Illusion A false representation of the environment Perception Selection Organization

1. Perception • Illusion • A false representation of the environment • Perception • Selection • Organization • Interpretation

2. Illusory Contours • Perceived edges that do not physically exist • Visual system fills in the gaps • Inspired Gestalt School: • Max Wertheimer (1880-1943) • Wolfgang Kohler (1887-1967) • Kurt Koffka (1886-1941) • Gestalt Grouping Rules

3. Perception: Selection Selective attention “Cocktail party effect” The process whereby the brain sorts out, and only attends to, the important messages from the senses. Feature detectors Specialized cells in the brain that respond only to certain sensory information. Based on experience. Habituation The tendency of the brain to ignore environmental factors that remain constant.

4. Perception: Organization • Form • Constancy • Color • Depth

5. Organization: Form Gestalt ability to perceive the whole stimulus rather than perceiving its discrete part as separate entities good continuation

6. Organization: Form Figure and Ground see a main object relative to ground

7. Organization: Form Proximity items near each other are grouped together

8. Organization: Form Continuity perceive smooth as continuous patterns

9. Organization: Form Closure fill in the gaps

10. Organization: Form Similarity image chunks that are similar to each other will be grouped together

11. Violations of Perceptual Organization by Form: Ambiguous Figure

12. Violations of Perceptual Organization by Form: Ambiguous Figure

13. Violations of Perceptual Organization by Form: Impossible Figure

14. Violations of Perceptual Organization by Form: Impossible Figure

15. Violations of Perceptual Organization by Form: Impossible Figure

16. Organization by Constancy Perceptual Constancy: the tendency for the environment to be perceived as remaining the same even with changes in sensory input Size Shape Color Brightness

17. Organization by Color Trichromatic Theory: color perception results from mixing three distinct color systems - red, green, and blue Opponent-Process Theory: color perception is based on three systems of color opposites - blue-yellow, red-green, and black-white

18. Organization by Depth Depth Perception: the ability to see three dimensions although the images that strike the retina are in two dimensions Binocular Cues Monocular Cues

19. Depth Perception

20. Binocular Cues: Retinal Disparity

21. Binocular Cues: Retinal Disparity

22. Monocular Cue: Relative Size assuming same size can discriminate distance

23. Monocular Cue: Interposition blocked objects will appear closer

24. Monocular Cue: Relative Clarity hazy objects are perceived to be further away

25. Monocular Cue: Texture Gradient coarse objects are perceived as being closer

26. Monocular Cue: Relative Height higher objects are perceived to be farther away

27. Monocular Cue: Relative Motion nearer things are perceived to move faster

28. Monocular Cue: Linear Perspectives more line convergence gives the perception of greater distance

29. Monocular Cue: Relative Brightness dimmer is perceived to be farther away

30. Perception: Interpretation Perceptual Adaptation we adapt to changes in perceptions Perceptual Set previous experiences affect our perceptions Individual Motivation personal interests affect our perceptions Frame of Reference perceptions change as context changes

31. Object Recognition • Naïve Template Theory • Visual object would have to match existing template to be perceived • Structural Description Theories • Visual object is recognized by its specific parts and the relationships between its parts. • Multiple Recognition Committees • Visual objects are recognized by multiple means simultaneously • Grandmother Cell Theory • Single cells are responsible for recognizing specific objects

32. Naïve Template Theory

33. Structural Description Theories

34. Multiple Recognition Committees

35. Grandmother Cell Theory