Shownotes Transcript
Thank you.
WBUR Podcasts, Boston.
This is On Point. I'm Meghna Chakrabarty. Now, you've heard of the mom brain phenomenon. And if you haven't, just go ask a mom. But have you heard of dad brain? My first kid just had a fourth birthday. So that's the anniversary of my sleep deprivation. And of course, that was a big part of dad brain for me. I've never been in love with any other adult as much as these kids.
I definitely noticed a shift. I was an emotional person before, but now I feel like I'm always crying at the most little things. Being hypervigilant, just becoming more aware of
noises and sounds and you know when you try to sleep at night when you could get some sleep just being extra sensitive to the sound of their cry or the murmurs. I have dad ears. When my first son was born I was a chimney sweep in the Black Hills and I climbed on ladders all the time. When my son was born I noticed that taking that last step onto the roof
Or descending from the roof onto the first step of the ladder, I always got a very queasy feeling. Clarity, purpose, and moral grounding suddenly overwhelmed me. Even though I was very young, 21 when I first was born, it was powerful. On point listeners there. Pegasus in Essex Junction, Vermont. Brent and Eric in Philadelphia. Bucky in Atlantic Mine, Michigan. And Sean in Barrie, Vermont.
Well, Darby Saxby is a professor of psychology at the University of Southern California. And researchers have taken a look at how women's brains change during motherhood. Professor Saxby is researching the same questions about fathers. And she's at work on a book about dad brain and joins us now. Professor Saxby, welcome to On Point. Very happy to be here. OK, let me just check first. Are you a mom? I'm a mom of two.
I am a mom of two. I have two teenagers. Okay, so you then have personal experience, as have I, mom brain, which is definitely a thing. I have to say, just in listening to those dad's
I was quite moved because I was shocked at how similar the dads were talking about that I've experienced. Like, first of all, suddenly having a sense of the dire need for self-preservation, hypervigilance, you know, crying at the drop of a bucket. I used to not be a big crier, but now just put on Little Drummer Boy and I'm a sea of tears. And the clarity that parenthood brings.
I mean, do those things sound familiar to the dads that you've spoken with or worked with in your research?
Absolutely. And, you know, so both I resonate with those dads, both personally and professionally. And, you know, if you think about what evolution needs us to be able to do to keep a baby alive, you hear a lot of those themes in those dads' experiences, right? They're being more vigilant about safety, both their own and presumably their children's safety, right?
And their empathy is kind of tuned way up so that they can be sensitive to the signals that they're getting from their kids. And those are the kinds of things, you know, if you think about a new parent, even just in the first few minutes after a baby cries, you have to figure out what's going on. Why is the baby crying? What do I need to do to figure out how to soothe this baby? How can I modulate my own stress, my own annoyance to be patient with the baby, you
It requires a lot of skills, and a lot of the skills map onto some of the things that we see looking different in the brain. Okay, so we're going to talk about the actual imaging and what you see in just a second here, but...
I mean, obviously trying to understand what happens in a woman's brain after she becomes a mother, that makes a lot of sense, right? Because for better or for worse, women are the primary physical caregivers, at least for an infant after they're born. What got you interested in similar questions about dads?
Yeah, so I actually think dads are fascinating because they're so variable. Yeah.
With fathers, you see this big range of engagement. You see dads who've never met their child. You see dads who are really hands-on, you know, primary caregivers. And it makes me curious about how does experience shape our brains and our motivations? Right. So this is essentially in the case of dads, it's almost exclusively external stimuli of having become a dad versus the internal physiological changes from carrying a baby. Right.
Exactly right. So moms have this kind of head start from pregnancy, birth and then breastfeeding if they're breastfeeding. And men aren't experiencing those big hormonal events. Their hormones are changing, often in tune with their partners, but they don't necessarily get that same kind of kick. It's more about their motivation, their motivation.
and the time they invest. Which in a sense makes it even more interesting. So we're going to talk about the correlations that you found a little bit later, but let's get down to the nitty gritty of the brain imaging. So you've been doing neuroimaging on men that you've recruited, right? And you do what the imaging before their children are born and then after, is that right? Yeah.
That's right. We image them during their partner's pregnancy and then again when their babies are about 6 to 12 months old. Okay, so after the first year postpartum. And what kind of imaging are you doing?
So we put them in the MRI scanner, and we can take a few different kinds of images. We can take what are called structural images, which is like a still photograph of the brain to see kind of the shape and size of different structures. And then we also do functional imaging, which is more like a camcorder recording of what your brain is doing when, for example, you hear a baby cry or you see your baby's face. Okay, so that's actual, like, real-time neural activity then. Mm-hmm. So...
Here's the big headline I gather from your research is similar to mothers, fathers experience a reduction in gray matter volume. Sounds a bit dire, but it's not necessarily.
Yeah, it sort of sounds like a bad joke, right? Like the shrinking parental brain. But there's some evidence that that remodeling might be adaptive. And our brains lose gray matter volume at other periods in the lifespan. So in early childhood, we actually prune and streamline connections to work faster and more efficiently. In puberty, the same thing happens.
So the initial study looking at this was done in moms. Can I just jump in for a second? No. Because this is really important, the neural pruning that you're talking about. It serves a purpose, right, as you know, when you're like, what, five years old and again at puberty. But especially in the first massive neural pruning that happens laterally.
A huge percentage of the neural networks that are basically no longer deemed efficient or important enough for the brain in a five-year-old because they're just like absorbing everything from the time they're born, that actually sets up the brain to operate differently.
in a sense, even better or more efficiently. Is that right for that neural pruning? Exactly. Yeah. So we sort of start to, you know, it's like having a bunch of little dirt roads branching off in different directions versus having a highway, right? We start to figure out, well, we're going to go the same way to get to work every day. So let's pave that road and make it a little easier to travel on. And so that's kind of what's happening with that process of pruning is we're developing these processes
kind of pathways that talk to each other. And we're using some more than others, and we're going to get rid of the ones we don't need. And so you're saying you are seeing evidence of the same thing in the brains of
But let me ask you, when we say reduction in brain matter, the first presumption is that like it's just an overall equal volumetric or percentage reduction across the whole brain. Is that true or do you see specific places in which the gray matter is shrinking? Yeah.
Right. So we see the volume reductions are happening in a part of the brain called the cortex, which is kind of like the top layer of the brain. And it's the most recently evolved. It's kind of, you know, what you would consider to be like your primate brain, as opposed to your lizard brain or your rat brain, which are the parts of the brain that sort of deal with more gut feelings and instincts. Right.
So your cortex is the part of the brain that has your prefrontal areas that help with executive functioning, thinking, and reasoning. It also has what's known as the mentalizing network, which is this kind of interconnected suite of structures that come into play when we think about the contents of other people's minds and we imagine how other people are feeling. And you can imagine how important that network might become when you're taking care of a
who, you know, can't tell you what they need and you just have to be able to kind of tune in. Before we talk more about sort of what the consequences or behavioral consequences are of that pruning in the cortex for fathers, is this for first-time dads only or for similar things to happen every time a man becomes a father? Yeah.
So that's a great question that we don't know the answer to. So the studies to date have only looked at first-time dads. And I should emphasize, this is a really small research literature. So there's a lot we still don't know because we haven't studied it. Yeah.
We think that when fathers go on to have more kids, you might see more of these changes and maybe more pervasive changes, but we just don't have that evidence yet. Okay. I was just wondering because in thinking about like if these –
behaviors, brain-driven behaviors are persistent, right? That's really fascinating. Or do they sort of like fall off over time? But that would require like a very significant longitudinal study, right? Yeah. So we're actually bringing our families back to the lab right now. Our kids are seven. So these are the kids that we first recruited the parents during pregnancy. And
And so we're scanning the men and hopefully we'll be able to see how many of these changes are sticking around. There was a study done in moms that found that some of the brain changes in the moms did seem to endure.
six years after birth. So there's some evidence that this remodeling is pretty long term. Oh, that's really interesting. Okay. So today we're speaking with Professor Darby Saxby. She's a professor of psychology at the University of Southern California. She's at work on a new book about dad brain and the new science of fatherhood. When we come back, Professor Saxby, I definitely want to hear more about how
how these cortex changes sort of correlate to the experience of being a father or behavior changes that we see in new dads. So we'll talk about that in just a moment. This is On Point. Support for On Point comes from Indeed. You just realized that your business needed to hire someone yesterday. How can you find amazing candidates fast? Easy. Just use Indeed. There's no need to wait. You can speed up your hiring with Indeed.
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And we need to address that. That's more difficult to argue with than taking the chainsaw to it. Follow wherever you get your podcasts and stick around until the end of this podcast for a preview of the episode. I was afraid of holding babies. My wife, for example, would ask me to hold babies.
And I was afraid they were going to smell my fear or something like that. Once I had my first baby, we have two now, it was much easier to just hold them and accept that they might cry on me. From the moment my daughter was born, I became a papa bear, being incredibly protective. And that has persisted for 20 years. There was often challenges with just remembering basic things and focus and attention.
Realizing that I had other people that were depending upon me for their existence. I had to take him for some blood work. As soon as she poked his foot, I could feel him clench up and then start crying. And it was like, it broke my heart. Like, I felt so connected to him. Even with the tiredness and the, you know, the waking up and...
Having to help my wife and all these different things, like, I just feel like everything is him first, everything else second. Wow. On Point listeners Matthew in Renton, Washington, Anthony in Boston, Massachusetts, Eric in Philadelphia, Howard in Elkhart, Indiana, and Zachary in Lakeview, New York. Professor Darby Saxby, you talked about how the brains of new fathers...
One of the changes that you've been able to measure is a reduction in gray matter volume, specifically in the cortex. So does that map to actual behavior changes then?
So we're just starting to look at that. In my lab, we linked dad's gray matter volume changes to their motivation and engagement in parenting. And we found that when dads told us during pregnancy that they felt more bonded to the baby and that they hoped to take more time off after the birth of the baby, they subsequently lost more cortical gray matter volume.
And at three months postpartum, they said they were more attached to the baby. They enjoyed spending time with the baby. They were spending more time with the baby and they were experiencing less stress related to parenthood. So it seems like similar to what's been seen in moms.
These brain changes are adaptive in the sense that they're supporting a closer bond to the baby and more sensitive parenting. Okay. But you've also seen that it's variable depending on, I shouldn't say depending, but correlating with the amount of engagement, however you define it, that the father has in the baby's life.
Exactly. Yeah. So if you look at mom's brains, you can use a machine learning algorithm to essentially distinguish mothers from non-mothers. With dads, the changes tend to be worse. Wait, wait, hang on, hang on. That was really interesting. Tell me more about, you can, like, basically what an AI can detect the difference between...
Exactly. Yeah. So I should back up a little bit and tell you about how some of the mom brain work was done. So the first big study about this came out of Barcelona. Researchers recruited a sample of women from a fertility clinic that were trying to have kids. And they were trying to have a baby.
And they followed women from before pregnancy to a few months after birth. And they found this really pervasive gray matter volume decreases across the whole brain.
And compared that to a sample of women that were followed across the same time span but didn't become mothers. And if you use AI, if you use machine learning to basically say, here are a bunch of brain scans. Which brain scans belong to women that became mothers during this time period? Which belong to women who didn't become mothers? The computer can tell them apart because the changes are sort of that clear cut, that profound. Right.
So that's not the case with the dads that we looked at. Their changes were more variable. You know, not every dad decreased in gray matter volume. Some stayed flat. Some showed very slight increases. So it was a little bit more of a mixed bag, and it seemed to track with dad's caregiving time. So when dads were spending more time with the baby—
more time as a primary caregiver of the baby, they showed greater gray matter volume decreases. So in other words, their brains looked a little bit more like the mom's. Was that a strong correlation or kind of weakish? I mean, how would you describe it? Yeah, it was a
A moderate correlation, but we also had a pretty small sample. So we don't want to get too excited about this work until it gets replicated a few more times. Well, do you care to theorize about correlation versus causation here? Because I wonder if, you know, is it that the gray matter change is what potentially triggers the more caregiving...
impulses in the man or is it that the experience of doing more caregiving of the infant is what causes the brain matter reduction or maybe it's both?
Yeah, it's a really interesting question. And I think it's bidirectional, right? I think it's both. That's kind of the wishy-washy answer. But we did find that when the men told us during pregnancy that they were more attached to their unborn child, they wanted to take more time off after the baby was born, those men subsequently showed greater gray matter volume decreases, you know, in the sort of coming months.
So it seems like there's a motivation piece and there's kind of an engagement piece. And, you know, I think we often think about sort of we're innately wired to provide care, like the brain is sort of set in a way that makes, you know, for example, women great caregivers and men maybe not always so great. And I actually think, you know, what I've learned from this work is maybe the opposite is true. Like we provide care and that shapes the brain, that shapes our hormones, right?
And, you know, much like kind of learning any new skill or, you know, like changing in any important way. Right. We see echoes in the brain. Our brains are very plastic. So this is really important because the way you just phrased it about learning new skills, I think I'm going to it makes me want to stop saying gray matter reduction. And instead, I'm going to call it brain plasticity. Right. Right.
Because I think what you're describing, I mean, okay, so there might actually be a number of neural connections getting pruned. But what you're talking about is...
evidence of change in the brain when a whole new chapter of life begins or a whole new set of skills is activated or learned, which is actually really quite inspiring. We talked about the cortex. Are there other sort of particularly notable parts of the brain that show a similar change upon the advent of fatherhood? Yeah. So before I get into that, though, I kind of want to pick up on what you just said about plasticity, because I think that's really important. And I
there's actually some new evidence coming out of the Spanish group looking at moms that we see some increase in volume. There's some rebound a certain period after birth. So some changes are pervasive. Some changes actually seem to be kind of reversing. And you see the same in rodents, in primates, you know, around parenthood. It's not necessarily that things are shrinking or growing in one direction. It's that there's just remodeling that's taking place.
And in fact, in our dads, we did find the hippocampus, which is a part of the brain that didn't show overall changes in our men. It's considered to be part of the subcortex. So it's kind of like tucked under the cortex. And it's sort of like these seahorse-like structures that are kind of on either side of the ears. And the hippocampus helps us with memory.
It helps us not just kind of remember experiences from our lives. It also helps us remember kind of where we have left things, which is very useful if you're a rodent parent and you've stashed your little babies all around the nest and you need to retrieve them. So seriously, like the hippocampus plays a role in pup retrieval. And that's one reason that people think it changes in new parenthood and in rat models.
And we found that in our dads, the hippocampus was actually larger or it became larger from prenatal to postpartum in the dads who were more involved in caregiving and more bonded with their infants and also tracked with their hormone levels. So dads who had higher oxytocin levels had more hippocampal volume increases. Right.
And the reverse was true for testosterone. We know that testosterone tends to dip
in new dads around the transition to parenthood and lower levels of testosterone were linked with increases in the hippocampus. Well, we're going to go back to hormones specifically in just a second. But the only reason I'm giggling right now, Professor Saxby, forgive me, is that when you said the hippocampus is important in terms of remembering where you put things, in my N equals one of myself...
My experience of mom brain was like all of these like sort of beautiful behavior changes and hypervigilance, et cetera, that we're talking about.
In addition to like a complete collapse of my executive function. Like I could not remember where I put things. And so I'm wondering, does that same hippocampus increase or is that seen in women? Because like I don't feel like I went through that phase of mom brain. Yeah, it's a great question. When we think about mom brain, we often use this kind of deficit model of like impaired cognitive functioning.
And the latest research on MomBrain, actually, it's like a little bit more of a subtle story, which is that we have a lot more inputs that we're keeping track of. And in some ways, we get enhanced memory and retrieval when it comes to things like
you know, our baby, right? Like we don't forget where we left our baby generally. Generally. Generally. I mean, you know, it could still happen. I had a recurring fear as a new mom that I was going to put the kid's car seat on top of the car and drive off because I've done that with my wallet and my keys and everything else I need. And thank goodness I never did that. Well, that's your hypervigilance. Right. Exactly. So there's a reason that I didn't do that, right? Because I had more specialized...
Yeah.
So it's not that we're seeing this kind of overall deficit, right? It's more that we're sharpening and kind of honing our memory when it comes to things that are really salient for the survival of our offspring. Yeah. Maybe that's a more charitable way. Well, I think it makes a lot of sense. Yeah. Right. Like, again, it's that plasticity thing. Like the brain is shaping itself in a way that makes it the most sort of potent material.
thinking tool in this new phase of life and this new person that you have to take care of. Also, just to state the obvious, I think part of my perceived executive function collapse came from lack of sleep. But maybe that's another thing. Okay, so getting back to male brains or the brains of new dads.
There's another part of the brain that I actually did not know anything about until we came across your research. Tell me if I'm pronouncing this correctly. The precuneus?
Yes, the precuneus. Very nice. And why is it significant in the brains of dads? So the precuneus is part of the cortex. So again, it's kind of part of that top layer and it's a major node of the mentalizing network. So that's that region of areas that kind of fire together when we're thinking about other people's minds and intentions.
And the pericuneus is actually a little hard to study because you can't injure it very easily. It's sort of like it's like where you would wear a beret kind of on the back of your head, but kind of deep, deep within.
And so a lot of our studies of the brain originally come from injuries like Phineas Gage who had a metal rod that was through his eye socket that kind of impacted his prefrontal lobes. The railroad spike, exactly. Exactly, right? So we know a lot about the prefrontal cortex, right? Because it's a part of the brain that gets injured. And so we can see these lesion studies will tell us about it.
You don't have a lot of lesion studies of the precuneus. So it's been this kind of mysterious dark horse region of the brain. But we think it's really important for this kind of empathetic mentalizing network processing. And it was a region that seemed to particularly decrease in gray matter volume in our dads. It was also a region, I told you we did functional imaging as well, which is where we saw, you
You know, what happened in the brain when dads were watching videos of their own baby?
And we saw that the precuneus was responsive to one's own baby versus an unfamiliar baby or one's own baby versus one's own partner. So there was this kind of unique own baby salience that seemed to be lighting up their precuneus. Okay, so let me pause there to get more clarity from what you're saying. So you basically were doing these...
let's call it real-time imaging, right? And you put pictures of different babies in front of the dads, including their own, and you measured very different responses in the pre-cuneus. Is that what you're saying? Yes. We actually gave them video clips. So we had recorded our babies in the lab, and we had recorded a baby that wasn't theirs, and then they watched brief clips of their own baby versus another baby.
And so we were able to see kind of all over the brain what was lighting up kind of uniquely in response to their own baby. And the precuneus was one of those regions. And this extends even further, right? Because you also showed them pictures or videos of attractive women. And what? That you find in a typical male, the attractive woman would produce a greater mental or brain response than a random baby. But that's not what you found in dads?
Yeah. So actually, that's a different study. That was a study that was done by James Rilling's lab at Emory. He did a really cool study where they looked at showing men who are both fathers and non-fathers images of baby faces and attractive women, like scantily clad women. And, you know, the non-fathers are way more interested in the good-looking women than
But the fathers actually had sort of less of a preference in the brain. They had brain activation in kind of reward regions to the baby faces as well as to the attractive women. I think they still had a slight preference for the attractive women, but it was buffered. It was modulated when the men became parents.
In our lab, we actually looked at their own partners. So we had them watching the video clips of the babies, and then they also looked at their partners and an unfamiliar pregnant partner. And we contrasted, because we wanted to tease out
Your partner is very familiar to you, as is your baby, and is related to you and relevant to you. And so we wanted to tease out that kind of familiarity and self-relevance from what's unique about baby stimuli in particular. And again, the precuneus was an area that helped differentiate, that was sort of special to
Well, we have a minute before we have to take our next break, Professor Saxby. And can I just take us for a second out of the scientific analysis and into your own brain in terms of how, like, the reactions that you had as a researcher when you saw these differences emerge? I mean, like, you're sitting there, the dad's in an MRI, and you're, like, looking at a brain being activated in different ways. I mean, like, kind of what was your reaction? Yeah.
Yeah, I mean, I never get over the chills that I feel when I can see what's happening in someone's brain in real time. I just think it's like this unbelievable miracle of science.
And I think it tells us that, you know, like dads are wired to care in the sense that they have this biology that can turn on when they're encountering a baby, particularly their own baby. And I think it sort of upends a lot of what we think about kind of who the instinctive parent is. And it tells us, again, going back to this word we keep using, plasticity, how very plastic we are that men who don't undergo pregnancy can't.
still show these changes that, you know, kind of entrain with this transition to parenthood. Okay. So when we come back, I want to talk with you more about how your research may ask us to rethink what our, let's say, our moral and societal presumptions are about fatherhood. So we'll talk about that in just a moment. This is On Point.
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I realized that my generic vernacular included a whole lot of swear words and I knew that that wasn't going to be a situation that would be cohesive with raising the daughter. I tried to look for certain ways to curb my enthusiasm with my vocabulary. I decided instead of swearing, I would absolutely yell out the names of
NPR reporters. Magna Chakrabarty was definitely one of them. So was Steve Inskeep, Rachel Martin, and Ari Shapiro. I found myself happy to kind of show off my daughter and send pics unwarranted and unsolicited to random colleagues and work folks.
I do think I have dad brain. I don't know, I just feel like more goofy and I've been watching all of my old favorite PBS shows like Arthur and Wishbone and all these different things and how much I want him to experience these things. It's been a change, certainly, but it's a good change and I don't know, he's my little guy.
Well, that last voice you heard was Zachary again in Lakeview, New York. Then there was Peter in Brooklyn. And at the top, Brendan in Seattle, Washington. And Brendan, I have got to know. First of all, I'm touched that you consider me worthy enough to replace an expletive in your vocabulary. But I want to know which one. You got to tell me. So like get back on the On Point Vox Pop app and let me know.
Anyway, that's actually probably one of the best calls we've ever seen, Professor Saxby. Before we get to just the whole way fathers experience fatherhood and what our society expects of them, I want to get back to another aspect of the physiological change that you have mentioned. And that actually had to do with hormones.
It's obvious why in a woman's body there's massive hormonal changes. But you've detected them in men, too. And I was very surprised to read that testosterone actually changes the amount of testosterone in a father's body. Yes. And that's actually been seen in animals as well as in humans. So some of the very first work on testosterone was done in birds, in songbirds and birds.
found that testosterone spikes at the start of breeding season in males and then drops after kind of mating has been achieved and men are men. Male birds are taking care of their hatchlings. And birds are actually a very sort of father-intensive species. Dads do a lot of the care in birds. But we've seen that in, you know, other biparental mammals as well, in mice, for example. And so the
Best study, I think, of testosterone changes in fatherhood, it was done by Lee Gettler, who's at Notre Dame. He had a longitudinal study of men recruited from the Philippines, measured testosterone a couple different times, and he was able to measure testosterone a couple different times.
and found that men who had higher testosterone at age 21 were more likely to become fathers. But then after they had children, their testosterone levels went down. And so that tells us that it's not just that low-T men are selecting into parenthood, but rather there is something about becoming a father that seems to modulate our testosterone levels. And
You know, from an evolutionary survival perspective, it makes a lot of sense. It's actually taxing to the body to maintain high testosterone levels. And they might be adaptive when you're competing for mating opportunity. But when your job is really to nurture and invest in the survival of offspring, it's much better to turn those hormones down and
You know, be more tolerant of little babies instead of aggressive and competitive. This is so fascinating to me, Professor Saxby, because, you know, for I would say perhaps the majority of species out there, the survival strategy in terms of evolutionary strategy for males is to have as many offspring as possible. Right. But but in in species, you know,
like primates specifically, where the survival of the extant offspring is a very energy-intensive and long-term thing.
duty for parents, the reduction in testosterone, what you're saying, it would be, it's helpful in focusing the father's energy on the offspring that exists. That is so fascinating to me. Yeah, that's right. And actually, as human societies get wealthier and better resourced, you do see this shift from kind of a quantity-oriented mating strategy. Let's have as many babies as possible. Infant mortality is high. We're hoping some will survive. And
versus let's have a couple of babies and really invest in their thriving. And so that is what we would consider to be kind of a lower testosterone strategy of fatherhood. One thing that's interesting looking at other animals is 95% of mammals don't have father involvement in infant care. So us
us humans are actually pretty unusual. It's us, the California mice, the prairie bulls, you know, some other species we could name. But I would argue that father involvement is a sort of secret to our success as humanity.
In the sense that we have these kind of caregivers on, extra caregivers on hand, we practice cooperative breeding, which means we help each other raise our children. And sort of the more contributors, right, the better the fate of our offspring. Hang on here for a second, because actually I read it in kind of a really different way, that this sort of very immediate, active parenting from fathers is very...
very, very recent in human history, right? In terms of the kind of day-to-day interaction with the infant versus the, what, 99% of human history, which may have had a different role for fathers in a family group. Well, so yes and no. So if you think about hunter-gatherers, right, there are hunter-gatherer societies where males actually are very involved in infant care.
There's a society called the ACA that's gotten a lot of study there in Central Africa. Males are holding infants or within arm's reach of infants about 50 percent of the time. So that's a really unusually high level of father involvement. I think the story is less, you know, dads are checked out and then suddenly they check back in. It's more about variability across culture and it's about what different cultures have at stake.
So in this particular society, you know, they do net hunting. Women are really good net hunters. So are the men. And they work together in cooperative couple pairs. In societies that have different models of provisioning, it might make more sense to be specialized, right? So you have, you know, more traditional gender roles. In our society, you know, we're a service and knowledge economy society.
It makes a lot of sense to have women in the workforce. They have the same skills that men do when it comes to the sort of wage earning that we do for the most part. And that means we need fathers to be involved in parenting at home. And you have seen these big changes in father investment. Yeah. You know, but actually it's so interesting in the examples that you gave of different cultures.
The takeaway I got is that, well, our society right now, let's just stick to the United States, is definitely not constructed to make it easy for fathers to be within arm's reach of their babies 50% of the time. We actually don't have a society that's supporting what it seems like your research is finding that dad's brains are actually built on.
That's exactly right. Yeah, we're sort of in this tension, right? We're kind of like caught in between these two different moments in history where women are in the workforce, and men are in the workforce.
We haven't fully embraced that dads can be part of the childcare team to the same extent. You know, most men are not taking long paternity leaves. You know, certainly there are examples of other countries that have longer, more protected paternity leaves. We sort of still have this model of masculinity that's really built around the wage earner, the breadwinner, while at the same time, you know, many men and women are...
Wow. Wow.
Well, I mean, honestly, for policymakers, I hope they're hearing this because now you can be like the brain. The brain wants to take care of the child. Before we get to sort of things that we can at least, if not conclude right now, because as you said, the research is in its own right.
Sorry, pun intended. But sort of takeaways. There's one more hormone that I wanted to talk about because oftentimes oxytocin, right, is very associated with maternal feelings and maternal care, like the so-called love hormone. Do we see fluctuations in that in fathers as well?
So we do, and my lab actually looked at dads' oxytocin levels after a play interaction with their infants. We found that when they spent more time touching
And physically playing with their infants, dads had higher oxytocin. And that's something a couple researchers have found as well. I mean, speaking of literatures that are in their infancy, there's a lot we don't know about oxytocin. And I think there are a lot of overblown claims. People love to say it's the cuddle hormone or the love hormone. It's actually a lot more subtle and in some ways very hard to measure.
But we do see, like in prairie voles, I mentioned one of the biparental mammals out there, oxytocin levels play a really important role in social bonds and sort of motivate a lot of the cuddling and huddling. In the same way that testosterone might motivate kind of competitive or aggressive behavior, it seems like oxytocin is something that kind of shores up our affiliation and is also dynamic in males as well as in females in new parenthood. That's so, so interesting. Yeah.
So one takeaway, even though it might seem kind of basic and a no-duh, having science to sort of affirm this conclusion I think is really important.
You're proving that the male brain in human beings is actually designed to take part in parenthood, right? Because if it weren't, you wouldn't be able to detect any changes before and after a child is born in the brain of a man. That's right. I think of it as like we have brains and hormones that are designed to kind of turn on humans.
when we engage in care? Does that mean that every father is going to spontaneously step up and be an amazing parent?
Not necessarily, but it means that when we choose to invest, our biological milieu will follow suit, right? We were equipped with this kind of plastic, adaptable brains and bodies that can change as we devote more time and practice and energy and motivation to caring for little people. And then, of course, I'm not going to ask you to give us the solution to fix society, but what flows from that in my mind is...
Well, then in that case, we as a society ought to be doing even more to facilitate, of course, not just dads being a greater part of their child's upbringing, but moms as well. Or, you know, whatever your family unit is like, there's just a lot of evidence that there's much more we can do to facilitate that.
Yeah. Yeah. I mean, I think the more that I study the transition to parenthood, the more I think of it, it's a time of vulnerability, but also of opportunity. It's a time that warrants much greater investment than we currently give it. We spend a lot more taxpayer money on the last three years of life than the first three years of life. And we don't do a lot to support parents' time at home with kids in the early years, even though we know that that time and practice is
is really important for sort of building that internal infrastructure that makes us great caregivers.
And I think in the larger context of like the birth rate is dropping and lots of young people say they do not want to have children. We've sort of developed this society that pits itself against parents. And I think it becomes an existential issue. Like how do we encourage healthy family formation through the supports that make parents' lives better? Yeah. Yeah.
I just have two more questions for you for now, Professor Saxby. As your research continues, I'd love to have you back. But I can't talk to a working scientist right now without asking how the sort of the recent retraction of the administration's support for science is having an impact on you, your lab, your colleagues.
Yeah, I mean, it's shocking and devastating. And there has always been bipartisan support in this country for science and research. I think there's been a recognition that having strong science is great for our economy. It's an investment in human capital. And yet we've had these attacks on science.
Wow.
Do you find that you or your colleagues are having to do even things like comb through grant applications just to remove triggering keywords for the administration?
Yeah. I mean, so I was actually the person that released that word list that you might have seen circulating around on social media. That was something that came from a colleague of mine who got it from his program officer at the National Science Foundation. It was the list of terms that included things like women and socioeconomic. Essentially, any kind of work you're going to do on humans is rendered ineligible by these kinds of terms.
You know, it feels like we're living in, you know, Soviet Russia or Maoist China. And this is not how we build a free society. I don't even know what to say. Me neither. That is genuinely shocking. Like, don't put the word woman in your grant application. Oh, my God. Okay.
Not that, you know, 50% of humanity doesn't deserve more research done on their experience. Yeah. Okay. So let me just switch gears once again, because the last question I do have for you for now, Professor, is what does your husband think about all of this, about your research? Oh, my gosh. That's a million-dollar question. Yeah.
Um, my, thankfully I married a great dad with a great sense of humor and, um, and he's been a, you know, he's, he's read every chapter of the dad book, including the chapters that, um, you know, that talk about him and tell stories about his parenting. Um,
And, you know, has been a big supporter. He thinks it's funny that, you know, so much of my work is about motivating men to care and step up more around the household because he's actually terrific at that. And I'm the slacker. I'm the one who's like always distracted staring at my laptop while he's doing the dishes and taking the kids places.
So, you know, he generally puts me to shame, but... Clone that guy. I know. He's... I'd like to take credit, but I think he's just a genuinely good guy.
Well, Darby Saxby is a professor of psychology at the University of Southern California, and she's at work on a book called Dad Brain, The New Science of Fatherhood. Professor Saxby, thank you so much for joining us. Thank you so much for having me. This was such a pleasure. I'm Magna Chakrabarty. This is On Point. On Point.
Support for this podcast comes from Is Business Broken? A podcast from the Mehrotra Institute at BU Questrom School of Business. Listen on for a sneak preview of a recent episode with J.D. Chesloff, President and CEO of the Massachusetts Business Roundtable. I do think it's instructive to think about the philosophy behind this current environment. And I think philosophically, what is driving it is an attempt to
reverse or address globalization. And I think that's an interesting opportunity for a debate. Do we acknowledge that we're in a global economy or do we want to be more insular? When we were down in D.C. last week, we were having a conversation about this and someone said to us, you know, we were talking about the uncertainty that tariffs are creating in each of our states. There are probably, like I said, 17 or so state roundtables down there. And the response was, look, if our country is beholden
to another country, if they control our supply chain, if there's a trade imbalance that's in their favor, then they could impact the supply chain and our economy at a moment's notice. And that is what the proponents of this current policy, terror policy, are trying to address, right? There is uncertainty there, is what we were told. And that uncertainty is something we want to address.
So it's a different philosophy. And so if you are looking to be less active in globalization and a global economy, then yeah, I think what they're doing makes some sense. If you don't believe that and you believe we are a citizen of a global economy, then perhaps it's not the right strategy. Find the full episode by searching for Is Business Broken wherever you get your podcasts and learn more about the Mayrothra Institute for Business, Markets, and Society at ibms.bu.edu.