Interestingly enough, research has shown that there is no difference in child development between those mothers that breastfeed and those that don't. Infant formula comes pretty damn close to breast milk. Breast feeding, in and of itself, is more about the attachment to the mother. Feeling the mothers closeness, the touch of her skin, her heartbeat, etc. As long as mothers hold their babies in that same position they would if they were breast feeding, then normal child development should ensue. Obviously, this is assuming all other factors are taken into account which can effect the trajectory of infant/child development.