Dynamic Interactions between Top–Down Expectations and Conscious Awareness
- 1Donders Institute for Brain, Cognition and Behaviour, Radboud University and Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands,
- 2Department of Psychology, and
- 3Amsterdam Brain and Cognition Centre, University of Amsterdam, 1001 NK Amsterdam, The Netherlands
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Author contributions: E.L.M., H.A.S., F.P.d.L., and S.v.G. designed research; E.L.M. performed research; E.L.M., H.A.S., F.P.d.L., and S.v.G. analyzed data; E.L.M., H.A.S., F.P.d.L., and S.v.G. wrote the paper.
Abstract
It is well known that top–down expectations affect perceptual processes. Yet, remarkably little is known about the relationship between expectations and conscious awareness. We address three crucial outstanding questions: (1) how do expectations affect the likelihood of conscious stimulus perception?; (2) does the brain register violations of expectations nonconsciously?; and (3) do expectations need to be conscious to influence perceptual decisions? Using human participants, we performed three experiments in which we manipulated stimulus predictability within the attentional blink paradigm, while combining visual psychophysics with electrophysiological recordings. We found that valid stimulus expectations increase the likelihood of conscious access of stimuli. Furthermore, our findings suggest a clear dissociation in the interaction between expectations and consciousness: conscious awareness seems crucial for the implementation of top–down expectations, but not for the generation of bottom-up stimulus-evoked prediction errors. These results constrain and update influential theories about the role of consciousness in the predictive brain.
SIGNIFICANCE STATEMENT While the relationship between expectations and conscious awareness plays a major role in many prediction-based theories of brain functioning, thus far few empirical studies have examined this relationship. Here, we address this gap in knowledge in a set of three experiments. Our results suggest that the effect of expectations on conscious awareness varies between different steps of the hierarchy of predictive processing. While the active use of top–down expectations for perceptual decisions requires conscious awareness, prediction errors can be triggered outside of conscious awareness. These results constrain and update influential theories about the role of consciousness in the predictive brain.
- Received July 10, 2017.
- Revision received November 9, 2017.
- Accepted November 26, 2017.
- Copyright © 2018 the authors 0270-6474/18/382318-10$15.00/0
