The minimum stimulation needed to detect a particular stimulus 50 percent of the time
(1) The process by which the eye's lens changes shape to focus near or far objects on the retina. (2) Adapting our current understandings to incorporate new information.
the point at which the optic nerve leaves the eye, creating a spot where there are no receptor cells, a spot in which is not visible.
Analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.
A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses.
A device for converting sounds into electrical signals and stimulation the auditory nerve through electrodes threaded in the cochlea.
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.
Retinal receptor cells that are concentrated near the center of the retina and that function in well-lit conditions. The cones detect fine detail and give rise to color sensations.
The ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance.
The minimum difference between two stimuli required for detection 50 percent of the time.
nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement
the processing of many aspects of a problem simultaneously; the brains natural mode of information processing for many functions, including vision
Young-Helmholtz Trichromatic (three-color) Theory
the theory that the retina contains 3 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
the theory that opposing retinal processes (white-black, red-green) enable color vision. ex: some cells are stimulated by green and inhibited by red, or vice versa
the number of complete wavelengths that pass a point in a given time (for example, per second)
the chamber between the eardrum & cochlea containing 3 tiny bones (hammer, anvil & stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window
the innermost part of the ear, containing the cochlea, semicircular canals, & vestibular sacs
in hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated
in hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches that frequency of a tone, thus enabling us to sense its pitch
Sensorineural Hearing Loss
hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness
the theory that the spinal cord contains a neurological "gate" that blocks 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 & is closed by activity in larger fibers or by information coming from the brain
the organization of the visual field into objects (figures) that stand out from their surroundings (ground)
a binocular cue for perceiving depth: by comparing images from the retinas in the 2 eyes, the brain computes distance; the greater the disparity, the closer the object
depth cues (such as interposition & linear perspective) available to either eye alone
an illusion of movement created when two or more adjacent lights blink on & off in quick succession
perceiving objects as unchanging, even as illumination & retinal images change
in vision, the ability to adjust to an artificially displaced or even inverted visual field
the process by which our sensory receptors & nervous system receive & represent stimulus energies from our environment
the process of organizing & interpreting sensory information, enabling us to recognize meaningful objects & events
information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience & expectations
the study of relationships between the physical characteristics of stimuli, such as their intensity, & our psychological experience of them
Signal Detection Theory
a theory predicting how & when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold & that detection depends partly on a persons experience, expectation, motivation & alertness
the activation, often unconsciously, of certain assosciations, thus predisposing one's perception, memory or response
the principle that, to be perceived as different, 2 stimuli must differ by a constant percentage (rather than a constant amount)
conversion of one form of energy into another. ex. sensation: stimulus energies to neural impulses our brains can interpret
the ring of muscle tissue that forms the colored portion of the eye around the pupil & controls the size of the pupil opening
the transparent structure behind the pupil that changes shape to help focus images on gthe retina
the light-sensitive inner surface of the eye, containing the receptor rods & cones plus layers of neurons that begin the processing of visual information
retinal receptors that detect black, white, gray; necessary for peripheral & twilight vision, when cones don't respond