Having children and having children – of course. Less obvious: It also changes the brain. And radical and continuous as in puberty. EF author Nina Berendonk asked American science journalist Abigail Tucker to explain this in more detail.
Anyone doing Zoom interviews with Abigail Tucker couldn’t help but admire the calm and uncluttered interior in the background. How does a woman do it – after all, she has young children herself? But not just her New England home, Tucker’s head seems to be quite tidy. In the next hour, you’ll cite study after study without stopping once. You have to listen carefully so as not to miss anything exciting.
ELTERN FAMILY: Mrs. Tucker, in your house now, it’s not as if being a mother and becoming a mother would mix up your whole life. It changes the brain permanently. But that is exactly what you write in your book. You have to explain it in more detail.
Abigail Tucker: Of course, the physical changes are the most noticeable. Pregnant women and new moms look different than before, and all these crazy things happen: Moles can get darker, mosquitoes go crazy for your blood, and hair suddenly becomes frizzy after it’s been straight your whole life — or vice versa. But while researching this book, I realized that the most profound and persistent changes are the ones we can’t see because they happen in our brains: they are responsible for what happens on the outside.
What is going on in our mother’s heads?
We’re about to find out. There are a number of studies on this topic, but it is very difficult to conduct them. First you have to find women who are planning to become pregnant in the near future and scan their brains using near-infrared spectroscopy. Then again during pregnancy and several times over the following years. What we know so far is that a lot is remodeled, especially in the areas of the brain responsible for social relationships – for example in the prefrontal cortex and amygdala. The latter is an emotional blaster in our heads. Plus, total gray matter is reduced by seven percent – which sounds very frustrating at first: great, so you become a totally stupid mom (laughs). But it is not that easy.
Science still doesn’t fully understand what’s going on in key areas. But one guess is that the gray matter is reduced in size to increase effectiveness. For all we know, changes are permanent. An algorithm has been developed that can use a brain scan to say with certainty whether the person being scanned is a mother or not.
When people talk about brain reshaping, people tend to think of teens going through puberty…
exactly. What you see in mothers in terms of brain plasticity and development was previously known only from children and adolescents, that is, in the most important stage of brain development. Scientists now see this maternal transformation as the most important development in adulthood. So it can be said that the brain is the most important organ in becoming a mother. It controls how the mother acts and what her body does. Without these behavioral changes, she would not be taking enough care of her baby.
How do we imagine this shift in practice?
Above all, mothers’ brains react differently to key stimuli – such as images of laughing babies or the sound of a crying baby. Other areas that are actively blinking can be seen on examination and stronger reactions are observed in women without children. They are very sensitive to children, especially their own. This also explains why mothers are often unable to watch films where their youngsters suffer. It seems inappropriate in this context, but the best way to study and explain maternal behavior is in animals.
why is that?
Humans are very complex beings, and so are their emotions. This is not the case with other mammals. They do not know any socially desirable behavior – they do not pretend, for example, that they are not trying to be polite. You can see this in mice that are not yet pregnant: they do not like small animals. So you’re not like us, who says “sweet” to the neighbor’s kid, even though we think it’s a little too small.
What do childless mice do when they see a stranger’s droppings?
They run away because they can’t stand the squeak and may eat it if you let them. On the other hand, what they are really hot for is the food. But if a mouse gives birth to its young, a 180-degree change in behavior can be observed: it finds young animals 1,000 times more exciting than eating. Whenever she has the opportunity to get more youngsters into the cage by operating one crane and food across another, she repeatedly hits the baby crane until they are literally buried under it – because she thinks they are too cute. The researchers had to stop the experiment, otherwise the poor would starve to death! The areas in the brain where reward and stimulation are located suddenly excite completely differently.
When applied to human mothers, this means that we wash clothes after wash without complaint, wash calves and wash calves without much sleep. Is this the famous maternal instinct?
I don’t think there is such a thing. These fixed patterns of behaviour, mechanical or behavioral according to some kind of unwritten text – animals show this much more strongly than we do.
Is nature failing us?
My personal theory is that since people live in such different places and under such different conditions, it wouldn’t make sense for a mother to behave in the south of the Sahara like she does in the Arctic. For us humans, it’s less about fixed instincts as much as the need to respond to our children’s cues as sensitively as possible.
How is the father’s brain?
Research into mothers has not progressed much – but research into fathers is subject to criminal neglect. What is clear so far: hormonal, brain, and behavioral changes can also be demonstrated in them. But it appears to be optional rather than automatic. When two people have a baby in one night, the mother changes for the rest of her life – whether she raises her or puts her up for adoption. If the father does not communicate with the mother and the child again after this, his brain will not change.
Some research suggests that a pregnant woman’s scent also increases the father’s sensitivity to cues. What is certain is that men are absolutely dependent on receiving external signals from the mother and child. Sensing your baby’s cues begins soon afterwards and can easily last for weeks, months or years. So dads can do it just like moms. However, the prerequisite is that they participate in the care – and they are allowed to do so.
They allude to the mother’s ‘gatekeeper’.
exactly. By the way, it is often the parents who have the best feelings for their child and his signs who raise him with another man – so no mother knows everything better. An Israeli study shows that the brains of gay fathers are more similar to the brains of mothers than straight fathers.
What about adoptive mothers?
Childbirth and breastfeeding provide a kind of jump-start to motherhood, but once the baby is weaned, the brain is reconfigured to go on with its maternal task on its own, without constant hormones. And adoptive mothers are often the ones who are good at responding to their children’s cues. Can I quote from another study with mice?
It has long been thought that a childless rat could be a mother with oxytocin. But then it turned out that it was enough to bring her together with her mothers and her young – of course in a way that left her young to themselves. The amazing thing is that after about a week she started lovingly caring for the little ones. Without the hormones of pregnancy and lactation, simply because they are exposed to the situation. If it is applied to humans, it means that a woman who begins to take care of a strange child in reality learns to love him. It may take a little longer than the biological mother. But we were created to develop that love and care. This knowledge can be reassuring for adoptive mothers. Humans are parenting by nature.
So what is this?
This means we are fond of babies and toddlers and take care of a stranger right away. Whether the child looks like us is completely irrelevant. This is exactly the interesting aspect, because man is subconsciously completely racist. But not with children.
Aside from reshaping the brain, are there any other effects of our children in the body lingering with us?
yes. During pregnancy, embryonic stem cells enter our bodies from the fetus. These cells from our children stay with us for life, even when we are in our 80s and our children are in middle age. But it’s not just a nice keepsake. They aid in wound healing and protect against certain types of cancer. Alzheimer’s disease is also less common in mothers.
Speaking of 80: You write that positive changes in a woman’s body transcend even generations.
It is about the longevity of a woman even after she has lost her ability to conceive. Nature’s plan is supposed to be that a woman who is unable to have children but still has her brain connected to her is the ultimate babysitter. This is why a maternal grandmother is so important. So it is not certain that your life will go on as before after the first hard days. Motherhood is a never ending series of changes: you are constantly being transformed into a mother – and later reborn as a grandmother.
Parents’ brains particularly react to the so-called “small child’s schema”: that is, large eyes, a round forehead, and a small nose. According to Abigail Tucker, cats and dogs especially benefit from our fondness for what we find irresistibly cute. By the way, there is no word for it in the English language, which is why the German term is used there as well.
Abigail Tucker lives in New Haven, Connecticut, with her husband and four children, and is an award-winning science writer. Her book What It Means to Be a Mother (Ullstein, €17.99) is an exciting, lively and funny tour of a mother’s body, which provides many aha moments – for mothers as well as fathers and grandmothers.