Lecture on Perception

Key Concepts

• Perceptions are Relative:
  • Perception depends heavily on context and not just objective stimuli.
  • Color and size perception can vary depending on surrounding elements.
  • Functional perspective of perception emphasizes evolutionary benefits.

Examples of Contextual Perception

Color Perception

• Illustration of Color Perception:
  • Same color can appear differently based on context (e.g., pink X on a square).
  • Context influences how colors are perceived in terms of brightness and hue.

Size Perception

• Ebbinghaus Illusion:

  • Center circle appears different in size depending on surrounding circles.
  • Contextual information alters perception of size in objects.

• Predator-Prey Example:

  • Importance of relative size perception for survival in natural environments.

Opponent Process Theory

• Visual Illusions:
  • Gray spots perceived at intersection of white squares illustrate opponent process theory.
  • Perceptions depend on detection and interpretation of changes and contrasts.

Importance of Context-Dependent Perception

• Video Demonstration:
  • Shows how perception changes when an object is moved between light and shadow.

Size Constancy

• Illustration with Hallway and Creatures:
  • Brains assume constant size for objects (e.g., bricks, floor tiles), impacting perception of size.
  • Illustrates how context can distort perceived size.

Visual Illusion Examples

• Monster Illusion:

  • Perception of size influenced by surrounding bricks and tiles.

• Architecture Illusion:

  • Perception of depth and size constancy in relation to poles or pillars.

Linear Perspective and Depth Perception

• Leaning Tower of Pisa Illusion:

  • Parallel lines should converge with distance; non-convergence alters perception of angles.

• Red-Dressed Girl Example:

  • No perceived distortion due to lack of depth cues.

Conclusion

• Questions and Interaction:
  • Encouragement to post questions on discussion board for collective learning.
  • Q&A sessions available for further discussion.