How Motherhood Makes You Smarter

New studies on rats show that being a mom does more than change her body, it may maximize her brainpower too

Research shows that mothers are better than others at problem solving, handling stress and at completing certain memory tasks. (© Ocean / Corbis)

Adam Franssen, a biology professor at Longwood University, has a bold theory: mothers are smarter than other women.

He and other researchers, including Craig Kinsley of the University of Richmond, have found that there’s more science than previously thought to being equipped for motherhood. Mothers are better at problem solving, handling stress and at completing certain memory tasks.

Franssen’s aim has been to figure out what is happening in the brains of mothers to warrant these advantages. He designs experiments with mother and non-mother (but still female) rats to see how both groups perform on tasks such as navigating a maze. Then, he studies brain tissue samples from the rats to determine what neurons were activated. Does being a mother give a woman more neurons? Or, are a mother’s neurons bigger or more efficient? Franssen explains.

You have this theory about revving racecar engines and pregnant women’s brains. Can you explain? What do the two have in common?

It is funny comparison. At the revving stage, a racecar’s engine is getting prepped for that race. It seems like there is a lot of evidence to suggest that is actually what’s happening in the mother’s brain during the period of pregnancy. There are changes happening to neurons. They are increasing in size or some neurons have been shown to not only grow but to potentially increase their capacity to produce protein in one part of the brain or perhaps increase their neuronal branches to make communications from one neuron to another neuron that it wasn’t talking with before—all in anticipation of the high workload of caring for a child.

So, what advantages do mothers have over non-mothers, behaviorally?

It is quite the gamut of things that moms can do better than non-moms in the rat world. It is always fair to start by pointing out that rats are uni-parental. That is, the female is the only one that takes care of the pups. The males don’t play a role.

There is a big difference between a non-mother rat and a mother rat, just in terms of caring for their young in the first place. If you put a virgin rat in a cage or a maze with rat pups, it really stresses her out. She will avoid the pups and get as far away as possible. She will exhibit stress grooming behaviors and is generally not interested in these pups, whereas after pregnancy, a mother rat is much more interested. She will collect pups. She will lick them, groom them, feed them, keep them warm and protect them from predators.

A bunch of studies have shown that moms are actually better at all types of learning. If you were to put mother rats in a maze and virgin rats in a maze and train them, the mother rats will complete the maze faster.

Moms are better at memory. So, if you put food in a location and train the rat to find food there, mom rats are much better at finding that food the next time. Retrospective memory is you remember what happened yesterday or what your birthday was like last year. Prospective memory is planning for a future event. You wake up in the morning and you pack a lunch knowing that you are going to be hungry at noon. One of the projects that I am collaborating with Dr. Kinsley on at the moment is seeing if prospective memory is present in rats. Our preliminary unpublished studies suggest that mother rats are better at planning for the future versus non-mothers.

Mothers are less stressed out when you put them in a stress-inducing situation. They don’t show as much fear. They are more efficient at foraging. They will find food, collect it quickly and get back. They are more aggressive at defending their offspring; if there is an intruder or any sort of threatening presence, moms will fight it more than non-mothers. A recent study showed that moms are better at recognizing emotions than others. Mothers are able to recognize hostility, disgust, fear or the types of emotions that would trigger some sort of danger to their offspring.

 Is it fair to say that the more kids a woman has, the smarter she becomes?

I am not going to say that it is not true, but we haven’t shown conclusively. Studies with mothers that have had multiple birthing events suggest in some cases that they are better at some of these things. Essentially, the moms become more efficient at being moms the second time around. But, I don’t have conclusive, concrete, “Yes, have 15 children, you’ll be successful.”

“The bodily changes of childbearing are obvious, but as we are discovering, the changes in the brain are no less dramatic,” you and your research partner, Craig Kinsley, wrote in Scientific American in 2010. How so?

You can actually look and find neurons that are bigger in mothers than in non-mothers. You can do a stain just to look for the number of branches that come off of a neuron to make connections with new neurons. There are large differences in the number of neurons that are firing. We can see that there are more receptors for certain hormones that are present. Then, we can also see things indicating that different areas of brains are being affected. A mother brain might be using more brain regions to figure out a memory task.

It is sort of like the physical changes in pregnancy. In the cases of rats and people too, you can see, oh, look, you are six months or eight months or nine months pregnant. That’s a very obvious physical change. I think a lot of those similar things are happening in the brain, you just don’t see anything taking place there.

You can sort of see these things happen in human females. I know that when my wife was pregnant one of the things that she was very sensitive to was fried chicken. It was one of those things where she would put a fist to her mouth and run in the opposite direction. It just made her sick to her stomach. I think what is happening there is a rewiring of the brain. Smells that were appetizing beforehand are now repulsive. That may not be a long-term thing. Now, my wife likes chicken again.

Again, I hope my wife doesn’t mind too much here. She was very emotional and would cry at not only Hallmark commercials but also other seemingly innocent commercials, which would have me very confused as to what was going on emotionally. But again, I think that’s the brain rewiring. It is rewiring from, okay, I have a standard reaction to other individuals, or a standard amount of empathy, and that empathy is now increasing so that I can better protect my offspring when it gets here.

What are your major unanswered questions?

Previous research has shown some of the stuff I’ve talked about—that there are neurons getting bigger and more efficient. But, in some of the memory scenarios or aggression or foraging, we are not necessarily sure. Is it more neurons? Is it longer bursts of period for neurons that are activated to help make moms more efficient or better at these tasks?

Are the maternal effects coming from just the process of being pregnant or is the exposure to the pups after mothers are pregnant, or is it a combination of both? There is a lot of evidence that just being exposed to pups, in absence of pregnancy can actually be helpful.

Then, being a dad, I want to know what dads can do to be smarter. This is the question I get a lot when I talk about this work. Well, I am not ever going to be a mother, what can I do? It can be dads or any sort of non-mothers. There is evidence that hormone therapy works, that estrogen can help the brain a little bit. Or, what is the role maybe of other environmental enrichment? Is there a way to boost your brain without becoming a mother?

What are you currently working on?

This summer, I am working with an undergraduate here at Longwood University looking at mothers and their relationships with their own pups versus other pups—alien or adopted pups. Previous research has shown that if you put a mother rat in a cage with a pile of rat pups, that mother will be able to go in and identify her pups. She’ll pick them up, gather them and care for them, do the whole maternal process with those pups, but then she will also take care of the other pups. She will care for them, make a nest and keep them warm and feed them.

Behavior studies have been done on that, but not any of the underlying neurological processes. This summer, we’ll set up these scenarios: moms with just their pups, moms with just alien pups and then moms with this mixed groups of pups. We will try to find out what if any differences there are in the actual behavior. How quickly are pups retrieved and cared for? Are there differences in the amount of care that their own versus alien pups get? Then we’ll look at the brain regions underneath and say, are there different reactions neurologically in a response to one’s own pups versus another? I notice that as a parent, I am much more interested in looking out for other kids than I was when I wasn’t a father. So, what is going on in the brain there?

One of the things that I find very exciting—we published it last year—was a study showing that mothers actually recover more quickly from a traumatic brain injury. Can we compare non-mom rats with mothers and see if there is a way that we can start getting some of these neural benefits to individuals who for one reason or another aren’t going to have children? Is there a mechanism there, maybe just in terms of enrichment in the environment that could lead to neuro-protective benefits? I think there are a lot of implications for it—from individuals who suffer in car accidents to the NFL. 

Has your research and what you’ve learned affected your relationship with your own mother? 

It has. I have been fortunate; I am close with my mom. My research on this topic coincided quite closely to the birth of my first child. Combining that type of research with my own experience of taking care of my daughter, I have a lot of respect for my mom and what she did taking care of me growing up. I probably still don’t call home enough.


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