Chapter 4

Synesthesia

A condition in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

Perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

Transduction

The conversion of one form of energy into another.

Psychophysics

The study of the relationship between physical stimuli and the sensations and perceptions they produce.

Absolute Threshold

The minimum intensity of a stimulus that can be detected 50% of the time.

Just Noticeable Difference (JND)

The smallest difference in stimulus intensity that a specific sense can detect.

Weber’s Law

The principle stating that the JND is a constant proportion of the original stimulus intensity.

Signal Detection Theory

A theory predicting how and when we detect the presence of a faint stimulus amid background noise.

Sensory Adaptation

The diminished sensitivity to a stimulus as a consequence of constant exposure to that stimulus.

Blind Spot

The area of the retina lacking photoreceptors where the optic nerve exits the eye.

Color Perception

The ability to perceive colors based on the responses of three types of cones to different wavelengths of light.

Feature Detectors

Neurons that respond selectively to specific features of a stimulus.

Perceptual Constancy

The ability to perceive objects as stable despite changes in sensory input.

Gestalt Principles

Rules that describe how we perceive things as organized wholes.

Monocular Depth Cues

Cues available to each eye alone, such as relative size and linear perspective.

Binocular Disparity

The difference in images between the two eyes that helps with depth perception.

Change Blindness

The phenomenon of not noticing changes in a scene.

Inattentional Blindness

Failing to notice a fully visible but unexpected object because attention was engaged on another task.

Haptic Perception

The ability to perceive and identify objects through touch.

Gate Control Theory

A theory suggesting that pain perception is controlled by a 'gate' mechanism in the spinal cord.

Vestibular System

The system in the inner ear that helps maintain balance and spatial orientation.

Taste

The detection of five tastes: sweet, salty, sour, bitter, and umami, by taste buds on the tongue.