The Direction of Motion of Machine Tool Controls

Abstract

The experiments presented in this report were designed to measure the strength and direction of population stereotypes in the use of machine-tool handwheel controls. A close simulation of the real-life task was attempted. It was found that, where stereotypes existed, experienced machine tool operators conformed with normal machine tool design practice in their expectations. Secondary school boys (potential operators) had no expectations: university students' expectations were not always in line with design practice. The stereotypes of apprentices were often weaker versions of those of operators. The effects of allowing each subject to perform several different tasks involving handwheels were examined: expected directions of motion were not affected, but the overall tendency to respond clockwise was affected. There was some sequential dependence in the responses. The conclusion is reached that standardization of control-display relations is important but in most cases there are no "natural" stereotypes (obvious ones were not studied) - the stereotypes are learned by the operators, from the machines they operate.