Normative social influence is about norms, i.e. what is 'normal' or typical behaviour for a social group
Norms regulate the behaviour of groups and individuals so it is not surprising that we pay attention to them
People do not like to appear foolish and prefer to gain social approval rather than be rejected, so NSI is an emotional rather than a cognitive process
NSI is most likely to occur in situations with strangers where you may feel concerned about rejection
It may also occur with people you know because we are most concerned about the social approval of our friends
It may be more pronounced in stressful situations where people have a greater need for social support