Tutorial by Tsuchiya & Kanai : Towards the neuroscientific definition and empirical investigation of qualia

Finding the neuronal correlates of consciousness (the NCC) has become a central issue in cognitive neuroscience. However, the definition of the key word, "qualia", remains elusive, and even researchers within the same field use “qualia” in many different ways, to the extent that we cannot answer simple questions such as "whether percepts of faces are qualia?" or “emotion of fear a quale?” Here, we offer a possible definition of “qualia” by considering what are irreducible units of perception from a neuroscientific point of view. We propose that whether a percept should be considered as a single quale or compound of qualia hinges on whether the percept requires top-down attention for binding or not. Our hypothesis predicts that “qualia” emerge from neuronal circuits that bind elements of percept via genetically instructed wiring or via rewiring through extensive learning. Chunked qulia can be bound flexibly via top-down attention, yet this is just a combination of qualia, which needs to be distinguished from genuine qualia. We believe the effort to make a clearer consensus of what qualia are could lead to a surge of neuroscientific investigation of consciousness, based on an analogy with researches on ‘elementary features’ following the proposal of Feature Integration Theory by Anne Treisman. We propose that our new hypothesis will facilitate empirical research into qualia by illuminating more focused issues directly relevant to the Hard Problem.