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. German 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 2.5 times the average individual performance, and 8 pulled at less than a fourfold performance. The group result was much less than the sum of individual efforts. This violates the notion that group effort and a sense of team participation leads to increased effort. In the social psychology of groups, social loafing is the phenomenon that persons make less effort to achieve a goal when they work in a group than when they work alone. ... Coordination or Co-ordination is the regulation of diverse elements into an integrated and harmonious operation. ... Coils of rope used for long-line fishing A rope is a length of fibers, twisted or braided together to improve strength, for pulling and connecting. ... A strain gage (alternatively: strain gauge) is a device used to measure deformation (strain) of an object. ... This article may be too technical for most readers to understand. ...

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. Inverse typically means the opposite of something. ...

Subsequent work was carried out by Ingham (1974), developing the theory further. In a replication of Ringelmann's experiment, Ingham placed participants in one of two groups: 1) much the same as in Ringelmann's original conditions, with real participants in groups of various sizes or, 2) pseudo-groups with only one real participant. In the pseudo-groups, the condfederates were to pretend to pull on the rope whilst making actions as though they were really exerting themselves. A decrease in the participant's performance was, as one might expect, still found. What proves of interest here is that as there was no coordination between the participant and the stooges (they weren't physically taking part in the actions), poor communication cannot account for the decrease in effort. Therefore, motivational losses must be the cause of the performance decline. Additional losses were seen in the real groups, which can be attributed to coordination losses.

References

Ingham, A.G., Levinger, G., Graves, J. and Peckham, V. (1974). The Ringelmann Effect: Studies of group size and group performance. Journal of Experimental Social Psychology, 10, 371-84.