Trade is closeley related to justice; it is based on an assumption of power. Each satisfies the other inasmuch as each receives what he esteems more than the other does. One gives another what he wants, so that it becomes his and in return one receives what one wants. Thus justice is repayment and exchange on the assumption of approximately equal power positions. Revenge belongs to this domain; also gratitutde.

To trade women then, in light of the extraordinary differences between tool cultures and other symbolic relics (I'm unaware of any Neanderthal art), flies in the face of "equal" power positions. That Cro-Magnon ate Neandethals seem much more likely than that they would trade with such weaklings; assuming they ever encountered them at all. Why trade when you can take? Why not herd? Or enslave?