Direction of Motion Relationships between Controls and Displays Moving in Different Planes

While the human engineering literature provides an adequate account of the natural, expected, or preferred direction of motion relationships between displays and controls mounted in the same plane, evidence about those moving in different planes is sparse and sometimes contradictory. Since it may be accepted that in many situations display-control relationships affect performance, there are several reasons for an attempt to supply the missing data. In the first place, different-plane relations are in fact in engineering use. Secondly, study of these may reveal general principles applicable to the whole field of display-control relationships. Finally, display-control relationships have been used to vary task difficulty in, for instance, transfer of training experiments; and establishing the neutrality or otherwise of different-plane relationships may thus be of instrumental value for such experiments.