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Sagi, D.

Publications and source records attributed to Sagi, D..

2 recordsLinked to original sources

Real-time visual interactions across the boundary of awareness

The relationship between our conscious experiences of the visual world and the neuronal processes involved in the processing of visual information is a central theme of current research. However, it is not yet known whether conscious experiences possess unique quantitative or qualitative processing features. Recently we have shown that two visual stimuli, one consciously experienced and one not, interact as function of features and objects similarity, pointing to preserved visual representations in the absence of perceptual awareness. Here we ask whether these representations can be modified in the absence of perceptual awareness by testing interactions while the unperceived stimulus is being modified outside of ones awareness. Observers performed a Motion Induced Blindness task, wherein a plaid Target was morphed into a Gabor patch once disappearance was reported. Reappearances of the morphed target were induced by a visible Cue. Our results indicate that the effectiveness of the cue depends on the target representation during the time of suppression. Reappearance rates were highest when the morphed target and the cue share the same orientations. Our findings indicate that the target-cue interactions do not depend on memory-stored representations, but rather on the current state of the consciously unavailable target. We conclude that visual representations can be modified in the absence of conscious perception.

neuroscience

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