The Temporal Window of Visuotactile Integration

Abstract

The simultaneity judgment (SJ) and temporal order judgment (TOJ) tasks are the two widely used methods for measuring the window of multisensory integration; however, there are some indications that these two tasks involve different cognitive processes and therefore produce unrelated results. The present study measured observers’ visuotactile window of integration using these two tasks in order to examine whether or not SJs and TOJs produce consistent results for this particular pairing of modalities. Experiment 1 revealed no significant correlations between the SJ and TOJ tasks, indicating that they appear to measure distinct processes in visuotactile integration, and in addition showed that both sensory and decisional factors contribute to this difference. These findings were replicated in Experiment 2, which, along with Experiment 3, also showed that the reliability of the SJ and TOJ tasks may in part be responsible for the lack of agreement between these two tasks. A secondary result concerned the point of subjective simultaneity (PSS), which were tactile-leading across all three experiments. This contradicts some of the previous literature in visuotactile integration. Manipulating the spatial distance between the visual and tactile stimulus (Experiment 2) and the certainty of stimulus location (Experiment 3) did not lead to significant changes of the location of the PSS.