Interaction between top-down decision-driven congruency effect and bottom-up input-driven congruency effect is correlated with conscious awareness.

Abstract

In a conventional (Stroop) priming paradigm, it was well documented that objective prime-target incongruency delays response time (RT) to target compared to prime-target congruent condition. Recent evidence suggests that incongruency between the target and subjectively reported prime identity also delays RT over and above the classic congruency effect. When the prime is rendered invisible, the former effect is fundamentally a bottom-up (BU) stimulus-driven congruency effect and the latter a top-down (TD) guess-driven congruency effect. An influential theory of consciousness, global neuronal workspace theory, postulates that the long-lasting simultaneous and reciprocal interaction between TD decision network and BU input network is preserved during conscious processing and disabled during unconscious processing. Current study is focused on testing this theoretical postulation using two behavioral experiments. Our results showed that indeed TD-congruency and BU-congruency produced additive RT effects on prime-invisible trials, which implies that TD and BU prime representations are activated in independent neuronal populations. Meanwhile, an underadditive interaction effect was observed as prime visibility rose, which is a signature that TD and BU prime representations recruited overlapping neuronal populations during conscious perception. In addition, we suggest that current behavioral paradigm might be a financially friendly alternative to detect the presence of representational overlap in the brain between a wide range of mental representations, such as expectation, prediction, conscious/unconscious perception, and conscious/unconscious working memory. Public Significance StatementWhen the perceptual environment is noisy, what we think we hear or see (subjective identity) often trumps what we in fact hear or see (objective identity). Previous literature has shown that both subjective and objective identities of previous experience could significantly influence our current behavior. In this study, we demonstrated that these two identities of previous experience impact our current behavior completely independently when we have no conscious experience of seeing the sensory input. However, they shape our current behavior in an interactive fashion as the visibility of the sensory input increases. This observation is highly congruent with the global neuronal workspace theory of consciousness, which predicts representations from both BU stimulus-driven processing (objective identity) and TD decision-driven processing (subjective identity) will be activated in shared overlapping neural networks during conscious perception and in largely distinct networks during unconscious perception. We believe our approach could be a very financially friendly way to detect representational overlap between expectation, conscious/unconscious working memory and conscious/unconscious perception in the brain.