]In psychology, egocentrism is defined as a) the incomplete differentiation of the self and the world, including other people and b) the tendency to perceive, understand and interpret the world in terms of the self.
Psychological egoism is the view that humans are always motivated by rational self-interest, even in what seem to be acts of altruism.
La differenza è sottile ma c'è. Siamo OT, comunque.