This is an interesting study from researchers at Berkeley published last year. Abstract:
Multitouch workstations support direct-touch, bimanual, and multifinger interaction. Previous studies have separately examined the benefits of these three interaction attributes over mouse-based interactions. In contrast, we present an empirical user study that considers these three interaction attributes together for a single task, such that we can quantify and compare the performances of each attribute. In our experiment users select multiple targets using either a mouse-based workstation equipped with one mouse, or a multitouch workstation using either one finger, two fingers (one from each hand), or multiple fingers. We find that the fastest multitouch condition is about twice as fast as the mouse-based workstation, independent of the number of targets. Direct-touch with one finger accounts for an average of 83% of the reduction in selection time. Bimanual interaction, using at least two fingers, one on each hand, accounts for the remaining reduction in selection time. Further, we find that for novice multitouch users there is no significant difference in selection time between using one finger on each hand and using any number of fingers for this task. Based on these observations we conclude with several design guidelines for developing multitouch user interfaces.
Here are the guidelines they give (but please read the paper for the limitations/caveats).
Design Guidelines: Based on our experiment we recommend the following set of design guidelines for developing applications for multitouch workstations. Since our studies focus on multitarget selection, all of these guidelines are aimed at applications where target selection is the primary task.
- A one finger direct-touch device delivers a large performance gain over a mouse-based device. For multitarget selection tasks even devices that detect only one point of touch contact can be effective.
- Support for detecting two fingers will further improve performance, but support for detecting more than two fingers is unnecessary to improve multitarget selection performance.
- Reserve same-hand multifinger usage for controlling multiple degrees of freedom or disambiguating gestures rather than for independent target selections.
- Uniformly scaling up interfaces originally designed for desktop workstations for use with large display direct-touch devices is a viable strategy as long as targets are at least the size of a fingertip.
Bimanual, and Multifinger Input on a Multitouch Workstation
(Via multitouchup and google alerts.)