2.1A-B Principles of Perception and Visual Perceptual Processes

AP Psychology: Principles of Perception

Sensation and Perception

  • Sensation: The process of detecting, converting, and transmitting raw sensory information from both external and internal environments to the brain.
  • Perception: The process of selecting, organizing, and interpreting sensory information.

Information Processing

  • Top-Down Processing:

    • Guided by higher-level mental processes, it involves using existing knowledge and expectations to interpret sensory information.
    • Starts in higher brain centers and affects how we interpret incoming stimuli.
    • Example: Stereotyping where the whole (stereotype) influences individual components.

  • Bottom-Up Processing:

    • Analysis that begins with sensory receptors and progresses to the brain's integration of sensory information.
    • It involves recognizing stimuli by analyzing available external information.
    • Starts with raw sensory data and works 'up' to higher-level analysis.

Schemas

  • Schema:
    • A collection of basic knowledge about a concept that guides perception and problem-solving.
    • Helps in making connections and facilitating new learning by freeing up working memory space.

Vulnerability to Illusion

  • Top-Down Processing and Illusion:
    • Example: The ability to read jumbled words as long as the first and last letters are in place, illustrating how our mind processes words as wholes, not by individual letters.

Perceptual Set

  • Perceptual Set: A mental predisposition to perceive one thing and not another, influencing perception under specific circumstances.

Context Effects

  • The context in which information is presented can significantly influence perception.

Principles of Sensation and Perception

  • Stroop Effect: Demonstrates interference in reaction times in a color-naming task when the color of the text and meaning of the word differ.

Influence of Culture and Experience

  • Cultural background and personal experiences shape perception and influence assumptions about perceptions.

Selective Attention

  • The ability to focus on one stimulus while filtering out others, crucial for processing only important details:
    • We observe about 11 million bits of information per second, but only manage to process approximately 40 bits.

Divided Attention

  • The ability to focus on multiple tasks simultaneously (multitasking) can reduce attention quality on individual tasks.

Cocktail Party Effect

  • The ability to focus on a single sound (like a conversation) while filtering out background noise, showing selective auditory attention.

Inattentional Blindness

  • Occurs when focus on one relevant stimulus results in missing other stimuli, demonstrating limitations in attention.

Change Blindness

  • The failure to notice large changes in a visual scene when attention is focused elsewhere.

Perceptual Organization

  • Gestalt Psychology: The brain naturally organizes sensory information into wholes.
    • Principles include:
    • Figure and Ground: Differentiating the primary object (figure) from the background (ground).
    • Proximity: Objects close to each other are perceived as a group.
    • Closure: The brain fills in gaps to perceive incomplete shapes as whole.
    • Similarity: Objects sharing similar characteristics are grouped together.

Depth Perception

  • Depth Perception: The ability to see the world in three dimensions and estimate distance.
  • Binocular Cues:
    • Retinal Disparity: The difference in images seen by each eye, greater for closer objects.
    • Convergence: The inward angle of the eyes when focusing on a close object.
  • Monocular Cues:
    • Linear Perspective: Parallel lines appear to converge at a distance.
    • Interposition: One object obstructing another indicates that it is closer.
    • Relative Size: Smaller images are perceived as further away.
    • Texture Gradient: Objects appear less detailed when farther away.

Perceptual Constancies

  • Perceptual Constancy: The tendency to perceive objects as stable despite changes in sensory input.
    • Types include:
    • Color Constancy: The brain's perception of color relative to context.
    • Size Constancy: Objects are perceived as the same size despite distance.
    • Shape Constancy: Objects are perceived as maintaining their shape regardless of angle.
    • Lightness Constancy: Perception of brightness remains consistent under varying illumination.