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Akila Kadambi, Angela Pham, Luke Miller, Ayse Saygin; Biological motion processing under interocular suppression. Journal of Vision 2015;15(12):498. doi: https://doi.org/10.1167/15.12.498.
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© ARVO (1962-2015); The Authors (2016-present)
Biological motion processing is crucial for survival, social interaction, and communication. Since ecologically important stimuli can be prioritized in visual processing even when they do not reach awareness, we hypothesized biological motion would also receive preferential processing even when rendered unconscious. In three experiments, we used a stereoscope and the breaking continuous flash suppression (CFS) paradigm, where we gradually increased the contrast of masked point light walker (PLW) stimuli, and measured the time (i.e., contrast) at which the stimuli reached awareness. In Experiment 1, PLWs were presented either intact or spatially scrambled, a manipulation that disrupts the coherent form of the stimuli. We found that intact PLWs reached awareness significantly earlier (i.e., at lower contrast) than their scrambled counterparts. In Experiment 2, we added a speed manipulation. We replicated the results of Experiment 1, intact PLWs reaching awareness earlier. We also observed that faster PLWs broke through significantly earlier than slower PLWs, likely driven by differences in motion energy. There was no interaction between PLW coherence and speed. In Experiment 3, investigated whether the characteristics of the CFS mask would modulate the effect. The mask consisted either of rectangular or circular Mondrians (congruent shape with the dots of the PLW). We again found that intact PLWs broke through suppression earlier. There was also a significant main effect of mask type: circular Mondrians led to significantly greater suppression. There was no interaction with mask type and PLW coherence. Overall, we present evidence that biological information is processed below the threshold of awareness. Specifically, we showed (and twice replicated) an effect of PLW coherence: Intact PLWs reach awareness earlier (at lower contrast) compared with spatially scrambled ones. This coherence advantage was maintained across different levels of PLW speed and for both mask types, demonstrating the importance of biological form during unconscious processing.
Meeting abstract presented at VSS 2015
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