The effect of different navigation voices on trust and attention while using in-vehicle navigation systems

Automobiles are suffused with computers and technology designed to support drivers at all levels of the driving hierarchy. Classic secondary devices, such as in-vehicle navigation systems (IVNS), present strategic and tactical information to drivers. In order to mitigate the potential distraction and workload when interacting with these devices while driving, IVNS often employ voices to deliver navigational instructions. In contrast, voices are used during interpersonal encounters to engage the listener, provide clues about the speaker's personality and make judgments about them, for example, whether to like them and to trust them.

A study conducted within a fixed-based medium-fidelity driving simulator investigated if drivers made similar 'personality' attributions to voices emanating from an IVNS and if this subsequently affected how they engaged with the device while driving. Twenty-nine experienced drivers and IVNS users drove to a specified destination with a simulated IVNS and authentically reproduced UK road signage to support their route-finding. Either of two navigation voices were used; one considered 'high-trust' and the other 'low-trust.' Presented with a conflict scenario, where the verbal route guidance differed to the road signs, 22 drivers followed the IVNS instruction rather than the road signs. Of these, the majority were using the 'high-trust' voice.

A post-drive questionnaire revealed that, despite the fact that message content and delivery remained equivalent, participants recognized different attributes ('personalities') associated with each of the navigation voices. This influenced their attitudes towards them, including how much they liked them, their preferences for use, and the level of trust that they associated with each voice.

While these, so-called, social responses may be invited and indeed encouraged in other contexts, in the automotive domain they are likely to conflict with the intended benefits of using a voice to deliver route guidance and therefore have implications for road safety and design.