PS 280: Sensation & Perception Exam 2 Review

A set of vocabulary flashcards based on key concepts from the PS 280: Sensation & Perception course lecture notes.

Object’s Form

The shape and structure of an object, crucial for understanding visual perception.

Spatial Scale

Refers to how we perceive and interpret the sizes of objects in relation to one another, relevant for determining detail in image perception (gross and fine).

Multichannel Model

A theory important to form perception that involves multiple pathways for processing visual information. Neurons with different sized receptive fields represent different scales.

Grating

a stimulus that consists of parallel light and dark bars, characterized by spatial frequency, contrast, and orientation.

Contrast Sensitivity Function (CSF)

A measure of the ability to detect changes in contrast, related to photopic (daylight) and scotopic (low light) vision.

Pattern Vision Alteration

the ability to discriminate between shapes, sizes, and other features of objects in the environment by visual patterns. Sensitivity or perception changes temporarily, Lingering aftereffects.

Gestalt Movement

A psychological approach emphasizing that the whole of perception is greater than the sum of its parts, with principles aiding spatial vision.

Theories of Object Recognition

Recognition by objects theory: the process by which visual objects are identified based on their features and structural properties, we create a 3d classification of objects.

Gestalt Principles: The brain tends to organize visual information into whole forms. Uses principles like: Proximity, Similarity, Closure, Continuity. Helps in filling in gaps and identifying objects quickly

Inferotemporal Cortex (IT)

A brain region involved in object recognition (form perception), known for its plasticity and adaptability in neural responses.

Prosopagnosia

A condition characterized by the inability to recognize faces, associated with specific brain regions (fusiform gyrus of the inferotemporal cortex)

Color as a Psychological Phenomenon

The understanding that color perception is subjective and varies between individuals.

Hue, Brightness, Saturation

The three qualities of color: the first refers to color type, the second refers to light intensity, and the last refers to color purity.

Trichromatic Theory of Color Vision

A theory explaining color vision based on three types of cones sensitive to different wavelengths. (red, green and blue)

Opponent Process Theory of Color Vision

A theory that explains color perception based on opposing color pairs. cells that process one color process the opposite color, leading to perception of complementary colors.

Color Vision Deficiencies

Protanopia (Red-blindness) Cause: Missing or non-functioning L-cones

Deuteranopia (Green-blindness) Cause: Missing or non-functioning M-cones

Tritanopia (Blue-blindness) Cause: Missing or non-functioning S-cones

Rod Monochromacy (Achromatopsia) Cause: All cones are non-functional; only rods are working

Absolute vs Relative Distance

Absolute distance refers to the actual space between objects, while relative distance compares distances, each important for depth perception.

Oculomotor Cues

Visual cues provided by the movements of the eyes that aid in depth perception.

Binocular Vision (Stereopsis)

Depth perception that arises from the slightly different views of the world from each eye.

Neurobiological Basis of Stereoscopic Vision

Stereoscopic vision uses binocular disparity to perceive depth. The brain uses disparity-selective cells in V1 and beyond to detect whether an object is nearer, farther, or at fixation. These signals are combined and refined across the visual cortex to give us a rich sense of 3D depth.

Monocular Depth Cues

Visual cues for depth perception that require only one eye.

Static Cues for Monocular Depth Perception

Cues like texture gradient, interposition, and linear perspective that convey depth in images. use visual tricks like size, overlap, and shadow to help you judge depth with just one eye.

Moon Illusion

where the moon appears larger near the horizon than when overhead, causing perceived distortions in size and distance.

Motion Parallax

Objects closer to someone moving will appear to be moving the opposite direction whereas objects further away will appear to be moving the same direction

Depth Theory of Size Perception Errors

A theory explaining perceptual errors in size judgment as influenced by contextual depth cues. (two arrows illusion)