All of this begs the question-- at what point does the "other" aspects of breastfeeding (attention, talking, contact, etc) influence the outcome of child development as much as the milk and its properties? How much of this new study is actually the result of nurture?
I haven't had time to look in to the study as deeply as I would like, but Breastfeeding 1-2-3 pulled this information, which I think is particularly relevent.
MSNBC quotes researcher Dr. Michael Kramer from McGill University in Montreal, Canada:
So-- is it nurture? The milk? Both?
“It could even be that because breast-feeding takes longer, the mother is interacting more with the baby, talking with the baby, soothing the baby,” he said. “It could be an emotional thing. It could be a physical thing. Or it could be a hormone or something else in the milk that’s absorbed by the baby.”
Also, one thing that frustrates me... why in the hell are we so stuck on proving the benefits of breastmilk versus the harms or risks of formula? It annoys me to no end. Oh, and why are we so squeemish about human milk, but we drink and use cow's milk like it is water? Grrr... I'll end my tangent rant now!