Unit 4 Meyers Terms to Remember

Sensation

Sensation

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

Perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

Bottom-up processing

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

Top-down processing

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

Selective attention

The focusing of conscious awareness on a particular stimulus

Inattentional blindness

Failing to see visible objects when our attention is directed elsewhere

Change Blindness

Failing to notice changes in the environment

Psychophysics

The study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them

Absolute threshold

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

Signal detection theory

A theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and alertness

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. We experience the difference threshold as a just noticeable difference (jnd).

Weber’s law

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

Sensory adaptation

Diminished sensitivity as a consequence of constant stimulation

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

Wavelength

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

Hue

The dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth

Intensity

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

Pupil

The adjustable opening in the center of the eye through which light enters

Iris

A right of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

Lens

The transparent structure behind the pupil that changes shape to help focus images on the retina

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

Blind spot

The point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there

Fovea

The central focal point in the retina, around which the eye’s cones cluster

Feature detectors

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

Parallel processing

The processing of many aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions, including vision. Contrasts with the step-by-step (serial) processing of most computers and of conscious problem solving

Young-Helmholtz trichromantic (three-color) 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

Audition

The sense or act of hearing

Frequency

The number of complete wavelengths that pass a point in a given time (for example, per second)

Pitch

A tone’s experienced highness or lowness; depends on frequency

Middle ear

The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum of the cochlea’s oval window

Cochlea

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

Inner ear

The innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs

Place theory

In hearing, the theory that links the pitched we hear with the place where the cochlea’s membrane is stimulated

Frequency theory

In hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch

Conduction hearing loss

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

Sensorineural hearing loss

Hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerves; also called nerve deafness