Overview

Perception is how we build our world. Sensation is just raw data (light hitting the eye); Perception is the brain making sense of it (“That’s a cat”).

Core Idea

The core idea is construction. We don’t see reality as it is; we see a model our brain builds.

  • Bottom-Up Processing: Building from raw data (lines -> shapes -> objects).
  • Top-Down Processing: Using expectations to fill in gaps (reading t_is sent_nce).

Formal Definition

The process of organizing and interpreting sensory information.

  • Gestalt Principles: The whole is greater than the sum of its parts. (We see a square, not 4 lines).

Intuition

  • The Dress: Blue/Black or White/Gold? Your brain makes assumptions about the lighting, changing the color you see.
  • Blind Spot: You have a hole in your vision where the optic nerve leaves the eye. Your brain fills it in with Photoshop.

Examples

  • Visual Illusions: The Müller-Lyer lines (arrows). Proof that perception is subjective.
  • Synesthesia: Crossed wires. Seeing colors when you hear music.
  • Proprioception: The sense of where your body is in space. (Close your eyes and touch your nose).

Common Misconceptions

  • Misconception: We have 5 senses.
    • Correction: We have many more (Balance, Temperature, Pain, Proprioception).
  • Misconception: Eye = Camera.
    • Correction: A camera records pixels. The eye/brain extracts edges, motion, and meaning.

Applications

  • Design: Using color and shape to guide the eye.
  • Magic: Magicians exploit perceptual loopholes (misdirection).

Criticism and Limitations

  • Naive Realism: The belief that we see the world exactly as it is. We don’t.

Further Reading

  • The Man Who Tasted Shapes by Richard Cytowic
  • Incognito: The Secret Lives of the Brain by David Eagleman