[bryony]

Of course, there is always the comfort obtained by releasing the pressure of a full breast, but once that has gone there would be no incentive to be fully drained unless additional pleasure was obtained.

What about the maternal instinct/bond and the release of the hormone oxycontin during breastfeeding? I think it's plausible the additional pleasure could be more psychological than physiological. After all, breastfeeding can be an uncomfortable experience for the mother, but she may still do it because she wants what's best for her child.

I don't disagree at all. Of course, wanting what's best for the child in instinctive, but knowing what's best needs education, which is a fairly recent development, whereas the pleasure centres of the brain are deeply embedded.

I was just hypothesizing that mutating away from purely physiological pleasure could be a recent phenomenon, which might explain the different scores in your survey. I'm sure there are lots of holes in the theory.

B.