Visual Perception and Attention Flashcards

A vocabulary-style flashcard set covering object recognition, perception theories, eye anatomy, and attention mechanisms based on lecture materials.

Parallel processing

The brain's ability to process many aspects of a visual stimulus, such as color, movement, and shape, at the same time.

Serial processing

Processing information in a specific, sequential order.

$V1$ (Primary Visual Cortex)

The first stop for visual information in the occipital cortex, primarily concerned with detecting oriented lines.

Ventral stream

The "what" system located in the temporal cortex areas, specialized for recognizing and identifying objects.

Dorsal stream

The "where" system located in the parietal cortex areas, specialized for determining the location of objects.

Fusiform Facial Area (FFA)

A region in the ventral stream that responds more strongly to faces than other objects; lesions in this area can cause prosopagnosia.

Prosopagnosia

A condition characterized by the inability to recognize faces while often retaining other object recognition abilities.

Computational theory

The first of Marr's levels of analysis, which asks what problem the system is solving and why it is being solved.

Representation and algorithm

The second of Marr's levels of analysis, focusing on the processing steps, rules, and representations used to solve a problem.

Hardware implementation

The third of Marr's levels of analysis, which explores how the procedural steps are physically or biologically realized in a system.

Bottom-up processing

Also known as "data-driven" or stimulus-driven effects, it involves information moving from less complex sensory areas to more complex conceptual areas.

Top-down processing

Also known as "concept-driven" or knowledge-driven effects, where more complex or higher-level areas send information and context back to lower-level areas.

Feature net model

A bottom-up model suggesting object recognition occurs by combining simple features into increasingly complex representations, such as letters and words.

RBC model (Recognition By Components)

A model proposing that object recognition is based on geons, which are simple shapes like cylinders or blocks, and their specific 3D relationships.

Geons

Simple 3D geometric shapes that serve as the building blocks for identifying objects in the RBC model.

Deep Neural Networks (DNN)

Modern computational models consisting of multiple layers of nodes that mimic the visual cortex to achieve human-level object recognition performance.

Distal stimulus

The actual physical object in the environment that is being perceived.

Proximal stimulus

The retinal image of an object, which serves as the sensory signal for the brain.

Percept

The meaningful interpretation or recognition of a stimulus constructed by the brain.

Perceptual constancy

The ability to perceive object properties, such as size, shape, and brightness, as constant even when sensory information changes.

Unconscious Inference

Von Helmholtz's theory that vision is a process of active guessing based on exploiting visual regularities and previous experiences.

Retinal disparity

A binocular depth cue based on the fact that the two eyes receive slightly different images because they are in different positions.

Convergence

A binocular depth cue where the brain uses information from eye muscles about the angle at which the eyes cross to infer distance.

Gestalt principles

Inherent perceptual "rules" such as simplicity, proximity, similarity, closure, and continuity that determine how we organize visual input.

Rods

Color-blind photoreceptors that have lower acuity but are highly effective in dim light; they are absent in the fovea.

Cones

Color-sensitive photoreceptors that provide higher acuity but cannot function in dim light; they are concentrated in the fovea.

Lateral inhibition

A processing mechanism in the eye where excited photoreceptors reduce the activity of their neighbors to enhance the appearance of edges.

Receptive field

The specific area in space or set of stimuli that causes a particular sensory neuron to fire more.

Tuning curve

A plot showing how a neuron's response strength varies depending on how closely a stimulus matches its preferred features.

Inattentional blindness

A lack of awareness of an object or event that occurs because it is not being attended to.

Change blindness

The inability to detect changes in a scene when there is a brief interruption of visual input.

Dichotic listening

A procedure where different messages are presented to each ear, and the participant is asked to "shadow" one of the messages.

Cocktail party effect

The phenomenon where personally important information, such as one's own name, captures attention even when it is in an unattended channel.

Early selection model

Broadbent’s theory that a filter occurs before semantic processing, allowing only some information to reach conscious awareness.

Late selection model

Deutsch & Deutsch’s theory proposing that all semantic information is processed, and the filter occurs after processing is complete.

Biased competition theory

The idea that attention is implemented by adjusting the weights of different inputs to neurons, enhancing some while suppressing others.

Stroop effect

A task demonstration showing that some stimuli, like word meanings, are hard to ignore and interfere with the goal-driven task of naming ink colors.

Spatial cueing task

Also known as the Posner cueing task, it measures reaction times to demonstrate that people perform better at cued locations and worse at uncued locations.

Feature integration theory

Treisman's theory stating that without attention, features are not bound together, and attention is required to integrate color, shape, and orientation into one object.

Parallel search

A visual search task where a unique salient feature "pops out," making performance independent of the number of distractors.

Serial search

A visual search task where a target shares features with distractors, requiring sequential top-down focus that slows as the number of distractors increases.

Illusory conjunctions

Misbound features resulting from a lack of spatial attention, providing evidence for feature integration theory.

Hemineglect

A condition resulting from parietal lobe damage where clinical patients ignore the contralateral half of their visual field.

Simultagnosia

The inability to see more than one object at a time, a defining symptom of Balint's syndrome.