sensation
Detecting physical energy (stimulus) from the environment and converting it into neural signals
perception
Selecting, organizing and interpreting sensations
stimuli
Physical energy that we can detect
psychophysics
Study of the relationship between physical characteristics of stimuli and our psychological experience with them
transduction
The transformation of stimulus energy (sights, sounds, smells) into neural impulses in human sensation.
absolute
Threshold for which the minimum stimulation needed to detect a particular stimulus 50% of the time.
subliminal
Threshold for which a stimulus is below one's absolute threshold for conscious awareness.
sensory adaptation
reduced sensitivity in response to constant stimulation. Occurs for every sense except vision.
light energy
The stimulus input vision
wavelength and intensity
The physical characteristics of light and sound
hue
The dimension of color that is determined by the wavelength of light, which we know as the color names blue, green, etc.
wavelength
The distance from peak of one light or sound wave to the peak of the next, which we perceive as hue (for vision) or pitch (for hearing).
brightness
How bright or dull a visual stimulus is.
intensity
The amount of energy in a light or sound wave, determined by its amplitude, which we perceive as brightness (for vision) or loudness (for hearing).
pupil
The hole in the iris that lets light into the eye
cornea
The transparent tissue through which light enters the eye
iris
The muscle that expands and contracts to change the size of the pupil
lens
The transparent structure behind the pupil that changes shape to focus light rays on the retina.
retina
The light sensitive inner surface of the eye that contains sensory receptor rods and cones and other layers of neurons that process visual information and sends it to the brain.
accommodation
The process by which the eye's lens changes shape to help focus near or far objects on the retina.
optic nerve
Part of the eye that carries neural impulses from the eye to the brain
blind spot
Point where the optic nerve leaves the eye, with no receptor cells.
cones
Photoreceptors located in the center of the retina that detect color and work in light conditions
rods
Photoreceptors located at the periphery (edges) of the retina that do not detect color, but work in dark conditions
feature detection
Nerve cells in the visual cortex of the brain that respond to specific features of a stimulus, such as edges, angles, and movement.
parallel processing
Processing of several aspects of a stimulus simultaneously. For example, where the brain divides a visual scene into subdivisions such as color, depth, form, movement, etc.
Trichromatic
Theory of vision, that the eye must contain three receptors that are sensitive to red, blue and green colors. Suggested by Young and von Helmholtz.
Process Theory of Opponent Color
Theory of vision which suggests cones exist for pairs of colors, red/green, blue/yellow, black/white
color blindness
Genetic disorder in which people are blind to green/red, blue/yellow, or all colors.
outer ear
Part of the ear that collects and sends sounds to the eardrum.
middle ear
Chamber between eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window.
inner ear
Innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.
cochlea
Coiled, bony, fluid-filled tube in the inner ear that transforms sound vibrations to auditory signals.
audition
The sense or act of hearing
touch
Sense that is a mix of four distinct skin senses: pressure, warmth, cold, and pain.
taste
Chemical sense that consists of sweet, salty, sour, bitter and Umami.
sensory interaction
The principle that one sense affects another sense, as when the smell of food influences its taste
smell
Chemical sense that is processed in the brain near the limbic system (part of the brain involved with memories)
kinesthesis
Our sense of the position and movement of individual body parts.
vestibular sense
Our sense that monitors the head's (and thus the body's) movement and position, including the sense of balance.
perceptual organization
Forming meaningful perceptions from sensory information.
grouping
A perceptual tendency to organize stimuli into meaningful groups, such as proximity, similarity, and continuity.
figure-ground
The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).
gestalt
An organized whole, which emphasizes our tendency to integrate pieces of information into meaningful wholes.
retinal disparity
A binocular cue for perceiving depth by comparing images from two eyeballs and comparing the difference between the two images.
relative size
Monocular cue: if two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away.
interposition
Monocular cue: objects that occlude (block) other objects tend to be perceived as closer
relative height
Monocular cue: objects that are higher in our field of vision are farther away than those that are lower.
relative motion
Monocular cue: objects closer to a fixation point move faster and in opposing direction to those objects that are farther away from a fixation point, moving slower and in the same direction.
linear perspective
Monocular cue: parallel lines, such as railroad tracks, appear to converge in the distance. The more the lines converge, the greater their perceived distance.
light and shadow
Monocular cue: nearby objects reflect more light into our eyes than more distant objects. Given two identical objects, the dimmer one appears to be farther away
monocular cues
Relative size, interposition, relative height, relative motion, linear perspective, and light and shadow, which are used to denote distance.
perceptual constancy
Perceiving objects as unchanging (having consistent color, brightness, shape and size) even as illumination and retinal images change.
perceptual adaptation
Visual ability to adjust to an artificially displaced visual field, e.g., prism glasses
perceptual set
A mental predisposition to perceive one thing and not another, for example, to see the Loch Ness monster in a photo of a tree trunk.
context effect
A perceptual adaptation where context radically alters our perception of a stimulus, for example, cultural context
cultural context
A perceptual adaptation where our culture alters our perception of stimuli.