You know how newborn babies can smell so good? Well that reaction might be more nature than nurture—at least for women.

Researchers had 30 women sniff various mystery scents while their brains were scanned. Have the women had recently given birth. The other half never had.

When the subjects sniffed clothes that, unknown to them, had been worn by newborns, their brains all showed specific activity. What got turned on were the same dopamine pathways that are activated by doing cocaine, by eating when hungry or by engaging in other reward-inducing behavior, like playing a slot machine.

And while all the women’s brains lit up, the brains of those who had recently given birth showed significantly more activity than did the others’.  [Johan N. Lundström, Maternal status regulates cortical responses to the body odor of newborns, in Frontiers in Psychology]

So the reaction to a newborn’s scent may be a hard-wired bonding mechanism between mothers and infants—a biochemical reward for mom in the midst of all her hard work.

—Erika Beras

[The above text is a transcript of this podcast.]