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novembre 2012

  • 19 nov Metacognitive approach to phenomenal and access consciousness

    19 nov 2012
    Séminaires/Colloques

    Speaker: Ryota Kanai, University of Sussex

     

    In many circumstances, conscious perception fails despite activations of  relevant brain regions by subliminal visual presentation. Conceptually,  failure to register a stimulus in awareness could be attributed to  suppression of early sensory signals (perceptual blindness) and/or  failure of attention to register suprathreshold signals (attentional  blindness). However, these two types of failure of awareness are  difficult to distinguish behaviourally because in both cases, observers  would report the absence of conscious percepts. To distinguish these two  types of subjective blindness, we have previously developed a  metacognitive framework called subjective discriminability of  invisibility, which is derived from the so-called Type 2 signal  detection framework (Kanai, Walsh & Tseng, 2010 in Consciousness & Cognition). This new analysis method distinguishes blindness due to  signal reduction such as lowering of contrast, backward masking and  interocular suppression as perceptual blindness, whereas it classified  reduction of visibility due to attentional distraction, attentional  blink and enhanced spatial uncertainty as attentional blindness.  Moreover, when we explicitly manipulated decision criterion by changing  the likelihood of target present trials, the percentage of target misses  increases. When the blindness induced by criterion shift was induced by  conservative criterion, the same experimental paradigm shifted from  perceptual blindness to attentional blindness. The relevance of these  findings for philosophical concepts of phenomenal and access  consciousness will be discussed.

     

    Location : Salle de réunion du LPP, H432, Centre Biomédical des  Saints-Pères, 45 rue des Saints-Pères, 75006 PARIS

    Time: 11am