The psychological processes are different. For familiar others, you recall a judgment (e.g., how much you trust them). For unfamiliar others, you construct a judgment. The process of constructing judgment can be influenced by a number of irrelevant factors. This includes an emotional state from an unrelated source (e.g., good or bad news you received earlier in the day), which can profoundly influence how much you trust others.
This is something I’ve been pondering for a while, and one which I cannot quite make a post around. For me, it brings to mind the idea that religion is a Milgram Experiment. Why? Because cults and other sects use trust to do awful things. By the way, it is not just bad religion which does this, but so too bad-non-religion.
Anyway, it’s been sitting in my drafts folder for a while and I thought I’d get it out.