Unit 2- Perception and Visual Processing

Perception

The process of organizing and interpreting stimuli into meaningful knowledge

Bottom-Up Processing

Perception based on sensory information. Processing incoming stimuli by their parts to recognize, interpret, or categorize.

Top-Down Processing

Perception based on internal prior expectations. Using previous experiences, knowledge, or hypotheses about incoming stimuli, recognize, interpret, or categorize.

Perceptual Set

A schema that influences the way a person perceives

Schema

A collection of knowledge about a concept that shapes how one perceives

Context Effect

Context can alter the way a person perceives. Cultural context changes schemas.

Gestalt

Integrating elements to create a whole configuration not possessed by the individual parts.

Proximity

Organizing objects that are close to each other into a group

Similarity

Organizing objects with similar qualities into a group

Closure

Perceiving incomplete forms as complete by closing gaps

Figure-Ground

Perceiving one object as the foreground that stands out from the indistinct background. Illusions can switch the figure and ground.

Cocktail Party Effect

Attention is directed at one conversation while blocking out others. However, the other conversations are still processed at some level. For example, mentioning one's name across the room changes attention from the current conversation to the direction of whoever said the name.

Inattentional Blindness

The failure to notice stimuli is caused by the fact that one's attention is directed elsewhere.

Change Blindness

The failure to notice changes in an environment or scene.

Binocular Depth Cues

Using information from both eyes to determine the depth of an object

Convergence

When the eyes rotate inward toward an object to help determine its depth. The closer the object, the larger the angle it creates.

Retinal Disparity

The right and left retinal images are compared by the brain and fused into one image with depth.

Monocular Depth Cues

Using information from one eye to determine depth.

Relative Size

When two objects are similar in size, the one that casts a smaller retinal image, the viewer perceives it as further away.

Interposition

When an object obstructs the view of another, the viewer perceives the one blocked as further away.

Relative Clarity

When an object is hazy, it is perceived as further away because it usually indicates that it passes through more light to reach the retinas.

Texture Gradient

When object texture becomes more indistinct, the viewer perceives it as further away.

Linear Perspective

Parallel lines converge at a point on the horizon as the distance from the viewer increases.

Perceptual Constancy

An object's properties are perceived as unchanged even though the stimulus did change. Brightness constancy, color constancy, shape constancy, size constancy, lightness constancy.

Apparent Movement

One perceives movement when objects are not actually moving.