PSY1004: Cognitive Psychology - Lecture 3: Perception

Vocabulary practice flashcards covering sensory systems, bottom-up and top-down processing, Gestalt principles, environmental regularities, Bayesian inference, and the dorsal/ventral visual streams from Cognitive Psychology Lecture 3.

Perception

The experience resulting from the stimulation of the senses; a complex set of processes by which sensations received from environmental stimuli are organized, recognized, and made sense of.

Interoception

The perception of internal body sensations and physiological signals, such as hunger, heart rate, and fatigue.

Vestibular Sense

The sensory system that detects motion, head position, and spatial orientation to maintain balance.

Distal Object

The physical object in the external environment that serves as the source of sensory stimulation, which the perceptual system reproduces and interprets rather than purely reflects.

Homunculus

A neurological map along the somatosensory or motor cortex representing the human body, where cortical area corresponds to sensory sensitivity or motor control rather than physical size.

Mantis Shrimp Vision

The most complex visual system in the animal kingdom, possessing 16 types of photoreceptors and 2 distinct types of stereovision.

Blaschko Lines

Unique, stripe-like cellular lines in human skin normally invisible to the human eye, but detectable under strong ultraviolet (UV) light or visible in individuals with chimerism or mosaicism.

Inverse Projection Problem

The computational difficulty of determining the actual three-dimensional distal object responsible for a specific two-dimensional pattern projected onto the retina.

Viewpoint Invariance

The human capacity to recognize and identify an object correctly regardless of the angle, perspective, or viewpoint from which it is seen.

Direct Perception Theories (Bottom-Up Processing)

Theories proposing that perception begins directly with environmental energy stimulating receptors, processing incoming raw data from the senses before higher-order recognition occurs.

Constructive Perception Theories (Top-Down Processing)

Theories proposing that perceptual processing originates in the brain, relying on a person's existing knowledge, expectations, and previous experience to construct perceptions.

Direct Pathway Model

An early bottom-up model proposing that pain perception results directly from skin pain receptors sending signals along an uninterrupted pathway to the brain.

Speech Segmentation

The top-down perceptual ability to discern where one word ends and the next begins within a continuous stream of spoken sound.

Transitional Probabilities

The implicit statistical knowledge held by a language user regarding the likelihood that one particular sound will follow another sound in a word.

Helmholtz's Unconscious Inference

A top-down theory proposing that many visual perceptions are determined by automatic, unconscious assumptions made about the physical world based on past experiences.

Likelihood Principle

The principle stating that we perceive the object or scene that is most likely to have caused the specific pattern of sensory stimulation received.

Gestalt Principles of Perceptual Organization

Intrinsic, stimulus-driven rules describing how the brain groups visual elements into unified structures, arguing that the whole is different from the sum of its sensations.

Figure-Ground Principle

A Gestalt organizational principle asserting that perceptual awareness requires distinguishing a distinct central shape (the figure) from its background (the ground).

Principle of Good Continuation

A Gestalt principle stating that points connecting to form straight or smoothly curving lines are perceived as belonging together and following the smoothest path.

Law of Prägnanz (Principle of Simplicity)

A central Gestalt law stating that every stimulus pattern is perceived in such a manner that the resulting perceived structure is as simple as possible.

Principle of Similarity

A Gestalt grouping principle stating that elements sharing physical attributes, such as shape or color, are perceived as belonging together.

Oblique Effect

The perceptual phenomenon in which humans perceive horizontal and vertical orientations more readily and with greater precision than slanted or oblique orientations.

Light-from-Above Assumption

An environmental heuristic in visual perception where humans assume light shines from overhead, utilizing the resulting shadows to infer depth and three-dimensional contours.

Semantic Regularities

The standard characteristics, meanings, and human functions typically associated with the activities carried out in specific types of scenes.

Scene Schema

An individual's stored mental expectation and knowledge concerning what elements and layouts typically exist within a particular environment.

Prior Probability (Prior)

In Bayesian inference, a person's initial belief concerning the baseline frequency or probability of a particular outcome prior to receiving current evidence.

Likelihood (Bayesian Inference)

In Bayesian inference, the extent to which available sensory data or evidence is consistent with a given hypothesis or outcome.

Bayesian Inference

A statistical approach to perception stating that the brain calculates the probability of an outcome by combining a prior belief with the likelihood provided by sensory data.

$\mu$ Rhythm

A distinct electrophysiological oscillatory frequency through which the primary sensory cortex and primary motor cortex communicate, not used by other neuronal networks.

Ventral Visual Pathway

The lower visual processing stream traveling from the occipital lobe to the temporal lobe, dedicated to object perception, identification, and categorization (the 'What?' pathway).

Dorsal Visual Pathway

The upper visual processing stream traveling from the occipital lobe to the parietal lobe, dedicated to spatial localization and visually guided action (the 'Where?' pathway).

Domain-General Cortices

Higher-order cortical regions responsible for integrating sensory and cognitive information across multiple sensory and functional domains.

Patient DF Dissociation

Clinical evidence demonstrating that ventral stream damage impairs explicit perceptual orientation matching while leaving dorsal visuomotor actions, such as 'posting' a card through a slot, intact.

Object Discrimination vs. Landmark Discrimination (Macaque Lesion Study)

An experimental demonstration showing that temporal lobe ablation selectively impairs object identification ('what'), whereas parietal lobe ablation selectively impairs spatial localization relative to a landmark ('where').