the brain stem which directs incoming signals to the appropriate areas of the cerebral cortex

pheromones

chemical signals that provide info to members of the same species

gustation

taste is a chemical sense cause a substance is what is detected (not just energy like in sight or hearing)

traditional taste sensations

sweet, sour, salty, bitter, umami, and oleogustus

taste receptors

specialized cells located within taste buds that detect chemical molecules dissolved in saliva and trigger taste sensation

supertasters

individuals with more papillae (therefor more tastebuds) on their tongues

medium tasters

make up approximately 50% of the population and they have 15 to 35 taste buds per section

nontasters

likely to have 15 or fewer taste buds per 6 millimeter section

sensory interaction

the principle that one sense may influence another such as how smell of food heavily influences its perceived taste

warm/cold receptors

specialized sensory receptors in the skin that respond to changes in temperature

gate control theory

melzak and wall proposed that our spinal cord contains neurological “gates” that either block pain or allow it to be sensed

phantom limb

amputees feel painful sensations that seem to be originating from the missing part

vestibular sense

monitors the head (and whole body) position in space

semicircular canals

helps with balance and spatial orientation by detecting rotational movement

kinesthesis

the sense of our individual body parts positions and movement

signal detection theory

a way to measure how we discern a faint stimulus (signal) that conveys information and separates it from random background stimulation (noise)

cornea

transparent outer covering of the eye

iris

muscle that controls (pupil) how much light enters the eye

pupil

hole that allows light to enter the eye

dark adaptation

the ability to adapt to quickly darkening conditions such as when we go from daylight into a dark movie theater

fovea

central point in the retina within which the eyes cones cluster together

optic chiasm

some of the fibers from each optic nerve cross into the opposite side of the brain at the optic chiasm

young - Helmholtz theory

based on behavioral experiments Helmholtz suggested that the retina contains 3 receptors (cones) sensitive to red, blue, and green colors

pinna

helps capture sound waves and funnel them into the ear canal

ear canal

carries sound waves from the pinna to the eardrum

eardrum

vibrates in response to sound waves

ossicles

transmits vibrations from the eardrum to the inner ear

perception

the mental process of organization sensory input into meaningful patterns

bottom-up processing

analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information (sensation first)

top-down processing

information processing guided by higher level mental processes as when we construct perceptions drawing on our experiences and expectations (experience first)

schemas

mental frameworks or structures that help us organize and interpret information about the world

perceptual set

a mental predisposition to perceive one thing and not another

context

external factors can impact how we perceive information

cultural context

context installed by culture also alters perception

gestalt principles

helps us organize information into meaningful wholes

closure

the idea that your brain will fill in the missing parts of a design or image to create a whole

figure ground

organization of the visual field into objects (figures) that stand out from their surroundings (ground)

proximity

it refers to how close elements are to one another and the strongest proximity relationships are those between overlapping subjects but just grouping objects into a single area can also have a strong proximity effect

similarity

similar elements are visually grouped regardless of their proximity to each other

Attention

focusing our conscious awareness on a particular stimuli’s

cocktail party effect

the ability to focus one’s attention on a particular stimuli’s when filtering out a range of other stimuli

inattention

the failure to notice or pay attention to incoming sensory stimuli because attention is directed elsewhere

change blindness

failing to notice changes in the environment

depth perception

relies on the converge of both eyes upon a single object - the relative differences between the shape and size of the images on each retina the relative size of objects in relation to each other and other cues such as texture and constancy

binocular cues

a depth cue that only depends on the use of the 2 eyes

monocular cues

a depth cue that is available to either eye

retinal disparity

images from the 2 eyes differ and the greater the difference between the 2 objects the closer the object

convergence

the merging of the retinal images by the brain and it is based on how far inward the eyes need to move when focusing on an object (eyes move inward toward the nose to see near objects an outward away from the nose to see further objects)

relative clarity

a monocular cue that helps people judge the distance of objects by their apparent sharpness and detail

relative size

a depth cue that causes us to perceive something as farther away because it looks smaller than an object in the foreground that we assume is similar in size

texture gradient

indistinct (fine) texture signals decrease with increased distance

linear perspective

parallel lines like railroad tracks appear to converge with distance and the more the lines converge the greater their perceived distance

interposition

objects that block other objects tend to be perceived as closer

perceptual constancies

perceiving objects as unchanging even as illumination and retinal image change

Apparent movement

the visual perception of movement when objects are not actually moving

Selective attention

focusing our conscious awareness on a particular stimulus

visual cliff experiment

depth perception is the visual ability to perceive the world in 3 dimensions coupled with the ability to gauge how far away an object is

expectations

through experiences we expect certain results

motivations

like research bias we see what we want to see

emotions

our feelings at the time can alter what we experience

Color constancy

the perception that the color of an object remains the same even if lighting conditions change

size constancy

the tendency for the brain to perceive objects as the same apparent size regardless of their distance from us

shape constancy

when our viewing angle changes or an object rotates and we still perceive the object as staying the same shape