Conjunctive tasks can differ in their productivity effect depending on whether they are unitary or divisible.
This is known as the Kohler effect, where performance gains are seen in weaker individuals who are striving to keep up with the accomplishments of other group members.
[5] Individuals who perform inferior work compared to someone else show improvement relative to those deprived of this comparison.
Delaying or restricting feedback to after the task is complete, and no more than identifying the superior or inferior member, reduces the effect but does not eliminate it.
[8] The Kohler Effect has been studied and applied to many different areas, including extensive application to athletics and group exercise.
The Kohler effect has been demonstrated in swimming and track and field athletes, such that inferior group members showed the greatest motivational gains compared to their more highly performing teammates.
[9] Inferior athletes showed the greatest performance gains between preliminary and final races.
Weaker athletes also showed more performance improvement when going from individual to group competition than did middle-ranked or higher-ranked teammates.