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Poster B96 in Poster Session B - Thursday, August 8, 2024, 1:30 – 3:30 pm, Johnson Ice Rink
Distinct metacognitive and decisional process for fission and fusion illusion
Rao Xie1 (), Steffen Buergers2, Uta Noppeney3; 1Radboud University, 2University of Birmingham; Royal HaskoningDHV, 3Radboud University; University of Birmingham
Combining sensory inputs into a single unified perceptual decision poses an important cognitive challenge in everyday life. In the fission and fusion illusion, the number of perceived flashes is biased towards the number of concurrently presented beeps. While both illusions have been explained by Bayesian principles of reliability weighted integration, neuroimaging research has pointed towards divergent underlying processes. In this electroencephalography (EEG) study, observers were presented with 1 or 2 flashes together with 0, 1 or 2 beeps. On each trial, they performed a flash discrimination task followed by a confidence rating. Behaviourally, we observed that metacognitive efficiency in the 2-beep condition was significantly higher than in the 0-beep and 1-beep conditions. Multivariate EEG decoding locked to observers’ decisional responses showed that the neural representations generalized between the 0 and 1-beep conditions, yet were distinct from the fission illusion. Our findings show that despite being governed by shared computational principles the fission and fusion illusions are distinct in terms of their neural decisional processes and their metacognitive outcomes.
Keywords: sound induced flash illusion confidence metacognitive efficiency EEG decoding