Landmarks’ use in speech map navigation tasks

Tools for assisting human navigation, especially in-vehicle systems, have been extensively investigated. However, few studies have explored the design of speech-based over-the-phone guidance systems. This study examined the effect of landmarks' use and the effect of landmarks’ frames of reference in route instructions on navigation efficiency during map navigation tasks and satisfaction. Twenty-seven participants performed map navigation tasks using a simulated speech navigation system in three experimental conditions: instructions containing no landmarks, instructions containing landmarks located without reference to either the traveler’s body or the surrounding environment, and instructions containing landmarks located with respect to the traveler’s body. Navigation performances on maps were higher and landmarks enable participants to make fewer directional errors and find their routes more efficiently. Satisfaction levels and navigation performances were lower when instructions did not contain any landmarks. Landmarks’ frames of reference shifting turned out to be different between human–human situations previously used and human–computer situations used here.

► The results confirm the benefit of landmarks’ use in map navigation tasks by showing that, during an interaction with a simulated speech-based guidance system, landmarks improve both participants’ performances and their level of satisfaction.
► Concerning both frames of reference used here, complement results from the ones obtained in previous human–human situations were observed.
► Landmarks’ frames of reference shifting turned out to be different between human–human situations previously used and human–computer situations used here.
► The results showed that addressee-centered landmarks could be useful in the design of speech-based guidance systems since they 1) can be produced by a guiding system that exceeds the human production’s limitation and 2) they are easier to understand by the user and they are also more appreciated.