Psych Chapter 4 Vocab

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Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

Top-Down Processing

Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

Bottom-Up Processing

Analysis that begins with the sensory receptors and works up to the brain's integration of sensory information

Transduction

Conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.

Absolute Threshold

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

Subliminal

Below one's absolute threshold for conscious awareness

Priming

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

Difference Threshold

The minimum difference between two stimuli required for detection 50 percent of the time

Weber's Law

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

Sensory Adaptation

Diminished sensitivity as a consequence of constant stimulation

Perceptual Set

A mental predisposition to perceive one thing and not another

Retina

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

Accommodation

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

Rods

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

Cones

Retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.

Optic Nerve

The nerve that carries neural impulses from the eye to the brain

Young-Helmholtz Trichromatic Theory

The theory that the retina contains three different color receptors—one most sensitive to red, one to green, one to blue—which, when stimulated in combination, can produce the perception of any color.

Opponent-Process Theory

The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green

Gestalt

An organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes.

Figure-Ground

The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).

Grouping

The perceptual tendency to organize stimuli into coherent groups

Depth Perception

The ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance

Visual Cliff

A laboratory device for testing depth perception in infants and young animals

Binocular Cues

Depth cues, such as retinal disparity, that depend on the use of two eyes

Monocular Cues

Depth cues, such as interposition and linear perspective, available to either eye alone

Perceptual Constancy

Perceiving objects as unchanging (having consistent lightness, color, shape, and size) even as illumination and retinal images change

Perceptual Adaptation

The ability to adjust to changed sensory input, including an artificially displaced or even inverted visual field

Cochlea

A coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses

Gate-Control Theory

The theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.

Vestibular Sense

The sense of body movement and position, including the sense of balance

Sensory Interaction

The principle that one sense may influence another, as when the smell of food influences its taste