Make the Unconscious Explicit to Boost the Science of Consciousness

摘要

If we are to understand the how’s and why’s of conscious processing we need to compare itwith unconscious processing and see how they differ (Baars, 1988). An accurate characterizationof unconscious processing is therefore crucial for continued progression in the science ofconsciousness. The scope and limits of unconscious processing have been extensively investigatedfor more than a century (see e.g., Kouider and Dehaene, 2007, for a historical perspective), buta consensus has yet to emerge. While some argue that unconscious processing is very limited(e.g., Holender and Duscherer, 2004), others have proposed that anything that can be doneconsciously can also be done unconsciously (Hassin, 2013; but see Hesselmann and Moors, 2015).The controversy continues in part for methodological/technical reasons, for example that it is nontrivial to present a stimulus below the limen of consciousness while maintaining the possibilityfor the brain to process the information. We argue here that this aspect is particularly relevant toconsider when evaluating the possibility of unconscious high-level cognitive functions: if a certainlevel of processing of the input stimulus cannot be verified to start with, a lack of related high-levelcognition would be expected. Such situation provides little evidence against the possibility of aparticular type of unconscious high-level cognition. We also argue that evidence against particularunconscious high-level functions should be framed in an experimental context where at least theconscious analog can be demonstrated—otherwise the evidence is again weak. Lastly, we note thatan explicit characterization of the unconscious is crucial also in research on the neural correlatesof consciousness.