AO1:
Conformity is a form of social influence and is the tendency to copy other people's behaviour and attitudes from within a group.
Normative social influence occurs when a person desires to be liked and accepted by a group. They will publicly conform and change their behaviour but they will still privately reject their views. This change in behaviour is often temporary as this type of social influence leads to compliance.
Informational social influence is where someone conforms to the views and behaviours of the group because they both publicly and privately agree with them. This type of conformity is called internalisation and stems from the desire to be correct. It occurs when a person is in a new or ambiguous situation and doesn't know what to do. Therefore, they look to the group for guidance as they assume they have better knowledge. Because of this, the change is often permanent as they believe their behaviours and actions are correct.
AO2:
One strength of this theory is that it has research to support it from Asch's 1951 study into conformity. The interviews that were taken after the experiment had finished, stated that there were two main reasons that the participants conformed. The first reason was that they didn't want to be ridiculed by the rest of the group from differing in opinions. They wanted to fit in so went along with the majority group, typical of normative social influence. The second reason was that they honestly thought that the rest of the group knew better than them and that their own judgements were incorrect, typical of informational social influence.
Although some psychologists will argue that the two processes work in sync instead of two separate influences. For example, upon seeing a queue in a shop a person may join the end of it because that is what everyone else is doing but they may also be guessing at the same time that the people in the queue