At least since Plato and Aristotle the hardly ever questioned common wisdom of the entire philosophical tradition was that while the universal is grasped by the intellect, the senses perceive the individual. Even in the "moderately realistic" Aristotelian-scholastic setting (perhaps best represented by Aquinas) where universalis are situated "in rebus", this axiom naturally generated the idea of two separated realms of objects of cognition - individuals and universals - whose ontological status, mutual relations etc. would, in turn, be philosophically investigated.
In my reading, Scotus does not share this common preconception at all, but instead takes the position that ultimately there is just one single realm of cognized objects - the individuals or particulars. Thus, although it may be argued that his theory of cognition does not represent any radical departure from the moderate-realistic, Avicenna-inspired paradigm of the 13th century, but rather its specific elaboration, in a closer look we can see that Scotus takes an entirely new perspective on the problem and reinterprets the old approaches from a new standpoint.
And yet, this new perspective can at the same time be understood as merely being a consistent completion of the anti-Parmenidean and anti-Platonic movement in philosophy initiated by Aristotle - namely that of epistemic rehabilitation of the world of ordinary particular things. Scotus's epistemic thought thus can be described as being simultaneously consistently traditional and revolutional.