Measuring Perceptual Consciousness

Abstract

Conscious perception is typically assessed with either objective or subjective measures (Seth et al.,2008). Measures are considered objective if conscious perception is estimated from performancein a discrimination task; inability to discriminate between stimuli is taken as evidence thatparticipants had no conscious perception (Hannula et al., 2005). Measures are considered subjectiveif participants report their visual experience on each trial (Sergent and Dehaene, 2004; Del Culet al., 2007). One type of subjective measures consists of metacognitivejudgments; the relationshipbetween metacognition and perceptual awareness is a matter ofdebate (Fleming and Lau, 2014;Jachs et al., 2015) and I will not discuss these measures further. Likewise, I will not discuss post-decision wagering approaches as they are affected by the participants’ risk aversion (Schurger andSher, 2008). Proponents of subjective measures stress that objective measures (discrimination)provide only task performance and are not suitable for capturing visual experience (Lau, 2008).The major objection against subjective measures is contamination by response bias. Becauseit has been argued that participants can perform discrimination in the absence of perceptualawareness, many researchers currently favor subjective measures. In this paper, I show thatobjective measures (discrimination) and subjective measures (detection) are similar and bothmeasure task performance. I further propose that task performance can be used as a valid measureof conscious perception.