Perception Notes

Perception

Brain function: selecting, organizing, and interpreting sensations.

Bottom-Up Processing

  • Information processing starts with sensory receptors and works up to the brain's integration.
  • Brain absorbs information and detects features like lines, angles, and colors to form images.
  • Begins with the stimulus; for example, looking at the cockpit of a plane without being a pilot and seeing gauges without knowing what they mean.

Top-Down Processing

  • Information processing is guided by higher-level mental processes; constructing perceptions using experience and expectations.
  • Interpretation of what the senses picked up.
  • Using background knowledge to perceive what is being sensed; for example, missing typos because you know what was intended.

Schema/Schemata

  • General knowledge about a particular situation.
  • Can be harmful or helpful in memory, based on distortions or limited experiences.
  • Concept or framework that organizes and interprets information.
  • Built from memory and experiences.
  • Example: understanding a prom even if never been to one.
Perceptual Set
  • Tendency to perceive things in a certain way based on expectations and past experiences.

Context

  • Situation/context matters in one’s perception.
  • Example: Players storming the gym floor because they won the championship vs. an opposing player punched one of their teammates

Culture

  • Perceptions based on cultural experiences.
  • Example: Placing painted eggs with a rabbit (Easter bunny) in America, even though rabbits do not lay eggs.

Gestalt Laws

  • German word for "whole."
  • The whole is greater than the sum of its parts.
Figure-Ground
  • Organize stimuli into a dominant figure and background.
Similarity
  • Organize stimuli where similar elements in the perceptual field tend to be grouped together.
Proximity
  • Nearness; objects near each other tend to be grouped together and perceived together.
    Illustration: "c m f u ran b t"
Closure
  • Tendency to fill in gaps in incomplete stimuli.
  • Subjective contour is perceived even though it doesn’t exist.

Selective Attention

  • Cognitive (mental) process that limits the amount of information allowed into consciousness.
Cocktail Party Phenomenon
  • Conversation with one individual/group but attempting to attend to another conversation with another individual/group at the same time.
  • Try to attend to both; can’t do this successfully
Context Effects
  • Describes how the environment influences how people perceive and interpret stimuli.
  • Can lead to inaccurate judgments and decisions.

Change Blindness/Inattentional Blindness

  • Failing to notice changes in the environment; a form of inattentional blindness.
  • Examples: Basket passes- Who Dunnit and Person Swap.

Depth and Distance/Binocular Cues

  • Cues that rely on both eyes working together.
Convergence
  • Eyes point more inward as an object gets closer; this information goes to the brain.
Retinal Disparity
  • Eyes are in slightly different locations, so each has a slightly different view of an object that falls on each retina.
  • The difference is greater the closer the object is to the eyes.

Depth and Distance/Monocular Cues

  • Cues that are registered by each eye independently.
  • Depth/distance can be detected by one eye alone.
Relative Clarity aka Aerial Haze/Aerial Perspective
  • Hazy items are perceived to be at a distance.
  • Closer objects in focus tend to be viewed as closer.
Relative Size
  • Large objects appear closer, smaller objects appear farther away.
Interposition
  • Closer objects block one’s vision of objects that are farther away.
Linear Perspective
  • Parallel lines, such as railroad tracks, appear to converge as they get farther away.
Texture Gradient
  • Closer to an object shows more texture/details; farther from an object, it appears smooth, losing details.

Perceptual Constancies

  • Perceive objects as relatively stable in size, shape, and color.
Emmert’s Law
  • Closer an object is, the larger the image it casts onto our retina. As object goes away, a smaller image is cast on retina.
  • We know the object is not really changing size.
Shape Constancy
  • Perceptual process allows objects to maintain a constant shape even though orientation or position of object is changed.
    Example: View of a door open vs closed…still perceived as a rectangle.
Color Constancy
  • Perceive the color of familiar objects as constant even though the sensation of color has changed (due to lighting).
  • Higher degree of this for objects that are more familiar.

Motion Perception

Stroboscopic Movement
  • An illusion of continuous movement (as in a motion picture) experienced when viewing a rapid series of slightly varying still images.
Phi Phenomenon
  • An illusion of movement created when two or more adjacent lights blink on and off in quick succession (Christmas lights that appear to run around the house).
Autokinetic Effect
  • The illusory movement of a still spot of light in a dark room.