Revisiting the Koehler effect: Does diversity enhance motivation and performance in groups.

Based on systematic experimental research, we explore in this chapter whether increases in group performance might be a function of diversity in group members‘ capabilities, and how aspects of this group diversity can be used to produce "synergy" in teams. After a short review of experimental research on motivation gains in groups, we particularly focus on the "Köhler effect" that (a) demonstrated conditions under which group members were motivated to exert more efforts for their group than under individual working conditions, and (b) suggested that these motivation gains only occurred when coworkers differed moderately in their abilities. After discussing results of Köhler’s original work (1926, 1927) and possible explanations, we describe two recent studies that replicated essential features of Köhler’s paradigm in a more controlled setting. Results demonstrated reliable performance gains in groups only under conjunctive task conditions, suggesting that perceived instrumentality of own contribution for the group outcome is an important factor to understand synergetic processes. However, no moderation of these performance gains by group diversity was found, demonstrating that these effects can be more general than Köhler (1926, 1927) assumed. The implications of these results for applied questions are discussed