Gorea, A. | bioRxiv Science

bioRxiv2017

AWARENESS OF THE OUTCOME OF SELF-INITIATED POINTING ACTIONS

Are we aware of the outcome of our actions? The participants pointed rapidly at a screen location marked by a transient visual target (T), with and without seeing their hand, and were asked to estimate (E) their landing location (L) using the same finger but without time constraints. We found that L and E are systematically and idiosyncratically shifted away from their corresponding targets (T, L), suggesting unawareness. Moreover, E was biased away from L, toward T (21% and 37%, with and without visual feedback), in line with a putative Bayesian account of the results, assuming a strong prior in the absence of vision. However, L (the assumed prior) and E (the assumed posterior) precisions were practically identical, arguing against such an account of the results. Instead, the results are well accounted for by a simple model positing that the participants E is set to the planned rather than the actual L. When asked to estimate their landing location, participants appeared to reenact their original motor plan.

animal behavior and cognition↗

bioRxiv2017

Discrete confidence levels revealed by sequential decisions

Whether humans are optimal decision makers is still a debated issue in the realm of perceptual decisions. Taking advantage of the direct link between an optimal decision-making and the confidence in that decision, we offer a new dual-decisions method of inferring such confidence without asking for its explicit valuation. Our method circumvents the well-known miscalibration issue with explicit confidence reports as well as the specification of the cost-function required by opt-out or post-decision wagering methods. We show that observers inferred confidence in their first decision and its use in a subsequent decision (conditioned upon the correctness of the first) fall short of both the ideal Bayesian strategy, as well as of an under-sampling approximation or a modified Bayesian strategy augmented with an additional bias term to accommodate global miscalibration of confidence. The observed data are instead significantly better fitted by a model positing that observers use only few confidence levels or states, at odds with the continuous confidence function of stimulus level prescribed by a normative behavior. These findings question the validity of normative-Bayesian accounts of subjective confidence and metaperceptual judgments.

neuroscience↗