Pieter Moors, Johan Wagemans, Lee de-Wit BAPS 2016, Antwerp On high-level unconscious processing in a continuous flash suppression paradigm Pieter Moors, Johan Wagemans, Lee de-Wit BAPS 2016, Antwerp

Continuous Flash Suppression (CFS) Left eye Right eye

breaking CFS (b-CFS) Left eye Right eye

Example Jiang et al., 2007

Example Jiang et al., 2007

b-CFS Suppression time as an index of unconscious processing Recent studies indicating extensive processing of invisible stimuli Face orientation (Jiang et al., 2007, …) Emotional expressions (Yang et al., 2007, …) Scene processing (Mudrik et al., 2011, …) Word valence (Yang & Yeh, 2011) Crossmodal integration (Zhou et al., 2010, …) Reading and arithmetic (Sklar et al., 2012)

Implications This type of studies has important implications for theories of conscious and unconscious processing

Main question Do these b-CFS findings really reflect high-level processing of a perceptually suppressed stimulus?

Motivation Alternative measures have mostly pointed at limited processing during CFS Adaptation to the suppressed stimulus Binocular rivalry studies also have shown limited processing of the suppressed stimulus

Motivation Neural activity related to the supprssed stimulus confined to early visual areas (Logothetis, 1998) Simple (lower-level) stimulus features are preserved The suppressed stimulus as a collection of simple features

Overview Illusory surfaces Scene processing Word processing

Previous finding Wang, Weng, and He (2012)

Previous finding Wang, Weng, and He (2012)

Current study Stimulus set Regular Irregular Kanizsa Surface Cross Moors et al. (2016) AP&P

Current study Results N = 20 Main effect Stimulus and Regularity (BF = 48) Moors et al. (2016) AP&P

Current study Follow-up experiment Conclusion Suppression time benefit likely due to differences in the orientation amplitude spectrum of the stimuli Conclusion No evidence for processing of illusory surfaces during CFS Moors et al. (2016) AP&P

Overview Illusory surfaces Scene processing Word processing

Previous finding Can Mudrik et al. (2011)

Previous finding Mudrik et al. (2011)

Current study Moors et al. (in press), Psychological Science

Current study Two additional experiments No effects of scene congruency Consistency in suppression times related to image characteristics of the stimuli Conclusion No evidence for scene integration during CFS Moors et al. (in press), Psychological Science

Overview Illusory surfaces Scene processing Word processing

Previous finding Conflicting evidence: Negative words break suppression slower (Yang & Yeh, 2011) or faster (Sklar et al., 2012) than neutral words Congruency relations: Congruent faster (Costello et al., 2009) Incongruent faster (Sklar et al., 2012)

Current study No study addressed whether words per se break suppression faster than pseudo/non-words If words are processed, a word frequency effect is expected to be observed Heyman and Moors (2014), PLoS ONE

Current study Experiment Word type (word vs. pseudo-word) Word frequency Heyman and Moors (2014), PLoS ONE

Current study Results Null model (BF = 26) Null model (BF = 11) N = 18 Heyman and Moors (2014), PLoS ONE

Current study Results Null model (BF = 15) Null model (BF = 10) N = 20 Heyman and Moors (2014), PLoS ONE

Current study Other effects: Conclusion Pixel density Trial No evidence for word-related processing during CFS Heyman and Moors (2014), PLoS ONE

Conclusions CFS suppresses the stimulus at an early level of visual processing No evidence for processing of Illusory surfaces Scenes Words High-level processing of invisible stimuli? Due to low-level stimulus related factors Type I errors

Johan Wagemans Lee de-Wit Raymond van Ee

Thank You