AP Psych Sensation and Perception

Sensation

the detection of physical energy emitted or reflected by physical objects

Perception

processes that organize sensory impulses into meaningful patterns

Doctrine of specific nerve energies

signals received by the sense organs stimulate different nerve pathways, which terminate in different areas of the brain

Synesthesia

occurs when stimulation of one sense evokes sensations in another

Psychophysics

how the physical properties of stimuli are related to our psychological experience of them

Absolute threshold

the smallest amount of energy a person can detect reliably (50 percent of the time)

Difference threshold

the smallest difference in stimulation that a person can detect reliably (50 percent of the time); also called just noticeable difference (jnd)

Signal detection theory

Accounts for response bias (tendency to say yes or no to a signal)

Sensory Adaptation

Decline in sensory responsiveness occurs when a stimulus is unchanging; nerve cells temporarily stop responding

"Cocktail party phenomenon"

we routinely block out unimportant sensations

Selective attention

protects us from being overwhelmed with sensations

Hue

color that is related to wavelength

Brightness

intensity, corresponds to amplitude of the wave

Saturation

colorfulness and complexity of the range of wavelengths

Physical properties of light

wavelength, intensity, complexity

Cornea

front part of the eye; protects the eye and bends light rays toward lens

Lens

located behind the cornea; focuses light by changing curvature

Iris

muscles that control the amount of light that gets into the eye

Pupil

round opening surrounded by iris; widens and dilates to let light in

Retina

located in the back of the eye, contains visual receptors

Rods

sensitive to light, not to color

Cones

see color, but need more light to respond

Fovea

center of retina, sharpest vision, contains only cones

Dark adaptation

time it takes to adjust to dim illumination; reflects mainly increase in sensitivity of rods

ganglion cells

axons converge to form optic nerve, that carries information out of the eye to the brain

Optic nerve

leaves the eye at optic disc; no rods or cones; blind spot on retina

Trichromatic (Young‐Helmholtz) theory

This approach applies to the first level of processing (in the retina); Retina contains three types of cones: one responds to blue, another to green, another to red; these combine to make all colors c. People with color deficiencies lack particular types of cones

Opponent‐process theory

Second stage of color processing in the ganglion cells of the retina and neurons in the thalamus and visual cortex (opponent process cells); They turn off to one wavelength in a pair and on to the other

Visual perception

the mind interprets the retinal image and constructs the world using information from other senses

Form perception

how people organize the visual world into meaningful patterns

perceptual units

figure/ground distinction, proximity, closure, similarity, and continuity

Depth and distance perception

object's location inferred from distance or depth cues

Binocular cues

dependent on information from both eyes

Retinal disparity

disparity in the lateral separation between two objects as seen by the two eyes is used to infer depth or distance

Monocular cues

cues that do not depend on using both eyes include interposition and linear perspective

Perceptual constancy

our perception of objects is unchanging though the sensory patterns they produce are constantly shifting

Visual constancies

shape, location, size, brightness, and color; when seeing is believing

Visual illusions

When seeing is misleading; visual constancies may occasionally fool us, resulting in ______

Loudness

intensity of a wave's pressure; decibels

Pitch

frequency (and intensity) of wave; hertz

Timbre

complexity of wave; the distinguishing quality of a sound

white noise

occurs when all frequencies of the sound spectrum are present

the hammer, anvil, and stirrups

amplify sound waves

cochlea

contains the receptor cells called cilia, or hair cells, that are embedded in the basilar membrane stretching across the _______

basilar membrane

the hair cells initiate a signal to the auditory nerve, which carries the message to the brain

basilar membrane

influences the pattern and frequency of how the neurons fire, which determines what is heard

Perception

is used to organize patterns of sounds to construct meaning

Papillae

bumps on tongue, contain taste buds

Taste receptors

are replaced every 10 days; number of taste buds and receptor cells declines with age

salty, sour, bitter, sweet

four basic tastes