Strength of component principles determining direction of turn stereotypes - Linear displays with rotary controls

Three experiments on direction of turn stereotypes are reported for (i) two-dimensional horizontally moving displays (ii) three-dimensional display/control arrangements and (iii) the relationship between response times and the strength of stereotypes. In each case, equations were written for the strength of the stereotype (proportion of clockwise movements) in terms of the direction predicted by various principles; clockwise to increase, clockwise to the right, clockwise away, scale-side and Warrick's for two-dimensional arrangements and modifications of these for three-dimensional arrangements. Solution of these equations gave the contribution of each principle to the strength of the overall stereotype. There were found to be strong effects of subject groups (engineers and psychologists) in the strength of component principles. The important result was that the strength of the stereotype was a linear sum of the strength of each contributing principle. The work was extended to the case of three-dimensional display/control relationships, where the rotary control was not in the same plane as the display. One experiment used paper and pencil tests and the other simulated displays and controls. It was found that (i) the paper and pencil tests gave a good prediction of data obtained with the simulated displays in cases where Warrick's principle was applicable; (ii) strong stereotypes were found for cases in which Warrick's principle was applicable, but not in cases where the axis of the control was parallel to the direction of motion of the display; (iii) in all cases where Warrick's principle was applicable, the stereotypes were reversible, whereas in a number of the tests where Warrick's principle could not be applied this was not the case. In a further experiment, subject's reaction time to move a control was measured for a set of 64 different combinations of linear displays and rotary controls. It was found that, for horizontally moving displays, the response time for an arrangement having a strong stereotype was faster than one with a weaker stereotype, however there was no significant relationship for any of the vertical layouts. Response time was found to be dependent on the magnitude of the component principle making the greatest contribution to the strength of the overall stereotype.