This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Jehoel, S. Articles by Sterr, A. Search for Related Content PubMed Articles by Jehoel, S. Articles by Sterr, A. Social Bookmarking                         What's this?

Tactile Elevation Perception in Blind and Sighted Participants and Its Implications for Tactile Map Creation

University of Surrey, Guildford, United Kingdom

Paul T. Sowden

University of Surrey, Guildford, United Kingdom, p.sowden{at}surrey.ac.uk

Simon Ungar

University of Surrey, Guildford, United Kingdom

Annette Sterr

University of Surrey, Guildford, United Kingdom

Objective: Our goal was to determine the optimal elevation of tactile map symbols. Background: Tactile perception research predicts that symbol elevation (vertical height) and texture on tactile maps could influence their readability. However, although research has shown that elevation influences detection and discrimination thresholds for single tactile stimuli and that the physiological response of fingertip receptors varies with texture, little is known about the influence of these parameters on the identification of stimuli in the context of multiple symbols as found on tactile maps. Method: Sighted and visually impaired participants performed tactile symbol identification tasks. In Experiment 1, we measured the effect of elevation on identification accuracy. In Experiment 2, we measured the effect of elevation and symbol texture on identification speed. Results: Symbol elevation influenced both speed and accuracy of identification; thresholds were higher than those found in work on detection and discrimination but lower than on existing tactile maps. Furthermore, as predicted from existing knowledge of tactile perception, rough features were identified more quickly than smooth ones. Finally, visually impaired participants performed better than sighted ones. Conclusion: The symbol elevations necessary for identification (0.040 to 0.080 mm) are considerably lower than would be expected on the basis of existing tactile maps (generally 0.5 mm or higher) and design guidelines (0.4 mm). Application: Tactile map production costs could be reduced and map durability increased by reducing symbol elevation. Furthermore, legibility of maps could be improved by using rough features, which are read more easily, and smaller symbols, which reduce crowding of graphics.

Key Words: symbol elevation • tactile map • haptic perception • visual impairment • haptic impairment • haptic and other displays • displays and controls • haptics and other senses • sensory and perceptual processes • vision

Human Factors: The Journal of the Human Factors and Ergonomics Society, Vol. 51, No. 2, 208-223 (2009)
DOI: 10.1177/0018720809334918


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?