Internalisation: Think group is right. Person genuinely accepts group norms. Public as well as private change in opinions/behaviour. Usually a permanent change and persists in absence of group.
Identification: value the group and want to be part of it. Public change of behaviour/opinion even if we don't privately agree with everything.
Compliance: Temporary agreement. Involves 'going along with others' publicly, no private change in behaviour/opinions. Superficial change, stops as soon as group ceases.