1. Two Views of Perception: Bottom-up processing: -Low-level -Feature driven Top-down processing -Knowledge driven -Unconscious inference (Helmholtz)

2. What do you see in this picture?

4. Vertical Line Stimulating Receptive Field of Single Cell

5. Stimulation of a Single Cell by Downward Motion

6. BRIGHTNESS CONTRAST

7. Stimulus Luminance Profile

8. Mach Bands - Edge Enhancement Illusion

9. How the Eye Accentuates Edges

10. Mach Bands

11. Recording From a Single Cell of the Visual Cortex

12. Frequency of Firing of Single Receptor in Response to Stimuli of Different Amplitude

13. Inhibitory Effects of Stimulating Adjacent Receptor

14. Simple Cell in Visual Cortex

15. Complex Cell of Visual Cortex

16. On-Off and Center Cells (Retina)

17. How the Visual System Responds to Edges

18. Lateral Inhibition

19. Excitatory & Inhibitory Cells

20. Which column is largest?

22. Which Line is Longer?

23. Which lines are parallel?

24. Are lines a and b parallel?

25. Which Line is Longer?

26. Which central dot is larger?

27. Necker Cube

28. What is This a Picture of?

29. Excitatory & Inhibitory Cells

30. Bottom-up Perception

31. Which woman is taller?

32. Binocular Cues for Depth Convergence Binocular disparity

33. Monocular Cues for Depth Interposition Linear perspective Height in vertical plane Texture Shadow Relative motion

34. Visual Angle

35. Interposition. Which is closer? A or B? B A

36. Which column is largest?

37. Linear Perspective

38. Which red line is bigger?

40. Linear Perspective

41. Height in Visual Field

42. Texture gradients

44. Texture Gradient

45. Which woman is taller?

46. “AMES”Room

47. Direction of Shadow

48. Haze

50. Shading

51. Relative Motion

52. Moon Illusion

55. Pop out effect