Unit2: Perception

Bottom-Up Processing

Data‑driven perception that builds meaning from individual sensory details.

Top-Down Processing

Concept‑driven perception that uses prior knowledge, expectations, and context to interpret sensory input.

Selective Attention

Focusing on specific stimuli while filtering out irrelevant information.

Cocktail Party Effect

The ability to focus on one conversation in a noisy environment and shift attention when personally relevant information is heard.

Inattentional Blindness

Failing to notice an unexpected stimulus when attention is directed elsewhere.

Change Blindness

Failing to detect major changes in a visual scene during a disruption.

Schemas

Mental frameworks that organize and interpret information based on past experiences.

Perceptual Set

A predisposition to perceive something in a particular way due to expectations and context.

Gestalt Psychology

The idea that we perceive whole, unified objects rather than isolated parts; “the whole is different from the sum of its parts.”

Figure-Ground

The ability to distinguish an object (figure) from its background (ground).

Depth Perception

The ability to judge distance and perceive the world in three dimensions.

Binocular Depth Cues

Depth cues requiring both eyes.

Retinal Disparity

The slight difference between the two eyes’ images used to estimate depth.

Convergence

The inward turning of the eyes when focusing on close objects.

Monocular Depth Cues

Depth cues available to one eye.

Relative Clarity

Clearer objects appear closer.

Relative Size

Larger‑appearing objects are perceived as closer.

Texture Gradient

Textures appear finer and denser with increasing distance.

Linear Perspective

Parallel lines appear to converge as distance increases.

Interposition

When one object overlaps another, the overlapping object is perceived as closer.

Perceptual Constancies

The ability to perceive objects as stable despite changes in retinal image (shape, size, color).

Apparent Movement

The illusion of motion created by rapidly presented static images.