More or Milgram's participants resisted orders if there were other participants present who refused to obey. This suggests that people find it easier to stand up to authority if they have support from others, because they no longer have to take full responsibility for rebelling.
This ties in with Asch's research on conformity. He found that participants were more likely to resist the pressure to conform if one of the confederates agreed with them. It seems that people are more likely to display independent behaviour if they've got the support of others.
Locus of control
Your resistance to social influence may also be affected by a personality characteristic called locus of control.
People with an internal locus of control feel a stronger sense of control over their lives than people with an external locus of control. This means that they're more likely to show independent behaviours as they believe that what happens in life results from your own behaviour.
People with an external locus of control are more likely to conform/ obey - Belief that events are caused by external factors e.g. luck.