Investigating the Effect of Polarity in Auditory and Vibrotactile Displays Under Cognitive Load

Abstract

When users are undertaking mentally demanding visuals tasks, it can be beneficial to convey information through the auditory or tactile modality instead. A fundamental problem when mapping information to sound or vibration is establishing which polarity the mapping should use. Magnitude estimation is a popular method of establishing polarity preferences, however the effectiveness of this approach remains unclear, especially in more ecologically valid contexts. We investigate what impact the polarity of a data-sound or data-vibration mapping has on how well users can interpret these mappings, under two different levels of mental workload. Our results show that polarity does not affect error rate or cognitive workload, although may affect response time. We also found that induced cognitive load may influence usability. An implication of this is that commonly used methods of establishing data mappings need to be revisited, with cognitive load in mind, to help designers create more usable auditory and vibrotactile displays.