1. Cognition and Perception: A Short Review

2. To add: non-tech error stuff Attention blindness demos Speech errors and disfluency Emotion and design (3 teapots) Just noticeable differences (JNDs) Just noticeable differences Add Strayer cell phone study

3. Relevant topics Perception Motor abilities Attention Reading Sensory memory Working memory Long-term memory Reasoning Decision-making Speech perception and production Discourse

4. Perception Vision Rods and cones Visual acuity Color: hue, intensity, saturation Distance estimated by size (+intensity) Gestalt principles

5. Gestalt theory says perception is: Emergent Constructive Multistable Invariant Subjective contour can “create" a figure.

6. What do you see?

8. Some Gestalt Principles Proximity Similarity Good continuation Closure

9. Gestalt Principles Proximity

10. Gestalt Principles Similarity

11. Gestalt Principles Good continuation

12. Gestalt Principles Closure

13. Gestalt Principles Closure

14. What do you see?

16. Figure-ground segregation (stable) Figure  more thing-like, more memorable, smaller  seen as being in front of the ground Ground  seen as unformed material  extends behind the figure

17. Figure-ground segregation (stable) Smaller areas seen as figures

18. Figure-ground segregation (stable) Vertical/ horizontal orientations seen as figures

19. Perception Vision Hearing Pitch, loudness, and timbre Pitch range: 20 Hertz - 15,000 Hertz Resolution Speech vs. other sounds

20. Perception Vision Hearing Touch Mechanoreceptors, thermoreceptors, nociceptors (pain) Different resolution at different points Feedback is important

21. Perception Vision Hearing Touch Smell Taste

22. Modalities; speed/accuracy; practice effects Reaction times differ by modality Integrating 2 modalities into 1 percept Speed trades off with accuracy Skill increases with practice (Power Law of Practice)

23. Attention Pop-out and serial vs. parallel search

24. Attention Pop-out and serial vs. parallel search 0 0 0 0 0 0 0 0 0 0 0 V 0 0 0 0 0 0 0 0

25. Attention Pop-out and serial vs. parallel search 0 0 0 0 0 0 0 0 0 0| | | | | | | | | | 0 0 0 0 0 0 V 0 0 0| | | | | | | | | | 0 0 0 0 0 0 0 0 0 0| | / | | | | | | | 0 0 0 0 0 0 0 0 0 0| | | | | | | | | |

26. Attention Pop-out and serial vs. parallel search O N N N O O O N N O N O O O O N O O O N N O N N N O O N O O N O O N N O O N O N O N O O O N O N N O O N O O O N N O O N

27. Attention Pop-out and serial vs. parallel search Highlighting Motion, flicker Sounds

28. Change blindness Some fun demos: http://viscog.beckman.uiuc.edu/djs_lab/demos.html

29. What’s changing?

30. What makes seeing the change so hard?

31. Change blindness Inability to detect what should be obvious changes in a scene |400 ms| 40-80 ms |400 ms| Original Image BlankModified Image

32. Mud Splashes

33. No Mud Splashes

34. Change blindness Inability to detect what should be obvious changes in a scene. This is affected by  Interrupting with a blank screen  Distraction such as the “mud” (captures attention) |400 ms| 40-80 ms |400 ms| Original Image Blank/MudModified Image

35. Flicker

36. No Flicker

37. More examples: http://www.usd.edu/psyc301/Rensink.htm

38. Conversations and cell phones Auto accidents increase during cell phone use Yet people safely talk to their passengers all the time So it follows that the problem must be due to dialing, handling the phone, etc. Or does it?

39. Strayer & Johnston’s expts (in press) Visual tracking task with joystick Conditions: hands free or handheld  Converse with someone in another room  Listen to the radio or books on tape  Shadowing  Prompted word generation task

40. Results: Performance was worse for subjects on cell phones than for subjects listening to radio, books on tape, or shadowing. Twice as many red lights were missed, and RTs increased!! Whether the phone was hand-held didn’t matter at all! What do you think causes the poor performance of people on cell phones?

41. Inattention Blindness (IB) When observers fail to notice an unexpected object or event Occurs when attentional resources are directed toward another task

42. Attention Influences Perception Inattentional Blindness: involves missing a (remarkable!) change because you’re not expecting it and not attending to it. Example: Man/office/phone movie http://viscog.beckman.uiuc.edu/grafs/demos/23.html Notice anything strange? Simons & Chabris (1999)

43. Attention Influences Perception Inattentional Blindness: involves missing a (remarkable!) change because you’re not expecting it and not attending to it. Example: http://viscog.beckman.uiuc.edu/grafs/demos/15.html http://viscog.beckman.uiuc.edu/grafs/demos/15.html Count passes made by the white team or the black team (easy task) Count bounce passes and also count aerial passes (hard task) Simons & Chabris (1999)

44. Attention Influences Perception Inattentional Blindness: involves missing a (remarkable!) change because you’re not expecting it and not attending to it. Example:  More people see gorilla with easy task  More people see gorilla when attending to black team (83%) than white team (42%)  Similarity matters! Simons & Chabris (1999)

45. Inattentional Blindness - another ex. Pilots landing an aircraft simulator Experimenters were interested in a new heads-up display Pilots didn’t notice a large plane placed on the runway at the last minute Haines (1991)

46. Stages of cognitive processing (Reed, p. 3, Figure 1.1)

47. Sensory memory Iconic memory - fleeting, hi-res buffer  Must be attended to to be remembered Echoic memory Haptic memory (Characteristics vary with context)

48. Working memory Rapidly accessed, rapidly decays Capacity limitation: “7±2” (Miller) Baddeley’s 3 part model  Visuospatial sketchpad  Phonological loop  Central executive Interference

49. Long Term Memory Unlimited capacity, slower to access Interference and forgetting Encoding specificity, transfer-appropriate processing Levels of processing theory retrieval depends on encoding! graph. < rhyme < semantic < personal Visual imagery, dual coding theory

50. Long Term Memory (cont.) Semantic organization Tip-of-the-tongue effect (interference) Schemas Distortions in memory

51. Reasoning Wason’s 4-card task

52. Reasoning Wason’s 4-card task

53. Decision making Framing effects  Program A: save 200 people  Program B: 1/3 probability of saving all 600 2/3 probability of saving no one

54. Decision making Framing effects  Program A: save 200 people  Program B: 1/3 probability of saving all 600 2/3 probability of saving no one 72% choose A; 28% choose B!!

55. Decision making Framing effects  Lose a $50 ticket  Lose a $50 bill Would you buy another ticket?

56. Decision making Framing effects  Lose a $50 ticket 46% YES, 54% NO  Lose a $50 bill 88% YES, 12% NO Would you buy another ticket?

57. Decision making Framing effects Anchoring effects Do you think Dr. Brennan is older or younger than 20/60? Please give your best estimate of her age.

58. Decision making Framing effects Anchoring effects Do you think Dr. Brennan is older or younger than 20/60? Please give your best estimate of her age. Anchored at 20: 37.7 years old Anchored at 60: 39.3 years old (p <.05)

59. Conclusion: Review your knowledge of cognitive and perceptual psychology! You can distill principles of human- computer interaction and explain people’s performance and errors from what you know about human cognition and perception!