Why It Takes a Village: Ruth Mace on Evolution, Family, and Modern Parenting

Ruth Mace

So if you find a primate species that no one's ever described before and you look at their testes, you could immediately hazard a guess on their mating system. So if you find humans, you're not quite sure what their mating system is. We're basically a bit less monogamous than a gorilla, but a lot more monogamous than chimpanzees. So male testes are sort of from or in the middle there, but nearer the gorilla than the chimpanzee. So that's one bit of evidence that we're pretty monogamous.

Nickilina Herrmann

Today I am speaking with Professor Ruth Mace, an evolutionary anthropologist whose work focuses on how human behaviour, family systems, and cooperation have been shaped by evolution. She has spent much of her career studying how people make decisions about family, reproduction, and social life in different environments, and what that can tell us about how humans have adapted to live. Her research sits right at the intersection of biology, culture, and everyday life. Which makes her perspective especially interesting when we think about how modern lifestyles compare to the environments humans evolved in. Ruth, welcome. It's such a pleasure to have you on the podcast.

Ruth Mace

well, thank you for inviting me.

Nickilina Herrmann

Let's begin at the beginning. What originally drew you to study human behaviour from an evolutionary perspective?

Ruth Mace

Well, I actually did. originally studied zoology, and I did my PhD actually on the evolution of animal behavior. So I came from a background of evolutionary biology and behavioral ecology, which is actually the study of what is reason of evolutionary and ecological basis of behavior. So that was my training. But very soon, sort of during my PhD or even before, I was always interested in anthropology. And it occurred to me that the models I was animal behavior could easily help us try and understand human behavior as well. So as soon as I finished my PhD, I actually got some postdoctoral money to start working in evil engineering anthropology. Actually, the very first studies I did were with people called the Gabra, Gabra pastoralists in Northern Kenya. And that was quite a long time ago. And then I've just been working in evilish anthropology ever since.

Nickilina Herrmann

With that in mind, when you look at modern life today, what stands out to you as particularly unusual based on everything else that you've seen? Is there anything?

Ruth Mace

Well, I guess one of the things I was working on right at the beginning was trying to understand birth rates and rates of reproduction. So that was one of my very early questions. And I was trying to model what we call sort of reproductive decision making, which is just a sort of fancy word for, you know, your demography really. births, deaths, timing of births and deaths, how many children do you have, what's the marriage pattern? I mean, these are really classic topics in kind of evolution and in demography and in anthropology. And so I was working on that with gabbera pastoralists and trying to model what was the kind of optimal birth rate. And we found that it was very much responded to resources. So individuals with a lot of access to resources were having more children, having more surviving children. That society also allows religious marriage. So they were getting married earlier. Men were more likely to have more than one wife, even, or if their wife died, they were more likely to marry again. looking at all those decisions, wealth, which if you were a Gabbro pastoralist meant camels actually, they were basically camel herders in the deserts of Northern Kenya. And so it was very easy to measure wealth really compared to our society because. They just had these big herds of camels and you could just count them or ask them to count them and you had a pretty good measure straight off the bat. And a lot of the predictions that we were making about that sort of based on this field known as behavioral ecology were coming true. So all those predictions about resources being converted into basically using kind of births and deaths as a currency was quite easy to explain the patterns that we were seeing.

Nickilina Herrmann

So

Ruth Mace

It was as if the behavioural ecology paradigm worked quite well for this population that was living this very nomadic lifestyle in a very harsh environment. And the time that I was there, which was kind of in the 1990s, people were not really using contraception. There wasn't even very much medical care. So life is pretty tough. One of the things that's puzzled behavioural ecologists is when we study our own society. It's often the case that those patterns don't exist and all those links have been broken. And so there's a lot of debate about whether you can even use these models based on evolutionary and ecological principles anymore to try and understand how many children people have or anything like that. That's been a bit of an evolutionary puzzle. But having said that, evolutionary puzzles, think, for me some of the more interesting. areas to work. I that's actually where I spend most of my thought processes at the moment, because I mean, it's nice to show that the pattern works in some cases, but it's also very interesting to ask what's going on in cases where the pattern doesn't work. certainly in our own society, didn't really look like wealth was being converted into babies anymore. So that was one big puzzle that kind of hits you pretty early on. So I would say that's probably the biggest evolutionary conundrum issue lately, what's going on, why are we having children anymore?

Nickilina Herrmann

Yeah, for sure. Yeah, it looks quite different today. So a lot of your work looks at how humans make decisions about family, children and cooperation. Yes. So how should we think about those behaviors from an evolutionary perspective?

Ruth Mace

So behavioral ecology, like I explained, is trying to understand the evolutionary basis of behavior. And when you say evolutionary basis, there are actually more than one way of interpreting that question. mean, you could ask a kind deep evolutionary question, like, you know, what is the history of this behavior? Did it evolve from here? Did it evolve from there? Whatever. Or you could ask, what is the kind of minutiae of our decision making and does it serve an evolutionary function? And function in evolutionary terms means better survival or better reproduction because that's how natural selection acts. So there's several different ways you can answer that question. In fact, there was this well-known evolutionary biologist, Nico Timberlain, who was one of kind of early founders of the field really of behavioral ecology, which didn't quite exist when he was sort of working in the 1960s. But he's very famous for describing these kind of four different kinds of questions you can ask about the evolution of behavior. Well, he was working on animal behavior. He did actually work on humans at the end of his life, but he was mainly working on animal behavior. So he identified these things called Tinbergen's Four Questions. And a bit previous to that, Another biologist called Ernst Mayr had talked about proximate and ultimate explanations. the proximate ones are kind of how questions like nature nurture or these kind of angles, development, much more sort of how did that, what are the cues for that behavior? And then most behavioral ecologists are more working on the more evolutionary questions, which is more like what is the evolutionary function of that behavior or? What is the evolutionary history of that behavior? And those two questions are just a different kind of question. They're not wrong or right. They're just different ways of answering it, different ways of addressing it. And I think I was always more interested in the last two. So what was the evolutionary function and whatever. And that was really how Timberlake and it's defined those two questions. So when we say evolutionary function, like I say, we're really saying Why did that evolve? mean, why has that persisted? Why hasn't natural selection got rid of that behavior? It must be, in some way, promoting either your survival or your reproductive success or your children's survival or a close relative's survival through kin selection. So there are several mechanisms by which genes can be selected for or behaviors can be selected for, however they develop. And that's really the question that I think... my sister answering. And you can answer that in a very sort of... simple way you can make a sort of verbal model which is quite simple or you could make a more detailed mathematical model where you actually try and work out what are the costs and benefits and really make very precise predictions about what you think these relationships might be and the thing about having a formal model is you can then get data from the real world and see if your model predicts what people do. So it becomes a

Nickilina Herrmann

Quite.

Ruth Mace

know, theoretically powerful way of working out whether we are doing what evolution predicts we should do or whether we're not, which is an equally possible answer, you know. But I mean, if you don't have a model, you can't even really answer that question because you don't know what is predicted or it's sometimes called the optimal, but by optimal it just means optimizing, you know, fitness, as in fitness in the Darwinian sense, not in any other sense. Yeah, that's really what behavioral colleges do. But as you say, if your model doesn't work, then you update your model. And that's how the process kind of works. Because you say, OK, well, that was my theory. I went out. I got some data that explained this kind of variation within a population or this kind of variation between two different populations. And OK, I didn't see that. So my model must be wrong. So you then have to go around again and think, OK, how do I change my model? And that's kind of how the scientific process works. It never ends really, you're always learning more and more about what you do, but that's the method.

Nickilina Herrmann

I have taken from anthropology is that there doesn't really seem to be one natural way to live. How do you think about that? The aspect of the model. There is a model, but or is there one right way to live? Or or well, no not right, but natural.

Ruth Mace

I think that's why the huge misunderstanding is about evolutionary theory is that so behavioral code really is about predicting variation like we're saying. Some of the early models did something like if you're a hunter gatherer, do you eat this food or do you eat another food if you're going out? Which ones are worth hunting? Which ones are not worth hunting? Because you're not going to have enough of them. Can we predict the diet of hunter gatherers? So people made what they called optimal foraging models. So they said, OK, we worked out the calories in all the different food. We looked at how long it took people to find them and process them and everything like that. And then you say, OK, how do you maximize your calorie intake rate? And some of the early models that did this, for example, with plant foraging, and there's a famous study of this group called the Ache in Paraguay, think, foragers. And the model kind of predicted that It was very efficient to eat plants, but like hunting didn't really seem to make sense. It took so long to find everything. So they predicted an optimal diet and it worked pretty well for women, but it didn't really work for men. So they thought, okay, our model's wrong. Something's wrong here. And then you can sort of revise your model. So one thing that might be wrong is that we're not making individual decisions. mean, men and women are sharing food and therefore maybe instead of having the individual as your decision-making unit, perhaps you should have. The couple is a decision-making unit. then men, maybe their costs and benefits are better for hunting than women, because they're stronger or something like that, and therefore they have more success. So you might predict that men should specialize in one thing and women should specialize in another. And then another wedge, look at the model, is that just calories is not good enough. Meat has something special in it. So even though it takes much longer to get 100 calories of meat than it does to get 100 calories of plants. there's something special about meat. Men can definitely kind of improve their status and their social standing by being good hunters. So they can trade that meat for sort of prestige or friends or girlfriends or male friends or whatever it is. So basically your model can become, you know, your simple model is rejected and you have to fit a more advanced model. So when I say model, it's just really a hypothesis. That's all it is. And that's how you update your hypothesis. So exactly that procedure has been followed by people studying. foragers, for example. So that's a way of just learning more. I mean, it's a different way of doing it. You could ask me, why do I go shopping four times a week? Why do I have two children? I have no idea to the answer to either of those questions. But, you know, and if you ask the same question to an actual forager, they probably look at you equally man. You can use a model by just kind of, you can't really make predictions about an individual, but when you've got a whole population worth of data, you can sort of say, I predict this pattern. And then do you see that pattern? And then, okay, we see this division of labor and men and women foraging for different things, and then you can test your models. So it's just a way of getting at a more fundamental currency. That's not to say don't ask people and talk to people, because it really depends on the question you're asking. That's always how an anthropologist is going to start addressing questions, just asking people. But there are some kinds of questions that almost don't make sense. And asking people how many, why they have the number of children they have, I... Never got a good answer to that one.

Nickilina Herrmann

Can imagine. Can imagine. huh. It's not that easy to maybe explain. No not even know.

Ruth Mace

Think theoretical models and try and predict what patterns you might see. And once you've got a population of thousands of people, you can go and look at that, see if those patterns are there. So it's just a different way of doing anthropology, really. There's different ways work better for different questions, really.

Nickilina Herrmann

Let's talk little about one of my favourite subjects, parenting. So when we think about how humans evolved to raise children, what did that typically look like?

Ruth Mace

Human child raising does look like, for certain measures, to be pretty costly. We have children that are born pretty helpless. They're very dependent. Even they need breastfeeding. But once they stop breastfeeding, they need some food that they can't eat really adult food. They often need specially processed food. So that's yet more work. babies tend to be born quite fat. They're quite large. So there are a lot of things on the face of it that make them look quite costly. But paradoxically, the thing that I think really makes them costly is that we have them at a rapid rate. We have them like every three years or something like that. If you're not using any contraception, you could quite easily be having babies every three years or every two years even when you're young. so then you have this additional problem that once your baby is weaned, it's actually not independent. So then you've got several non-independent children all eating, feeding at the same time. And just to kind of go back to the biology of it. If you look at our nearest neighbors like chimpanzees or orangutans, know, primates, species, they actually have longer interbirth intervals than we do. They have like five or six years sometimes. But the whole system is a bit different because once they've weaned their offspring, their offspring are off feeding themselves. So they're independent. So they might hang around for a bit, but in an orangutan, they don't even do that. They just off. So a female rangchang is not that different in weight from a female hunter-gatherer. She's having one baby every six years, where a female hunter-gatherer might have one every three or four years, and then have multiple dependent children. Whereas the female hunter-gatherer, she's doing it all on her own. She's not getting any parental care or help from anyone else. Whereas humans have families. So you get this incredibly energy-intensive period where you're not only trying to feed yourself, but you're also trying to feed more than one set of children now. Children do start foraging quite young, and they even start helping to feed their younger siblings sometimes, or look after them, or entertain them, or whatever. But the data suggests that they don't really start making a net profit, if you like, until they're like late teenage, or even 20 years old. So human children appreciate this really. It takes them a long time. to be self-sufficient. So it's a completely different game from raising your orangutan or your chimp because they're pretty, they're pretty functional, at least in terms of food, at the age of five or six. And obviously a human five or six year old can't do anything. So, so it's a completely different game. And so that's, that is the problem that we're facing. Now, obviously the first major difference is that you're not doing it on your own. So, Pair bonds run pretty deep in human evolution. We think we're always have been pair bonded. That doesn't necessarily mean for life. I mean, obviously, but we tend, we think we're fairly monogamous. And then there might be some serial monogamy, especially if someone dies or a couple split up. But on the whole, we're quite monogamous. there's, again, if you compare with our primate species, you can look at our anatomy. So like, for example, male testes size is strongly correlated with sperm competition. So sperm competition means that if more than one man is mating with the same female, then it sort of turns into a numbers game. Basically, the more sperm there is, you know, the more likely they are to father the offspring. So chimpanzees have absolutely enormous testes, right? Because there's lots and lots of males of sperm competition. So females are mating with males. If you look at a gorilla, it's actually bigger than a chimpanzee, but they've got tiny testes because they defend this group. They kill any other males that try to come anywhere near. It's a very strong family group. So even though it might have multiple females, all those females are only mating with that one male. So the sperm competition is kind of zero. And therefore they don't need very big testes. So it's just natural selection. So if you find a primate species that no one's ever described before and you look at their testes, you could immediately hazard a guess on their mating system. So if you find humans, you're not quite sure what their mating system is. We're basically a bit less monogamous than a gorilla, but a lot. monogamous than chimpanzees. So male testes are sort of from or in the middle there. But nearer the gorilla than the chimpanzee. that's one bit of evidence that we're pretty monogamous. So it doesn't mean to we're totally monogamous. We're definitely not. But. That suggests that males are sticking around and that suggests that they've been contributing to parental care, feeding the family for a long time. So that's one reason why we can pull off this very fast birth rate is because we're getting help from males. We may also be getting help from our own children and we may also be getting help from grandmothers in particular because we also have menopause, which is a really weird thing. that. There's a bit of debate, but basically our primate relatives don't have anything like what we have, which is absolute shutting down of all reproduction by 50 at the latest, possibly earlier, when your life expectancy is still at least another 20 years. So even if you're a hunter gatherer, there are old people, there are, you know, aged hunter gatherers. This post-reproductive life, we think, is one of the many weird characteristics of our species, which... I mean, some people have found a few post-reproductive chimpanzees in certain populations where there's low mortality, and similarly, there's a suggestion of a few gorillas, but it's just... It's nothing like a kind of universal, extended, post-reproductive lifespan, but all human populations. There's obviously no human population without menopause. It's a species typical characteristic. And one of theories for menopause is that... we become more useful as grandkids than as parents after a certain age. So rather than having more children of our own, maybe it's better for your intrusive fitness to help your children stay alive and help them reproduce rather than going on having yet more children. That's a verbal model. Making a mathematical model of that has proved very complicated. And there's all sorts of different versions which all don't necessarily agree with each other. But that could also explain this slightly strange life history where we have, sometimes you can think of the female life history as having three stages. You have a long childhood where you don't reproduce. And that is pretty long, because we grow pretty fast in the first five years. And then we really slow down. It's like we don't want to get big. And then we go through puberty and we suddenly take off. And then we become adults. so we've got this long extended pre-reproductive period where we're children. Then if you're female, you suddenly get Well, and probably for now, you suddenly then have this high reproductive rate. So you start growing, you start having babies, and that's extremely energetically expensive. And it looks like it's pretty much impossible to bring in enough calories on your own. So you need help from your husband. You need help probably from either your mother or your mother-in-law. maybe from the older children that she's got, she's got a family already and... Then you can just about kind of make the caries work out. And then at about the time that you're hitting menopause. you're entering into, again, another long period where you don't reproduce. And your mother's probably dying. So when you're reaching reproductive age as a female, it's kind of not that unlikely that your mother will be going through menopause. And when you're reaching menopause, it's not that unlikely that your mother will be dying. So you can think of it as like a lot of animal species, people talk about pre-reproduction and post-reproductive, and that's it. Or sorry, yeah, you know, like. juvenile and adult basically. As humans seem to have these three phases. I mean, that's circumstantial evidence, but it really does seem that the timing is kind of all, so within a family, you're not competing with your children or your mother or your mother-in-law, but you'll sort of take it in turns to do the reproductive bit. There's a certain time of your life where you do it, and that is the hectic time of life where you find yourself completely overwhelmed. But I think that's something nothing new. mean, that seems to be our species life history, basically.

Nickilina Herrmann

That's good to hear because I sometimes really find myself wondering, is it just me or maybe it's not just me then. Good to know. Good to know. It s sounds to me that evolutionary, maybe there's a big point of having then your say your mother, the grandmother around. Since we have these three stages. Cause I mean, my life today is not like that. I don't have my mother or my mother-in-law nearby, like many of my friends. So we, for instance, use instead childcare. we spend a lot of time with our children, like me and my husband as much as we can. It gets quite ex but but we are also only two. Is that a bit of a mismatch or does it make sense evolutionary?

Ruth Mace

There's no kind of society where say, the women here are just like female orangutans. They just, they live on their own. They have their own baby. They do it all themselves and blah. I mean, that is just, don't, that is really, really hard. If you didn't have what's called alocare from a parent, you need alocare in the form of schooling or paid childcare or the child being at school. because otherwise it wouldn't be possible to sort of do everything. And it wasn't as a hunter-gatherer, and it's still extremely difficult now unless there's a school that can support your children for some of the day or some source of help, basically. Now, not everyone is going to have a grandmother because that may not happen. There've been quite a number of studies, including one we did where... We looked at this data actually from the Gambia where we compared children who, about 50 % of children had a grandmother and about 50 % of them didn't because it's quite a high mortality environment there with lot of malaria and high child mortality particularly. And we found we could actually demonstrate that there was a slight increased chance of survival if you had a grandmother and we could also demonstrate that you were taller, you were better fed. So that was very good, sort of, I mean, it's not experimental, but it's very good circumstantial evidence that there's a definite fitness benefit to having a grandmother. And then that has actually been replicated. That's been shown in historical fins, where they had like several generations of daycare. They were able to show that the longer your grandmother lived, the more grandchildren survived. So, I mean, there've been now tons and tons of studies showing that grandmothers... At least there's a correlation. mean, it's, you know, one of the really difficult things about working on human beings is, I mean, the good thing now, you can get all this historical data and you can ask people about their past so you can get all this really detailed data about reproductive history. And the bad thing is obviously there's no experiments. So you're looking at kind of natural experiments or whatever. then, so you're ending up with a lot of correlations rather than manipulating people, obviously you can't manipulate people. birth rates. There's quite a lot of circumstantial evidence now that this is really, know, grandmothers are normally pretty helpful in helping to keep their grandchildren alive in an actual measurable way. And then even in modern populations we've got quite a lot of evidence of help with education and all that, know, various, various inputs. Obviously we don't really have very high mortality anymore so you're not going to see these effects in... populations with low mortality, but you can still see other kinds of benefits of expanded social network, having aloe parents, you know, parental care is really costly and expensive and basically the more people are willing to do it, the better normally for children. So that's been shown pretty well. I would say there's, it hasn't been shown very well in hunter gatherer populations. So I wouldn't say that means there's still room for controversy because obviously menopause evolved in hunt-gatherer populations. So I still think grandmother effects are very important. But lots of people who study hunt-gatherers, I mean, the trouble is that the life expectancy is shorter. So the opportunity for grandmothers to help is often lower. The sample size of the studies that been done is much smaller because obviously hunt-gatherers are pretty much extinct now. And from farming populations, we can get these big they'd set so we can get these long historical records and we don't have anything like that on hunter-gatherers. So I'm just putting a little caveat there that some people don't believe in the grandmother effect, but I do. And it is a kind of annoying inconvenience that the hunter-gatherer data is not that great, or not that great in terms of supporting this hypothesis, but I think the evidence is pretty strong that grandmothers can be very helpful. There could be all sorts of... confounding effects like, you know, if you're living in a wealthy household with lots of benefits, you're on a good bit of land, something like that, then grandchildren will survive better and grandparents will survive better. So you'll end up with what's known as a phenotypic correlation, which is not really a causal effect. It's just that they're both correlated with something else like living in a good situation. So we've got to be a bit careful about interpretation, but the The basic idea is that we, mean, grandmothers, again, even though the demographic data is not that clear, there is plenty of evidence of grandmothers carrying on foraging right up into their old age and giving that food to others. So they are a net gain basically, until they get too old. obviously then in the end, age will catch up with you. But quite like to be a grandmother by the age of 40 or 50, and naturally. producing population and you still got a lot of foraging potential if you're a forager or other potential if you're not a forager at that age so you could be very helpful. There's quite a lot of evidence in terms of that. But it's still... The verbal model, there's still a lot of questions that come out of that. One is, so if you, there's lots of other species where family members help raise children. So something like hunting dogs. Like, she'll have one set of pups and then she'll have another set of pups and the first set of pups have all grown up and they're out hunting and they'll come back and they'll regurgitate food for the mother while she's feeding the new pups. So the siblings are being really helpful. to their little baby new siblings. in most other species when there's helping going on, it's the younger ones who are helping the mother or the father, not the way around we do it. So that hasn't been completely resolved. So that's another problem. Okay, maybe we've got this communal breeding system. When I say communal or cooperative breeding system, I'm just saying we've got some non-reproductive life phases helping reproductive life phases. So grandmothers have lost their fertility specifically so that they can help. where that's happened in other species, it's normally just the juveniles who are doing the helping. And it's normally like a shortage of breeding slots. So they're kind of waiting around in the hope that, you know, when one of their parents dies, they'll be able to kind of... take over and become the breeding female in the group or whatever. And that is not what humans do. So there is something a bit weird going on. One of the hypotheses that I also quite like is that most humans you're living with your mother in the law rather than your mother, because it seems to be much more common for females to disperse at marriage than males. So normally, if you are living in a family group, across the world it's just statistically more common that you're living with your in-laws if you're female. And so it has been pointed out that If you have a baby and you're living with your mother-in-law, that baby is her grandchild. So she's going to help you bring it up. But if your mother-in-law has a baby, that baby is not related to you at all. So if you have what's sort of known as a kind of evolutionary arms race, it's like, grandmother's going to blink first because she's not going to her grandchild to starve if you're in difficulties. But if you're in difficulties and you don't have the spare capacity, don't. You ask me, what do I mean by decision making? Well, a behavioral ecologist means how does natural selection work? So natural selection won't particularly favor women helping their mother-in-law reproduce because the offspring are completely unrelated to her. That's her husband's relatives, but not hers. People have argued that if there's reproductive conflict in the family, in other words, only enough food for so many babies, then the younger one's going to win because the grandmum's going to blink first and always help her, and the other way, it's not going to happen. There's not a lot of evidence of that model, but I really like it because I think it really makes sense. They've modeled it quite formally. And amongst humans, it does seem that

Nickilina Herrmann

Yeah.

Ruth Mace

Children are more likely to be living with their paternal grandmother and their maternal. They might be living with both, but often they're... You're probably living in your husband's households, and if that's the case, there might be conflict. So it's a great... I love that theory. I can't say that it's right, but...

Nickilina Herrmann

But yeah, absolutely.

Ruth Mace

When I say conflict, don't mean like having arguments, I just mean in an evolutionary arms race that has happened. That's why menopause evolves. So in other words, selection on mothers in order to stop early was stronger than in species where mothers were living with their daughters, where you might as well just get your daughter to help you, because it's symmetrical in that situation.

Nickilina Herrmann

For sure.

Ruth Mace

Whereas in species where you're living with your patrilineal relatives, natural selection would favor the loss of, the bringing forth of men of course. So when we say reproductive conflict, we don't actual conflict. It's kind of shorthand, a metaphor for how natural selection is working. And that just might be why. human physiology is the way it is because of our social system. I'm not sure there's any overwhelming. But there is a lot of evidence that there's very little intergenerational reproduction in households. like I said before, it's quite rare that once...

Nickilina Herrmann

Mm-hmm.

Ruth Mace

one generation has started reproducing, but the older generation is still reproducing. There's normally pretty clear delineation. And some, like when we work in the Gabra, they even recognize that culturally. It's like you kind of move, when your son gets married and his wife moves into your compound, you always change your status from being a mother to being a grandmother, and it's a different status. And you're not really meant to reproduce anymore. And she's then doing the reproducing, and also she's meant to help you with all sorts of work. of staff and it's almost like you've reached your retirement. So it's even culturally recognised as such but again in the Finnish data they showed that there's not very much overlap. And when there is overlap, the grandmothers can't be very helpful because they're too busy looking after their own so it's not a good situation. And the other, I forgot to mention, I mean the other big mammal species that has menopause is killer whales and there's a lot of new research coming out on killer whales which is really exciting. because there's so few mammals that have menopause and killer whales are one of the few that do. And obviously they're quite understudied because they live in the sea and rest of it. But we're learning more and more about them and they have a strong grandmother effect as well. But they also show reproductive conflicts. So if there is sort of overlap in reproduction between mother and daughter, it's not as good as if there's no overlap. So all this help pain is a bit contingent on Because being a parent is so costly, you're overwhelmed sorting out your own parenting. You don't have much bandwidth to help anyone else. So a lot of this helping from other kin does seem to depend on them not having any children, either because they're a grandmother or because they're one of your children, and they're helping a younger sibling. So that's how reproductive conflict might have created the kind of human life history, really.

Nickilina Herrmann

Yeah, and it makes a lot of sense, really. Yeah, yeah, yeah. So

Ruth Mace

You can get help from your aunts and uncles or whatever, but there's not much evidence for that. it's not because they're not with you. It's just because if they're in the same reproductive generation as you, they've got their own problem. I they've got their children to look after, right? So you're not going to expect a net benefit on your siblings because they're busy raising, you know, if they're the same age, nearly the same age generation as you, they're going to be busy raising their children. So they're not going to have much free time.

Nickilina Herrmann

No, for sure. For sure. That really is is it. But then you you've looked a lot at cooperation, social life. I mean this is mm to me like really cooperation maybe at its most intense, the the raising children. But how important has cooperation been otherwise? Like has there been other parts where cooperation has been really important when we look at human evolution?

Ruth Mace

I guess an evolutionary model boils down in the end to a currency that relates to reproduction. So children are always sort of in there somewhere, or survival. That's kind of the same thing. mean, childcare is only one dimension, right? There might be cooperation in sharing food. There might be cooperation in warfare. I mean, there can be cooperation in almost any kind of human behavior. And men might cooperate in warfare. They might cooperate in farming, or whatever. Women might cooperate in farming. So there's a lot of cooperation going on all over the place, left, and central. And it's pretty specific to context. So I would argue you just have to look at the costs and benefits. And they might be direct costs and benefits. Like there's just kind of a win-win efficiency situation. Like you can't, you can't go and steal someone's herd of livestock on your own, but if you get together with some friends, maybe you can, you know, or it might be. some kind of reputational benefit, like if you gain a reputation for being a good cooperator, you help someone when you have got some spare resources because they're sick or they need help or something like that, then when you're sick or when you need help, either that person directly may help you back or you may have gained the reputation for being a good person and then you'll get sometimes called network responsibility, that you are a good person. then you will have a good standing and therefore you will be more likely to get help if you need it from someone else in the group. So there are models like that which, on the face of it, might look like a bit of a puzzle, like why am I helping this person who's not related to me? Well, it doesn't really matter, it's just a cost benefit thing. It's reciprocity and it might be immediate reciprocity, but more often than not, it's some kind of delayed reciprocity or reciprocity that you might just be bigging up your reputation as a good member of the community. And if you have a bad reputation for being uncooperative, then no one's going to help you when you need help. And if you have a good reputation, you're probably more likely to get help. And some people argue that religious networks are also built on these kind of ideas. And so there is a lot of reasons why you might cooperate. And sometimes it's a bit indirect. You can't see an immediate benefit, so it can look a bit puzzling. We always say our corporations are such huge puzzle, but then. People have been modeling it for 50 years now and there's so many different circumstances that do generate cooperation now that I always feel it's no longer really appropriate to necessarily call it a puzzle because there's been so many papers solving that puzzle, but it's just very context specific. And of course, sometimes we don't cooperate. I think it's very context specific, so I don't think it's true. We are generally cooperative. I think it really depends on the context, who you're helping. how costly is the help, whether the person you're helping is a relative or not. All of that is highly benefit.

Nickilina Herrmann

Speaking of puzzles, do you see any gaps today between what I would call modern life and how humans have evolved to live? Like is there anything that seems strange, weird, puzzling? Anything that doesn't make sense really? Or that we are maybe doing wrong? I don't know.

Ruth Mace

mean, there's two questions there. I mean, there's the mismatch question. In particular with parenting, I think we are often finding ourselves in a situation where... We have got into this situation where earning a living is very different now. And it seems to involve having a lot of education. So a lot of the time that we might normally have been reproducing, are now choosing to spend that time educating ourselves, or either formally or learning how to do some kind of skill trade. We're not really just wandering out into common property and gathering food anymore. We have to have some skill that can bring in the money. And that's getting us to start reproducing pretty late. And then we're moving around more, so we're less likely to be living with our friends and family. We're less likely to get that help. And we are needing to educate our children probably a lot more. So that's putting a lot of stress. Now there's also mechanisms in there to relieve that stress like schooling, which is the state helping to look after our children for a certain number of hours a day, hopefully teaching them something at the same time, but at least looking after them. So it's arguable, but I think there's a lot of competition now for jobs. I as I mentioned, I wrote a paper quite a long time ago now where I used the word run away parental investment, because when you've got competition, There's no longer a kind of concept of enough education. It's not really like it's enough. It's like everyone's competing. So everyone's trying to get into the same university or everyone's trying to get the same job or whatever. So there's no longer an enough. There's sort of a runaway process. So the classic evolutionary example is the peacock's tail. It's not really enough tail. You've got to have the best tail, you know? And that females are tuned to sort of... seeking out, in that case, good genes that could make you have an amazing peacock's tail and mating with that male. And therefore, the trait gets more more elaborate in this kind of process. And so when you see something really exaggerated in evolutionary biology, you wonder where the competition is behind it. Something is driven. I don't know, but I think it's not impossible that parental investment has got caught up in that a little bit. That there's no longer a sort of good enough parenting, which is probably was fine not long ago, but huge competition about what you do. And that's also tied up with mating competition. other words, doing all that competition, partly so that your child gets well educated. and that they get into position where they can earn a lot of money and therefore they will be in a better position to find a mate to bring up children of their own that are highly educated. And so it becomes a kind of circular process around that might be happening and we might be almost, you know, it is entirely possible that we are overdoing it.

Nickilina Herrmann

Think so indeed. Sometimes it definitely feels like it at least. Yes.

Ruth Mace

That's I mean, my children are high 20s, low 30s now, so even I can see a difference between how my, you know, like my PhD students' children are. Just things like whether it's okay for a child to walk to school now. You're meant to pick them up at the age of 12 or whatever, where it's like, I can't remember what time I started making my own way to school, but it was a lot younger than that. You know, there's cultural changes that have like... said, no, no, no, parents have to do this. And oh, you're not doing it. You're not being a proper parent if you're not doing this, that, and the other. So something is happening. that parental investment does seem to be a lot more intense. But that's something we have to get a date on. But the amount of time that children are spending with their parents is going up. And it might be partly because We're having fewer children anyway, so children want to be running around entertaining themselves all the time. And they might normally have done that in the street. And if they can't do that, then they have to do it with their parents. Or it might be that parents are just intensely over-parenting and trying to do too much with their children and not really daring to let them just go make their own mistakes and find out, you know. how life is just by playing in street with other kids when they might get hit or into a fight or whatever. I think that's still a question to be answered. Have we gone over the top? Or are we being driven by competition to go over the top? And I think it's entirely possible that we are.

Nickilina Herrmann

Mm.

Ruth Mace

As we were talking about before, there's quite good evidence now that poverty is becoming a bit of an impediment to becoming a parent. So it used to be that there were different strategies. There was the highly invested middle class strategy of highly educating your children, starting rather late, but then giving them a very expensive education and whatever, and waiting till you bought a house and had plenty of money to take them on holiday before you ever even started. And that's still going on. But then there was kind of another strategy of just kind of like, I'll just have children anyway. Get help with your mom. If you don't have a husband or if you do have a husband, just don't worry about all these like extra activities. Just, you know, get on with it. And that was kind of leading poor rich people to have the same number of children or even poor people to have more children than rich people. But just very recently, there seems to be quite a lot of evidence that Poor people are finding it more difficult to enter parenthood in the first place. There's just these sort of barriers to becoming a parent and getting married and having long-term committed relationships and maybe it's also, I mean, in England it's a lot to do with buying a house. don't know if that's necessarily the same in other parts of the world, but there's more and more evidence. So as we discussed at the beginning, fertility is still going down. It's not anymore that rich people are not having very many children. They're having two, which they've been having for a while. And some of them are even having three. no. Or even four. But that's pretty unusual. But what's really happening in Europe now, I'm not sure about Asia, but I think there's something that I've got quite interested on, haven't I look at, is that The poor are now having four. I mean, I've just took the averages down, not talking about individuals, but the probability of less well-educated or no-income people having babies is going down a notch.

Nickilina Herrmann

So

Ruth Mace

down first in older people, but now it's going down in absolutely everybody. So that is why fertility is still heading down. And it's rather sad reason because it suggests that lots of people will just, for whatever reason, feel that they can't afford to have a family. I mean, there's also some relationship crisis going on. People are judging, perhaps correctly, that it's going to be really hard to bring up a child if they don't have a long-term relationship. And long-term relationships are also still experiencing a decline. that's happening at the same time. And that might almost be another one of the drivers of these very small family sizes is just that more people are single and more young people are single. So there's all sorts of things going on at once, which might all be to do with the resources, which is what a behavioral etiological model currently predicts, which wasn't true even 20 years ago. There's more and more cases coming out now showing this effect. So I think the demographic landscape is changing a little bit. But there's a lot of unanswered questions there, because we don't really know what's going on. But whatever is going on, is becoming more more difficult to have a child, or at least it's being perceived as, well, it might be correctly perceived as. I'm not saying people are getting it wrong or right. There's no right answer, but for whatever reason, people are not having children as news frequently as they were, and much later than they were, and often not at all.

Nickilina Herrmann

Yeah, that's really yeah. Fascinating and a little sad actually. It is a bit sad, yeah.

Ruth Mace

Especially if it's resources driven. Yes, there's lots of people who would like to have a family, for some reason it's often interpreted as, people don't want to have children anymore, which might be part of it. But another part of it might be, well, I just don't want to have children in this economic situation. Not that I don't want them ever, but I just feel like right now I don't own enough or whatever.

Nickilina Herrmann

that's sad. And I see the time is really flying. I have so many questions, but let's end with a practical one then. So if a modern family wanted to live slightly more in line with human nature, what is one thing they could experiment with? So what can I do next week?

Ruth Mace

Well, I think you are living in line with human nature. mean, human nature is always changing, right? It's like, if you just mean, we different from chimps? Of course we are. Are we different from the antitols? Yep. If you mean, are we all the same? on one level, we are in the sense of, I mean, as a behavioral ecologist, if you change your environment, you can change very quickly. We did a study. way back looking at Bantu speaking peoples in Africa and we could show that as soon as you bring kind of cattle into the situation, then suddenly wealth inheritance becomes very important because these cattle are very valuable, they tend to be controlled by men, so societies were becoming much less matrilineal and much more patrilineal because the males were controlling the wealth. the marriage system just changed and suddenly marriage went from being not very important to being very important because you're trying to marry one of these wealthy guys. And I mean, I'm just giving a kind of example from anthropology where you can see something change in the environment and the way people behave can change almost in one or two generations. It can change really quickly. So we're very flexible and you know. We're changing all the time and now we're trying to change to a different kind of economy where, you know, everything's based on earning money at the moment and so that we don't even know what is going to be the best environment for our children to earn money on. Does it even matter or whatever? It's very hard to plan where you don't know what the cost of benefits are going to be. So that is a difficult question because I think that we're sort of always trying to second guess, I suppose, what's going on. I think we're being overly driven by competition and maybe we need to kind of and dial back on that because it's ruining our quality of life and it might even be ruining our children's quality of life. But I can't with my hand on hand say that it's not a competitive world out there. So I'm not going to say, you know, do or don't do this because like everyone else, I don't really know what is, I mean, we all seem to have decided that an education is a great idea. I still believe that I'll work in education. So wouldn't work at a university if I didn't think education is a great idea. So I, I still think that's the case. Maybe parenting's got too intensive. I do think we need to give children a bit of freedom to explore the world, by which I don't mean on the internet, of course, because that definitely seemed to worked out too well. But, but in real, you know, real face-to-face contact, real socializing, maybe socializing across generations where, you know, not just saying, okay, children do that, children eat over there. Adults do this, adults eat over there. adults socialize here, children socialize there. I think that's kind of the environments in which humans used to live. So I'm not in favor of living how humans used to live because we were all dead by the time we were 65. But I am suggesting that some of the recent problems might be the loss of that kind of social space that I think was pretty important in all of, not just in the US, all of human history until very recently in trying to replace your social space with your iPad is... and partially successful. And then your iPad can of course feed you all sorts of stuff that you're not meant to see. There's something called the naturalistic fallacy. In other words, it's a very bad idea to try and make moral arguments from evolutionary arguments. Because evolution is just what happens. So male lions committing fantasies of cubs. That doesn't really mean they're a good male lion or a bad male lion. That's just what male lions do. I always start my lecture course actually by saying it's pretty dangerous territory to try and give anyone any advice on the basis of the ignition. But I mean, it does seem pretty overwhelming that we are a pretty social species and we need to try and... There are some things about modern life that make it very hard to be sociable and I think we just need to try and... I mean, I can't talk, I do all those things. I stare in the computer most of the time. I'm not practicing what I preach, but I do think that the more you can do to socialize across generations, better.

Nickilina Herrmann

Yeah, that sounds really wise. So give kids more independence and let them socialize like with each other, with adults. Yeah, with adults. Maybe more help from grandma is also maybe advisable.

Ruth Mace

And with that, I'll- They did this situation where children were being brought up by grandma because they have this weird residence system whereby lots of people were moving into cities to try and earn money, but they weren't allowed to take their children with them because the children were registered in their home areas. So the children had to go to school in their home area. And so a lot of children were raised just by grandparents and a lot of those children said they were lonely. it's not... It's not that one's better than the other. It's just that the more people that can help, the better, basically. Yes, it's great if you can, you know, can't look after your child, if your mother can help, that's fantastic. But it shouldn't matter if you can vote.

Nickilina Herrmann

Yeah, super makes a lot of sense. Makes it nicer for for the parent as well, I would say. Then lastly, if people want to learn more about you and your work, where can they do that?

Ruth Mace

well, it's... As it happens, I am actually in the process of putting some of these things into a book, but they can't find it yet because I haven't finished it yet. I am writing a book, a first draft of which has been dispatched to the publishers. I'm told it takes about a year to go from that phase to the next phase. So watch this space. I have been working on a book about all this stuff. I have a website.

Nickilina Herrmann

Exciting.

Ruth Mace

from my work at University College London where I talk about some of these things. think that... There's tons and tons of books about the evolution of behavior. I think a lot of them are getting into your psychology and a lot of them have talked about cultural evolution, but I'm not sure that there are that many popular books about taking a more ecological view of reproduction and parenting and everything like that. So in the end, I mean, there are lots of them, but I just saying that you know, if you're in the airport, something like that. Most of them tend to be on psychology or culture. If you're interested in parenting, Sarah Hurdy's been writing about this for a long time. She wrote Mothers and Others a long time ago and she's just recently written one called Father Time, so I'll just plug her books. She's a behavioural ecologist, but she's also very interested in psychology. Those fields are all strongly interrelated, but I think the kind of English in demography and behavioural ecology... Maybe there's too many ologies. It doesn't slip off the tongue very easily. So we have to think of a better PR. But yes, watch this space. A book is happening on all the...

Nickilina Herrmann

Super. It was really exciting about that book. I'll put a link to your page there.

Ruth Mace

do videos up of me talking about things, but I am aware that I, unfortunately, I promised this book to my publisher 10 years ago. And I thought, no, no, I really do need to write this book. So I got in touch with them said, do you remember me, by the way? You I did promise you this. I looked up the date and it was exactly 10 years ago. And I said, swear this is 10 years late, but will you still read it? They're like, yeah, well, I'm very happy. So, yeah, I hope she imprints them and publishes something.

Nickilina Herrmann

Really fascinating. Cool. Yeah, I'm looking forward. Right. Yeah.

Ruth Mace

than when it comes out.

Nickilina Herrmann

Super, super. Yeah. Well, thank you so much, Ruth. It's been so nice talking to you and I've learned a lot. Really, really fascinating. So thank you for coming on. Yes. And I'm looking forward to talking to you again when your book is out. Okay. Thank you. Have a good time. Bye. Bye.

Ruth Mace

was fun. Okay. Thank you.