Penn State undergraduate Amy Mook interviews Dr. David Puts, Associate Professor of Anthropology about his research. Puts’ Behavioral Endocrinology and Evolution Lab focuses on the evolutionary and neuroendocrine bases of human sexuality and sex differences.
HOST:
Samantha Muller, Penn State Undergraduate Student, Forensic Science, minor in Anthropology
GUEST:
Dr. David Puts, Associate Professor of Anthropology
Penn State undergraduate Amy Mook interviews Dr. David Puts, Associate Professor of Anthropology about his research. Puts’ Behavioral Endocrinology and Evolution Lab focuses on the evolutionary and neuroendocrine bases of human sexuality and sex differences.
HOST:
Samantha Muller, Penn State Undergraduate Student, Forensic Science, minor in Anthropology
GUEST:
Dr. David Puts, Associate Professor of Anthropology
Mark Shriver:
From Penn State’s Center for Human Evolution and Diversity, this is Tracking Traits.
[MUSICAL THEME]
Mark Shriver:
Hello and welcome to the eighth and final episode of the first season of theTracking Traits podcast. I’m Mark Shriver, co-director of CHED – the Center for Human Evolution and Diversity at Penn State University.
Nina Jablonski:
And I’m Nina Jablonski, the other co-director of CHED. Welcome to the podcast.
Mark:
Well Nina it’s hard to believe that we’re already wrapping up the first season of Tracking Traits.
Nina:
I Know, Mark. This first season has just flown by. All of the episodes have been wonderful, and I think we’re going out with one more great one.
Mark:
Agreed. Each one of the conversations we shared on the podcast gave us a look into the research of a different scientist, as well as a little bit of the story behind what inspired them to pursue science and their particular lines of research.
Nina:
For this last episode of our first season, Sam Muller rejoins us one last time to conduct the interview. She is an undergraduate Forensic Science student at Penn State with a minor in Anthropology.
Mark:
Sam is a natural at interviewing, always asks great questions, and helps us finish out strong here as she interviews David Puts about his work.
Nina:
David is an Associate Professor of Anthropology here at Penn State where he heads up the Behavioral Endocrinology and Evolution Lab. His main interest is the evolutionary and neuroendocrine bases of human sexuality and sex differences.
Mark:
Like all of our guest scientists, David a deep passion for his work. He’s investigating so many aspects of sexual differentiation; physical differences, psychological differences, comparisons of humans to other species, and of course the very hot topic of gender, puberty and the hormonal control of these.
Nina:
Yes you can see it everywhere in our culture today that we are taking a fresh look at gender identities and David’s research really speaks to that. And of course human sexuality is always a hot topic.
Mark:
It always is. And it’s a topic that brings in other dimensions of doing research. Like, what is culturally appropriate to study in particular cultures around the world? This can vary greatly, and it’s another one of the areas Sam and David touch on in their conversation.
Nina:
There’s also a very funny reference to the “Coolidge Effect” in there, which – for anyone who hasn’t heard of that before – it’s a great little piece of history that’s also really entertaining.
Mark:
Yeah, like we were saying earlier, I think we’re really finishing out this first season with a great podcast.
Nina:
Absolutely. So why don’t we queue it up here and give it a listen?
Mark:
Sounds good. Here’s Sam Muller interviewing David Puts about exploring the endless mysteries of human sexual selection.
[MUSICAL INTERLUDE]
Samantha Muller:
Thank you so much for joining me today. We're just going to start off. I'm just going to have you really briefly introduce your research.
David Puts:
I study the evolution and development of human sex differences.
Samantha Muller:
All right. So what does that entail? That's such a broad subject.
David Puts:
I'm interested in human sexual selection, which is the natural selection that favors traits that win mating opportunities. So you can think of like peacock's tail feathers or antlers in male deer, you know, traits favored because they helped win mating opportunities in the ancestral past, because they helped attract mates or helped in excluding competitors by force or threat of force, that sort of thing. So that's the evolutionary part.
And then I'm interested in also how sex differences develop and especially the hormone, the endocrinology of sexual differentiation. And we study both anatomical and behavioral and psychological traits in the lab, but I'd say we focus more on psychology and behavior, than we do one on anatomical traits. But one of the traits that we use, you could say it's behavioral, or you could say it's anatomical, we study the voice and especially sex differences in voice pitch or vocal fundamental frequency because that's a trait that is highly sexually differentiated. At puberty males voices drop by about an Okta so that the fundamental frequency it's called, it's the rate of vibration of the vocal folds during phonation, that's about half, and adult males is about half what it is in adult females.
And so that's a trait that is really sexually differentiated and develops at puberty and is related to mating success and mate attraction and dominance and that thing. So that's been a really useful model trait for us trying to understand the evolution of human sex differences. And we're also interested in the hormonal basis for the sex differences too.
Samantha Muller:
Is this something that we know a lot about currently, or is this a newer field?
David Puts:
Some parts that we know a lot about, like we know about the increases in testosterone at puberty cause males vocal folds to grow longer and thicker and that sort of thing. We understand a lot about the mechanics. But there are important questions that we don't understand, like one of the things that, by the way, this is completely different from what we talked about previously. So I'm happy to go in another direction. But anyway, where was I? Oh, we don't know a lot about what voice pitch advertises to others, so we know that people pay a lot of attention to it, that it seems to have big effects on say mate attraction and the appearance of dominance or formidability to others.
But then another question is, yeah, why do we pay attention to that trait? What does it actually say about a potential mate or a competitor? And that's an area that we're actively doing a lot of research in and so are others. But, we really don't know a whole lot about that yet. It seems to be related to hormonal profiles. And very weakly related to strength within sex, but big relationship between sexes. And we're looking at other things like the genetic causes of variability in that trait as well. But so yeah, there's some things we know a lot about some things we don't.
Samantha Muller:
Yeah. So how would you say your research is impacting not just your field, but the average everyday person, what information would you like the average person to take from your research?
David Puts:
Well, my interest in this stuff is mostly nerdy, that I just want to understand how we got to be in the way we are. And I mean, that was when I was an undergrad thinking about what I wanted to do with my life, it was really about not how could I make a lot of money or how can I cure cancer or anything, it was just, what are the intellectual questions that I find fascinating? And then I wanted to pursue those things. And so I have to admit that that's the primary motivation for me. And probably a lot of the students in my lab is that we just want to understand how humans became the way they are. And to me, the most interesting questions about the way we are, our behavior, our psychology, our cognition, and those are also some of the ways in which we differ the most from other primates as well.
David Puts:
And so, yeah, I mean, as somebody who studies sex and sex differences there's a lot of attention to my research and that's without looking for it, it's what people are interested in and sex differences and sex and sexual motivation. And we also study things like sexual orientation, gender role behaviors, gender identity and orgasm. That's probably the number one because it's probably about 10% of the research in my lab and 90% of the media interviews I do. So people are interested in it, but I don't have any illusions about, and I think a lot about how the research that we do can do real good in the world. But a lot of it, especially the evolutionary stuff is mostly about, I think that people want to know where we came from and how we got that way, how we got the way that we are.
And so that's my motivation, and I think that's the primary motivation of my students and the people who are interested in talking to us about our research for newspapers or podcasts or whatever generally. But there is some of it that definitely has real health implications. And that's the research that looks at how hormones influence the development of our psychology and behavior and the sexual differentiation of our psychology behavior. And how changes in hormones, like say changes in hormones over the ovulatory cycle, influence psychology and behavior. Those are things that are important because there are various health conditions that are associated with variation in hormone signaling either because sex hormones are higher or lower than normal, or because there's higher or lower sensitivity to sex hormones.
And then of course, hormones change over people's lives. They change daily, like testosterone is highest in the morning and goes down over the day. There are ovulatory cycle fluctuations and estrogens and progestogens like progesterone. And it's important to understand those effects as well. And then these also have important implications for things like hormonal treatment, like hormone replacement therapy that people with endocrine conditions can take hormone replacement therapy, but also transgender people will take hormone replacement therapy.
And so understanding, what are the effects of taking these hormones? And what about the timing? If they're taken earlier, does that have a different effect than later? And then same thing with changes over the cycle. And also what happens if you don't have cyclic changes in hormones, because say you're on a hormonal contraception. Then there are the big fluctuations over the cycle. And so, some of this research definitely has important health implications, but a lot of it maybe more than half of the research that we do in the lab, I think the real motivation is not some direct translational value to human health, but just the interest that almost all of us has about how we got to be the way that we are.
Samantha Muller:
I think you mentioned in there a primate comparison. How do you compare between humans and primates and can you even do that?
David Puts:
Well, it depends on what you're talking about, what sorts of traits, because there's some traits that we can just say compare very directly. Like you could say, well, if there's been strong sexual selection on males, and primates males tend to be larger than females especially, I mean, so in animals, females are generally the larger species. I mean, if you picked an animal at random, it'd probably be an insect. And if you picked... And it'd probably be a beetle. There are a lot of those but in most species, females are larger than males because of selection for fecundity, for producing more eggs, bigger eggs. But males tend to evolve larger body size when they fight each other for mates. And so those are lots of the species that we're familiar with, like in mammals males tend to be larger and not all species, but they tend to be larger and especially when they fight each other.
So that's true in primates that in species where males are more competitive for mates and they usually compete mainly through threats and actual fighting, then males tend to be bigger. And so then you can just say, well, what about human sexual? It's called sexual dimorphism, but sex differences in body mass or sex differences in body size, how do we stack up compared to other primates? And then you could just say, well, in humans, males, they're about 15 to 20% heavier. And that looks like maybe a little bit bigger sex difference than you tend to see in monogamous species. Maybe something closer to what you'd see in a multi male, multi female primate, but a little bit low compared to one of those. And that's really, I mean, this is something that I talk in my classes about and I published about.
It's not really a fair comparison because humans aren't like other primates, it's an important domain, which is in body composition. Comparing just mass works fine in other primates mostly because there aren't big sex differences in body fat, but in humans, females have about 40% more body fat than males. And that is not like any other living primate that we know of. And so if you look at fat free mass or lean mass or muscle mass, then we're well outside the range of a monogamous species. And so with a trait like that, you can just directly compare one species to another. But some of them, like one of the questions we're interested in studying right now is ovulatory cycle of variation in women's traits, behavioral and psychological and outward appearance, things like changes in facial appearance, voices. There's a characteristic where it would be hard to compare, say visual changes in appearance over the ovulatory cycle in humans, and compare them to non-human primates for most of the traits that change in non-human primates.
Samantha Muller:
Can you elaborate on that and what that means a little bit more?
David Puts:
Yeah. So one of the questions that we're interested in addressing in this research is the extent to which human females have evolved to either advertise estrus, that is the fertile part of the cycle that is associated in other primates with changes in mating behavior and changes in outward appearance. To the extent to which human females have evolved to advertise that which exists in some species with genital swellings in some primates, for example or suppress those cues. And it looks like in our ancestors, there was selection to suppress cues of ovulation. That it's really difficult to tell where human females are within the ovulatory cycle compared to certainly species that advertise it with genital swellings, like chimpanzees, but even species that don't have such pronounced advertisements, but just you can tell there are changes in behavior, changes in say facial coloration in female rhesus macaques.
And so this is one of the really important questions in studying the evolution of human mating, is the extent to which ovulatory cues have been suppressed or whether they're still advertised. It'll tell us something about the ancestral human mating environment and to do that, and to engaging in cross-species and say, how conspicuous are female ovulatory cues compared to other species, or how suppressed are they compared to other species? We need some metric for comparing humans to non-human primates. And you can't just look at say genital swellings, because we know that human females don't have that. And you can say, "Well, maybe it changes in redness." Sure. But what about other changes that have been observed, like changes in odor or changes in voice? We've found in one study and some other authors have as well that that women's voice attractiveness changes over the cycle.
So how do you compare apples to oranges there? Compare ovulatory cycle shifts and outward observable traits and other species and in humans. And one metric that we've come up with, we think this shouldn't allow us to compare traits across species is to look at how conspicuous are the changes within females compared to the differences between females? And so if you measure the size of these shifts across the ovulatory cycle in females of a given species, and you compare those two between individual differences. So if it's say, if you're looking at facial redness and female rhesus macaques, female rhesus monkeys, you could look at how much does facial redness change over the cycle? And what are the average differences between females and the facial redness?
And if the within cycle differences are large, then that's a conspicuous trait. That means that you could more readily identify where females are in the cycle, because the really red females will be females who are close to mid cycle rather than just females who have at high average red color. And so we can do the same thing with human traits, like changes in vocal, acoustic parameters, or perceptions of women's voices, say how attractive they appear over the cycle. And that allows us looking at the ratio of within female changes to between female differences, will allow us to compare different traits in different species.
Samantha Muller:
Gotcha. Yeah. So you're not looking at that size in actual measurement, like you're looking at the ratio of that change over time. Right?
David Puts:
Right.
Samantha Muller:
Cool.
[MUSICAL INTERLUDE]
Samantha Muller:
I know that we have so many different cultures where gender and sexuality is so fluid. There are so many variations and so many different ways to interpret it. How has that impacted the way you're studying it? And do you look at that diversity differently across your samples?
David Puts:
Yeah. And again, that's going to depend on the question and the accessibility of the data, because in some societies, like let's say we're interested in studying sexuality and sexual orientation. In some societies that just would not be appropriate to ask that question. But there are some studies that are cross-cultural that we're working on. Like I mentioned our voice research and one of one consistent results across studies so far where we've used computer software to manipulate voices so we can look at the perceptual effects. We're interested in vocal characteristics, or signals, they're signals to others in your group, to potential mates, to competitors. And so, one important question is what is the effect of those signals on the perceptions of the receiver? For example, if we're looking at voice pitch and we think, okay, so males develop this low voice pitch at puberty and suddenly boys and girls have the same voice pitch. And then suddenly, sometime between the ages of say 10 and 15 voice pitch drops precipitously in males.
So there's this big sex difference in voice pitch that develops at puberty as males, voice pitch drops precipitously, and then that has a big effect on perceivers, on potential mates, on competitors. And so one of the questions we have is, what is the effect? What does a low voice pitch in males, what does that signal to receivers? Does it signal mate quality and attract mates, or does it intimidate competitors and make a male seem bigger and scarier and more formidable? And one consistent result that we've had so far is that deep voices look like they evolve to make human males and other male primates look big and scary. And we've found in other anthropoid primates, that is in monkeys and apes, that males tend to evolve relatively low pitch vocalizations in species where males compete more intensely for mates like in polygynous species compared to monogamous ones.
And in the human research that we've done, where we can actually ask about perceptions, we can take voices and manipulate them to make them higher or lower in pitch, we found that lowering pitch makes guys' voices seem scary to competitors, makes them sound like they're a good fighter or something or high in social status. And that effect is bigger than it is on attraction to women. Women don't like a really high voice, but otherwise they don't care too much. And the effect is just, it's not as big of an effect. But where has that research been conducted? Primarily in the US, Canada, the UK, there've been some non Western societies, Korean Apicella and University of Pennsylvania has done some research in the Hadza. And we've collaborated with her on that. And we also published some data from the Chimani who are... Hadza are foragers from Tanzania. And we've published a paper just a year ago on the Chimani, who are forager horticulturists from Bolivia. So there is research and other societies, but we really don't know about the cross-cultural variation in that, and how vocal masculinity or femininity influences perceptions across societies, and what the cultural variables are that influence those things.
For example, we have a hypothesis that if a deep voice makes guys seem scary and competitive for mates then women, maybe prefer less masculine voices when there's a higher risk of domestic violence. And there's some evidence of that from a women's preferences for both voices and faces. And so we've collected some data, cross-cultural data and within cultural variation, and we found some evidence for that.
When you think, okay, so also a deep voice makes the guy seem scary, and what would be the societies where males would pay most attention to that and ones where they don't have a lot of other information about the male? So in other words, more anonymous ones where people tend to interact with strangers more often and there's some evidence that that's the case in nonhuman primates as well, that males evolve more conspicuous signals in species where the group sizes are bigger. And there's more interaction with unfamiliar individuals that then it's more important to evolve this signal that's easy to see right away without knowing the interlocutor or the other individual that you're interacting with.
And so we're finding some evidence for that too, that in societies where people interact with strangers more often, voice pitch has a bigger effect on perceptions. So there's a case where we're interested in looking at cross-cultural variability and trying to understand the sources of it.
Samantha Muller:
So, when you're administering these studies, you're doing these perceptions studies, are they self-reported, are they self-sampled, or have you been having people come into the lab? Like, how are you collecting this data?
David Puts:
So we are collecting them in nature and not having them come into the lab. And that was something that we thought a lot about because we've done plenty of lab research where we have participants come into the lab and put on some headphones and sit in front of a computer and listen to some voices and rate them or choose which one is more, whatever, attractive, dominant, something. But we knew that we wanted to send this study to collaborators around the world who might be collecting data in Madagascar and pastoral community or something like that, where there is no lab and there's no laptop computer, or a desktop computer or something. And so we wanted to have the same methods everywhere. So we collected data in state college at Penn State, but then we had our lab members go out into the community and approach people and say, "Do you want to participate in this study? And if so, then you can put on these headphones."
And we used iPods.There's specialized computer software for administering psychometric studies like this, but using an iPod there really isn't. And so we had to think about, well, how would we do this? We can make an album of voice clips and we can randomize the order of presentation by using the shuffle function and so on. So we bought a bunch of iPods and a bunch of professional quality headphones and some fancy protective cases and that sort of thing. And then we reached out to collaborators and sent those things around the world and yeah, collected a bunch of data from people in their natural settings to the extent possible. I mean, the researchers would say, "Okay, let's walk over to this place where it's quiet or something like that." But yeah, that's how we collected the data. I don't remember how many participants we have. I think it's maybe over 3,100 people from 22 societies, there are 22 nations, and then some multiple local localities and in some of those places. So we're excited, we're getting some cool results.
Samantha Muller:
So you seem super passionate about this subject. How did you get interested in this field? It seems so niche, but also so broad. How did you find your way into this research?
David Puts:
When I was a college student, I knew I wanted to study anthropology, but I didn't know that that was going to be my major. I actually went to this little college in Ohio Kenyon College in this little town, Gambhir Ohio. And I went there because I wanted to go to a small liberal arts college. And I thought I would study poetry writing. My mom and her two sisters were all English teachers. And my mom's older sister is a poet and was the poet Laureate of Delaware. And I'd read her poetry when I was growing up and wrote some in high school. And I thought I wanted to study that, which I did, but you had to take a year of freshman English, and then you had to submit a writing sample to get into this tiny class of I think like 12 students or something, poetry writing.
And by the time I'd done all that, I'd taken a bunch of anthropology, which I knew I liked anyway. And I was debating between anthropology and philosophy, which I liked a lot because I just liked thinking about big questions about human existence and I just thought in anthropology, it was a little bit more, at least at the time, or at least in the courses I was taking, it was more empirical. It seemed like philosophy relied on introspection a lot. And you need to go back and forth between your big ideas about the world and actual data and test them, and then go back and adjust your ideas and then test them again. And I thought anthropology seems at least, like I said, with my exposure to it is stronger in that regard.
David Puts:
And I was really interested in questions about human evolution, and especially about behavior. And I got some of that. But in a small college you can't get anybody a terribly specialized. And then really once I got to graduate school and started, I went to the University of Pittsburgh and I started with my advisor, and he was interested in sexual selection and sex differences. I was too, but I think I could have gone in a bunch of different ways in terms of studying human evolution and human behavioral evolution. I think there was a lot of research in the area of sexual selection, sex differences, sexuality, because it's so intimately tied to reproduction. And the more important a trait is to reproductive success, the stronger selection operates on it.
And so I think it was easier to make predictions about behavioral traits and sex differences in traits at that level than to make predictions and be right about your predictions, about traits that are more distantly related from reproduction. And so it just seemed like a really fruitful avenue for trying to understand human evolution. And it almost seemed like, look where the light is. Here's a place where we can make some clear predictions and start there and then branch out once we've got that solid foundation about traits that are more, that are very closely related to reproduction, then move more broadly out there and understand the more peripheral traits that contribute, yeah, to reproductive success. And so I think that's what got me into it. And there wasn't any special interest in insects or sex differences or anything like that. I don't think, I mean not more than the normal person.
Samantha Muller:
Well, it is very intriguing.
David Puts:
Yeah. Well...
Samantha Muller:
Also you mentioned a lot of interdisciplinary elements. I think that is a crucial theory in research, getting all of those different perspectives. Would you say that that's something that drew you to the field, or something that’s even just strengthened the field in your eyes?
David Puts:
I know that that's true of our department and I think that's probably generally true of the field that anthropology researchers tend to be interested in broad questions and then they will go out and find the theory and tools that they need to address those questions. There are plenty of labs in the world that have a method, that “this is what we do and what other questions can we apply this method to? And like we do micro array analysis where we look at differences in gene expression or differences in genotype across the different types of tissues or something across individuals.” And they say, "Okay, well we have a tool and let's see what other questions that we could bring this tool to bear upon."
David Puts:
And the anthropologists, I think, tend to focus on a big question about human evolution or human variation, and then go out and learn the tools that they need. And certainly for me, that's been the case that I'm interested in broad theoretical questions about human evolution. And then and I gradually learned bits about various theories and methodologies that I need to address those questions. And so things like endocrinology and genetics and psychometrics, like studying, “how do you measure psychology? How do you measure behavior?” Things like that. So yeah.
Samantha Muller:
Is that where you see yourself going in the future of your research, just continuing to pursue these really broad questions and trying to find these answers?
David Puts:
Yep. I do. I don't have any intention to get bogged down by specific methodology. I think I would find that frustrating. But the questions themselves I mean, some of them, I'm probably going to continue to try to answer my whole life because the reality of science, right, is that you never know anything for certain. I mean, you can make observations and feel very confident that your observations are accurate, but ultimately those things informed theories, and you can fail to disprove a theory, but you're never absolutely certain that it's correct. There could always be new data that accumulates that say, "That old explanation that we had for how things got to be the way they are, that doesn't actually hold up anymore and this other one."
And so I think a lot of these questions I'll never stop studying and some things I might feel like, I've addressed that one and I've gotten it about as good as it's going to get. And this other avenue was more interesting and something that's nice about being in a big research university like Penn State is that you have a constant stream of new minds coming in, new graduate students coming in with their own interests and their own ideas. And I've got a student right now who is interested in studying the Coolidge effect. Allow me just tell you what the Coolidge effect is.
It's a sexual disinterest and a mate that a male has already mated with. It could occur in females too, in species, but it's first observed in males that, like say you get a bull to mate with a cow, and then he won't mate again with that same female for a while, there's a lag, but he'd mate with another female sooner. And that's something that's observed in a lot of species and is named after Calvin Coolidge, by the way, because the president and first lady were touring a poultry farm. And the first lady was first, and the tour guide mentioned to her that this rooster can have sex hundreds of times per day. And she said, “please tell that to the president when he comes through.”
And so then Calvin Coolidge came through and they said, "Mr. President, the first lady would like you to know that this rooster can have sex hundreds of times a day." And he said, "All with the same hen?" And the tour guide said, "No, Mr. President, with all different hens." And he said, "Kindly tell that after the first lady." (LAUGHTER)
But anyway, this became known as the Coolidge effect, this idea that males of some species can copulate more readily with new females. The reasoning being that if they've already inseminated one female, then mating with her multiple times right now is not going to increase reproductive success. And there's evidence that, that occurs in humans too. And it happens in rodents and so on. But we really don't know much about it.
And it's an interesting evolutionary question, but also you can imagine it'd be really relevant to understanding romantic relationship quality and maintenance and duration and everything. And so there is a question that I recognize is interesting, but had no plans to study it. And then a student came in and said, "I'm interested in this." And I said, "Yeah. Okay, me too. Let's think about how we can study that across species, across societies, within a society, we're using experimental prompts and whatever, that kind of thing." And so that's a nice thing about research, is that you have new ideas that not only that you develop, but the students bring in and new interests.
Samantha Muller:
So speaking of students, just to wrap up, one final question for you is what piece of advice would you give to the next generation of scientists?
David Puts:
Well, I don't know if I'm great for giving career advice. But if I did, and if I thought about what has predicted the success that I've seen, it's hard work and fire and dedication. Scientists are–if you go to graduate school and you get a PhD and get a postdoc–they're all smart. So that's not really what distinguishes the greatest scientists from the others, just how brilliant they are. That's important, but what really seems to distinguish the most productive people who make the biggest contributions is just this drive that they have, this fire. And it's very difficult to have that if you're not doing something that you're really interested in.
And so I would encourage people to find out what is just the most exciting area for them, the most exciting questions and pursue that because that's where you're going to have your drive, your fire, your energy. And that's going to lead to productivity versus getting into, say a graduate program and doing a dissertation that you're not really that interested in. And it just becomes this tedious thing that you just want to be done. That's not good for anybody. And so I would say, if you're doing something that excites you and that fascinates you, then you'll be good at it.
Samantha Muller:
Definitely. That's great advice. Thank you so much for chatting with me and having this great conversation. It's been really great talking to you.
David Puts:
Thanks, you too.
[MUSICAL INTERLUDE]
Mark Shriver:
Tracking Traits is a production of Penn State’s Center for Human Evolution and Diversity. Our producer, audio engineer and musical theme composer is Cole Hons, and our logo was designed by Michael Tribone of mtribone design.
If you enjoyed this podcast, please subscribe through your favorite app, and help us reach more people by sharing it with others and rating us on Apple podcasts.
You can also follow us on social media and learn more about CHED and all of our interviewers and guests at our website, ched – that’s C H E D dot L A dot P S U dot E D U.