THE EFFECT OF MOTIVATION ON SHOULDER-MUSCLE TENSION IN ATTENTION-DEMANDING TASKS

This paper evaluates motivation as a task-related factor causing the development of psychologically mediated ('psychogenic') shoulder-muscle tension. In four separate experiments using a visual display unit (VDU) based complex reaction-time task, motivation was established by means of continuous feedback on the level of performance (relative to a preset target performance level) or by means of a money reward for good performance. In all experiments motivation improved the performance, but an increase in the psychogenic shoulder-muscle tension was only observed in the money-reward condition. It is discussed whether this difference in the muscle-tension response is due to changes in the subjects' attitude unrelated to performance or due to a superior performance in the money-reward condition.