PERCEPTION OF OBJECTS Problems for Perception Gestalt Heuristics Intelligent Perception Figure-Ground Separation

Problems for Perception We are remarkably good at correctly perceiving the environment To do this, our brains must overcome problems with the input from sense organs

Ambiguous Information Any particular pattern of stimulation on the retinas could be caused by many different patterns in the environment This is called the inverse projection problem

Viewpoint Invariance Ability to recognize an object even when seen from different viewpoints

Gestalt Heuristics Heuristics are problem-solving strategies that are based on previous knowledge The Gestalt approach emphasizes perceiving whole patterns, not individual parts

Law of Pragnanz Perceive the simplest possible object, given the sensory information received

Law of Similarity Objects that look similar are grouped into the same pattern

Law of Good Continuation Points are grouped together when they form smooth, continuous lines or curves

Law of Proximity Objects that are close together tend to be grouped into the same pattern

Law of Common Fate Objects that are move together are grouped into the same pattern

Law of Familiarity Objects are more likely to be grouped into patterns that are familiar

Law of Common Region Objects in the same region of space tend to be grouped together

Law of Uniform Connectedness Uniform areas that are connected appear to be part of the same object

Law of Synchrony Events that occur at the same time are grouped together

Intelligent Perception Top-down processing allows us to correctly interpret sensory information We are typically unaware of the top-down strategies that we use: unconscious inference

Figure and Ground Accurate perception requires segregating the object we are perceiving (figure) from its background (ground)

FigureGround Seen as in frontSeen as behind Thing-likeUnformed More memorableLess memorable MeaningfulLess meaningful Owns the border Not grouped with border