Nobody decided to clap less. They just did.

In 1979, researchers asked people to clap and cheer as loudly as they could, first alone, then in groups.

In pairs, each person made 29% less noise than alone. In groups of four, 49% less. In groups of six, 60% less.

Nobody chose to clap less. The effect has a long history: a French engineering professor, Maximilien Ringelmann, measured people pulling on a rope and found that the more people pulled, the less hard each one pulled. His studies are sometimes called the first experiments in social psychology.

Latané and his colleagues called the effect social loafing. Psychologists have since described a related idea, the sucker effect: if you suspect others are coasting, you ease off too, because nobody wants to be the one doing all the pulling.

Ringelmann’s name is now attached to one of the patterns in the KOZMO model. The research is a hundred years old. Most of us still recognise it from last week.