clarke@csri.toronto.edu (Jim Clarke) (01/09/89)
GRAPHICS & INTERACTION SEMINAR - Thursday, January 19, 3.30 p.m. in Room GB248
(GB = Galbraith Building, 35 St. George Street)
Ben Shneiderman
University of Maryland
"Touchscreen vs. the mouse for hypertext:
Empirical data on pointing at small targets"
For several years we have been developing new strategies for touchscreens
that lead to dramatically improved precision with small targets. By pro-
viding continuous feedback on the screen about the current position, by al-
lowing the cursor to be dragged with the finger, and by delaying initiation
of action until lift-off, we have provided increased user control to en-
able pointing at small targets.
We have installed touchscreens with the Hyperties hypertext system in
several museums and this talk will present usage data. In these applica-
tions, users needed to point to single characters. In our most recent
study we succeeded in enabling users to point at and select single pixels.
The touchscreen was faster with targets that were 4 by 4 pixels and larger,
while the mouse was faster with single pixel targets. Improved touchscreen
strategies seem possible. A variant of Fitts' Law is offered to predict
touchscreen pointing times.
Touchscreens still have some disadvantages, but there is an opportunity for
much wider application with rapid high precision pointing.
--
Jim Clarke -- Dept. of Computer Science, Univ. of Toronto, Canada M5S 1A4
(416) 978-4058
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