Sensation & Perception: Vision

Front 1

Sensation

Back 1

Process by which our sensory receptors & nervous system receive & represent stimulus energies from our environment

Front 2

Perception

Back 2

Process of organizing & interpreting sensory info, enabling us to recognize meaningful objects & events

Front 3

Bottom-up Processing

Back 3

Analysis that begins w/the sensory receptors & works up to the brain's integration of sensory info.

Front 4

Top-down Processing

Back 4

Info. processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience & expectations

Front 5

Psychophysics

Back 5

Study of relationships between physical characteristics of stimuli, such as their intensity & our psychological experience of them

Front 6

Absolute threshold

Back 6

Minimum stimulation needed to detect a particular stimulus 50 percent of the time

Front 7

Subliminal

Back 7

Below one's absolute threshold for conscious awareness

Front 8

Priming

Back 8

The activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response

Front 9

Difference threshold

Back 9

Minimum difference between 2 stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference (or jnd)

Front 10

Weber's law

Back 10

Principle that, to be perceived as different, 2 stimuli must differ by a constant minimum percentage (rather than a constant amount)

Front 11

Wavelength

Back 11

Distance from the peak of 1 light or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short blips of cosmic rays to the long pulses of radio transmission

Front 12

Hue

Back 12

Dimension of color that's determined by the wavelength of light; what we know as the color names blue, green, & so forth

Front 13

Intensity

Back 13

Amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude

Front 14

Retina

Back 14

The light-sensitive inner surface of the eye, containing the receptor rods & cones plus layers of neurons that begin the processing of visual info.

Front 15

Accommodation

Back 15

Process by which the eye's lens changes shape to focus near or far objects on the retina

Front 16

Rods

Back 16

Retinal receptors that detect black, white, & gray; necessary for peripheral & twilight vision, when cones don't respond

Front 17

Cones

Back 17

Retinal receptors cells that are concentrated near the center of the retina & that function in daylight or in well-lit conditions. Cones detect fine detail & give rise to color sensations

Front 18

Optic nerve

Back 18

Nerve that caries neural impulses from eye to the brain

Front 19

Blind spot

Back 19

Point at which the optic nerve leaves the eye, creating a "blind" spot b/c no receptor cells are located there

Front 20

Fovea

Back 20

Central focal point in the retina, around which the eye's cones cluster

Front 21

Feature detectors

Back 21

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement

Front 22

Parallel processing

Back 22

Processing of many aspects of a problem simultaneously; the brain's natural mode of info. processing for many functions, including vision. Contrasts w/the step-by-step (serial) processing of most computers & of conscious problem solving

Front 23

Young-Helmholtz trichromatic (3-color) theory

Back 23

Retina contains 3 different color receptors--1 most sensitive to red, 1 to green, 1 to blue--which when stimulated in combination can produce the perception of any color

Front 24

Opponent-process theory

Back 24

Opposing retinal processes (red-green, yellow-blue, white-black) enable color vision