Sensation
the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
Perception
the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events
bottom-up processing
analysis that begins with the sensory receptors and works up to the brain's integration of sensory information
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.
Psychophysics
the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them
absolute threshold
the minimum stimulation needed to detect a particular stimulus 50 percent of the time
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, a
subliminal
below one's absolute threshold for conscious awareness
Priming
the activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response
difference threshold
the minimum difference between two stimuli required for detection 50 percent of the time
Weber's Law
the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)
sensory adaptation
diminished sensitivity as a consequence of constant stimulation
perceptual set
a mental predisposition to perceive one thing and not another
perceptual adaptation
in vision, the ability to adjust to an artificially displaced or even inverted visual field
Extrasensory Adaptation
the controversial claim that perception can occur apart from sensory input; includes telepathy clairvoyance and precognition
parapsycholgy
the study of paranormal phenomena, including ESP and psychokinesis
audition
the sense or act of hearing
Frequency
the number of complete wavelengths that pass a point in a given time
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 through which sound waves trigger nerve impulses
inner ear
the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs
sensorineural hearing loss
hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness
conduction hearing loss
hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea
cochlear implant
a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea
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
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
sensory interaction
the principle that one sense may influence another, as when the smell of food influences its taste
embodied cognition
in psychological science, the influence of bodily sensations, gestures, and other states on cognitive preferences and judgments
kinesthesis
the system for sensing the position and movement of individual body parts
blind spot
the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there
optic nerve
the nerve that carries neural impulses from the eye to the brain; formed by axons of ganglion cells
Young-Helmoltz 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.
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
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
thalamus
on the way to the visual cortex, neural impulses from the retina are first relayed to here.
cones
retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations; help us distinguish different wavelength of light
rods
retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond
iris
regulates the amount of light entering the eye
retina
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
order in which the retina's neural layers process visual stimulation
rods and cones, bipolar cells, ganglion cells
humans view the longest electromagnetic waves as the color
red
humans view the shortes electromagnetic waves as the color
blue-violet
pupil
the adjustable opening in the center of the eye through which light enters
cornea
The clear tissue that covers the front of the eye
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