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 ?
Divide the male college students into groups of 2, 4, and 6 each. Ask them to shout loudly and record the volume of each person. It turns out that the individual's volume decreases as the number of groups increases.