Psychology Chapter 4


The process by which stimulation of sensory receptor produces neural impulses that the brain interprets as a sound, visual image, an odor, a taste, a pain, or other sensory image. Sensation represents the first series of steps in processing of incoming information.


the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events. Perception draws heavily on memory, motivation, emotion, and other psychological processes.


conversion of one form of energy into another. In sensation, the transforming of stimulus energies into neural impulses

Sensory Adaption

A decrease in a sensory response to an unchanging stimulus.(Swimming in cold water, you get use to it)

Absolute Threshold

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

Difference Threshold

the smallest change in stimulation that a person can detect

Just noticeable difference (JND)

Same as the Difference Threshold

Weber's Law

says that theres a constant proportional relationship between the JND and the original stimulus intensity (the stronger the stimulus, the bigger the change needed for a change in stimulus intensity to be noticeable)

Fechner's Law

Magnitude of a stimulus can be estimated by the formula-S = K Log RS~Sensation K~ A constant the differs for each sensory modality (touch, sight, temp.) R~Stimulus

Steven's Power Law

More accurate than Fechner's Law & covers more variety of Stimuli.S=KI (a)S~ Sensation, K~ A constant. I~Stimulus Intensity A ~ Power exponent that depends on the sense being measured.

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 detection depends partly on a person's experience, expectations, motivation, and level of fatigue.


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.


Light sensative cells (neurons) in the retina that convert light and energy to neural impulses. They are as far as light gets into the visual system.


rod-shaped receptor in the retina of the eye that is sensitive to dim light but not color. (seeing black, white, grays)


cone-shaped cells within the retina that are color sensitive and respond to bright light


Small area of sharpest vision of the Retina.

Optic Nerve

the nerve that carries information from the eye (retina) 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.Where you cant see


a psychological sensation caused by the intensity of light waves


the appearance of objects (or light sources) described in terms of a person's perception of their hue and lightness (or brightness) and saturation.Also called Hue

Electromagnetic Spectrum

Entire range of electromagnetic range of electromagnetic spectrum energy. (Radio waves, x rays, microwaves, visible lights.)

Visible Spectrum

the portion of the electromagnetic spectrum that can be seen by the human eye[Small Window]

Trichromatic Theory

Visual theory, stated by Young and Helmholtz that all colors can be made by mixing the three basic colors: red, green, and blue; a.k.a the Young-Helmholtz theory.

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.


visual images that remain after removal of or looking away from the stimulus.

Color Blindness

a variety of disorders marked by inability to distinguish some or all colors.(mostly red or green)


the number of complete waves that pass a given point in a certain amount of timeEx- 40 beats a second.


The physical strength of a wave. This is usually measured from the top to the bottom on a graph of the wave.

Tympanic Membrane

eardrum.Vibrates to sound


Snail shaped. A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses. Primary organ of hearing, sound waves are transformed into nerve messages. Vibrates the little hairs in the basilar membrane.

Basilar Membrane

part of the inner ear; divides the cochlea lengthwise; stiff near the oval window but becomes flexible by the other end; as the fluid in the cochlea begins to move, the basilar membrane ripples in response. (little hairs that vibrate when sound hits)


the property of sound that varies with variation in the frequency of vibration. Sensory characteristic of sound produced by the frequency of the sound wave.


the human perception of how much energy a sound wave carries. Sensory characteristic of sound produced by the amplitude (intensity) of the sound wave.


the distinguishing quality of a soundTimbre- greek word- drum = eardrum

Conduction Deafness

hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.problems with the bones of the middle ear

Nerve Deafness

Hearing loss created by damage to the hair cells or the auditory nerve fibers in the inner ear.

Vestibular Sense

the sense of body movement and position, including the sense of balance. Located in the inner ear. Carried to the brain on a branch of the auditory nerve.

Kinesthetic Sense

-the sense of body position and movement of body parts relative to each other-system for sensing the position and movement of individual body parts


sense of smell


-odorless chemicals that serve as social signals to members of one's species-external stimuli; like primary drive, affects sex drive in animals; indirect evidence suggests that humans secrete pheromones to promote sexual pheromones to promote sexual readiness in potential partners; in sweat glands of armpits and genitals


sense of tastealso called gustatory sense

Skin Senses

The senses of touch, pressure, pain, heat, and cold

Gate Control Theory

theory that pain is only experienced in the pain messages can pass through a gate in the spinal cord on their route to the brain

Placebo Effect

experimental results caused by expectations alone.Ex: This bracelet helps you balance, (when its a normal bracelet) and the results are better balance than w/o the bracelet.


The meaningful product of perception - often an image that has been associated with concepts, memories of events, emotions, and motives.

Feature Detectors

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

Binding Problem

-refers to the process used by the brain to combine the results of many sensory operations into a single percept-major unsolved mystery in cognitive psychology concerning physical processes used by the brain to conbine many aspects of sensation to a single precept

Bottom up Processing

recognition that depends on info coming from the sensory systems

Top down Processing

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

Perceptual Constancy

perceiving objects as unchanging (having consistent lightness, color, shape, and size) even as illumination and retinal images change


misleading vision or visual image; false idea or belief;

Ambiguous Figures

Images that are capable of more than one interpretation. There is no "right" way to see an ambiguous figure.Ex: the two faces and the wine glass in the middle

Gestalt Psychology

school of psychology that studies how people perceive and experience objects as whole patterns


The part of a pattern that commands attention, The figure stands out against the ground.


The part of the pattern that does not command attention. the background.


a Gestalt principle of organization holding that there is an innate tendency to perceive incomplete objects as complete and to close or fill gaps and to perceive asymmetric stimuli as symmetric

Laws of Perceptual Grouping

The Gestalt principles of similarity, proximity, continuity, and common fate. These 'laws' suggest how are brains prefer to group stimulus elements together to form a percept.

Law of Similarity

a Getalt principle of organization holding that (other things being equal) parts of a stimulus field that are similar to each other tend to be perceived as belonging together as a unit

Law of Proximity

a Gestalt principle of organization holding that (other things being equal) objects or events that are near to one another (in space or time) are perceived as belonging together as a unit

Law of Continuity

the Gestalt principle that we prefer perceptions of connected and continuous figures to disconnected and disjointed ones

Law of Common Fate

a Gestalt principle of organization holding that aspects of perceptual field that move or function in a similar manner will be perceived as a unit

Law of Pragnanz

The most general Gestalt principle, which states that the simplest organization, requiring the least cognitive effort, will emerge as the figure.

Binocular Cues

depth cues, such as retinal disparity and convergence, that depend on the use of two eyes

Monocular Cues

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

Learning Based Inference

the view that perception is primarily shaped by learning or experience rather than by innate factors

Perceptual Set

a mental predisposition to perceive one thing and not another