The Fat Thumb: Using the Thumb's Contact Size for Single-Handed Mobile Interaction
Date
2011-12-02T21:11:14Z
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Abstract
Modern mobile devices allow a rich set of multi-finger interactions
that combine modes into a single fluid act, for
example, one finger for panning blending into a two-finger
pinch gesture for zooming. Such gestures require the use of
both hands: one holding the device while the other is interacting.
While on the go, however, only one hand may be
available to both hold the device and interact with it. This
mostly limits interaction to a single-touch (i.e., the thumb),
forcing users to switch between input modes explicitly. In
this paper, we contribute the Fat Thumb interaction technique,
which uses the thumb’s contact size as a form of
simulated pressure. This adds a degree of freedom, which
can be used, for example, to integrate panning and zooming
into a single interaction. Contact size determines the mode
(i.e., panning with a small size, zooming with a large one),
while thumb movement performs the selected mode. We
discuss nuances of the Fat Thumb based on the thumb’s
limited operational range and motor skills when that hand
holds the device. We compared Fat Thumb to three alternative
techniques, where people had to pan and zoom to a
predefined region on a map. Participants performed fastest
with the least strokes using Fat Thumb.
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Keywords
Design, Experimentation, Human Factors