Failure to integrate? Investigating multisensory acceleration perception on a cable-robot simulator

Current powertrains in vehicles offer a broad spectrum of driving modes that shape the driving experience. One crucial factor for determining the human factors aspects of this driving experience is the perception and evaluation of acceleration-a complex, multisensory process that integrates auditory, vestibular, and visual input. Two important questions that need to be answered in order to better characterize this percept include: How do individual sensory inputs influence acceleration perception? and How does acceleration perception change at different acceleration levels? To address these questions, here we used a unique setup based on a cable-robot simulator that allowed us to manipulate the different modalities at different levels of acceleration with real-world, in-car data for maximum realism. Specifically, we measured the just noticeable differences (JNDs) of acceleration perception in five different modality combinations with the same set of participants. Our results showed that auditory acceleration perception was less sensitive compared to other modality combinations. In addition, we found evidence for the validity of Weber’s law with JNDs increasing linearly with increasing acceleration level. Interestingly, the multisensory data showed little evidence for effective cue integration of auditory information in this setup. These findings lay the groundwork for a better understanding of how different modalities work together in acceleration perception.