absolute threshold
the minimum stimulation (stimulus intensity) needed to detect a particular stimulus 50 percent of the time
bottom-up processing
analysis that begins with the sensory receptors and works up to the brain's integration of sensory information. In the perceptual process of the visual system, this is a progression from the individual elements to the whole
cochlea
a fluid-filled, coiled tunnel in the inner ear that contains the receptors for hearing, held by the basilar membrane
cones
specialized visual receptors that play a key role in daylight vision and color vision
difference threshold
the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference (JND)
fovea
a tiny spot in the center of the retina that contains only cones; visual acuity is greatest at this spot
frequency theory
asserts that perception of pitch corresponds to the rate, or frequency, at which the entire basilar membrane vibrates
Gestalt psychology
an influential school of thought that emerged from Germany in the early 20th century; argues that the whole can be greater than the sum of its parts.
intensity
the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude
lens
the transparent eye structure that focuses the light rays falling on the retina
light
a form of electromagnetic radiation that travels as a wave, moving at the speed of light
monocoular depth cues
clues about distance based on the image in either eye alone; ex - familiar size, height in the field of view, linear perspective and relative size, overlap, shading, and texture gradient
opponent process theory of color vision
aserts that color perception depends on receptors that make antagonistic responses to 3 pairs of colors: red/green, yellow/blue, and black/white
optic chiasm
the point at which the optic nerves from the inside half of each eye cross over and then project to the oppoiste half of the brain; ensures that signals from both eyes go to both hemispheres of the brain
optic disk
a hole in the retina where the optic nerve fibers exit the eye. Because you can not see the part of an image that falls on this hole, it is also known as the blind spot.
optic nerve
a collection of axons from ganglion cells that connect the eye with the brain; these axons carry visual information, encoded as a stream of neural impulses, to the brain.
parallel processing
two specialized pathways within the main visual pathway (the magnocellular and parvocellular channels) engage in paralle processing, simlutaneously extracting different kinds of information from the same input
perception
the selection, organization, and interpretation of sensory input;the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events
perceptual constancy
a tendency to experience a stable perception in the face of continually changing sensory input; ex - size, shape, and color
perceptual hypothesis
an inference about which distal stimuli could be responsible for the proximal stimuli sensed
place theory
asserts that perception of pitch corresponds to the vibration of different portions of or places along the basilar membrane
priming
the activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response
psychophysics
the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them; how phsyical stimuli are translated into psychological experience.
pupil
the opening in the center of the iris that permits light to pass into the rear chamber of the eye
receptive field of a visual cell
the retinal area that, when stimulated, affects the firing of that cell
retina
the neural tissue lining the inside back surface of the eye; it absorbs light, processes images, and sends visual information to the brain
rods
specialized visual receptors that play a key role in night vision and peripheral vision
sensation
the stimulation of sense organs; the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
sensory adaptation
gradually diminished sensitivity as a consequence of prolonged stimulation
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
stimulus
any detectable input from the environment
subliminal perception
the registration of sensory input without conscious awareness
threshold
a dividing point between energy levels that do and do not have a detectable effect
top-down processing
information processing guided by higher-level mental processes, as when we construct perceptions by drawing on our experience and expectations. In the perceptual process of the visual system, this is a progression from the whole to the elements, such as s
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.
trichromatic theory of color vision
argues that the human eye has three types of receptors with differing sensitivities to different light wavelengths
Weber's Law
the principle that, to be perceived as different, two stimuli must differ by a constant percentage rather than by a constant amount; difference thresholds increase in proportion to the size of the initial stimulus
sensory receptors
specialized cells that detect stimulus info and transmit it to sensory nerves and the brain
photoreception
detection of light, perceived as sight
mechanoreception
detection of pressure, vibration, and movement perceived as touch, hearing, and equilibrium
chemoreception
detection of chemical stimuli, perceived as smell and taste
sclera
the white, outer part of the eye that helps to maintain the shape of the eye and protect it from injury
iris
colored part of the eye
cornea
a clear membrane just in front of the eye; brings the image into focus
pitch
the perceptual interpretation of the frequency of a sound
loudness
the perception of the sound wave's amplitude
timbre
the tone saturation, or perceptual quality, of a sound
outer ear
consists of the pinna and the external auditory canal
middle ear
channels sound thru the eardrum, hammer, anvil, and stirrup to the middle ear
eardrum
vibrates in response to sound; first structure that sound touches in the middle ear
FACT
hammer, anvil, and stirrup three smallest bones in the human body
inner ear
includes the oval window, cochlea, and basilar membrane; function is to convert sound waves into neural impulses and send them to the brain
basilar membrane
lines the inner wall of the cochlea and runs its entire length
tectorial membrane
jellylike flap that generates resulting impulses that are interpreted as sound by the brain
auditory nerve
the nerve structure that receives info about sound from the hair cells of the inner ear and carries these neural impulses to the brain's auditory areas
thermoreceptors
sensory nerve endings under the skin that respond to changes in temp at or near the skin and provide input to keep the body's temp at 98.6