The Mommy Brain

Every mom has a story that could support the notion that child rearing turns a woman's mind into mush: putting milk in the pantry and cereal in the fridge, losing the thread of a conversation in midsentence, misplacing the car keys for the 10th time. So widespread is the belief that babies make women brainless that when a satirical website released a fake study showing parents lost IQ points when their first child was born, MSNBC picked it up. But Katherine Ellison, a Pulitzer-prizewinning reporter and mother of two, doesn't believe in the dumbed-down mom. In her new book, The Mommy Brain: How Motherhood Makes Us Smarter (Basic Books; 279 pages), Ellison lays out the scientific evidence for a baby-boosted brain. She explained her thinking in an interview with TIME.

Q: Surely sleep deprivation and demanding toddlers are an intellectual distraction, not an asset?

A: As a mom myself, I would never deny that children challenge parents' mental resources. And of course sustained sleep deprivation can have a serious impact on your thinking, which is why you have to be smart enough from the get-go to negotiate for naps with your partner, spouse or mother-in-law. My argument is that there are many surprising and fundamental ways in which, despite all the boring time you now have to spend picking up Lego bits from the floor, the experiences of having and rearing children can stimulate and enrich your brain and make you smarter.

Q: Define what you mean by smart.

A: What I found so funny and interesting was that the very first definition [in Merriam-Webster's] is "causing a sharp stinging." What better description of children! They really tax you, push you to grow mentally. I felt smarter primarily because I could feel myself learning all kinds of new things at what seemed to me like an unprecedented rate. I was learning, and still am learning lessons every day about what we think of as "emotional intelligence"--how to understand and manage one's own and others' feelings. And I didn't get thrown so much by distractions, because there were so many, and I got used to them.

Q: Are there concrete changes to the brain during motherhood?

A: Craig Kinsley and Kelly Lambert, two Virginia neuroscientists who have done truly pioneering work, have dissected rats' brains and found that during pregnancy there was a tremendous blossoming of what are called dendritic spines--the parts of the neurons that reach out and form synapses, necessary for new learning. Dr. Kinsley compares it to a computer acquiring extra bandwidth to help it run more than one program at a time. There has also been some intriguing recent research on the impacts of two hormones important to motherhood, oxytocin and prolactin, on mental functioning--specifically, learning and memory and the reduction of fear and anxiety.

Q: If many of these effects are caused in part by hormonal changes during pregnancy, aren't they just short-term advantages?