Ringelmann effect

[3] According to Ringelmann (1913), group members tend to rely on their co-workers or co-members to furnish the desired effort required for a communal task.

Even if group members possess the abilities and expertise required to complete an assigned task, they may fail to coordinate their efforts in a productive way.

In their study, Ingham et al. (1974) directed confederates to pretend to pull on a rope by faking exertion, suggesting to the real participant that all members were working together.

What proves of interest here is that because there was virtually no coordination between the participant and the confederates (they were not physically taking part in the actions), poor communication cannot account for the decrease in effort.

[11] Therefore, Ingham et al. (1974) support the assertion that motivational losses largely determine an individual’s decline in performance when acting as a member of a group.

A tug of war is often used as an illustration of the Ringelmann effect. As more people are involved in a task, their average performance decreases, each participant tending to feel that their own effort is not critical.
Ice hockey is an example of an activity where coordination is critical for efficient performance.