parallel processing
processing many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions
blindsight
a condition in which a person can respond to a visual stimulus without consciously experiencing it
change blindness
failing to notice changes in the environment; a form of inattentional blindness
Young-Helmholtz 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
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
color constancy
perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
audition
the sense or act of hearing
frequency
the number of complete wavelengths that pass a point in a given time (for example, per second)
pitch
a tone's experienced highness or lowness; depends on frequency
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
cochlea
a coiled, bony, fluid-filled tube in the inner ear; sound waves travelling through the cochlear fluid trigger nerve impulses
inner ear
the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs
place theory
in hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated
frequency theory
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 sense its pitch (also called temporal theory)
conduction hearing loss
a less common form of 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 receptors cells or to the auditory nerves; the most common form of hearing loss, also called nerve deafness
cochlear implant
a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea
gate-control theory
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 and is closed by activity in larger fibers or by information coming from the brain
sensory interaction
the principle that one sense may influence another, as when the smell of food influences its taste
kinesthesis
the system for sensing the position and movement of individual body parts
vestibular sense
the sense of body movement and position, including the sense of balance
electroencephalogram
an amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp
PET (positron emission tomography) scan
a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task
MRI (magnetic resonance imaging)
a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. These scans show brain anatomy
fMRI (functional magnetic resonance imaging)
a technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. These scans show brain function as well as structure
plasticity
the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience
lesion
tissue destruction. A brain _____ is a naturally or experimentally caused destruction of brain tissue.
reflex
a simple, automatic response to a sensory stimulus, such as the knee-jerk response
CT or CAT Scan (computed tomography)
a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body
relative size
smaller objects appear to be further away
relative brightness
brighter objects appear closer than dimmer
height in field
objects higher in our field of vision appear to be farther away
superposition or interposition
objects that are perceived to overlap or obscure another object appear to be closer
linear perspective
parallel lines appear to converge as they move farther into the distance
figure-ground
perceptual process where some objects seem prominent, while others recede into the background
proximity
perceiving objects close to each other as forming a group
continuity
perceiving smoothly flowing or continuous forms rather than disrupted or discontinuous ones
closure
closing up or completing figures that are not, in fact, complete
ambiguous figures
figures that can be interpreted as two or more different images
impossible figures
figures that represent objects that cannot exist in the real world
perspective paradox
figures which exhibit tension between two or more contrary perspectives