Asch (1951) showed that people will conform to a majority view. This supports NSI.
Asch (1956) asked participants why they conformed and most said they did not want to lookdifferent, so went along with the group. This supports NSI.
Sherif (1935) asked participants to estimate how far a point of light had moved. When in groups, participants changed their personal view to that of the group. This supports NSI.
