Group Learning Curves: The Effects of Turnover and Task Complexity on Group Performance1

This study examined the effects of turnover and task complexity on group performance. Two hundred and forty subjects arranged into three-person groups performed a production-type task for six experimental periods. The design was a 2 (Turnover vs. No Turnover) x 2 (Simple vs. Complex Task) x 2 (Male vs. Female) x 6 (Periods) factorial with repeated measures on the last factor. The analysis revealed that group performance improved markedly as groups gained experience with the task. Groups which did not experience turnover (closed groups) produced significantly more products than did groups which experienced turnover (open groups). The superior performance of closed over open groups was amplified over periods. Groups produced more of the simple than of the complex product, and this difference was also amplified over periods. The gap in the performance of closed Versus open groups increased over periods, and the increase in the gap was greater for the simple than for the complex task. The lesser impact of turnover on the complex task is consistent with an innovation hypothesis, according to which increases in the production of complex tasks are due more to innovation than to repetition. Supportive analyses of innovation data are reported.