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Ch 3: Sensation and Perception

Exam 2
STUDY
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sensation
the process through which the senses pick up visual, auditory, and other sensory stimuli and transmit them to the brain.
perception
the process by which sensory information is actively organized and interpreted by the brain
absolute threshold
the minimum amount of sensory stimulation that can be detected 50% of the time
difference threshold
a measure of the smallest increase or decrease in a physical stimulus that is required to produce a difference in sensation that is noticeable 50% of the time
just noticeable difference (JND)
The smallest change in sensation that a person is able to detect 50% of the time
Weber's Law
The Law stating that the just noticeable difference (JND) for all the senses depends on a proportion or percentage of change in a stimulus rather than on a fixed amount of change
Sensory Receptors
Highly specialized cells in the sense organs that detect and respond to one type of sensory stimuli-light sound, or oder, for example- and transduce (convert) the stimuli into neural impulses
transduction
the process through which sensory receptors convert the sensory stimulation into neural impulses
sensory adaptation
The process in which sensory receptors grow accustomed to constant, unchanging levels of stimuli over time
visible spectrum
The narrow band of electromagnetic waves visible to the human eye
Cornea
the tough, transparent, protective layer that covers the front of the eye and bends light rays inward through the pupil
pupil
small opening in the center of the colored part of the eye
iris
Colored part of the eye that dilates and contracts the pupil to regulate the amount of light that enters the eye
lens
the transparent disc-shaped structure behind the iris and the pupil that changes shape as it focuses on objects at varying distances
accommodation
the flattening and bulging action of the lens as it focuses images of objects on the retina
retina
The layer of tissue that is located on the inner surface of the eyeball and contains the sensory receptors for vision
rods
the light sensitive receptor cells in the retina that look like slender cylinders and allow the eye to respond to low levels of light
cones
The light-sensitive, rounded receptor cells in the retina that enable humans to see color and fine detail in adequate light but do not function in very dim light.
fovea
A small area at the center of the retina that provides the clearest and sharpest vision because it has the largest concentration of cones
blind spot
The point in each retina where there are no rods or cones because the cable of ganglion cells is extending through the retinal wall.
optic nerve
The nerve that carries visual information from each retina to both sides of the brain
Primary visual cortex
The part of the brain in which visual information is processed
feature detectors
neurons in the brain that respond only to specific visual patterns (ex. lines or angles)
hue
the dimension of light that refers to the specific color perceived
saturation
the purity of a color, or the degree to which the light waves producing it are of the same wavelength
brightness
the intensity of the light energy that is perceived as a color
color blindness
the inability to distinguish certain colors from one another
opponent-process theory
The theory of color vision suggesting that three kinds of cells respond by increasing or decreasing their rate of firing when different colors are present
afterimage
A visual senstation that remains after a stimulus is withdrawn
gesalt
A German word that roughly refers to the whole form, pattern, or configuration that a person perceives
perceptual constancy
the phenomenon that allows us to perceive objects as maintaining stable properties, such as size, shape, and brightness, despite differences in distance, viewing angle, and lighting
depth perception
The ability to perceive the visual world in three dimensions and to judge distances accurately
binocular depth cues
depth cues that depend on both eyes working together
monocular depth cues
depth cues that can be perceived by one eye alone
real motion
perceptions of motion tied to movements of real objects through space
apparent motion
perceptions of motion that seem to be psychologically constructed in response to various kinds of stimuli
phi phenomenon
apparent motion that occurs when several stationary lights in a dark room are flashed on and off in sequence, causing the perception that a single light is moving from one spot to the next.
autokinetic illusion
apparent motion caused by the movement of the eyes rather than the movement of the objects being viewed
illusion
a false perception or a misperception of an actual stimulus in the environment
attention
the process of sorting through sensations and selecting some for further processing
inattentional blindness
the phenomenon in which we shift our focus from one object to another and, in the process, fail to notice changes in objects to which we are not directly paying attention
selective attention
screening out irrelevant sensory input in order to attend to a single source of information
bottom-up processing
information processing in which individual components of a stimulus are combined in the brain and prior knowledge is used to make inferences about these patterns
top-down processing
information processing in which previous experience and conceptual knowledge are applied in order to recognize the nature of a "whole" and then logically deduce the individual components of that whole
perceptual set
an expectation of what will be perceived, which can affect what actually is perceived
mirror neuron system (MNS)
a network of cells that the brain uses to interpret and produce motor actions and emotion-related behavior
subliminal perception
the capacity to perceive and respond to stimuli that are presented below the threshold of awareness
extrasensory perception (ESP)
Gaining information about objects, events, or another person's thoughts through some means other than the known sensory channels
synesthesia
the capacity for experiencing unusual sensations along with ordinary ones
trichromatic theory
The theory of color vision suggesting that there are three types of cones in the retina that make a maximal chemical response to one of three color-red, green, or blue.