absolute threshold

decibel

a measure of the physical intensity of sound, which is lawfully related to the sensation of loudness

color blindness

complete or partial inability to distinguish colors, resulting from malfunction in the cones

kinesthesis

the sense of movement and body position, acquired through receptors located in and near the muscles, tendons, and joints.

difference threshold

the smallest change in a physical stimulus that produces a change in sensation in half the trials

signal-detection theory

the study of mathematical relationships between motivation, sensitivity, and sensation

psychophysics

the study of the relationships between sensory experiences and the physical stimuli that cause them

parapsychology

the systematic study of ESP and other unusual phenomena

constancy

the tendency to perceive certain objects in the same way, regardless of changing angle, distance, or lighting

absolute threshold

The smallest amount of energy that will produce a sensation

lens

a flexible, transparent structure in the eye that, by changing its shape, focuses light on the retina.

extrasensory perception (ESP)

an ability to gain information by some means other than the ordinary senses (such as taste, hearing, vision, and so on)

gestalt

in perception, the experience that comes from organizing bits and pieces of information into meaningful wholes.

illusion

perception that misrepresent physical stimuli

cones

receptor cells in the retina sensitive to color, because they require more light than robs to function, they are most useful in daytime vision.

rods

receptor cells in the retina that are sensitive to light, but not to color. rods are particularly useful in night vision

motion parallax

the apparent movement of stationary objects relative to one another that occurs when the observer changes position. near objects seem to move greater distances then far objects.

retinal disparity

the differences between the images on the two retinas

retina

the innermost coating of the back of the eye, containing the light-sensitive receptor cells

auditory nerve

the nerve that carries impulses from the inner ear to the brain, resulting in the sensation of sound.

olfactory nerve

the nerve that carries small impulses from the nose to the brain

pupil

the opening in the iris that regulates the amount of light entering the eye

weber's law

the principle that the larger or stronger a stimulus, the larger the change required for an observer to notice a difference

binocular fusion

the process of combining the images received from the two eyes into a single, fused image

pitch

the sensation associated with a sounds frequency; the "highness" or "lowness" of a sound

referred pain

the sensation of pain in an area away from the actual source; most commonly experienced with internal pain

subliminal advertising

the unsuccessful attempt to influence people with messages that are below normal thresholds of detection

stereopsis

the use by the visual system of retinal disparity to give depth information-providing a three-dimensional appearance to the world

vestibular system

three semicircular canals located in the inner ear and connected to the brain by the vestibular nerve. they regulate the sense of balance