1. 2002/03/05Psyc202-005, Copyright Jason Harrison 20021 Cognition transforming perceptions into action and thought

2. 2002/03/05Psyc202-005, Copyright Jason Harrison 20022 Perception and Cognition Attention Memory Language Cognitive Modules Consciousness Animal Cognition Cognitive Science

3. 2002/03/05Psyc202-005, Copyright Jason Harrison 20023 Attention selection, processing, and consciousness of specific sensations

4. 2002/03/05Psyc202-005, Copyright Jason Harrison 20024 Attention recognized as very important to perception –how much can we do at once? why? difficult to describe in objective terms –clarity of perception; intensity; consciousness recent work: emphasis on selection selective access: –only certain parts of [visual] input sent on for further processing –examples: selective looking and selective listening

5. 2002/03/05Psyc202-005, Copyright Jason Harrison 20025 Example 1: Selective Looking (Neisser; Simons) Watch two teams of players –one in white shirts –one in black shirts Each player throws basketball to others on their team --- teams do not interact Select one of the colours (white or black) –Task: count number of times ball is exchanged

6. 2002/03/05Psyc202-005, Copyright Jason Harrison 20026 From http://www.wjh.harvard.edu/~viscog/grafs/demos/gorilla.shtml Pick the white or black team Count the number of times their basketball is exchanged Neisser; Simons

7. 2002/03/05Psyc202-005, Copyright Jason Harrison 20027 Neisser; Simons Result: –over half the observers do not see the person in the gorilla suit inattentional blindness: –if we don’t attend to something we won’t see it Instead of a complete, detailed world, we only see a small part of it –the part we are attending to! This is how magicians make things (dis)appear

8. 2002/03/05Psyc202-005, Copyright Jason Harrison 20028 Card Trick Pick a card

9. 2002/03/05Psyc202-005, Copyright Jason Harrison 20029 I’ve removed your card

10. 2002/03/05Psyc202-005, Copyright Jason Harrison 200210 Selective Looking and Inattentional Blindness Does anything get through? –picture of a smiley face (but not a sad one) –name of observer (Sara, George) but not close names (Sura, Geosge) –highly familiar stimuli –highly predictable or expected stimuli Some things “draw attention” to themselves –processed “without attention”, or very easily pass “perceptual filters”

11. 2002/03/05Psyc202-005, Copyright Jason Harrison 200211 each audio stream is independent of each other (streams don’t interact) Example 2: Selective Listening (Cherry and many others) Two audio streams: one input per ear repeat (“shadow”) what is being said

12. 2002/03/05Psyc202-005, Copyright Jason Harrison 200212 after the listener has finished shadowing, test what they remember from other stream… Cherry Select one of the streams (left or right) repeat (“shadow”) what is being said

13. 2002/03/05Psyc202-005, Copyright Jason Harrison 200213 Cherry Result –Listeners acquire almost nothing from unattended stream Inattentional deafness: –if we don’t attend to something, we won’t hear it Instead of a complete, detailed world, we only hear a small part of it –yes dear, of course dear, you’re so right dear

14. 2002/03/05Psyc202-005, Copyright Jason Harrison 200214 Selective Listening and Inattentional Deafness Does anything get through from unattended channel? –large change in volume –change in gender of speaker –not a change in language Again, some things” draw attention” to themselves –processed “without attention” Related: –“cocktail-party problem” -- multiple speakers –“could you repeat that?” -- short term auditory memory

15. 2002/03/05Psyc202-005, Copyright Jason Harrison 200215 Example 3: Selective Access (Posner) Focus visual attention to an area by using a cue –“Spotlight” or “zoom lens” measure time to identify target item when: –observer does not know where item will appear –observer does know where item will appear cue is a briefly presented dot at the location of target

16. 2002/03/05Psyc202-005, Copyright Jason Harrison 200216 Posner: Example 1 no cuing: what letter appears?

17. 2002/03/05Psyc202-005, Copyright Jason Harrison 200217 Posner: Example 1 no cuing: what letter appears? A

18. 2002/03/05Psyc202-005, Copyright Jason Harrison 200218 Posner: Example 2 with cuing: what letter appears?

19. 2002/03/05Psyc202-005, Copyright Jason Harrison 200219 Posner: Example 2 with cuing: what letter appears?

20. 2002/03/05Psyc202-005, Copyright Jason Harrison 200220 Posner: Example 2 with cuing: what letter appears? N

21. 2002/03/05Psyc202-005, Copyright Jason Harrison 200221 Time No Cue Cue Cue reduces time Advance knowledge of location improves performance Results: Cue versus No Cue

22. 2002/03/05Psyc202-005, Copyright Jason Harrison 200222 Amount of reduction depends on distance from cue Reduction of time Cued location Greatest reduction at location of cue -attention is like a spotlight or a zoom lens Results: Relative position of Cue

23. 2002/03/05Psyc202-005, Copyright Jason Harrison 200223 Cue triggers “formation of a spotlight” whatever is in spotlight is attended more it is attended, the better it is processed size, shape of spotlight can be controlled

24. 2002/03/05Psyc202-005, Copyright Jason Harrison 200224 Different types of cues a)exogenous (outside generating) low-level “reflexes” sudden changes (e.g., flash or movement) draws attention automatically b) endogenous (inside generating) high-level control instruction (via some kind of visual sign or pattern) sends attention to requested location

25. 2002/03/05Psyc202-005, Copyright Jason Harrison 200225 Exogenous Cuing

26. 2002/03/05Psyc202-005, Copyright Jason Harrison 200226 Exogenous Cuing

27. 2002/03/05Psyc202-005, Copyright Jason Harrison 200227 Exogenous Cuing No interpretation needed - cue is at target location N

28. 2002/03/05Psyc202-005, Copyright Jason Harrison 200228 Endogenous Cuing

29. 2002/03/05Psyc202-005, Copyright Jason Harrison 200229 Endogenous Cuing Observer need to interpret the cue

30. 2002/03/05Psyc202-005, Copyright Jason Harrison 200230 Endogenous Cuing C Observer need to interpret the cue

31. 2002/03/05Psyc202-005, Copyright Jason Harrison 200231 Effect of Cues Both types of cues control the same attentional mechanism (spotlight) but reflect different strategies a)exogenous (low-level control) bottom-up control of attention based on what’s actually happening in environment b) endogenous (high-level control) top-down control of attention based on what observer believes

32. 2002/03/05Psyc202-005, Copyright Jason Harrison 200232 Summary of Selection Selective Looking –inattentional blindness Selective Listening –inattentional deafness Selective Access –cuing, exogenous, endogenous

33. 2002/03/05Psyc202-005, Copyright Jason Harrison 200233 Attention: Selective Processing Selection of sensations (left ear, right ear) Selective access Selective construction

34. 2002/03/05Psyc202-005, Copyright Jason Harrison 200234 Selective Access Only certain parts of [visual] input sent on for further processing –some parts ignored, some filtered, some selected Perception: coordinated interaction of different perceptual systems Even if attention allows observer to see, how well are things put together?

35. 2002/03/05Psyc202-005, Copyright Jason Harrison 200235 Selective Construction Only certain parts of [visual] input are put together Attention both allows conscious vision and builds up visual representations Severe limits to what can be accessed or constructed…

36. 2002/03/05Psyc202-005, Copyright Jason Harrison 200236 Example 1: Visual Search - what visual properties are formed immediately? - diagnostic: visual search - e.g., is there a blue dot?

37. 2002/03/05Psyc202-005, Copyright Jason Harrison 200237 -Result: for some targets, search always fast - target “pops out” of display Search slope = 0 (“pop-out”) - e.g., is there a blue dot? Example 1: Visual Search

38. 2002/03/05Psyc202-005, Copyright Jason Harrison 200238 -Explanation: - for some properties, a unique value will draw attention (exogenous cue) Search slope = 0 (“pop-out”) - e.g., where’s the blue dot? -e.g., a single large item among small ones -e.g., a single curved item among straight ones Example 1: Visual Search Proposed application: data visualization

39. 2002/03/05Psyc202-005, Copyright Jason Harrison 200239 - e.g., is there a blue vertical line? -However, this is not always the case Example 1: Visual Search

40. 2002/03/05Psyc202-005, Copyright Jason Harrison 200240 - e.g., is there a blue vertical line? -Result: for some targets, search is slow - effort needed Example 1: Visual Search

41. 2002/03/05Psyc202-005, Copyright Jason Harrison 200241 - need to combine properties to detect target -combination is not automatic -spotlight of attention is needed to “weld” properties together -search is a serial process - time needed depends on number of items -spotlight travels at about 50 ms/item Example 1: Visual Search Explanation

42. 2002/03/05Psyc202-005, Copyright Jason Harrison 200242 Recall: -visual input via high-resolution fovea Retina has good acuity only in central 4° of vision -”clear vision” only in this range Example 2: Perception of Scenes

43. 2002/03/05Psyc202-005, Copyright Jason Harrison 200243 When perceiving a scene, can only get “pieces” of it at any instant -need to move eyes around to see scene Example 2: Perception of Scenes

44. Example 2: Fovea demo

50. Need to move eyes around to see the world - eye movements make jumps called saccades Saccades made about 3 times / second - jump to various parts of the world -by moving eyes around, a complete scan of world is made -eyes are almost always moving (unless something really interesting is seen) Saccades

51. 2002/03/05Psyc202-005, Copyright Jason Harrison 200251 Question: How do the “pieces” (individual fixations) get put together? Possible answer: The information from each fixation is collected into a visual buffer somewhere in the brain Construction of whole from saccades

52. (eyes being moved around) Visual Buffer Accumulates information

53. However, no evidence of this has ever been found Visual Buffer Accumulates information

54. Visual Buffer: Does not exist If it did, it should be easy to see any changes made to the image

55. 2002/03/05Psyc202-005, Copyright Jason Harrison 200255 Seeing changes sometimes very difficult to do… insert brief blank interval between original and changed images –eye blink –saccade or eye movement –occlusion –movie scene cut –see examples at http://www.wjh.harvard.edu/~viscog/lab/demos.html

56. 2002/03/05Psyc202-005, Copyright Jason Harrison 200256 http://www.wjh.harvard.edu/~viscog/grafs/demos/door.shtml Seeing changes in real-life Observers have great difficultly seeing a change made during an interruption –Change Blindness This can happen in real life

57. 2002/03/05Psyc202-005, Copyright Jason Harrison 200257 Explanation of Change Blindness Attention is needed to see change –without it, observers are “change blind” Attention combines pieces of the image –forms them into a coherent representation: token –tokens support perception (detection) of change –tokens describe actual objects in world (basis for action, e.g., grasping) –tokens can be “mis-mapped” across an interruption

58. 2002/03/05Psyc202-005, Copyright Jason Harrison 200258 1. In everyday life, we usually see change -if something changes, creates a motion signal -motion is an exogenous cue; draws attention -if something interferes with drawing of attention (flicker, occlusion) then attention doesn’t go to change -> won’t see it -attentional distraction is a major cause of traffic accidents (e.g., cell phone usage) Notes on Change Blindness

59. 2002/03/05Psyc202-005, Copyright Jason Harrison 200259 2. There is no accumulation of built-up representation -if observer looks at picture for several seconds before flicker sequence begins -> no effect -representation built up by attention (token) stays built up only as long as attention stays on it -token “remapped” after flicker/blind/saccade Attention acts like a hand: -token exists as long as pieces of input are “held” -if hand picks up drops and later picks up something else, token “remapped” to new item Notes on Change Blindness -token “dissolves” after attention withdrawn

60. 2002/03/05Psyc202-005, Copyright Jason Harrison 200260 3. If we only see a few objects at a time, why do we have the impression of seeing lots? -representation of object formed on demand -whenever it is needed, it is built -virtual representation -> “just in time” system -example: refrigerator light -only on when needed -> looks like it’s always on -example: object representation -only there when needed -> looks like it’s always there Notes on Change Blindness

61. 2002/03/05Psyc202-005, Copyright Jason Harrison 200261 Summary of Attention Selection is key: –selection of stimuli: looking, listening –processing of stimuli: access, construction Blindness comes in many forms –inattentional blindness –change blindness Tasks: –counting passes of ball, shadowing words, letter recognition, visual search, changes across blinks, flashes and interruptions.

62. 2002/03/05Psyc202-005, Copyright Jason Harrison 200262 You might be wondering Where in my head does this all happen? How do we know about these locations? Time for Neural Sites of Visual Attention! Michael Posner

63. 2002/03/05Psyc202-005, Copyright Jason Harrison 200263 Neural Sites of Visual Attention Studied via –human brain lesions (strokes, traumas) –brain scans of humans –cell recordings in monkeys Two different networks (Posner) –Posterior: expression of attention –Anterior: control of attention

64. 2002/03/05Psyc202-005, Copyright Jason Harrison 200264 Posterior Network parietal lobe (and south) movement and engagement of attention unconscious processing three interacting systems: –disengagement –movement –engagement

65. 2002/03/05Psyc202-005, Copyright Jason Harrison 200265 Posterior Systems disengagement –posterior parietal lobe –permits processing of attended source to end movement –superior colliculus eye movements: location map for tectopulvinar system –allows attention to be drawn to new location engagement –thalamus (pulvinar) –blocks input from unattended sources

66. 2002/03/05Psyc202-005, Copyright Jason Harrison 200266 Anterior Network control of attention provides contents of awareness conscious processing network includes: –anterior cingulare cortex (prefrontal) –frontal eye fields handles executive control –voluntary shifts of attention –responses to endogenous cues location of free will?

67. 2002/03/05Psyc202-005, Copyright Jason Harrison 200267 Summary of Neural Sites Posterior –automatic movement and engagement of attention Anterior –voluntary shifts of attention