Sensation and Perception

Amplitude (sound waves)

Determines loudness.

Frequency (sound waves)

Determines pitch.

Amplitude (light waves)

Determines brightness.

Wavelength (light waves)

Relates to frequency, length, and hue.

Absolute threshold

The minimum stimulation needed to detect a particular stimulus 50 percent of the time.

Place theory of hearing

The theory that different areas of the basilar membrane respond to different frequencies.

Frequency theory of pitch perception

Theory suggesting that nerve impulses sent to the brain match the frequency of the sound waves.

Cocktail Party effect

Ability to attend to only one voice among many.

Gate-control theory

Theory that the spinal cord contains a 'gate' that blocks or allows pain signals to the brain.

Five tastes

Sweet, sour, salty, bitter, and umami.

Rods

Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision.

Cones

Retinal receptor cells that detect fine detail and color in well-lit conditions.

Sensory adaptation

Diminished sensitivity as a consequence of constant stimulation.

Sensorineural hearing loss

Hearing loss caused by damage to the cochlea's receptor cells or auditory nerves.

Conduction hearing impairment

Occurs when sound vibrations cannot be passed from the eardrum to the cochlea.

Opponent process theory of color vision

Theory that receptor cells for color are linked in pairs, working in opposition.

Monocular depth cues

Aspects of a scene that yield information about depth when viewed with one eye.

Weber's Law

To be perceived as different, two stimuli must differ by a constant minimum percentage.

Gestalt Psychology

Approach emphasizing that we often perceive the whole rather than the sum of its parts.

Transduction

Conversion of one form of energy into another; transforming stimulus energies into neural impulses.

Bottom-up processing

Perception that recognizes and processes information about individual components of stimuli.

Top-down processing

Information processing guided by higher-level mental processes from past experiences and expectations.

Young-Helmholtz trichromatic theory

Theory that the retina contains three color receptors sensitive to red, green, and blue.

Feature Detectors

Nerve cells responding to specific features of stimuli, like color, form, motion, and depth.

Perceptual Set

A mental predisposition to perceive one thing and not another.

Monocular cues

Depth cues available to either eye alone.

Binocular cues

Depth cues like retinal disparity and convergence that depend on the use of two eyes.

Stroop Effect

Decreased speed in naming the color of ink when the ink color and word color differ.