During field day last year, psychology students observed elementary students pulling harder on a rope when they thought they were pulling alone than when they thought three others were pulling with them on the same rope. This best illustrates:

This best illustrates "social loafing."

We can define social loafing in social psychology as the phenomenon of an individual which is about applying effort, according to this a person apply a lesser amount of struggle or effort to attain a goal when they work in a group than when they work alone.