1. Surya Gayet Chris Paffen Stefan Van der Stigchel
The content of visual working memory is prioritized for conscious access.
Surya Gayet
Chris Paffen
Stefan Van der Stigchel

2. Awareness, not needed for well learned behaviors, such as walking and sometims driving But needed for demanding tasks (mental effort) such as memorizing phone numbers and playing chess. Aware of information that is required for computations

3. Awareness, not needed for most behavior, e. g. Breathing
Awareness, not needed for most behavior, e.g. Breathing. Nor for well learned behaviors, such as walking and sometims driving But needed for demanding tasks (mental effort) such as solving complex equations, memorizing phone numbers and playing chess. You are aware of that information that is required for computations

4. What information should reach awareness?
Visual awareness
The ability to subjectively report ones percept. Gazzaniga et al. (1977); Weiskrantz (1997).
Required for demanding tasks.
Dehaene, Kerzberg & Changeux (1998); Dehaene & Naccache (2001)
Limited capacity.
Baars (1997a; 1997b); Dennett (1991).
What information should reach awareness?
The present study focusses on awareness in the VISUAL domain

5. Visual working memory
Used to retain relevant information for imminent goal-directed behavior. E.g.: Baddeley (2003)

6. Visual working memory
Used to retain relevant information for imminent goal-directed behavior. E.g.: Baddeley (2003)
VWM
Priming
Pan et al. (2012)
Info in WVM good candidate! WVM guides attention towards matching stimuli. WILL IT WORK ON PERCEPTION? We now that WVM strengthens influence on behavior of subliminal stimuli.
Olivers et al. (2006)
Attention

7. Question
Will information matching the content of visual working memory receive priority in reaching visual awareness?

8. Method
Manipulate content of visual working memory (VWM). Measure how long it takes for stimuli to reach visual awareness.
Test whether this is influenced by VWM content.

9. Left/Right target detection.
Suppression task
Breaking Continuous Flash Suppression.
Tsuchiya & Koch (2005) ; Stein et al. (2011); Jiang et al. (2006)
Mask
Target
Left/Right target detection.
High contrast dynamic pattern. Stimulus ramped. Assumption: when reportable there is visual awareness.

10. VWM content

11. VWM content

12. VWM content

13. VWM content … Olivers, Meijer & Theeuwes, 2006 (colors)
Downing, 2000 (faces)
Lavie & De Fockert, 2005 (digits)
Morey & Cowan, 2004 (digits, audio)
Soto et al., 2003 & Soto et al., 2008 (shape and color)
Hollingworth, Matsukura & Luck, 2013 (shape and color) …

14. Memory task
Suppression task

15. Memory task
Suppression task

16. Memory task
Suppression task

17. Memory task
Suppression task

18. Memory task
Suppression task

19. Memory task
Suppression task

23. Hz

24. Hz

25. Hz

26. Hz

27. Hz

28. Hz

29. Hz

30. Hz

33. Stimuli for suppression task:
Saturated R, G or B
Luminance matched perceptually
Stimuli for memory task:
5 hues per color category
Pilot tested for R, G or B classification
NOT REAL COLORS! Pilot tested for comparable difficulty /// Luminance matched physically

34. Color memory condition
Congruent
Time

35. Color memory condition
Incongruent
Time

36. Passive viewing condition
Congruent
Ptc just look at the first stimulus, but don’t have to memorize it
Time

37. Passive viewing condition
Incongruent
Time

38. Experiment 1 Two memory conditions (blocked)
Color memory
Passive viewing
Two congruency conditions (intermixed)
Target is congruent with color of first stimulus
Target is incongruent with color of first stimulus

39. Accuracy
Suppression task
99% correct
Memory task
67% - 73% correct

40. Experiment 1: Results N = 10
Overview to compare the magnitude of the effects between experiments

41. Experiment 1: Results N = 10 Congruency effect
Dual task / single task -> cannot compare RTs

42. Individual participants
Number of participants
Individual differences
Congruency effect

43. Interocularly suppressed stimuli can be reported faster when they match a memorized color. Is it working memory?
Or a difference in initial processing? [conditions were blocked] PV stimulus discarded, less attentional resources

44. Postcue experiment
Time

45. Stimulus 1
Time

46. Stimulus 2
Time

47. Postcue
Time

48. Postcue = 1
Time

49. Stimulus 1
Initial processing between congruency conditions is kept constant.
Time

50. Target congruent with: Memorized color Discarded color Unrelated color
Time

51. Target congruent with: Memorized color Discarded color Unrelated color
Time

52. Target congruent with: Memorized color Discarded color Unrelated color
Time

53. Postcue experiment Is it working memory? YES
No difference in initial processing; only difference between condition is which stimulus is retained (both are potential targets)
Memorized
Discarded

54. Postcue experiment Experiment 1 N = 15
1st experiment: dual task and single task (cannot compare RTs)
Facilitation of congruent targets
Inhibition of incongruent targets
Unrelated
Memorized
Discarded

55. Postcue experiment Experiment 1 N = 15
Facilitation of congruent targets
Inhibition of incongruent targets
Unrelated
Memorized
Discarded

56. Postcue experiment Experiment 1 N = 15
Facilitation of congruent targets
Inhibition of incongruent targets
Unrelated
Memorized
Discarded

57. Postcue experiment Experiment 1 N = 15
So, VWM shortens response times to matching stimuli!!
Facilitation of congruent targets
Inhibition of incongruent targets
Unrelated
Memorized
Discarded

58. Did we measure breakthrough time?
OR, breakthrough time equal, but difference AFTER perception: response criterion / attention / motor priming

59. Monocular experiments (N = 10)
Target not suppressed. RAMP 1500,
Time

60. Monocular experiments (N = 10)
RAMP 5000, jitter 500
Time

61. Did we measure breakthrough time? YES
No difference in initial processing; only difference between condition is which stimulus is retained (both are perceived)

62. RT difference of about 14%
Overview
Replicated in two other experiments! (color as incidental feature; postcue shape color)
RT difference of about 14%

63. Conclusion

64. Conclusion
VWM content influences WHEN a stimulus reaches subjective experience. Hence, VWM content influences processing of visual information that is still non-conscious.

65. Conclusion
Actively holding a color category in working memory prioritizes conscious access of matching stimuli.

66. Final thought
The content of VWM is recruited to help funnel down the stream of sensory input, to that which requires conscious processing.
Functional link.
That is: related information that might be relevant for subsequent behavior.

67. Stefan Van der Stigchel
Acknowledgements
Stefan Van der Stigchel
Chris Paffen
This research was funded by a grant from NWO (Netherlands Organization for Scientific Research) - Grant to S.V.d.S. and C.L.E.P.

69. boost versus suppression in early visual areas.
Neuronal perspective
Visual awareness is associated with activation in early visual areas.
Ress & Heeger, 2003; Super, Spekreijse & Lamme, 2001; Weiskrantz, 1986; Weiskrantz, 1997.
Representations retained in VWM can be decoded from activity in early visual areas.
Harrison & Tong, 2009; Christophel, Hebart & Haynes, 2012; Serences, Ester, Vogel & Awh, 2013.
Interocular suppression: reciprocal inhibition of monocular channels.
Tong, 2001; Tong, Meng & Blake, 2006; Blake, 1989.
Competition:
boost versus suppression in early visual areas.