Modules 1.6a, b, c Review

Sensation

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

Sensory Receptors

Sensory nerve endings that respond to stimuli.

Perception

the process by which our brain organizes and interprets sensory information, enabling us to recognize objects and events as meaningful.

Bottom-Up Processing

Information processing 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.

Transduction

Conversion of one form of energy into another. In sensation, the transforming of physical energy, such as sights, sounds, and smells, into neural impulses the brain can interpret.

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 stimulus energy 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 (or JND).

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.

Wavelength

The distance from the peak of one light or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short gamma waves to the 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 wave or sound wave, which influences what we perceive as brightness or loudness. Intensity is determined by the wave’s amplitude (height).

Accomodation

(1) In sensation and perception, the process by which the eye’s lens changes shape to focus images of near or far objects on the retina. (2) in developmental psychology, adapting our current schemas (understandings) to incorporate new information.

Young-Helmholtz Trichromatic Theory

The theory that the retina contains three different types of 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, blue-yellow, 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.

Feature Detectors

Nerve cells in the brain’s visual cortex that respond to specific features of the stimulus, such as shape, angle, or movement.

Parallel Processing

Processing multiple aspects of a stimulus or problem simultaneously.

Audition

The sense or act of hearing.

Frequency

The number of complete wavelengths that pass a point in a given time.

Pitch

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

Sensorineural Hearing Loss

The most common form of hearing loss, caused by damage to the cochlea’s receptor cells or to the auditory nerve; also called nerve deafness.

Conduction Hearing Loss

A less common form of hearing loss, caused by damage to the mechanical system that conducts sound waves to the cochlea.

Place Theory

In hearing, the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated. (Also called place coding.)

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. (Also called temporal coding.)

Cochlear Implant

A device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.