Survey of Modern Psychology

1. Survey of Modern Psychology Optical Illusions

2. Illusions generally happen when: • The stimulus is unclear • Information is missing

3. When we do not have sufficient information about a stimulus, we fill it in ourselves • Gestalt theory • Learning based inference

4. Gestalt Theory The brain perceives patterns in stimulation For example, we see a triangle as a single figure rather than as three lines

6. Closure We fill in the blank space to form a closed figure

8. Figure and Ground • The figure is the part that grabs our attention • The ground is anything surrounding the figure • The figure can be seen as either a vase or as two faces

9. Huang, L., Pashler, H. (2009). Reversing the Attention in Figure-Ground Perception. Psychological Science, 20, 1199-1201.

10. A

11. When a person focuses their attention on the red lines, the red lines appear to be in front of a green background

12. B

14. Explanation We look for the simplest possible explanation of stimuli, and interpret them as 3-D In image B, when paying attention to the red lines we saw a picture of a face Normally, this would mean that we’re looking at a whole face with columns in front of it In image C, the strips were shuffled so the red or green did not form a continuous image anymore. It was therefore interpreted in the same was as figure A

16. Perceptual Grouping • We group together stimuli that appear to belong together • The X’s are similar to other X’s, and we therefore group them together as columns

18. Meaningfulness – “Prägnanz” • We look for the simplest interpretation possible, with the least amount of effort • We know what we expect to see, and that makes proofreading difficult

19. Meaningfulness – “Prägnanz” Note: humans are good at this, computers are not. This is why spammers use symbols rather than letters to get through filters

20. Learning Based Inference • We use what we know/have learned to interpret new stimuli • Our knowledge gives us a context for recognizing and interpreting new stimuli

21. Context and Expectation FOX; OWL; SNAKE; TURKEY; SWAN; D?CK BOB; RAY; DAVE; BILL; TOM; D?CK

22. Context and Expectation FOX; OWL; SNAKE; TURKEY; SWAN; D?CK BOB; RAY; DAVE; BILL; TOM; D?CK • In the first list, “U” made sense • In the second list, “I” made sense

23. Context and Expectation .rat eht saw tac ehT Turn this around in your mind and read it

24. .rat eht saw tac ehT People usually interpret the sentence logically as saying “The cat saw the rat.” In reality, when reversed the letters said, “The cat was the tar”

25. From Psychology Core Concepts Fifth Edition Zimbardo, Johnson and Weber What difference(s) do you see in these two pictures?

26. We have difficulty seeing details of faces that violate our expectations of a face

29. What do you see?

30. Priming (Priming is subconsciously cuing a particular response) The images or labels shown surrounding an ambiguous image will tend to lead to a particular interpretation. In this case, you may have been more likely to initially see the image as a young woman

32. The Ponzo Illusion We look at see the tracks as cues for distance. Because A appears to be further away, we perceive it as being larger than B

33. Hybrid Images

34. Hybrid Images

35. Dimensions “Spinning Dancer” illusion http://z.about.com/d/psychology/1/0/Z/5/Spinning_Dancer.gif • We tend to view objects as three dimensional even if they are really not • The image is not actually “spinning” but we interpret it as 3-D spinning • It is processed as both counter clockwise and clockwise, but one interpretation wins at any given time THIS IS NOT ACTUALLY LINKED TO BEING “LEFT BRAINED” OR RIGHT BRAINED”

36. Necker Cube

37. Cues for Depth Perception • If two objects that one would assume are the same size show different sized images on the retina, the observer judges them as being different distances away. • The relative size of the objects is used to judge depth and distance.

38. Cues for Depth Perception • Lighter colored objects seem closer to us, and darker objects seem further away

39. Cues for Depth Perception • Closer objects obstruct our vision of more distant objects behind them. • Partially hidden objects are therefore further away than the object that hides it.

40. Ames

42. Stare at this image

44. Negative Afterimage • Caused by a change in the rate of firing in retinal ganglion cells • After the cells are inhibited or excited for an extended time, they show a rebound effect (fire faster or slower than normal)

45. http://www.moillusions.com/2009/05/hidden-skoda-fabia-optical-illusion.htmlhttp://www.moillusions.com/2009/05/hidden-skoda-fabia-optical-illusion.html

46. M C Escher

47. M C Escher

48. Julian Beever

49. Julian Beever

50. Julian Beever