Illusory double flashes can speed up responses like physical ones: evidence from the sound-induced flash illusion.
ABSTRACT When a single brief flash is accompanied by two auditory beeps, participants often report perceiving two flashes. The present experiment examined whether the perception of illusory redundant flashes can result in faster responses as compared to the perception of a single flash, because previous research has shown such a redundancy gain for physical stimuli. To this end, participants were asked to respond as rapidly as possible to the onset of any flash. Following their response, they additionally indicated whether they perceived a single flash or a double flash. Most importantly, we observed significant shorter reaction times in response to redundant flashes, irrespective of whether they were physically presented or illusorily perceived. Taken together, our results suggest that an illusory percept can affect simple reaction time in much the same manner as the corresponding physical stimulation.
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ABSTRACT: In a go/no-go experiment, semantic redundancy gain was assessed for responses to single written words. Specifically, we asked participants to respond only to words whose meaning matched at least one semantic target feature-that is, the target category (e.g., animal), the target color (e.g., gray), or both. On redundant-target trials, the word (e.g., elephant) matched both semantic target features (i.e., gray and animal). On single-target trials, the word (e.g., beaver) matched one target feature (i.e., animal) and a nontarget feature (i.e., brown). We observed shorter reaction times in the redundant-target condition than in the faster single-target condition. Hence, the present study provides the first evidence that redundancy gain is not limited to responses to redundant proximal stimulus features but can also be observed for responses to semantic feature information.Psychonomic Bulletin & Review 12/2012; · 2.61 Impact Factor
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ABSTRACT: Selective attention and multisensory integration are fundamental to perception, but little is known about whether, or under what circumstances, these processes interact to shape conscious awareness. Here, we used transcranial magnetic stimulation (TMS) to investigate the causal role of attention-related brain networks in multisensory integration between visual and auditory stimuli in the sound-induced flash illusion. The flash illusion is a widely studied multisensory phenomenon in which a single flash of light is falsely perceived as multiple flashes in the presence of irrelevant sounds. We investigated the hypothesis that extrastriate regions involved in selective attention, specifically within the right parietal cortex, exert an influence on the multisensory integrative processes that cause the flash illusion. We found that disruption of the right angular gyrus, but not of the adjacent supramarginal gyrus or of a sensory control site, enhanced participants' veridical perception of the multisensory events, thereby reducing their susceptibility to the illusion. Our findings suggest that the same parietal networks that normally act to enhance perception of attended events also play a role in the binding of auditory and visual stimuli in the sound-induced flash illusion.NeuroImage 05/2012; 62(3):1334-41. · 6.25 Impact Factor