Abstract
Does sensory information reach conscious awareness in a discrete, all-or-nothing manner, or a gradual, continuous manner? To answer this question, researchers have used numerous paradigms that render stimuli invisible (e.g., backwards masking) and modeled the data from these paradigms using probabilistic mixture models (Zhang & Luck, 2008). This particular approach takes participants’ responses on a continuous reproduction task and models the errors using a combination of a von Mises distribution and a uniform distribution. Modeling responses in this manner allows researchers to quantify the precision of represented items and the rates of not having a representation of an item. Using this approach, numerous studies have claimed that paradigms that render stimuli invisible do so by affecting the guess rate of these mixture models, but not the precision parameter. In other words, these findings suggest that information reaches conscious awareness in a quantal, all-or-nothing manner. Recently, however, work by Schurgin et al. (2020) has undermined foundational assumptions of mixture models and shown that this modeling approach does not reveal two distinct psychological processes. Specifically, Schurgin et al. (2020) showed that precision and guess rate always change together, as though they are just different reflections of a single underlying construct that varies along a single continuum. Thus, in the current work, we asked how well this continuous model fits the data from four radically different paradigms that manipulate visual awareness: the attentional blink, backwards masking, the Sperling paradigm, and retro-cueing. In each of these cases, formal model comparisons showed that the continuous model outperforms the models that had been used to support an all-or-nothing view of consciousness. This result even held when re-analyzing data from prior studies that had argued for a discrete view of perceptual awareness. These results suggest that information is accessed by conscious awareness along a graded continuum.