Some inter­est­ing research has been attempt­ing to give an evo­lu­tion­ary psy­chol­ogy expla­na­tion for psy­cho­log­i­cal pro­jec­tion.

Using Silence of the Lambs, Things to Do in Den­ver When You’re Dead and Koy­aanisqatsi, no less.

We project emo­tions on oth­ers based on our own emo­tional state, but those pro­jec­tions are func­tional: We don’t project fear if we’re afraid — we project anger, the object of our fear. And this fear depends in large part on our pre-existing biases. If we’re pre­dis­posed to see a mem­ber of a par­tic­u­lar group as threat­en­ing, then we’re likely to project anger on that per­son, based on our fear of that group.