Sensation & Perception Flashcards
sensation
the process that occurs when special receptors in the sense organs are activated, allowing various forms of outside stimuli to become neural signals in the brain
transduction
the process of converting outside stimuli, such as light, into neural activity
just noticeable difference (jnd OR the difference threshold)
the smallest difference between two stimuli that is detectable 50% of the time
absolute threshold
the lowest level of stimulation that a person can consciously detect 50% of the time the stimulation is present
habituation
tendency of the brain to stop attending to constant, unchanging information
sensory adaptation
tendency of sensory receptor cells to become less responsive to a stimulus that is unchanging
visual accomodation
the change in the thickness of the lens as the eye focuses on objects that are far away or close
rods
visual sensory receptors found at the back of the retina, responsible for noncolor sensitivity to low levels of light
cones
visual sensory receptors found at the back of the retina, responsible for color vision and sharpness of vision
blind spot
area in the retina where the axons of the three layers of retinal cells exit the eye to form the optic nerve, insensitive to light
dark adaptation
the recovery of the eye’s sensitivity to visual stimuli in darkness after exposure to bright lights
light adaptation
the recovery of the eye’s sensitivity to visual stimuli in light after exposure to darkness
trichromatic theory
theory of color vision that proposes three types of cones: red, blue, and green
afterimages
images that occur when a visual sensation persists for a brief time even after the original stimulus is removed
opponent-process theory
theory of color vision that proposes visual neurons (or groups of neurons) are stimulated by light of one color and inhibited by light of another color
gustation
the sensation of a taste
olfaction (olfactory senses)
the sensation of smell
olfactory bulbs
areas of the brain located just above the sinus cavity and just below the frontal lobes that receive information from the olfactory receptor cells
somesthetic senses
the body senses consisting of the skin senses, the kinesthetic sense, and the vestibular senses
kinesthetic sense
sense of the location of body parts in relation to the ground and each other
vestibular senses
the sensations of movement, balance, and body position
perception
the method by which the sensations experienced at any given moment are interpreted and organized in some meaningful fashion
size constancy
the tendency to interpret an object as always being the same actual size, regardless of its distance
shape constancy
the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina
brightness constancy
the tendency to perceive the apparent brightness of an object as the same even when the light conditions change
figure-ground
the tendency to perceive objects, or figures, as existing on a background
reversible figures
visual illusions in which the figure and ground can be reversed
proximity
the tendency to perceive objects that are close to each other as part of the same grouping
similarity
the tendency to perceive things that look similar to each other as being part of the same group
closure
the tendency to complete figures that are incomplete
continuity
the tendency to perceive things as simply as possible with a continuous pattern rather than with a complex, broken-up pattern
depth perception
the ability to perceive the world in three dimensions
monocular cues (pictorial depth cues)
cues for perceiving depth based on one eye only
binocular cues
cues for perceiving depth based on both eyes
linear perspective
the tendency for parallel lines to appear to converge on each other
relative size
perception that occurs when objects that a person expects to be of a certain size appear to be small and are, therefore, assumed to be much farther away
overlap (interposition)
the assumption that an object that appears to be blocking part of another object is in front of the second object and closer to the viewer
aerial (atmospheric) perspective
the haziness that surrounds objects that are farther away from the viewer, causing the distance to be perceived as greater
texture gradient
the tendency for textured surfaces to appear to become smaller and finer as distance from the viewer increases
motion parallax
the perception of motion of objects in which close objects appear to move more quickly than objects that are farther away
accommodation
as a monocular cue, the brain’s use of information about the changing thickness of the lens of the eye in response to looking at objects that are close or far away
convergence
the rotation of the two eyes in their sockets to focus on a single object, resulting in greater convergence for closer objects and lesser convergence if objects are distant
binocular disparity
the difference in images between the two eyes, which is greater for objects that are close and smaller for distant objects
perceptual set (perceptual expectancy)
the tendency to perceive things a certain way because previous experiences or expectations influence those perceptions
top-down processing
the use of pre-existing knowledge to organize individual features into a unified whole
bottom-up processing
the analysis of the smaller features to build up to a complete perception
