Vocabulary

absolute threshold

minimum amount of stimulus intensity needed for a receptor to react

binocular disparity

difference in retinal image location between the two eyes, which aids depth perception

cochlea

part of inner ear that converts mechanical energy of eardrum vibrations into neural signals

cone

photoreceptor that responds best in high-light conditions to detect color and detail

cornea

transparent outer cover on the eye, which allows light to enter

extrasensory perception (ESP)

perception of information without the use of the five senses or the aid of previous experience

fovea

point of clearest focus in the retina

gestalt principles

principles that explain the human tendency to perceive whole objects as opposed to the individual parts of objects

gustation

sense of taste

hair cell

sensory receptor for the auditory and vestibular systems located in the cochlea

iris

ring of colored muscle tissue surrounding the pupil in the eye that controls the size of the pupil

just noticeable difference

minimum change in stimulus intensity that can be detected

lens

transparent structure found behind the iris that bends light to focus on the retina

olfaction

sense of smell

olfactory nerve

nerve that carries smell information to other regions of the brain, formed by the axons of neurons in the olfactory bulb

optic nerve

cranial nerve that transmits visual information from the retina to the brain

perception

identification and/or interpretation of a stimulus

perceptual constancy

tendency to perceive familiar objects as unchanging, even if there are slight changes in the stimulus

perceptual set

human tendency to perceive some stimuli but not others and to base expectations on past experience

proprioception

sense of the body's position, motion, and strength

pupil

opening in the eye formed by the iris that changes diameter to control the amount of light entering the eye

retina

innermost layer of the wall of the eye that contains several layers, including pigmented cells, photoreceptors, and neurons

rod

photoreceptor that responds well in low-light conditions and detects shape and motion

sensation

process of detecting an environmental stimulus and converting that stimulus into neural activity

sensory adaptation

sensory receptor cells’ decrease in response after continuous or repeated stimulation

subliminal perception

processing of environmental stimuli without conscious awareness

thalamus

brain structure below the cortex that acts as a relay station for sensory systems

transduction

conversion of an environmental stimulus energy into a neural signal

vestibular sense

system using feedback from head movements to help maintain balance and spatial orientation