Mapping candidate within-vehicle auditory displays to their referents

Speech, auditory icons (sounds imitating real world events), environmental sounds (naturally occurring sounds), and abstract warnings are all candidates for user interfaces. Such auditory displays and warnings for within-vehicle use must satisfy certain criteria such as being appropriately urgent, acceptable to users and commanding accurate and appropriately fast response times. Here such criteria are investigated and compared for these different forms of auditory display as an interface for a broad range of driving scenarios. In a computer task of identifying learned mappings of sound to scenario, speech and auditory icons produced both faster response times and greatest accuracy. Abstract sounds produced the slowest response times and least accuracy. Environmental sounds showed an intermediate pattern of performance for accuracy but the response times were similar to the abstract sounds. Urgency and pleasantness judgments showed an interesting contrast. Speech utterances were similarly and consistently rated as pleasant, but also of intermediate urgency (that is, speech sounds did not differ according to situational urgency). On the other hand the three other sound types mapped successfully onto their specified situational urgency levels, and showed a consistent relationship: sounds mapped to highly urgent scenarios were also judged less pleasant