Key Terms

absolute threshold

minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time

afterimage

continuation of a visual sensation after removal of the stimulus

amplitude

height of a wave

basilar membrane

thin strip of tissue within the cochlea that contains the hair cells which serve as the sensory receptors for the auditory system

binaural cue

two-eared cue to localize sound

binocular cue

cue that relies on the use of both eyes

binocular disparity

slightly different view of the world that each eye receives

blind spot

point where we cannot respond to visual information in that portion of the visual field

bottom-up processing

system in which perceptions are built from sensory input

closure

organizing our perceptions into complete objects rather than as a series of parts

cochlea

fluid-filled, snail-shaped structure that contains the sensory receptor cells of the auditory system

cochlear implant

electronic device that consists of a microphone, a speech processor, and an electrode array to directly stimulate the auditory nerve to transmit information to the brain

conductive hearing loss

failure in the vibration of the eardrum and/or movement of the ossicles

cone

specialized photoreceptor that works best in bright light conditions and detects color

congenital deafness

deafness from birth

congenital insensitivity to pain (congenital analgesia)

genetic disorder that results in the inability to experience pain

cornea

transparent covering over the eye

deafness

partial or complete inability to hear

decibel (dB)

logarithmic unit of sound intensity

depth perception

ability to perceive depth

electromagnetic spectrum

all the electromagnetic radiation that occurs in our environment

figure-ground relationship

segmenting our visual world into figure and ground

fovea

small indentation in the retina that contains cones

frequency

number of waves that pass a given point in a given time period

Gestalt psychology

field of psychology based on the idea that the whole is different from the sum of its parts

good continuation

(also, continuity) we are more likely to perceive continuous, smooth flowing lines rather than jagged, broken lines

hair cell

auditory receptor cell of the inner ear

hertz (Hz)

cycles per second; measure of frequency

inattentional blindness

failure to notice something that is completely visible because of a lack of attention

incus

middle ear ossicle; also known as the anvil

inflammatory pain

signal that some type of tissue damage has occurred

interaural level difference

sound coming from one side of the body is more intense at the closest ear because of the attenuation of the sound wave as it passes through the head

interaural timing difference

small difference in the time at which a given sound wave arrives at each ear

iris

colored portion of the eye

just noticeable difference

difference in stimuli required to detect a difference between the stimuli

kinesthesia

perception of the body’s movement through space

lens

curved, transparent structure that provides additional focus for light entering the eye

linear perspective

perceive depth in an image when two parallel lines seem to converge

malleus

middle ear ossicle; also known as the hammer

Meissner’s corpuscle

touch receptor that responds to pressure and lower frequency vibrations

Ménière's disease

results in a degeneration of inner ear structures that can lead to hearing loss, tinnitus, vertigo, and an increase in pressure within the inner ear

Merkel’s disk

touch receptor that responds to light touch

monaural cue

one-eared cue to localize sound

monocular cue

cue that requires only one eye

neuropathic pain

pain from damage to neurons of either the peripheral or central nervous system

nociception

sensory signal indicating potential harm and maybe pain

olfactory bulb

bulb-like structure at the tip of the frontal lobe, where the olfactory nerves begin

olfactory receptor

sensory cell for the olfactory system

opponent-process theory of color perception

color is coded in opponent pairs: black-white, yellow-blue, and red-green

optic chiasm

X-shaped structure that sits just below the brain’s ventral surface; represents the merging of the optic nerves from the two eyes and the separation of information from the two sides of the visual field to the opposite side of the brain

optic nerve

carries visual information from the retina to the brain

Pacinian corpuscle

touch receptor that detects transient pressure and higher frequency vibrations

pattern perception

ability to discriminate among different figures and shapes

peak

(also, crest) highest point of a wave

perception

way that sensory information is interpreted and consciously experienced

perceptual hypothesis

educated guess used to interpret sensory information

pheromone

chemical message sent by another individual

photoreceptor

light-detecting cell

pinna

visible part of the ear that protrudes from the head

pitch

perception of a sound’s frequency

place theory of pitch perception

different portions of the basilar membrane are sensitive to sounds of different frequencies

principle of closure

organize perceptions into complete objects rather than as a series of parts

proprioception

perception of body position

proximity

things that are close to one another tend to be grouped together

pupil

small opening in the eye through which light passes

retina

light-sensitive lining of the eye

rod

specialized photoreceptor that works well in low light conditions

Ruffini corpuscle

touch receptor that detects stretch

sensation

what happens when sensory information is detected by a sensory receptor

sensorineural hearing loss

failure to transmit neural signals from the cochlea to the brain

sensory adaptation

not perceiving stimuli that remain relatively constant over prolonged periods of time

signal detection theory

change in stimulus detection as a function of current mental state

similarity

things that are alike tend to be grouped together

stapes

middle ear ossicle; also known as the stirrup

subliminal message

message presented below the threshold of conscious awareness

taste bud

grouping of taste receptor cells with hair-like extensions that protrude into the central pore of the taste bud

temporal theory of pitch perception

sound’s frequency is coded by the activity level of a sensory neuron

thermoception

temperature perception

timbre

sound’s purity

top-down processing

interpretation of sensations is influenced by available knowledge, experiences, and thoughts

transduction

conversion from sensory stimulus energy to action potential

trichromatic theory of color perception

color vision is mediated by the activity across the three groups of cones

trough

lowest point of a wave

tympanic membrane

eardrum

umami

taste for monosodium glutamate

vertigo

spinning sensation

vestibular sense

contributes to our ability to maintain balance and body posture

visible spectrum

portion of the electromagnetic spectrum that we can see

wavelength

length of a wave from one peak to the next peak