| A | B |
|---|
| sense organs | Organs that receive stimuli. |
| sensory receptor cells | Cells in sense organs that translate messages into neural impulses that are sent to the brain. |
| sensation | The process of receiving, translating, and transmitting messages from the outside world to the brain. |
| perception | The process of organizing and interpreting information received from the outside world. |
| stimulus | Any aspect of the outside world that directly influences our behavior or conscious experience. |
| transduction | The translation of energy from one form to another. |
| absolute threshold | The smallest magnitude of a stimmulus that can be detected half the time. |
| difference threshold | The smallest difference between two stimuli that can be detected half the time. |
| sensory adaptation | Weakened magnitude of a sensation resulting from prolonged presentation of the stimulus. |
| psychophysics | A specialty of psychology that studies sensory limits, sensory adaptation, and related topics. |
| Weber's law | A law stating that the amount of change in a stimulus needed to detect a difference is in direct proportion to the intensity of the original stimulus. |
| retina | The area of the back of the eye on which images are formed and that contains the rods and cones. |
| rods | The 125 million cells located outside the center of the retina that transduce light waves into neural impulses, thereby coding information about light and dark. |
| cones | The 6 million receptor cells located mostly in the center of the retina that transduce light waves into neural impulses, thereby coding information about light, dark, and color. |
| fovea | The central spot of the retina, which contains the greatest concentration of cones. |
| optic nerve | The nerve that carries neural messages about vision to the brain. |
| blind spot | The spot where the optic nerve attaches to the retina; it contains no rods or cones. |
| dark adaptation | Increased sensitivity of the eye in semidarkness fololowing an abrupt reduction in overall illumination. |
| light adaptation | Regaining sensitivity of the eye to bright light following an abrupt increase in overall illumination. |
| trichromatic theory | The theory of color vision contending that the eye has three different kinds of cones, each of which responds to light of one range of wavelength. |
| opponent-process theory of color vision | The theory of color vision contending that the visual system has two kinds of color processors, which respond to light in either the red-green or yellow-blue ranges of wavelength. |
| audition | The sense of hearing. |
| eardrum | The thin membrane that sound waves cause to vibrate; a structure of the middle ear. |
| hammer, anvil, stirrup | Three linked bones of the middle ear, which help pass sound waves to the inner ear. |
| cochlea | A curved structure of the inner ear that is filled with fluid. |
| basilar membrane | One of the membranes that separates the two tubes of the cochlea and on which the organ of Corti rests. |
| organ of Corti | A sensory receptor in the cochlea that transduces sound waves into coded neural impulses. |
| vestibular organ | The sensory structures in the inner ear that provide the brain with information about movement. |
| kinesthetic receptors | Receptors in the muscles, joints, and skin that provide information about movement, posture, and orientation. |
| semicircular canals | Three nearly circular tubes in the vestibular organ that inform the brain about tilts of the head and body. |
| gustation | The sense of taste. |
| olfaction | The sense of smell. |
| sterochemical theory | The theory that different odor receptors can be stimulated only by molecules of a specific size and shape that fit them like a "key" in a lock. |
| perceptual constancy | The tendency for perceptions of objects to remain relatively unchanged, in spite of changes in raw sensations. |
| monocular cues | Eight visual cues that can be seen with one eye and that allow us to perceive distance. |
| binocular cues | Two visiual cues that require both eyes to allow us to perceive depth. |
