Normative social influence
We conform so others will accept and approve of us, because as huans we have a need for social companionship, and a fear of rejection. The result is compliance (publicly conforming to the behaviour of others, but privately maintaining their own thoughts/beliefs).
Informational social influence
When we look to others on how to behave, e.g. in the prescence of a professional, particularly in novel or ambiguous situations. The result is usually internalisation (adopting behaviours of a group privately and publicly, because you value membership to that group).
Social impact theory
Latane '81 explained that we only conform in certain situations.
Number: The more people, the more influence, up to about 3 or 4 as shown in Asch's study
Strength:The more important the person, the more influence
Immediacy: The more people present, the less influence one person could have.