AP Psychology Unit 4

Absolute Threshold

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

Accommodation (sensation)

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

Audition

The sense or act of hearing.

Binocular Cues

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

Blind Spot

The point at which the optic nerve leaves the eye and no receptor cells are located there.

Bottom-up Processing

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

Change Blindness

Failing to notice changes in the environment.

Cochlea

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

Cochlear Implant

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

Color Constancy

Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object.

Conduction Hearing Loss

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

Cones

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

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.

Difference Threshold

The minimum difference between two stimuli required for detection 50 percent of the time. Also called the just noticeable difference.

Feature Detectors

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

Figure-ground

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

Fovea

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

Frequency

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

Frequency Theory

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

Gate-control Theory

The theory that the spinal cord contains a neurological "gate" that clocks 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.

Gestalt

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

Grouping

The perceptual tendency to organize stimuli into coherent groups.

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.

Inattentional Blindness

Failing to see visible objects when our attention is directed elsewhere.

Inner Ear

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

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.

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.

Kinesthesis

The system for sensing the position and movement of individual body parts.

Lens

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

Middle Ear

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

Monocular Cues

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

Opponent-process Theory

The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.

Optic Nerve

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

Parallel Processing

The processing of many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision.

Perception

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

Perceptual Adaptation

In vision, the ability to adjust to an artificially displaced or even inverted visual field.

Perceptual Constancy

Perceiving objects as unchanging even as illumination and retinal images change.

Perceptual Set

A mental predisposition to perceive one thing and not another.

Phi Phenomenon

An illusion of movement created when two or more adjacent lights blink on and off in quick succession.

Pitch

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

Place Theory

In hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated.

Priming

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

Psychophysics

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

Pupil

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

Retina

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

Retinal Disparity

A binocular cue for perceiving depth by comparing images from the retinas in the two eyes, the brain computes the distance - the greater the disparity (difference) between the two images, the closer the object.

Rods

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

Selective Attention

The focusing of conscious awareness on a particular stimulus.

Sensation

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

Sensorineural Hearing Loss

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

Sensory Adaptation

Diminished sensitivity as a consequence of constant stimulation.

Sensory Interaction

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

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.

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 stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.

Vestibular Sense

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

Visual Cliff

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

Wavelength

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

Weber's Law

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

Young-Helmholtz Trichromatic (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.

Proximity

We group nearby figures together

Closure

We fill in gaps to create a complete object

Continuation

When uniform and linked we perceive each set as a unit

Shape Constancy

We perceive the form of familiar objects as constant even when retinal image changes

Size Constancy

We perceive objects to have a consistent size

Linear Perception

If an object is father away (and is technically the same size) we perceive it as larger

Relative Size

things small are perceived as farther away.

linear perspective

parallel lines appear to meet in the distance, the sharper the angle of convergence the greater perceived distance

cocktail party effect

ability to single out one voice in a room full of many

auditory canal

canal that caries sound waves to the ear

eardrum

membrane at the end of the auditory canal that vibrates due to sound waves

hammer, anvil, stirrup

3 small bones in the middle ear that relay vibrations of the eardrum to the inner ear

oval window

membrane across the opening between the middle ear and inner ear that conducts vibrations to the cochlea

basilar membrane

vibrating membrane in the cochlea of the inner ear that contains sense receptors for sound

auditory nerve

bundle of neurons that carries signals from each ear to the brain

semicircular canals

the liquid inside sloshes around and moves the tiny hairs that line each canal. These hairs translate the movement of the liquid into nerve messages that are sent to your brain.