Lecture Notes: Perception and Sensory Processing

Key Concepts

• Perception vs. Reality
  • Common sayings often misrepresent reality.
  • Perception is influenced by expectations, experiences, moods, and cultural norms.
  • The brain organizes raw data from senses into meaningful perceptions.
  • Perception sometimes leads to seeing what is not actually there.

Importance of Perception

• Senses and Perception
  • Senses provide raw data which the brain organizes.
  • Perception allows differentiating between various stimuli (e.g., faces, smells).
• Role of the Brain
  • The brain constructs perceptions, not the eyes.
  • Example: Upside-down faces confuse the brain because it is accustomed to right-side-up faces.

Perceptual Set

• Factors Influencing Perception
  • Expectations: Influence what we perceive (e.g., seeing a duck or a bunny in an image).
  • Context: The surroundings affect perception (e.g., the presence of Easter eggs suggests a bunny).
  • Emotions and Motivations: Alter perceptions of events or objects (e.g., hills seem steeper when feeling down).

Visual Perception

• Optical Illusions
  • Optical illusions demonstrate how perception can be misleading.
  • Example: Tables of the same size appearing different due to leg positions.

Form Perception

• Figure-Ground Relationship
  • Differentiates objects from their background.
  • Example: "Faces or vases" illusion.
• Grouping Rules
  • Proximity: Grouping nearby figures.
  • Continuity: Preferring continuous patterns.
  • Closure: Filling in gaps to form whole objects.

Depth Perception

• Binocular Cues
  • Retinal disparity: Differences in images from each eye help judge distance.
• Monocular Cues
  • Relative size, linear perspective, texture gradient, and interposition help judge distance and scale.

Motion Perception

• Motion Detection
  • Perception of motion helps infer speed and direction.
  • Large objects appear slower than small objects moving at the same speed.

Perceptual Constancy

• Consistency Across Conditions
  • Objects are recognized regardless of changes in distance, angle, or illumination.

Conclusion

• Understanding Perception
  • Perception involves constructing a model of the world from sensory data.
  • Learning perception reveals how we interpret and understand the world.

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Credits

• Written by Kathleen Yale
• Edited by Blake de Pastino and team
• Directed and edited by Nicholas Jenkins
• Consultants and graphics team acknowledged in original content.