Where does repression come from? Part of its origin, says Freud, is physiological. As hominids became erect our noses moved away from our genitals and anuses. At the same time, we began to rely more on sight and less on smell; our sense of smell withered in proportion to our strengthening eyes. Our once easy familiarity with our sexual zone became uneasy. What happens first as evolutionary biology repeats as evolutionary psychology: humans are distinguished from animals not just by our erect posture, strong eyes and weak noses, but by a mental economy of not knowing what we know. Out of a certain defensiveness about (ostensibly) not knowing sex morality is born.
So says Freud, if you can forgive my rough paraphrase. I think we are, today, generally skeptical of any story of this kind that roots the discoveries of a certain age (ie repression, Oedipus, etc) in a pre-historical proto-humanity. What I see of use in this story is a wedge for a particular critique of Freud. When he talks about the strong sense of smell of primitive or pre-humanity he is talking about animality, a general concept grounding the concept of humanity; but he is also talking about lots of species coeval with homo sapiens. Dogs are the obvious example, especially as they are distinctly "within" the polis, and in Freud's case within his office during sessions. But when we look on dogs and their amazing ability to track by scent, to approach the world through a different lens than humans--and the ineffability of butt-sniffing to the weak-nosed human--we don't see the Id incarnate. The history/prehistory divide set up in Freud's story introduces an unnecessary binarism that would divide ego from id and uncritically attach values based on a division that is at best heuristic (This tendency persists today in researchers showing that language-oriented dogs are "smarter" than scent-oriented dogs). The "uncanny," the general darkness of the libidinal region, are results of the very vertico-centricity that Freud is criticizing. It seems more the case that the ego as the human form of consciousness does not have one other (sex) but many, and the empirical evidence of this many lies quite simply in the lives of animals. Thus the Id is not frightening, as any dyadic Other must at first appear, but different in a non-competitive way (non-competitive because framed in a wide and generally flat field, rather than the top-bottom orientation of any two term set). From here it is not a long distance to an Anti-Oedipal reading of multiplicity in the unconscious, with the advantage that actual animals are irreducibly included, as actual and not symbolic, in the dialectic of human selfhood