Aristotle once quipped that, “Mothers are fonder than fathers of their children because they are more certain they are their own,” but recent work in the field of behavioral neuroscience has shown that maternal love involves a chemical stew far more complex than Aristotle’s simple saying.
In particular, scientists have identified the hormone oxytocin as important to human bonding, although researchers caution that they still only have a superficial understanding of how this chemical behaves in humans.
Oxytocin performs a number of roles in the human body, and is especially important in expecting and recent mothers, because it can help induce labor or stimulate lactation. That link to pregnancy made it a prime suspect for inducing mother-child bonding, and much research has concentrated on uncovering its role in maternal behavior, said Jennifer Bartz, an assistant professor of psychiatry at Mount Sinai Medical Center in New York.
"We know that oxytocin facilitates child birth and lactation, and that has led some to investigate its role in attachment between mother and child, and in adult-adult pair bonds,” Bartz told Life’s Little Mysteries. “It's pretty clear that the hormone oxytocin plays a role in bond formation in animals, but right now, we really know very little about the neurochemistry of bonding in humans.”
The exact mechanism by which oxytocin initiates bonding remains poorly understood. The chemical interacts with a number of other hormones associated with pleasure and social behavior, and scientists have not yet unraveled that complex web of biochemical interactions, Bartz said. However, research has shown that oxytocin helps individuals remember the faces of the people they like, and distinguish them from the people they don’t like.
“It seems like one of the things oxytocin does is facilitate social memory. It helps us establish a preference for particular individuals,” Bartz said.
And, as any mother who feels that her kids call too rarely can attest, the oxytocin-based mechanism that bonds mothers to children may not work reciprocally. While the role of oxytocin in childbirth helped researchers link it to motherly love, no evidence has yet shown what chemicals might endear mothers to their children, Bartz said.