Knowledge of partner's ability as a moderator of group motivation gains: An exploration of the Köhler discrepancy effect.

O. Köhler (1926, 1927) found that less able performers tried harder as team members under conjunctive task demands (Köhler motivation gain effect) and that the greatest gain occurred with moderately discrepant coworker abilities (Köhler discrepancy effect). Recent investigations have reproduced Köhler's overall motivation gain but not the discrepancy effect. The present research examined whether workers' foreknowledge of task abilities--present in Köhler's research, absent in contemporary studies--moderates the discrepancy effect. Participants worked alone or in 2-person teams under conjunctive task demands. Exp 1 manipulated foreknowledge of ability. Exp 2 manipulated discrepancy: a (confederate) teammate performed slightly, moderately, or substantially better. Both experiments found (1) overall motivation gains and (2) discrepancy moderation under foreknowledge conditions. Implications for understanding group motivation gains are discussed.