Psychogenic muscle tension: the significance of motivation and negative affect in perceptual-cognitive task...

Nineteen subjects volunteered to represent a stratified recruitment of serious-minded (goal-directed) and playful (impulsive) individuals balanced for gender. They all performed a perceptual-cognitive task under a neutral condition and with the contingency of monetary reward for good performance (counterbalanced order). Integrated electromyographic (IEMG) recordings were made from the biceps and triceps muscles of both upper arms, and from prebaseline, task performance and postbaseline periods. Verbal reports on motivational state during task performance (serious-minded/playful) and hedonic tone were also recorded. Results verified and extended earlier findings that IEMG activity increases over the course of task performance when a task is performed in the serious-minded state and even more so when a negative hedonic tone coincides with this motivational state. The increased IEMG occurred in all 4 recording sites under both incentive contingencies, although it was particularly marked in the right triceps muscle. These findings should be viewed in the light of the fact that both arms were allowed to remain in a passive resting condition during performance periods.