The Ringelmann effect refers to a combination of social loafing and coordination losses. Coordination loss refers to the lack of simultaneity of effort in groups, which interferes with efficiently combining individual inputs. French researcher Max Ringelmann (1861-1931) had people alone and in groups pull on a rope attached to a strain gauge to measure the pull force. Surprisingly, the sum of the individual pulls did not equal the total of the group pulls. Three people pulled at only 2.5X the average individual performance, and 8 pulled at less than 4x. The group result was much less then the sum of individual efforts. This vilolates the notion that group effort and a sense of team participation leads to increased effort.

Ringelmann noticed that, as you added more and more people to a group pulling on a rope, the total force exerted by the group rose, but the average force exerted by each group member declined. The Ringelmann Effect thus describes the inverse relationship between the size of a team and the magnitude of group member's individual contribution to the accomplishment of the task.