After Philip Zimbardo’s introduction to the topic the video above shows one of the classic experiments in social psychology.
Solomon Asch conducted those series of experiments in 1951 to investigate the extent to which social pressure from a majority group could affect a minority.
These findings are important for meetings or workshops, especially in brainstorming situations and also for focus groups: Gerald (1955) found that conformity even increases if the group members are interdependent – a situation which often occurs in meetings within a work/project context.
Asch also found that conformity is less dominant when decreasing the size of the majority (Asch, 1956): The bigger the majority group the more people confirmed (but only up to a certain point)
Additional studies by Allen & Levine (1968) showed that if there is an ally within the group conformity dropped because people that share views which are disagreeing with views of the majority may prevent other individuals staying quiet or agree with the majority because of fearing social sanctions when saying what they actually think.
Of course, conformity could be reduced also when people are not forced to make their opinion public.