HP Labs Technical Reports

Effect of Modes and Mode Feedback on Performance in a Simple Computer Task

Johnson, Jeff A.

HPL-91-167

Keyword(s):

Abstract: Very few experimental studies have been done to provide evidence for various claims that are made about modes in the user interfaces of computer systems. This paper describes four experiments on the topic of modes. Experiment 1 examined the effect upon performance of moded vs. modeless interfaces. Experiment 2 examined the effect of four types of mode feedback. Experiments 1 and 2 showed that modedness affects performance, but also manifested large individual differences, which may have masked other effects of interest. Experiments 3 and 4 were essentially replications of Experiments 1 and 2, respectively, with interfaces that had been redesigned to eliminate a major potential cause of individual differences. The effects seen in Experiments 1 and 2 were replicated and additional effects were seen. However, the within-cell variance was reduced only slightly, raising questions regarding design strategies that have been proposed for reducing individual differences among users of computers.

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