Sensation, Perception, and Vision

Vocabulary flashcards covering core concepts of sensation, perception, auditory and visual illusions, sensory thresholds, and eye anatomy from the lecture.

Sensation

The raw, individual data points and subparts of experience detected by sensory receptor cells, such as seeing a single color, tasting sweet, or hearing a specific tone.

Perception

The overarching mental experience created by combining individual sensations together with existing memories, expectations, and background knowledge.

Gestalt Switch

A perceptual shift in which an individual intentionally alters how they perceive an ambiguous figure, switching between two distinct interpretations of the same stimulus.

McGurk Effect

A perceptual phenomenon demonstrating that visual input alters what speech sound a listener believes they are hearing.

Tritone Paradox

An auditory illusion created by Diana Deutsch where tones contain both higher and lower frequencies, causing listeners to disagree on whether a sequence ascends or descends based on their geographic region and ancestral language.

Shepard Tone Illusion

An auditory illusion where multiple sine waves raise in pitch while one drops down an octave, creating the perception of a tone that climbs continually higher without end.

Transduction

The sensory process by which specialized sensory receptor cells convert an external environmental stimulus into action potentials that neurons can transmit.

Parallel Processing

The ability of the brain to take in and process multiple streams of incoming sensory information across different senses simultaneously.

Supraliminal Perception

The perception of environmental stimuli that are strong enough to cross the sensory threshold and be consciously noticed.

Subliminal Perception

Sensory stimulation that falls below conscious awareness, existing in the environment but failing to be consciously noticed.

Absolute Threshold

The boundary intensity at which a stimulus is successfully detected by an observer $50\%$ of the time.

Cocktail Party Effect

The brain's ability to focus attention on a specific, personally significant auditory stimulus—such as hearing one's own name spoken across a room—amid unattended background noise.

Visible Light Spectrum

The narrow band of electromagnetic radiation detectable by human eyes, spanning approximately $380$ to $760\text{ nanometers}$.

Hue

The color dimension of visual experience, which is determined by the wavelength of light measured from one peak of a wave to the next.

Brightness

The perceived intensity of light, determined by the amplitude (height) of the light wave.

Saturation

The relative purity of light, determined by whether light waves hitting the eye share the same wavelength (yielding a pure, saturated color) or consist of mixed wavelengths.

Sclera

The tough white outer covering that encloses the eyeball, responsible for maintaining its round shape so it sits securely in the socket.

Iris

The colored muscular portion of the eye that regulates the amount of light entering through the pupil.

Pupil

The adjustable opening in the eye through which light passes to reach the sensory cells at the back of the eyeball.

Pupillary Reflex

An automatic reflex that alters pupil diameter, causing dilation in dim lighting to gather more light and constriction in bright lighting to limit incoming light.

Accommodation

The physiological process whereby the lens changes shape—flattening to view distant objects and curving to focus on nearby objects.

Retina

The light-sensitive tissue at the back of the eye containing sensory receptor cells that convert light waves into action potentials.

Photoreceptors

Specialized sensory receptor cells in the retina—consisting of rods and cones—that perform transduction of electromagnetic energy into neural impulses.

Rods

Photoreceptor cells situated primarily in the periphery of the retina that facilitate peripheral vision and vision in low-light (dark) settings.

Cones

Photoreceptor cells concentrated in the center of the retina that are specialized for detecting color and fine visual detail.