Social loafing
People exert less effort on a shared task than they would working alone.
What it means
Social loafing is the tendency for individuals to put in less effort on a collective task than they would if working alone, so that average per-person output falls as the group grows. Two mechanisms drive it: when individual contributions cannot be identified or evaluated, accountability evaporates, and when many hands share the work, each person's sense of personal responsibility is diffused. It is distinct from coordination losses — it is a genuine motivational decline, demonstrated by the classic rope-pulling studies in which the force each person applied dropped steadily as the team enlarged. The effect is reduced when contributions are made visible and measurable, when the task is meaningful or involving, when group members value the outcome, and when the group is cohesive. It is closely related to free riding and to the diffusion of responsibility behind the bystander effect. It matters for the design of teams, committees, and crowd efforts, because it predicts that simply adding people can lower total motivated effort unless individual accountability is preserved.
Examples
In a tug-of-war, the average force per person drops as the team gets bigger — the Ringelmann effect — because no one's pull can be singled out.
In a group presentation marked as a single grade, two members quietly coast; when the tutor gives each person a named section with its own mark, the effort returns.
A shared support inbox watched by twelve people leaves a customer waiting all morning; assign one named owner per shift and the replies start arriving in minutes.
First described in Ringelmann; Latané, Williams & Harkins (1979).