Author(s):
James Robert Marston, Dr.* - Department of Geography & Research Unit on Spatial Cognition and Choice, University of California Santa Barbara
Roberta L Klatzky, Dr. - Department of Psychology, Carnegie-Mellon University
Nicholas A. Giudice, Dr. - Department of Psychology, University of California Santa Barbara
Jack M Loomis, Dr. - Department of Psychology, University of California Santa Barbara
Reginald G. Golledge, Dr. - Department of Geography & Research Unit on Spatial Cognition and Choice, University of California Santa Barbara
Abstract:
Navigation devices for the blind require some form of cognitive processing, as users must pay attention to, process, and act on the spatial information. This could be detrimental, distracting users from immediate needs and safety. To measure the cognitive demands imposed by the navigation interface, we imposed a secondary task: Users monitored an array that sent vibrotactile stimulation to three fingers and reported any instances of sequential stimulation to the same finger. Degraded performance in the navigation task under cognitive load would indicate competition with capacity required for the secondary task.
In an experiment, blindfolded participants were guided along virtual paths and information was provided en route about the direction of the next turning point, either by spatial language ("left," "right," or "straight") or virtual sound (i.e., the perceived sound location indicated the target direction). We hypothesized that virtual sound, being processed at direct perceptual levels, would have lower cognitive demands than even simple language commands, which require cognitive mediation. The guidance modes were equivalent in a no-load condition; however, when the secondary vibrotactile task was added, participants navigating with spatial language showed an increase in distance traveled and time to complete a path. By indicating the superiority of virtual sound for guidance in the presence of additional cognitive load, as is characteristic of everyday navigation, these results have important implications for the design of future navigation and guidance systems for visually impaired persons or those needing to direct their primary attention elsewhere, e.g. when driving.
