The Asch conformity experiments were a series of laboratory studies published in the 1950s that demonstrated a surprising degree of conformity to a majority opinion. These are also known as the Asch Paradigm.
Solomon Asch attributed his research on group conformity to an experience he had as a child growing up in Poland. When Asch stayed up late to participate in his first Passover, he witnessed his grandmother setting out an extra glass of wine out on the table. When Asch asked who would be drinking that glass of wine, his uncle replied that it was for the prophet Elijah. Asch was “filled with the sense of suggestion and expectation” and believed he saw the level of wine in the glass decrease slightly.
At the beginning of World War II, Asch began to study the effects propaganda and indoctrination at Brooklyn College. Asch came to the conclusion that propaganda was most effective when fear and ignorance played a part on the intended targets.
Source : http://en.wikipedia.org/wiki/Asch_conformity_experiments