Perception, Gestalt Laws, Prototypes, and Action Perception (Lecture Notes)

Vocabulary flashcards covering key terms and concepts from perception, Gestalt theory, prototypes, and action-perception research in the lecture notes.

PET

Positron Emission Tomography; measures blood flow with a tracer to provide functional localization similar to fMRI.

fMRI

Functional MRI; measures blood flow/oxygenation; good spatial localization but poor timing, expensive, noisy, claustrophobic, and limits movement.

ERP

Event-Related Potentials; records neural signals at scalp electrode sites; high temporal precision but poor spatial localization.

Top-down processing

Perception guided by prior knowledge and expectations rather than solely by sensory input.

Bottom-up processing

Perception driven by stimulus features and sensory input, often initiating processing.

Feature detectors

Neurons that respond to specific stimulus features; a key component of bottom-up processing.

Viewpoint invariance

The ability to recognize objects despite changes in viewpoint or perspective.

2D projection of a 3D world

The retina captures a flat image, requiring mechanisms to infer 3D structure and maintain recognition.

Likelihood principle

Idea that recognition follows the most probable interpretation given sensory data.

Size constancy

Perceiving an object as the same size despite changes in retinal image size due to distance.

Light-from-above heuristic

Assumption that illumination comes from above, influencing shading and shape perception.

Local contrast

Contrast between adjacent elements used to organize perception and grouping.

Gestalt laws

Principles for organizing percepts into wholes, e.g., Good continuation, Pragnanz, grouping by similarity.

Good continuation

Tendency to perceive smooth, continuous contours rather than abrupt changes.

Pragnanz (Simplicity)

Preference for the simplest, most stable interpretation of a scene.

Grouping by similarity

Elements that are alike are perceived as belonging together.

Prototype theory

Memory model where recognition is based on overlap with an idealized prototype stored in memory.

Recognition memory

Memory test distinguishing previously seen items (old) from unseen items (new).

Flicker paradigm

Change-detection method where a scene is intermittently blanked or altered to reveal changes.

Stage 1 (Flicker paradigm)

Participants guess whether a pattern is A or B and receive feedback.

Stage 2 (Flicker paradigm)

Recognition memory test asking if items are old (seen before) or new.

Ventral stream

The 'what' pathway (object identification) in the temporal lobe.

Dorsal stream

The 'where/how' pathway (action and location) in the parietal lobe.

DF (ventral stream damage)

A case illustrating impairment of the ventral (what) pathway.

Action-specific perception account

Perception is scaled to one’s action capabilities; e.g., hills look steeper when wearing a backpack.

Backpack manipulation

An experimental manipulation where carrying a backpack alters perceived task demands.

Estimate slope of hill

Participants’ perceived steepness of a hill, influenced by action capabilities and effort.

Perception → Action

Link where perceptual processes influence and prepare for subsequent actions.

Top-down influence in perception (Easter bunny effect)

Contextual/top-down factors bias perception (e.g., seeing a bunny during Easter season).