| A | B |
|---|
| absolute threshold | the level of sensory stimulation necessary for sensation to occur |
| binocular disparity | The difference between the image provided by each eye |
| sensation | the process of receiving information from the environment |
| perception | the process of assembling and organizing sensory information to make it meaningful |
| white light | light as it originates from the sun or a bulb before it is broken into different frequencies |
| cornea | the clear outer covering of the eye, behind which is a fluid |
| iris | a colored circular muscle that opens and closes, forming larger and smaller circles to control the amount of light getting into the eye |
| lens | the part of the eye that focuses an image on the retina |
| pupil | the opening in the eye |
| retina | the back of the eye, which contains millions of receptors for light |
| blind spot | the portion of the retina through which the optic nerve exits and where there are no receptors for light waves |
| rod | a visual receptor most sensitive to the violet-purple wave-lengths; very sensitive for night vision; "sees" only black and white |
| cone | a visual receptor that responds during daylight; "sees" color |
| color blindness | inability to perceive certain colors, such as red and green |
| afterimage | image that remains after stimulation of the retina has ended. Caused by the firing of the cones not used after viewing something steadily in order to bring the visual system back in balance. |
| audition | the sense of hearing |
| pitch | how high or low a sound is |
| timbre | the complexity of a sound |
| intensity | how loud a sound is |
| decibels | a measure of how loud a sound is (its intensity) |
| eardrum | a piece of skin stretched over the entrance to the ear; vibrates to sound |
| cochlea | a snail-shaped part of the ear, filled with fluid and small hairs that vibrate to incoming sound |
| hair cells | receptor cells for hearing found in the cochlea |
| cilia | hairlike extensions on cells found in the cochlea and the nasal cavity |
| auditory nerve | bundle of nerves carrying sound to the brain |
| cutaneous receptors | nerve receptors in the skin that respond to pressure, temperature, or pain |
| olfaction | the sense of smell |
| olfactory bulbs | units that receive odor molecules and communicate their nature to the brain |
| pheromones | odor chemicals that communicate a message |
| taste receptors | chemical receptors on the tongue that decode molecules of food or drink to identify them |
| size constancy | the ability to retain the size of an object regardless of where it is located |
| color constancy | the ability to perceive an object as the same color regardless of the environment |
| brightness constancy | see objects as equally bright even when the intensity of light around it changes |
| space constancy | the ability to keep objects in the environment steady by perceiving either ourselves or outside objects as moving |
| depth perception | the ability to see the relation of objects in space |
| visual cliff | an apparatus used to demonstrate depth perception |
| retinal disparity | the difference between the images provided by the two retinas. When the images are brought together in the brain they provide a sense of depth |
| texture gradient | how rough or smooth objects appear; used in depth perception |
| gestalt | an organized whole, shape, or form |
| similarity | a perceptual cue that involves grouping like things together |
| proximity | a perceptual cue that involves grouping together things that are near one another |
| closure | the process of filling in the missing details of what is viewed |
| illusions | inaccurate perceptions |
| Müller-Lyer Illusion | illusion in which one line in a picture with two equal-length lines seems longer |
| reversible figure | illusion in which the same object is seen as two alternating figures-first one, then the other |
| subliminal perception | Stimulation presented below the level of consciousness |
| adaptation | the gradual loss of attention to unneeded or unwanted sensory information |
