AP PSYCHOLOGY UNIT 5: Sensation and Perception Set I

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.

Transduction

Conversion of one form of energy into another. The transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brain can interpret.

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 amid background stimulation.

Subliminal

Below one’s absolute threshold for conscious awareness.

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.

ESP

The controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition.

Parapsychology

The study of paranormal phenomena, including ESP and psychokinesis.

Wavelength

The distance from the peak of one light or sound wave to the peak of the next.

Hue

The dimension of color that is determined by the wavelength of light.

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 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 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; detects fine detail and 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, no receptor cells are located there.

Fovea

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