Gestalt Rules of Perception

The Gestalt (shape/form) school of thought of of perception is that the whole is more than the sum of its parts. It's a reaction to the idea that perceptions are built up from tiny building blocks of sensations.

It's used to figure out how we group information from the visual cortex together.

Grouping Principles

  • Proximity - group nearby segments of images together
  • Similarity - group similar things
  • Good continuation - perceive continuous patterns
  • Closure - fill in the gaps

Proximity

We group nearby segments of things together; for instance we'd describe the following as, respectively, a grid, 4 columns and 4 rows.

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Similarity

Similarly here we group this as 4 columns and 4 rows, due to the colours.

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Continuation

We perceive continuous patterns, so we're more likely to continue shapes than see them as distinct.

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Closure

Closure allows us to fill in the dots/lines - we can generalise an image, or see an image through a railing as we drive past.

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Figure-Ground Perception

The problem of grouping is determining what to include/exclude from our image/idea of an object/concept.

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This is known as the figure-ground perception - what do we count as the background, and what as the foreground/subject, of an image.

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Perceptual Constancies

Despite continuous changes in image/optic array, perception of properties of objects in the environment remains stable. Perceptual constancies are important for object recognition and successful interaction with the environment.

  • Size constancy: perceived size of an object constant over distance despite changes in size of retinal projection
    • E.g. we can know that people close up and far away are the same people-size.
  • Shape constancy: perceived shape remains constant despite changes in object orientation and the shape of its retinal projection
    • E.g. we can open a door and still think of it as the same door-shape.
  • Colour constancy: perceived colour remains constant despite changes in illumination
    • E.g. we compensate for shadows or odd lighting and still view things the same colour.