Multistream auditory displays: The effects of amplitude modulation in the perception of multiple information streams

The growing trend in the use and reliance on information characteristic of current times has contributed to a saturation of information for the global community. This phenomenon has prompted researchers to investigate ways to increase the bandwidth of usable information by developing display systems for use in a wide range of situations and tasks. A shift from the use of static information to dynamic, real-time information has led display developers to pursue alternatives to traditional visual displays. Auditory displays have been suggested as excellent candidates, but their standard applications are currently limited to the communication of single stream information. This project attempted to bridge the gaps between research areas by demonstrating that amplitude modulation—a perceptual cue identified by both auditory scene analysis and speech perception researchers—could be used in multistream auditory displays to facilitate the perception of multiple information streams. Using auditory displays of time-series functions, it was found that amplitude modulation did not affect the perception of information in single stream displays. However, its effects in multistream displays varied depending on the nature of the decision task, the sequential or simultaneous format of stream presentation, and the specific combination of modulation rates applied to the streams. In addition, amplitude modulation appeared to employ basic perceptual properties for interpretation, and resulted in comparable judgments despite previous musical experience of participants. Overall, these investigations found that users with a wide range of experience could use these types of displays, that they could be used in contexts with reasonable levels of noise, and that amplitude modulation did not significantly distort information. These investigations found that sequential displays were not necessarily better than simultaneous ones, and that the nature of the task should be a critical factor when deciding on display format. The types of relationships uncovered by these investigations suggested that displays like those used in these investigations could be valuable tools in general auditory perception research