Sensation and Perception Key Vocabulary

Flashcards covering core terminology and concepts in sensation and perception, including sensory thresholds, visual depth cues, theories of vision and pain, and perceptual organization.

Bottom-up processing

Information processing that analyzes the raw stimuli entering through the many sensory systems.

Top-down processing

Information processing that draws on expectations and experiences to interpret incoming sensory information.

Difference threshold (JND)

The minimum amount of difference needed to detect that two stimuli are not the same.

Linear perspective

A depth cue where parallel lines appear to converge as they recede into the distance, helping the brain judge how far away objects are based on how the lines come together.

Interposition

A visual depth cue that occurs when one object overlaps another, leading us to perceive the overlapping object as closer.

Signal detection theory

A theory that predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise).

Color constancy

The ability to perceive colors of objects as stable under varying lighting conditions, helping identify and differentiate objects consistently.

Absolute threshold

The minimum amount of stimulation needed to detect a particular stimulus.

Sensory adaptation

Diminished sensitivity to constant and unchanging stimulation.

Lens

A transparent structure behind the pupil that changes shape to focus images onto the retina.

Convergence

A cue to nearby objects' distance, enabled by the brain combining retinal images.

Subliminal messages

Sensory inputs—such as hidden visual frames, masked text, or sub-audible audio—that fall below your threshold for conscious perception.

Gate-control theory of pain

A theory stating that a neurological "gate" in the dorsal horn of the spinal cord regulates whether pain signals are allowed to pass through to the brain.

Weber's Law

The principle that the just-noticeable difference (JND)—the smallest detectable change in a physical stimulus—is a constant proportion or ratio of the original stimulus intensity, rather than a fixed absolute amount.

Gestalt principle of closure

The human brain's natural tendency to automatically fill in gaps, missing lines, or fragmented parts of a visual stimulus to perceive a complete, unified, and coherent whole.

Texture gradient

A monocular depth cue in visual perception where a surface's texture appears coarse, detailed, and distinct up close, but gradually becomes finer, denser, smoother, and less distinct as distance increases.

Trichromatic theory

States that the human eye has three distinct types of photoreceptor cells—called cones—that are each sensitive to different wavelengths of light.

Retinal disparity

A binocular depth cue where each eye views the world from a slightly different angle, allowing the brain to compare the two images to calculate depth; greater disparity means objects are perceived to be closer.