AP Psychology - Unit 1.5 Vocabulary #1

Sensation

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% 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

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, etc.

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)

Cornea

the eye’s clear, protective outer layer, covering the pupil and iris

Pupil

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

Iris

a ring 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 back inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information

Accommodation

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

Rods

retinal receptors that detect black, white, and gray; and are sensitive to movement; necessary for peripheral and twilight vision when cones don’t respond

Cones

retinal receptors that are concentrated near the center of the retina and the function in daylight or in well-lit conditions. 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

Young-Helmholtz trichromatic theory

the theory that the retina contains 3 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 inhibiited 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 problems simultaneously

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