Spatially uninformative sounds can enhance visual search when the sounds are synchronized with color changes of the visual target, a phenomenon referred to as "pip-and-pop" effect (van der Burg, Olivers, Bronkhorst, & Theeuwes, 2008). The present study investigated the relationship of this effect to changes in oculomotor scanning behavior induced by the sounds. The results revealed sound events to increase fixation durations upon their occurrence and to decrease the mean number of saccades. More specifically, spatially uninformative sounds facilitated the orientation of ocular scanning away from already scanned display regions not containing a target (Experiment 1) and enhanced search performance even on target-absent trials (Experiment 2). Facilitation was also observed when the sounds were presented 100 ms prior to the target or at random (Experiment 3). These findings suggest that non-spatial sounds cause a general freezing effect on oculomotor scanning behavior, an effect which in turn benefits visual search performance by temporally and spatially extended information sampling.

Temporal discontinuities and delay caused by packet loss or communication latency often occur in multimodal telepresence systems. It is known that such artifacts can influence the feeling of presence [1]. However, it is largely unknown how the packet loss and communication latency affect the temporal perception of multisensory events. In this article, we simulated random packet dropouts and communication latency in the visual modality and investigated the effects on the temporal discrimination of visual-haptic collisions. Our results demonstrated that the synchronous perception of crossmodal events was very sensitive to the packet loss rate. The packet loss caused the impression of time delay and influenced the perception of the subsequent events. The perceived time of the visual event increased linearly, and the temporal discrimination deteriorated, with increasing packet loss rate. The perceived time was also influenced by the communication delay, which caused time to be slightly overestimated.

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