- Sensation: the activation of sensory receptors in various sense organs
- absolute threshold: the smallest amount of energy needed for a person to consciously detect a stimulus 50 percent of the time it is present
- binocular cues: cues for perceiving depth based on both eyes
- brightness constancy: the tendency to perceive the apparent brightness of an object as the same even when the light conditions change
- closure: the tendency to complete figures that are incomplete
- contiguity: the tendency to perceive two things that happen close together in time as being related
- continuity: the tendency to perceive things as simply as possible with continuous pattern rather than with a complex, broken-up pattern
- depth perception: the ability to perceive the world in three dimensions
- figure-ground: the tendency to perceive objects, or figures, as existing on a background
- habituation: the tendency of the brain to stop attending to constant, unchanging information
- 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
- just noticeable difference: the smallest difference between two stimuli that is detectable 50 percent of the time
- linear perspective: the tendency for parallel lines to appear to converge on each other
- monocular cues: cues for perceiving depth based on one eye only
- perception: the method by which the sensations experienced at any given moment are interpreted and organized in some meaningful fashion
- proximity: the tendency to perceive objects that are spacially close to each other as part of the same grouping
- 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 further away
- rods and cones: specialized sensory receptors found in the eyes
- saccades: constant, movements of the eyes--little vibrations
- sensory adaptation: tendency of sensory receptor cells to become less responsive to a stimulus that is unchanging
- sensory receptors: specialized forms of neurons that are activated by different stimuli such as light and sound
- shape constancy: the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina
- similarity: the tendency to perceive things that look similar to each other as being part of the same group
- size constancy: the tendency to interpret an object as always being the same actual size, regardless of its distance
- subliminal stimuli: stimuli below the level of consciousness that may act upon behavior