Consciousness under the spotlight: the problem of measuring subjective experience

<p>The study of consciousness is considered by many one of the most difficult contemporary scientific <br>endeavours and confronts several methodological and theoretical challenges. A central issue that <br>makes the study of consciousness so challenging is that, while the rest of science is concerned <br>with problems  that  can  be  verified  from  a  "third  person"  view  (i.e.,  objectively),  the  <br>study  of consciousness deals with the phenomenon of subjective experience, only accessible from a <br>“first person” view. In the present article, we review early (starting during the late 19th <br>century) and later efforts on measuring consciousness and its absence, focusing on the two main <br>approaches used by researchers within the field: objective (i.e., performance based) and subjective <br>(i.e., report based) measures of awareness. In addition, we compare the advantages and <br>disadvantages of both types of awareness measures, we evaluate them according to different <br>methodological considerations and discuss, among other issues, the possibility of comparing them by <br>transforming to a common sensitivity measure (d’). Finally, we explore several new approaches –such <br>as Bayesian models to support the absence of awareness –, as well as future challenges – such as <br>measuring the qualia, the qualitative contents of awareness – in consciousness research.</p>