Investigating the validity of the Perceptual Awareness Scale – The effect of task-related difficulty on subjective rating

Abstract

The Perceptual Awareness Scale (PAS) is often used to probe conscious experience, but the assumptions behind the scale and its validity are rarely tested. Using a continuous colour estimation task to assess perceptual quality, we focus on how well PAS follows perceptual quality and how the presence of the estimation task affects PAS ratings. We varied the number and presentation time of stimuli in a simultaneous presentation and target position in a sequential presentation. In all experiments, PAS rating closely followed colour precision. However, it was affected by task-induced response bias, even when the possible task difficulty was judged, without performing the task itself. Still, this bias was only observed on the absolute rating level rather than the scale's ability to capture changes in perceptual quality. Reported studies shed light on factors influencing scales outside of the scale formulation and construction.