Investigating the Effects of Encumbrance on One-and Two-handed Interactions with Mobile Devices

Ng, A., Brewster, S. and Williamson, J. (2014) Investigating the Effects of Encumbrance on One-and Two-handed Interactions with Mobile Devices. In: One of a CHInd, Toronto, ON, Canada, 26 Apr-1 May 2014, pp. 1981-1990. ISBN 9781450324731 (doi: 10.1145/2556288.2557312)

117068.pdf - Accepted Version



In this paper, we investigate the effects of encumbrance (carrying typical objects such as shopping bags during interaction) and walking on target acquisition on a touchscreen mobile phone. Users often hold objects and use mobile devices at the same time and we examined the impact encumbrance has on one- and two- handed interactions. Three common input postures were evaluated: two-handed index finger, one-handed preferred thumb and two-handed both thumbs, to assess the effects on performance of carrying a bag in each hand while walking. The results showed a significant decrease in targeting performance when users were encumbered. For example, input accuracy dropped to 48.1% for targeting with the index finger when encumbered, while targeting error using the preferred thumb to input was 4.2mm, an increase of 40% compared to unencumbered input. We also introduce a new method to evaluate the user's preferred walking speed when interacting - PWS&I, and suggest future studies should use this to get a more accurate measure of the user's input performance.

Item Type:Conference Proceedings
Additional Information:Published in: CHI '14 Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, pages 1981-1990.
Glasgow Author(s) Enlighten ID:Brewster, Professor Stephen and Ng, Dr Alexander and Williamson, Dr John
Authors: Ng, A., Brewster, S., and Williamson, J.
College/School:College of Science and Engineering > School of Computing Science
Copyright Holders:Copyright © 2014 ACM
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
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