A study in two-handed input

Two experiments were run to investigate two-handed input. The experimental tasks were representative of those found in CAD and office information systems.

Experiment one involved the performance of a compound selection/positioning task. The two sub-tasks were performed by different hands using separate transducers. Without prompting, novice subjects adopted strategies that involved performing the two sub-tasks simultaneously. We interpret this as a demonstration that, in the appropriate context, users are capable of simultaneously providing continuous data from two hands without significant overhead. The results also show that the speed of performing the task was strongly correlated to the degree of parallelism employed.

Experiment two involved the performance of a compound navigation/selection task. It compared a one-handed versus two-handed method for finding and selecting words in a document. The two-handed method significantly outperformed the commonly used one-handed method by a number of measures. Unlike experiment one, only two subjects adopted strategies that used both hands simultaneously. The benefits of the two-handed technique, therefore, are interpreted as being due to efficiency of hand motion. However, the two subjects who did use parallel strategies had the two fastest times of all subjects.