Exploring the function of consciousness by testing the life-time and complexity of unconscious processes in the human brain
02 / 2012 - 02 / 2015
Recent studies in Neuroscience and Psychology have revealed that unconscious processes can be extremely powerful. Unconscious stimuli have been shown to activate brain regions at all levels of the cortical hierarchy along with all the associated (high-level) cognitive functions. Therefore, many scientists and philosophers have claimed that consciousness does not play a (major) role in generating behavior and orchestrating cognitive functions and that this spells serious trouble for the existence of free will. However, others have claimed the opposite. Although the depth of unconscious processing is surprisingly powerful, the type of neural processing of conscious and unconscious information probably differs fundamentally. Crucially, the ?life-time? of unconscious neural activations seems limited, whereas conscious activations are not. Therefore, consciousness might be necessary in order to integrate information over an extended period of time. Further, conscious information processing seems uniquely marked by dynamic communication between brain regions. This neural process is thought to break the automatized nature of (unconscious) information processing, because brain regions can share information and recombine this into novel and more complex computations. Therefore, consciousness might be necessary to strategically and flexibly weigh incoming information based on our current goals and needs. In the proposed studies I directly test these assumptions. In two different decision making tasks, subjects have to combine sequentially presented conscious/unconscious stimuli across time. In combination with a set of brain imaging methods (MEG, EEG, intra-cranial recordings) we will examine the differences and similarities in how conscious and unconscious information is integrated in the brain, and how this guides and biases our decisions. By manipulating the relative importance of information across experiments, the flexibility and complexity of (un)conscious processing is carefully explored. Results from these experiments will further elucidate the scope and limits of unconscious processes and advance our understanding of the potential function of consciousness.