A psychologist at a girl’s college asked the members of his class to compliment any girl wearing red. Within a week the cafeteria was a blaze of red. None of the girls were aware of being influenced, although they did notice that the atmosphere was more friendly. A class at the University of Minnesota is reported to have conditioned their psychology professor a week after he told them about learning without awareness. Every time he moved toward the right side of the room, they paid more attention and laughed more uproariously at his jokes, until apparently they were able to condition him right out the door.

— W. Lambert Gardiner, Psychology: A Story of a Search, 1970