One scientist who believes that mothering behavior is learned and not instinctual is Sarah Blaffer Hrdy, professor emeritus of anthropology at the University of California at Davis and author of Mother Nature: A History of Mothers, Infants, and Natural Selection. Hrdy has studied primates for more than three decades and believes that the desire of a mother to care for a child depends on her desire to be a mother and the amount of time spent bonding together. Although she concedes that maternal responses exist, she believes they are biologically conditioned, but not true instincts. In an interview with Salon.com she said, "A woman who is committed to being a mother will learn to love any baby, whether it's her own or not; a woman not committed to or prepared for being a mother may well not be prepared to love any baby, not even her own.
-------
However, Hrdy maintains that "maternal responses that are biologically based are surely going on in the human species." But she believes that the bonding that takes place between mother and child occurs due to the flood of chemicals and hormones that occurs during pregnancy and after birth, and deepens the longer the baby is close. But this is not the definition of an instinct and although we may be vulnerable to maternal impulses, we are not "controlled or defined by them.""