AP Psychology: Unit 3 Sensation and Perception

transduction

converting one form of energy into another

ex. our brain converts vibrations into sound

sensation

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

perception

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

bottom-up processing

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sensation is experienced first and works its way up to the brain (sense first, then perceive)

ex. the rose example

top-down processing

constructs perceptions from sensory input by drawing on your experiences an expectation (perceive first, then sense)

ex. The Forest Has Eyes

psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience

thresholds

levels that we are able to recognize sensory information

Gustav Fechner

studied our thresholds

absolute threshold

the level of stimulation necessary to recognize a particular stimulus 50% of the time

subliminal threshold

below your absolute threshold of perceptions

ex. subliminal messages

priming

unconscious associations that predispose one's perception, memory, or response

difference threshold

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

Weber's Law

sensory differences have a minimum percent not constant amount

ex. to note the difference of the weight of two objects they have to differ by 2%

sensory adaptation

diminished sensitivity as a consequence of a constant stimulation

ex. walking into your house after a vacation it has a distinct smell

gestalt

an organized whole. Emphasized our tendency to integrate pieces of information into meaningful wholes

schema

a concept or framework that organizes and interprets information (basically an understanding of something)

accommodation

adapting our current understandings (schemas) to incorporate new information (adjust)

ex. a child who believes all four legged furry black and white animals are cows has to change their understanding when they see a dalmatian

assimilation

interpreting our new experiences in terms of our existing schemas

ex. a child sees a cow has four legs and is black and white. that child now thinks everything with four legs and is black and white is a cow

figure-ground

the organization of the visual field into objects that stand out from their surroundings

visual cliff

a laboratory device for testing depth perception in infants and young animals

depth perception

the ability to see objects in three dimensions although the images that strike the retina are 2D; allows us to judge distance; everyone is born with this

monocular cues

depth cues, such as interposition and linear perspective, available to either eye alone

binocular cues

depth cues, such as retinal disparity, that depend on the use of two eyes

linear perspective

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

interposition

if one object partially blocks our view of another, we perceive it as closer

perceptual constancy

our tendency to view familiar objects as unchanging (having the same color, brightness, shape, and size) even as illumination and retinal images change

ex. in a room a red apple is brown, but we still think its red

perceptual adaptation

the ability to adjust or adapt to a change in sensory input

perceptual set

a mental predisposition to perceive one thing and not another (top-down processing)

ex. newspaper photo of "the Lochness Monster" when it actually is just a tree branch, the title makes people see the monster before the branch

parapsychology

the study of paranormal phenomena, including ESP and psychokinesis

wavelength and its influence on color

the distance from one peak to the next which influences our perception of color

short = blue colors long = red colors

intensity and its influence on color

the amount of energy in a light wave; influences brightness

larger intensity = bright colors small intensity = dull colors

cornea

protects the eye and bends light for focus

iris

a colored muscle that adjust light intake

retina

converts light to neural signals to send to the brain

optic nerve

the nerve that carries neural impulses from the eye to the brain

fovea

central focal point in retina, cones cluster around it

rods

enables black and white (even gray) perception

low spatial activity

sees details

responsible for peripheral vision

cones

enable color perception

high spatial activity

located in the center of retina

trichromatic theory of color

Also known as the Young-Helmholz Theory of Color; Human eye has 3 types of cone receptors sensitive to different; People see colors because the eye does its own "color mixing" (blue/short; green/medium; red/long)

opponent processing theory of color

States we have three types of receptor cones and they each handle a pair of colors (red/green, yellow/blue, and black/white). If one sensor/color is firing, it slows the other from firing. The theory does a good job at explaining afterimages.

hammer, anvil, stirrup (ossicles)

the three small bones in the middle ear that relay vibrations of the eardrum to the inner ear

frequency

the number of complete wavelengths that pass a point in a given time

pitch

a tone's experienced highness or lowness; depends on frequency

cochlea

a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

semicircular canal

structures in the inner ear that are responsible for the sense of balance

basilar membrane

contains hair cells that bend and trigger nerve cells whose axons form auditory nerves, located in the cochlea

kinesthesis

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

vestibular sense

the sense of body movement and position, including the sense of balance

nociceptors

sensory receptors that detect hurtful temperatures, pressure, or chemicals

gate-control theory

the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. the "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity of larger fibers or by information coming from the brain

influences of pain

biological, psychological, social-cultural

taste receptors

chemical receptors on the tongue that decode molecules of food or drink to identify them (tastebuds)

sensory interaction

the principle that one sense may influence another

ex. when the smell of food influences its taste

olfaction

sense of smell

steps to process light

1. Light enters eye and causes reaction in rods and cones
2. Chemical reaction activates bipolar cells
3. Bipolar cells activate ganglion cells, whose axons form the optic nerve. Optic nerve transmits info to visual cortex.

steps to process smell

1. Odor molecules bind to odorant receptors
2. Olfactory receptor cells send electrical signals to olfactory bulb
3. Olfactory bulbs form olfactory nerve which takes info to the brain

steps to process sound

1. Outer ear channels the sound waves through auditory canal to the eardrum -outer ear
2. Ear drum vibrations are sent through hammer, anvil, and stirrup to cochlea -middle ear called ossicles
3. .Cochlea vibrates as well causing ripples in fluid that fills the tube. These ripples cause more ripples in the basilar membrane.
4. Hair cells in basilar membrane bend and trigger nerve cells, whose axons form auditory nerve
5. Auditory nerve takes it to the auditory cortex to be processed and stored

feature detectors

nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement

blind spot

the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there

synesthesia

describing one kind of sensation in terms of another ("a loud color", "a sweet sound")

selective attention

the focusing of conscious awareness on a particular stimulus

change blindness

when people fail to detect changes to the visual details of a scene

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

extrasensory perception (ESP)

the controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition