One of the best supported findings of social psychology is that if people can be induced by rewards, threats or a sense of obligation to act contrary to their beliefs, it is the beliefs that are more likely to shift in the direction of the behavior, rather than the other way around.
I took this from an article on a therapy cult. But the way cults operate is just a boiled down and spcied-up version of the way in which all authoritarian society operates. (Indeed, cults work very similarly to jails or concentration camps, except that people are kept in by moral pressure instead of guns).
Conversely, the idea that beliefs follow social action is a profoundly materialist insight. If people can be led into betraying everything dear to them if you take them along it a little at a time (viz. Orwell, Nineteen Eighty-Four), then conversely someone's world can become vaster and more full of possibilities if they just get a few positive reinforcements for taking action in their own interests. Success breeds daring and failure breeds passivity.
The final link between social psychology and Leninist political practice must be that to really change the world, and the self, all this has to happen on a democratic-collectivist basis. On your own, you can only figure out how to fit into the world better, not wield any power over it. Conversely, an authoritarian-collective can only act like a jail.