“Though the idea that partners influence each other is central in relationships research, we have identified a large domain in which friends show very little change— personality, attitudes and values, and a selection of socially-relevant behaviors.” She explains, “To be clear, we do not mean to suggest that social influence doesn’t happen in relationships; however, there’s little room for influence to occur when partners are similar at the outset of relationships.”

Source: New study finds our desire for ‘like-minded others’ is hard-wired