Regarding this post:
Muzafer Sherif's use of autokinetic effect for group norm (1935):
The autokinetic effect is when very small movements of the eyes make a spot of light in a darkened room appear to move because the eyes lack a stable frame of reference.
Sherif's participants (unaware of the effect) were initially tested individually, being asked to say how far the light moved and in what direction. (The light would seem to jump and then disappear, only to reappear a couple of seconds later.) Answers varied considerably amongst the individuals - from 2 inches to 12! - but each individual was consistent over 100 trials - i.e.: each had a norm.
When they were then tested a few days later in groups of 3 and asked to give their estimates out loud, their estimates began to converge until they were virtually identical - effectively reaching a group consensus. This happened repeatedly, thus demonstrating a group norm had superceded individual norms.
