A measurement of an individual's sense of control over their lives, ie to what extent they feel that events in their lives are under their own personal control, versus under the control of other external powers like fate
Oliner and Oliner (1988) interviewed two groups of non-Jewish people who had lived through the holocaust. They also interviewed 406 people who protected and rescued Jews from Nazis and 126 people who did not. The rescuers were found to have an internal locus of control and also scored higher on measures of social responsibility.
When one of the confederates did not conform, and gave the actual correct answer, conformity levels in the participant dropped to one quarter of what they were when the majority had been unanimous
This is not just due to the lack of unanimity of the majority, but the fact that the answer supports the participants true answer, it provides the participant with social support through also providing an alternative source of information
It gave them more confidence in their own perception by providing a small amount of confirmation of their answer, which is often enough to encourage the person to reject the majority position
In a variation of Milgram's study, where there were two other participants (who were actually confederates) and disobeyed the experimenter, the presence of the other person caused the level of obedience to reduce to 10%
Gamson et al also gave support to the idea that larger groups provide a stronger social support system, which makes resisting obedience/social influence much easier