The Ringelmann effect, or social loafing is a phenomenon which occurs in groups of people that limits the amount of effort that each group member exerts (thus reducing individual productivity).
Social loafing was first identified when French agricultural engineer Max Ringelmann was studying group performance, and found that groups (of people as well as animals) did not meet their potential, defining potential as the sum of the maximum output of each individual acting alone.
This effect was re-examined beginning towards the end of the 20th century, and has been actively studied since.
The history of the research into reduction of individual effort in collective tasks—what is now referred to as social loafing—began with a French agricultural engineer called Max Ringelmann (1861-1931).
Ringelmann (as cited in Ingham, Levinger, Graves, & Peckham, 1974; Kravitz & Martin, 1986) was interested in how agricultural workers could maximize their productivity. Ringelmann found that though groups outperform individuals, groups usually do not perform to the extent that they could if each individual was working at maximum capacity.
For instance, in one study, he had people pull on a rope attached to a pressure gauge and found that the more people pulled, the further below their potential they would perform.
If two individuals separately could each pull 100 units, together they would pull 186, not 200. Eight people working together could only pull 392, half of their sum potential of 800.
Ringelmann (1913) attributed this phenomenon to two sources: coordination losses and motivation losses.
He believed that coordination loss — “the lack of simultaneity of their efforts” — was the main cause of social loafing, but also acknowledged that in some cases, workers lose motivation due to each man “trusting his neighbor to furnish the desired effort.
Throughout the 20th century, many studies were published exploring the causes of social loafing.