Citation: Giudice, N.A., Marston, J.R., Klatzky, R.L., Loomis, J.M, & Golledge, R.G. (2008). Environmental learning without vision: Effects of cognitive load on interface design. Proceedings of the 9th International Conference on Low Vision (Vision 2008), Montreal, Canada.

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We report a vibrotactile version of the common n-back task used to study working memory. Subjects wore vibrotactile stimulators on three fingers of one hand, and they responded by pressing a button with the other hand whenever the current finger matched the one stimulated n items back. Experiment 1 showed a steep decline in performance as n increased from 1 to 3; each additional level of n decreased performance by 1.5 d′ units on average. Experiment 2 supported a central capacity locus for the vibrotactile task by showing that it correlated strongly with an auditory analogue; both tasks were also related to standard digit span. The vibrotactile version of n-back may be particularly useful in dual-task contexts. It allows the assessment of cognitive capacity in sensory-impaired populations in which touch remains intact, and it may find use in brain-imaging studies in which vibrotactile stimuli impose a memory load.

Citation:

Klatzky, R.L., Giudice, N.A., Tietz, J., Marston, J.R., Golledge, R.G., & Loomis, J.M. (2007). An n-back task using vibrotactile stimulation with comparison to an auditory analogue. Behavior Research Methods. 40(1), 367-372.

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A vibrotactile N-back task was used to generate cognitive load while participants were guided along virtual paths without vision. As participants stepped in place, they moved along a virtual path of linear segments. Information was provided en route about the direction of the next turning point, by spatial language (“left,” “right,” or “straight”) or virtual sound (i.e., the perceived azimuth of the sound indicated the target direction). The authors hypothesized that virtual sound, being processed at direct perceptual levels, would have lower load than even simple language commands, which require cognitive mediation. As predicted, whereas the guidance modes did not differ significantly in the no-load condition, participants showed shorter distance traveled and less time to complete a path when performing the N-back task while navigating with virtual sound as guidance. Virtual sound also produced better N-back performance than spatial language. By indicating the superiority of virtual sound for guidance when cognitive load is present, as is characteristic of everyday navigation, these results have implications for guidance systems for the visually impaired and others.

Citation:

Klatzky, R.L., Marston, J.R., Giudice, N.A., Golledge, R.G., & Loomis, J.M. (2006). Cognitive load of navigating without vision when guided by virtual sound versus spatial language. Journal of Experimental Psychology: Applied. 12(4), 223-232.

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