The direction of movement of machine controls

Experiments are described in which the relation between the direction of movement of a control and display was varied in order to determine what relationships are likely to cause least confusion to the operator of a machine. Two different types of task were used: a task consisting of intermittent stimuli whose rate of presentation could be varied, and a continuous pursuit task.

It is found that accuracy of performance varies with the degree of remoteiiess of the directional relationship from those met in everyday life, with the complexity of the task, with the ability of the subject, and there is some indication that under certain Conditions it may vary with the breadth of his attention. Awareness of the response aspect of the situation in these simple sensori-motor tasks, it is suggested, although necessary in the early stages of learning, may be associated in the later stages with confusion and error.