How can we measure awareness? An overview of current methods.

The study of consciousness requires a solution to the following fundamental problem: How can we measure consciousness? While there has been substantial progress in measuring the level of awareness, and researchers have made steady progress delineating the neural correlates of consciousness, it remains impossible to measure the contents of awareness directly and link a person’s subjective experience to an objective state of the world or the person. In a historical overview this chapter highlights how research has moved from a strict dissociation logic and the search for subjective and objective thresholds for awareness to more graded approaches in which conscious and unconscious processes are recognized to contribute to all measurements. Subsequently, it delineates the most important challenges to behavioral methods such as exhaustiveness, exclusiveness, and sensitivity. In particular it focuses on the risk of confounding awareness and metacognition, and the tension between exclusiveness of a measure and the information criterion.