Still no Evidence for Sustained Effects of Multisensory Integration of Duration

In studies on temporal order perception, immediate as well as sustained effects of multisensory integration have been demonstrated repeatedly. Regarding duration perception, the corresponding literature reports clear immediate effects of multisensory integration, but evidence on sustained effects of multisensory duration integration is scarce. In fact, a single study [Heron, J. et al. (2013). A neural hierarchy for illusions of time: Duration adaptation precedes multisensory integration, J. Vis. 13, 1-12.] investigated adaptation to multisensory conflicting intervals, and found no sustained effects of the audiovisual conflict on perceived duration of subsequently presented unimodal visual intervals. In two experiments, we provide independent evidence in support of this finding. In Experiment 1, we demonstrate that adaptation to audiovisual conflict does not alter perceived duration of subsequently presented visual test intervals. Thus, replicating the results of Heron et al. (2013), we observed no sustained effect of multisensory duration integration. However, one might argue that the prolonged exposure to consistent multisensory conflict might have prevented or hampered multisensory integration per se. In Experiment 2, we rule out this alternative explanation by showing that multisensory integration of audiovisual conflicting intervals is still effective after exposure to audiovisual conflict. This further strengthens the conclusion that multisensory integration of interval duration affects perception in an immediate, but not in a sustained manner.