Deconstructing a musical illusion: Point-light representations capture salient properties of impact motions

Although visual information affects auditory perception in a variety of tasks, audition is generally believed to be relatively immune from visual influence when judging tone duration. However, Schutz and Lipscomb (2007) report a musical illusion in which physical gestures influence the perceived duration of notes per-formed on the marimba. In order to better understand which aspects of these gestures are responsible for the illusion, we created a "schematic marimbist ” consisting of either a four-point skeleton or a single mov-ing dot. This schematic abstraction captured the essential properties of the gestures, replicating the effect under both conditions. Therefore, this illusion requires seeing only a sudden change in gesture direction — independent of the depiction of a struck object. As this finding means that it can be replicated with a mini-mum of visual information, it will be useful in facilitating future research aimed at uncovering the reason for this break with the widely accepted theory of ‘optimal integration’. RESUME Malgré les effets de l’information visuelle sur la perception auditive lors de plusieurs tâches variées, l’audition est généralement considérée relativement immune à l’influence visuelle lors d’un jugement de la durée d’un son musical. Cependant, Schutz et Lipscomb (2007) décrivent une illusion musicale dans la