There are 2 main propositions regarding multicultural psychology:
1. Assimilation: One is minority assimilation that assumes that the minority will eventually transfer and follow the majority and then there will be only one identity. The other one is melting-pot assimilation that assumes that both minority and majority will take part in creating a new identity.
The assumption of assimilation is that base on similarity-attraction, if there is only 1 identity, there will be less inter-group conflicts and greater cohesion.
2. Multiculturalism encourages all minorities to maintain their own identity, just like majority.
The assumption of multiculturalism is that if people all feel pride and confidence in their own group heritage, they will be more open and accepting toward out-groups, which in turns, will bring harmonious inter-group relations.