Subjective and objective approaches in the study of conscious perception

Science requires objective measurements to be able to falsify predictions, whereas consciousness is thought to be intrinsically personal and subjective. Consequently, behavioral measures of consciousness are often designated as “objective” or “subjective”. Surprisingly however, the exact meaning of the terms objective and subjective is typically not clearly defined. Moreover, applying this label to a given behavioral measure is misleading, as the same measure can often be analyzed within a “subjective” or “objective” framework. Thus, the objective-subjective designation is not only relevant to the measure that is used, but to several other dimensions as well. In this chapter we provide a brief overview of dichotomies along which one might conceptualize the difference between objective and subjective approaches, such as the empirico-analytical method (manipulation vs trial-by-trial sorting), the mode of stimulus presentation (forced-choice vs nonforced-choice), the response type (Type 1 vs Type 2), and the adoption of a ground truth when computing the outcome measure (performance vs appearance). Although these dichotomies often overlap, the correspondence between them is typically only partial. Problems and pitfalls are discussed. Finally, advice is formulated to always explicitly outline how one’s stimulus presentation, task, response measure, and analysis approach score on these dichotomies, requiring further explicit justification when claiming to capture “consciousness” as a construct.