Consciousness in context: Disentangling the paradoxical effects of prior expectations on subjective visual experience


Our subjective experience of the world is strongly influenced by prior expectations about which sensory inputs are likely. This phenomenon is captured well by the influential theory that the brain is a hypothesis-testing machine, continually generating predictions about what to expect and matching these to newly incoming stimuli. Although this has become a popular notion over the past decade, only very recently have experimental techniques become available that allow the tackling of several important outstanding issues related to this idea. Therefore, I now aim to answer the following two questions: (1) How do the generation and testing of perceptual hypotheses relate to conscious experience?; and (2) How are the computations required for these processes implemented in the neural microcircuitry? Prior expectations have paradoxical effects on perception. Unconscious expectations based on visual context can facilitate visual search, while they can hinder the conscious detection of a change in the visual world. In several experiments using magnetoencephalography in humans, I will study this paradox: when do expectations help, and when do they hurt? Which neural systems are involved? Additionally, to understand the involved neural microcircuitry in unprecedented temporal and spatial detail, I will analyze intracranial data from non-human primates. Finally, I will develop a biophysically plausible model that captures and explains the findings from experiments 1-3, thus generating new testable hypotheses at both the neural and conscious-perceptual levels. In summary, this research proposal will leverage the unique window offered by paradoxical contextual effects on visual perception to shed light on the intricate relationship between predictive neural processing and subjective experience. Furthermore, by combining several data modalities and novel data processing techniques, this research will bridge levels of analysis to provide not only descriptive quantification of the phenomena in question, but genuine insight into the underlying mechanisms.





Dr. E. Spaak MSc

Verbonden aan

Oxford Brookes University


Dr. E. Spaak MSc


01/12/2018 tot 31/08/2021