History proves that societies, dictators, and church leaders have impulsively sought to control, contain, harness, and even manipulate and exploit the young adults of the world. Their social, political, and religious importance and impact would itself be a fascinating study. But the objective here is to understand the developmental traits that lie behind those contributions. A Widening Perspective Physical might is behind the activism, as has already been suggested. They sense their own capacities and so are ready for life's challenging tasks.
Social factors are also at work.
The I am capable attitude is stimulated by their being welcomed into society at large. Permitted to go off to college or their own apartment, to marry, to vote, to buy alcoholic beverages, they are now finally on their own. Inner forces combine with new social roles. Young adults seem to face the world in a way that is distinct from their adolescent days. It is not that they were unexposed to world conditions during their teenage years.