To this I would add a couple of classic mid century studies on perception: Arnheim's "Art and Visual Perception" (which imo should be mandatory for any UI desig

To this I would add a couple of classic mid century studies on perception: Arnheim's "Art and Visual Perception" (which imo should be mandatory for any UI designer), and Merleau-ponty's "Phenomenology of Perception" (this one requires some extensive background reading, but it's well worth the effort)