Indispensability and group identification as sources of task motivation

Traditional Instrumentality × Value (I × V) models have attributed gains in performance groups to various conditions affecting the instrumentality of group members’ effort for a variety of valued outcomes. Social identity models have challenged this interpretation, suggesting that the instrumentality of effort may be irrelevant when group identification is high. A laboratory study is reported in which both indispensability and group identification are manipulated, and participants’ effort on a physical persistence task is assessed. Contrary to the social identity predictions but consistent with I × V predictions, the indispensability of effort had a positive effect on participants’ effort. Group identification had no direct or moderating effects on effort.