Psychological mechanisms underlying the Köhler motivation gain.

Sometimes group work conditions lead to motivation gains rather than to social loafing. Two theoretical explanations for the Köhler motivation gain effect are identified, one stressing social comparison and a second stressing the indispensability of one's effort to the group. The results of three new experiments are reported.

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 (Kohler 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.