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

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

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

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

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

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

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

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.

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.

VWM content

VWM content

VWM content

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) …

Memory task Suppression task

Memory task Suppression task

Memory task Suppression task

Memory task Suppression task

Memory task Suppression task

Memory task Suppression task

Hz

Hz

Hz

Hz

Hz

Hz

Hz

Hz

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

Color memory condition Congruent Time

Color memory condition Incongruent Time

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

Passive viewing condition Incongruent Time

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

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

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

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

Individual participants Number of participants Individual differences Congruency effect

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

Postcue experiment Time

Stimulus 1 Time

Stimulus 2 Time

Postcue Time

Postcue = 1 Time

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

Target congruent with: Memorized color Discarded color Unrelated color Time

Target congruent with: Memorized color Discarded color Unrelated color Time

Target congruent with: Memorized color Discarded color Unrelated color Time

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

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

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

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

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

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

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

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

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

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

Conclusion

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

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

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.

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 404-10-306 to S.V.d.S. and C.L.E.P.

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.