Perception: Selective Attention and the Power of Illusion

1. Myers’PSYCHOLOGY (8th Ed) Chapter 6 Perception Taken from: James A. McCubbin, PhD Clemson University Worth Publishers

2. Perception • Selective Attentionfocus of consciousawareness on aparticular stimulus • Cocktail party effect

3. From the Dr. Phil show…“Killer Texting”Oct. 23, 2008 “At the level of conscious awareness, our attention is divided. Talk while driving and your attention will shift back and forth from the road to the phone.” (Myers, 238) From Dr. Phil… “…you smoke a joint and drive, your control of your vehicle goes down 35%.  You text and drive, it goes down 95%.” Metrolink train wreck in Chatsworth, CA – train operator failed to stop and collided with another train killing at least 25 – “According to the National Transportation Safety Board, the passenger train’s engineer sent and received 57 text messages that day, and he sent a text just 22 seconds prior to crashing head-on with the freight train.”

4. Inattentional Blindness Definition:failing to see visible objects when our attention is directed elsewhere When attending to one task (counting basketball passes by one of the three - person teams) about half the viewers display inattentional blindness by failing to notice a clearly visible gorilla passing through.

5. Change Blindness

6. Pop-out Phenomenon When a strikingly distinct stimulus (such as the yellow flower or the blue chick) draws our eye.

7. Perceptual Illusions

8. Perceptual Illusions

9. Perceptual Illusions

10. Perceptual Illusions

11. Illusion (other than sight) Do you hear… Tick… Tick… Tick… Tick? Or… TICK… Tock… TICK… Tock? Although a steady beat strikes the ear, each listener unconsciously shapes an auditory pattern.

12. Perceptual Organization: Gestalt • Visual Capture • tendency for vision to dominate the other senses • Gestalt • an organized whole • tendency to integrate pieces of information into meaningful wholes

13. Perceptual Organization • Figure and Ground—organization of the visual field into objects (figures) that stand out from their surroundings (ground)

14. Perceptual Organization: Gestalt • Grouping • the perceptual tendency to organize stimuli into coherent groups • Grouping Principles • proximity--group nearby figures together • similarity--group figures that are similar • continuity--perceive continuous patterns • closure--fill in gaps • connectedness--spots, lines, and areas are seen as unit when connected

15. Perceptual Organization: Grouping Principles

16. Perceptual Organization: Closure • Gestalt grouping principles are at work here.

17. Perceptual Organization: Grouping Principles What's the secret to this impossible doghouse? You probably perceive this doghouse as a gestalt-a whole (though impossible) structure. Actually, your brain imposes this sense of wholeness on the picture. As the photo on page 253 shows, Gestalt grouping principles such as closure and continuity are at work here.

18. Perceptual Organization: Depth Perception STOP Visual Cliff

19. Perceptual Organization: Depth Perception • Depth Perception • ability to see objects in three dimensions • allows us to judge distance • Binocular cues • retinal disparity • images from the two eyes differ • closer the object, the larger the disparity • convergence • neuromuscular cue • two eyes move inward for near objects

20. Perceptual Organization: Depth Perception

21. Perceptual Organization: Depth Perception • Monocular Cues • relative size • smaller image is more distant • interposition • closer object blocks distant object • relative clarity • hazy object seen as more distant • texturegradientcoarse  closefine  distant

22. Perceptual Organization: Depth Perception Relative Size

23. Perceptual Organization: Depth Perception InterpositionWhich child is closest / farthest away from the photographer?

24. Perceptual Organization: Depth Perception Relative Clarity

25. Perceptual Organization: Depth Perception • Monocular Cues(cont.) • relative height • higher objects seen as more distant • relative motion • closer objects seem to move faster • linear perspective • parallel lines converge with distance • relative brightness • closer objects appear brighter

26. Perceptual Organization: Depth Perception high, therefore further away low, therefore closer "The Coast of Protrieux“ by Eugene Boudin Relative Height

27. Perceptual Organization: Depth Perception

28. Perceptual Organization: Depth Perception Linear Perspective

29. Perceptual Organization: Depth Perception Perspective Techniques

30. What’s for dinner? Monocular depth cues such as relative size and distance indicate to people familiar with artistic and photographic use of such cues that the hunter is not targeting the elephant.

31. Perceptual Constancy • Perceptual Constancy • perceiving objects as unchanging even as illumination and retinal image change • color • shape • size Shape constancy

32. Perceptual Constancy Perceiving ShapeDo the tops of these tables have different dimensions?We adjust our perceptions relative to our viewing angle.

33. Perceptual Organization-Brightness Contrast

34. http://www.youtube.com/watch?v=WX1yDQlnebo http://www.youtube.com/watch?v=z9Sen1HTu5o

35. Perceptual Organization: Grouping Principles Impossibledoghouse

36. Perceptual Interpretation • William Molyneux wondered… “a man born blind, and now adult, taught by his touch to distinguish between a cube and a sphere”… could he distinguish between the two if he regained his sight? • John Locke’s answer… NO… because the man would never have learned the difference. • Locke tested his theories and found that most formerly blind patients could not recognize by sight what they had learned by touch

37. “At First Sight”

38. Perceptual Interpretation • Perceptual Adaptation • (vision) ability to adjust to an artificially displaced visual field • prism glasses • Perceptual Set • a mental predisposition to perceive one thing and not another • experiences, assumptions, & expectations all play a role

39. Perceptual Set: Schemas What do you perceive in these photos? (a) Is this Nessie, the Loch Ness monster, or a log? (b) Are these flying saucers or clouds? We often perceive what we expect to see. Need a volunteer for the next slide… anyone??? 

40. Perceptual Set: Schemas Read the following out loud… Mary had aa little lamb.

41. Perceptual Set: Comic Relief 

42. Human Factor • Human Factors Psychology • explores how people and machines interact • explores how machine and physical environments can be adapted to human behaviors (a) With traditionally positioned stove controls, a person must read the labels to figure out which knob works which burner. (b) By positioning the controls in a natural map, which the brain understands at a glance, we can eliminate the need to ponder written instructions just to boil water.

43. Is There Extrasensory Perception? • Parapsychology • the study of paranormal phenomena • ESP • psychokinesis • Extrasensory Perception • controversial claim that perception can occur apart from sensory input • telepathy • clairvoyance • precognition

44. Is There Extrasensory Perception? • Are the spontaneous “visions” of everyday people any more accurate than psychics? • Do our dreams foretell the future? • Will we think of someone during the day and then later hear of their death? • With enough people, the improbable becomes inevitable.

45. Extrasensory Perception What movie is this from?What is this person called?

46. Extrasensory Perception Got it now?? MinorityReport!!