1. Introduction to Psychology Sensation and Perception Prof. Jan Lauwereyns jan@sls.kyushu-u.ac.jp jan@sls.kyushu-u.ac.jp

3. What do sensory systems do? Information about the world Each system responds in a specific way to a stimulus They use specialized cells, peripheral receptors Transduce the energy – Represent stimulus into brain signals

4. Different stimulus energies ( Platypus )

5. Different stimulus energies ( Platypus ) Electroreception through sensitive bill

6. Different stimulus qualities ( Bees, dolphins ) Separate groups of neurons Constantly updating

8. Rubin vase Interaction between Ascending, stimulus-driven Descending, goal-oriented (Focusing attention) This interplay shows: Difference between sensation and perception

10. While making eye movements, our eyes detect similar information on the same portion of the retina, and so they conclude that these things must have been moving along, but this can’t be…

11. Structure of the eye

15. Goodale & Milner: Dorsal, spatial = “Vision for Action” Ventral, object = “Vision for Perception”

16. The "Where" (Dorsal) Stream: Spatial Processing

17. Motion agnosia: inability to perceive motion How do I put this thing in that slot? e.g., Unable to see whether cars are moving or standing still Damage to area MT (Medial Temporal): Module in the dorsal stream ?

18. The “What" (Ventral) Stream: Object Recognition

19. Prosopagnosia: Face blindness

20. Feature Integration (simple to complex) Recognition by Components, RBC (Biederman) – Visual ‘alphabet’ – Infinite combinations –Viewpoint-independent

25. (a) A familiar object; (b) the same object seen from a viewpoint that obscures most of its geons and therefore makes it harder to recognize.

26. Can you read this?

27. The template-matching approach –E.g., bar codes –But requires infinite number, each template has to be learned as new, not robust against visual degradation –Matching to exemplars based on similarity –Viewpoint-dependent

28. Perceptual Organisation Gestalt laws: –Simplicity (Closure) –Similarity –Good continuation –Proximity –Common fate –Familiarity

30. a b c d e f g h i j k l n p o m q r s t

31. a b c d e f g h i j k l n p o m q r s t

33. Familiarity

34. Influence of context Objects are not presented in isolation Effects of visual context –E.g., 3D illusion Effects of semantic context –E.g., Effects of knowledge, expectation

39. Difficulties for machine vision: Maximal interpretation from minimal information