German psychologist Ringelmann has a famous tug-of-war experiment: When the number of people in the tug-of-war gradually increases, each person uses less power, which does not achieve the effect of power accumulation. This phenomenon is called ringelmann effect, also called social escape.
According to the above definition, which of the followings does not belong to the ringelmann effect ?
A group of people watched someone in need, but few people really offered a helping hand.