Abstract
Karasek (1979) noted that task demand and decision latitude had affected induction and reduction of work stress. Especially, high decision latitude had an important role in reducing stress responses. The present study was designed to examine the effect of decision latitude on stress responses, which was administered task intervals by oneself. Twenty undergraduates were served as subjects, who divided into two latitude conditions randomly. All subjects received both a mental arithmetic and an error detection tasks. In high latitude condition, subjects could control intervals between task presentations. While tasks were randomly presented at intervals of 1 to 3 s (2 s in average) in low latitude condition. To make task demands equal in both conditions, duration of task was restricted by mean response time in the practice session. Measures of stress responses were five subjective sub-scales (tension, boredom, depression, perceived control, and fatigue), correct response rate and reaction time, and autonomic responses (heart rate, respiratory rate, systolic blood pressure, and diastolic blood pressure).
Intervals between tasks in high latitude condition were 2.2 s at a mental arithmetic task and 1.8 s at an error detection task, which were nearly similar to 2.0 s interval set in low latitude condition. Task difference was observed in correct response rate, reaction time, and three of subjective responses (boredom, depression, and perceived control). On the other hand, respiratory rate was faster in low latitude condition than in high. Though systolic and diastolic blood pressures tended to increase in low latitude condition, there were statistically marginal differences and not significant. These results indicated that low decision latitude made increment of cardiovascular response reactivity which was becoming to a risk-factor of coronary heart disease.
