The lowest intensity at which a stimulus can be detected 50 percent of the time The vertical size of the sound wave, which gives rise to the perception of loudness and is measured in terms of decibels A membrane that runs the length of the cochlea and contains the organ of Corti and its sound receptor hair cells Depth cues that require the use of both eyes The binocular depth cue produced by the projection of slightly different images of an object on the retinas of the two eyes Perceptual processes that begin with the analysis of individual elements of the stimulus and work up to the brain's integration of them into a unified perception A small coil-shaped structure of the inner ear that contains the receptors for sound Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea Photoreceptors in the retina that function best in bright light and are differentially sensitive to red, green, or blue wavelengths A binocular depth cue produced by the muscles that rotate the eyes as they focus on nearby objects Limited time periods during which plasticity can occur as a result of experience or in response to injury; in development, a time period in which exposure to particular kinds of stimulation is required for normal growth to occur The progressive increase in brightness that occurs over time as photopigments regenerate themselves during exposure to low levels of illumination A logarithmic measure of sound intensity In signal detection theory, the potentially changing standard of how certain a person must be that a stimulus is present in order to report its presence The smallest difference between two similar stimuli that people can detect A modern theory of color vision that combines the trichromatic and opponent-process theories

1. Absolute Threshold

The lowest intensity at which a stimulus can be detected 50 percent of the time

2. Amplitude

The vertical size of the sound wave, which gives rise to the perception of loudness and is measured in terms of decibels

3. Basilar Membrane

A membrane that runs the length of the cochlea and contains the organ of Corti and its sound receptor hair cells

4. Binocular Depth Cues

Depth cues that require the use of both eyes

5. Binocular Disparity

The binocular depth cue produced by the projection of slightly different images of an object on the retinas of the two eyes

6. Bottom-up Processing

Perceptual processes that begin with the analysis of individual elements of the stimulus and work up to the brain's integration of them into a unified perception

7. Cochlea

A small coil-shaped structure of the inner ear that contains the receptors for sound

8. Conduction Deafness

Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea

9. Cones

Photoreceptors in the retina that function best in bright light and are differentially sensitive to red, green, or blue wavelengths

10. Convergence

A binocular depth cue produced by the muscles that rotate the eyes as they focus on nearby objects

11. Critical Periods

Limited time periods during which plasticity can occur as a result of experience or in response to injury; in development, a time period in which exposure to particular kinds of stimulation is required for normal growth to occur

12. Dark Adaptation

The progressive increase in brightness that occurs over time as photopigments regenerate themselves during exposure to low levels of illumination

13. Decibel

A logarithmic measure of sound intensity

14. Decision Criterion

In signal detection theory, the potentially changing standard of how certain a person must be that a stimulus is present in order to report its presence

15. Difference Threshold

The smallest difference between two similar stimuli that people can detect

16. Dual-Process Theory

A modern theory of color vision that combines the trichromatic and opponent-process theories. Light waves are coded by red-, blue-, and green-sensitive cones in the retina and by opponent processes thereafter in the visual system

17. Endorphins

Natural opiate-like substances that are involved in pain reduction

18. Feature Detectors

Sensory neurons that respond to particular features of a stimulus, such as its shape, angle, or color

19. Figure-Ground Relations

Perceptual organization in which a focal stimulus is perceived as a figure against a background of other stimuli

20. Fovea

A small area in the center of the retina that contains only cones and where visual acuity is greatest