The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.
The process of organizing and interpreting sensory information, which enables us to recognize meaningful objects and events.
Analysis that begins with the sense receptors and works up to the brain's integration of sensory information.
Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.
the focusing of conscious awareness on a particular stimulus
failing to see visible objects when our attention is directed elsewhere (e.g. looking for glasses when they are on your head)
failing to notice changes in the environment
the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them
the minimum stimulation needed to detect a particular stimulus 50 percent of the time
Signal Detection Theory
predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise) Assumes that there is no single absolute threshold and that detection depends partly on a person's experience, expectation, motivation, and level of fatigue
below one's absolute threshold for conscious awareness
the activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response
the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference. (Also called the just noticeable difference or JND.)
to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)
diminished sensitivity as a consequence of constant stimulation
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.
the distance from the peak of one light or sound wave to the peak of the next, in the electromagnetic spectrum
the dimension of color that is determined by the wavelength of light
the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude (height)
the adjustable opening in the center of the eye through which light enters
a transparent optical device used to converge or diverge transmitted light and to form images
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
the process where the lens focuses the rays by changing its curvature.
retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond.
retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. Detect fine detail and give rise to color sensations.
the nerve that carries neural impulses from the eye to the brain.
the point at which the optic nerve leaves the eye, creating a spot where there are no receptor cells located.
the central focal point in the retina, around which the eye's cones cluster
nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.
the processing of several aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision
Young-Helmholtz Trichromatic Theory
The theory that the retina contains three different color receptors—one most sensitive to red, one to green, one to blue—which combined can produce the perception of any color.
the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. Explained by the concept of afterimages
the sense or act of hearing.
the number of complete wavelengths that pass a point in a given time (for example, per second)
a tone's experienced highness or lowness; depends on frequency.
transmits the eardrum's vibrations through a piston made of three tiny bones (hammer, anvil, and stirrup) to the cochlea
a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses
the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs
in hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated. Best explains how we sense high pitches.
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 its sense of pitch. Best explains how we sense low pitches.
Conduction Hearing Loss
hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea
Sensorineural Hearing Loss
hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness
a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea
the system for sensing the position and movement of individual body parts
the sense of body movement and position, including the sense of balance
Melzack and Wall's theory that the spinal cord contains a neurological "gate" that blocks or allows pain signals to pass on to the brain.
the principle that one sense may influence another, as when the smell of food influences its taste
an organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes
the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).
the perceptual tendency to organize stimuli into coherent groups (proximity, similarity, continuity, connectedness, closure)
the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance
a laboratory device for testing depth perception in infants and young animals
depth cues, such as retinal disparity and convergence, that depend on the use of two eyes
a binocular cue for perceiving depth; by comparing images from the two eyeballs, the brain computes distance - the greater the disparity (difference) between the two images, the close the object
depth cues, such as interposition and linear perspective, available to either eye alone
an illusion of movement created when two or more adjacent lights blink on and off in quick succession
perceiving objects as unchanging (having consistent lightness, color, shape, and size) even as illumination and retinal images change
perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
in vision, the ability to adjust to an artificially displaced or even inverted visual field
a mental predisposition to perceive one thing and not another
Extrasensory Perception (ESP)
the controversial claim that perception can occur apart from sensory input. Said to include telepathy, clairvoyance, and precognition.
the study of paranormal phenomena, including ESP and psychokinesis