The effects of induced frontalis tension variation on aspects of cognitive efficiency.

Sixteen subjects performed a serial reaction-time task while varying frontalis tension levels. There were three levels of induced tension variation: high, moderate and low. Results indicated that reaction times were differentially affected across the three tension levels, and the slow response end of the reaction-time distribution was slightly more sensitive to frontalis tension changes than the median. The relative importance of errors of omission and errors of commission may determine which tension level is optimal for task performance, but the results reported here indicate that attempts to reduce frontalis tension levels may be inappropriate in situations requiring sustained alertness.