Speaker 1: Howdy, Extraordinaries. Most of this episode is about social behavior
Speaker 1: and cooperation in animals, and in particular human animals, but
Speaker 1: towards the end we talk a little bit about cases
Speaker 1: where humans and non human animals have not gotten the
Speaker 1: love that they deserve early on in life, in the
Speaker 1: implications of that for their behavior, which is a little
Speaker 1: bit hard to hear, So just a heads up so
Speaker 1: you can decide if you want to listen to the
Speaker 1: last third of the episode or not. Thanks. Natural selection
Speaker 1: doesn't exactly sound like the kind of mechanism that would
Speaker 1: result in a lot of cooperation and snugly social behavior.
Speaker 1: Let's imagine it. You take variation in some trait, say
Speaker 1: differences in running speed, and link that trait to survival
Speaker 1: and reproduction. And so imagine that running speed determines who
Speaker 1: escapes from predators and then goes on to survive and
Speaker 1: have babies. And if that trait is heritable, so if
Speaker 1: the babies of fast parents are fast themselves, then you
Speaker 1: have all the ingredients necessary for natural selection. Over time,
Speaker 1: you'd expect that fast individuals survive and become more common,
Speaker 1: while the slow individuals, well, they get eaten. That sounds
Speaker 1: kind of cutthroat, Yet somehow we've still ended up in
Speaker 1: a world where animals will call out to warn others
Speaker 1: of a nearby predator, even if calling out increases the
Speaker 1: risk that the predator goes after the caller in particular,
Speaker 1: and honey bees will sting us to protect their hive mates.
Speaker 1: Even though stinging us will pull out their stinger and
Speaker 1: effectively disembowel the bee. They give their lives to protect
Speaker 1: their buddies living inside the hive. So how did this
Speaker 1: seemingly brutal mechanism give rise to so much cooperation and
Speaker 1: helpful behavior. That's what we're going to talk about today.
Speaker 1: Welcome to Daniel and Kelly's surprisingly cooperative universe.
Speaker 2: Hi.
Speaker 3: I'm Daniel. I'm a particle physicist, and I think people
Speaker 3: are the most interesting thing in the universe and also
Speaker 3: the most terrifying.
Speaker 1: Oh hello, I'm Kelly. I study parasites and space and
Speaker 1: I completely agree with Daniel's assessment, and at the end
Speaker 1: of this episode when I describe human behavior, I will
Speaker 1: try not to cry.
Speaker 3: So my question for you today, Kelly is do you
Speaker 3: consider yourself an introvert or an extrovert? And when did
Speaker 3: you know?
Speaker 1: Oh? Yeah, definitely an introvert. I think I hide it well,
Speaker 1: but I very much enjoy hanging out with people. But
Speaker 1: at the end of like a conference or something, I
Speaker 1: will crawl into my bed and like just be absolutely exhausted.
Speaker 1: And I get very nervous when I go in a
Speaker 1: room and I have to like pick a group to
Speaker 1: go hang out with because I assume that nobody really
Speaker 1: wants to talk to me, And so I love situations
Speaker 1: where people come up to talk to me because then
Speaker 1: I don't feel like I'm putting anyone out. So if
Speaker 1: you ever see me somewhere, feel free to come up
Speaker 1: and talk to me, because that relieves the pressure on
Speaker 1: me and makes me feel so much better. And I
Speaker 1: don't know when I realized that. I think it was
Speaker 1: probably in undergrad when I had to like start meeting people. Yeah,
Speaker 1: I guess I don't know what about you.
Speaker 3: I'm not sure how I would classify myself, because on
Speaker 3: one hand, I feel the same way at the end
Speaker 3: of a lot of socializing that like at a conference
Speaker 3: when it was like, hey, let's go out to dinner
Speaker 3: and I'm like, no, thank you. But also I find
Speaker 3: that people are my best source of energy, you know,
Speaker 3: if I go and teach in the classroom. I love
Speaker 3: that engagement and the response. I love getting emails from listeners.
Speaker 3: I love hanging out with friends, Like moments laughing with
Speaker 3: your friends are more enjoyable than anything you could ever
Speaker 3: do by yourself. Yeah, and so people are like the
Speaker 3: greatest mystery and source of joy and happiness in the universe.
Speaker 3: And also they are completely exhausting.
Speaker 4: Yeah.
Speaker 3: So I'm not sure where that puts me on the spectrum.
Speaker 1: Maybe we're exo introverts intro exoverts. Because I agree, I like,
Speaker 1: I also really look forward to going to conferences because
Speaker 1: I cannot wait to see the people at conferences and
Speaker 1: hear about how they were doing and laugh about stuff
Speaker 1: and find out if they purposefully infected themselves with any
Speaker 1: parasites in the last year, and you know, all that stuff.
Speaker 1: But you know, on the other hand, at the end
Speaker 1: of the day, I am also like.
Speaker 3: I need to see Yeah, exactly. Well, today we are
Speaker 3: not just telling personnel stories. We are talking about the
Speaker 3: larger question of human being behavior. Why do people act
Speaker 3: the way they do? Is it driven by evolution or
Speaker 3: something else? Even weirder, and today's episode is inspired by
Speaker 3: a question we got from an eleven year.
Speaker 1: Old, didn't we Actually they're thirteen years old now and
Speaker 1: they are the child of some friends of mine, and
Speaker 1: I was super excited to get their questions. So let's
Speaker 1: go ahead and listen to it.
Speaker 5: Hi, Daniel and Kelly, I love your podcast, And I
Speaker 5: have a question why did humans evolve to be social?
Speaker 5: And why do we go crazy if we're isolated for
Speaker 5: too long? I also want to know what happened at
Speaker 5: the human related it's whole life without having contact with
Speaker 5: other humans, and why could some animals like whales go
Speaker 5: for so long without having contact with other whales but
Speaker 5: humans can, thanks, all right?
Speaker 3: So on one hand, this is a really fun question,
Speaker 3: but also a really deep question about evolution, because like
Speaker 3: the whole foundation of modern biology is evolution and natural selection,
Speaker 3: and things are the way they are because of this process,
Speaker 3: and that forces us to think about everything we see
Speaker 3: through that lens. But it can sometimes be hard to
Speaker 3: understand how something evolved to exist. You know, you have
Speaker 3: the examples of the eye and stuff, but human behavior
Speaker 3: is a great example. So tell us, Kelly, how do
Speaker 3: you interpret this question.
Speaker 1: Well, I'll be honest, I kind of put this question
Speaker 1: off for a while because I was like, Okay, I'm
Speaker 1: going to I'll look it up real quick and see, like,
Speaker 1: you know, what are people saying these days? And generally
Speaker 1: the answer I found was, oh, well, humans are social
Speaker 1: because it benefited us in our evolutionary past. And I
Speaker 1: was like, yeah, okay, well yeah, but how and like
Speaker 1: there's got to be a richer answer to that. But
Speaker 1: there was generally not a much richer answer. And I
Speaker 1: think at the end of the day, it's hard to
Speaker 1: know for a particular species why a behavior arose, in
Speaker 1: part because behaviors don't leave fossils. But at the end,
Speaker 1: I'm going to try to give a much better answer.
Speaker 1: But I thought that we could start by taking a
Speaker 1: look at why we think we see cooperation and social
Speaker 1: behavior in general in animals at all, because actually that's
Speaker 1: a little bit of a Darwinian puzzle.
Speaker 3: Yeah, I agree, it's really a fascinating question. On one hand,
Speaker 3: it seems like maybe it's simple because people learn to
Speaker 3: cooperate because that's more effective. But if everybody else is cooperating,
Speaker 3: then like the one jerk who's like lazy and then
Speaker 3: just steals the results of the mammoth hunt is going
Speaker 3: to benefit. So it's not obvious why cooperation is always
Speaker 3: a successful strategy. That's how you have to think about.
Speaker 1: It, right, yeah, right, exactly. So in order for natural
Speaker 1: selection to happen, you have to have variation in a trait. So,
Speaker 1: for example, maybe you have variation in speediness, and then
Speaker 1: that variation needs to be important for survival and reproduction.
Speaker 1: So maybe the faster individuals are able to run away
Speaker 1: from the predator and then they survive to reproduce, right,
Speaker 1: and that trait needs to be passed from parents to offspring,
Speaker 1: So the faster parents makes faster offspring, and over time
Speaker 1: you end up with faster individuals in the population, and
Speaker 1: the genes that produce faster individuals become more common in
Speaker 1: the population. And that doesn't necessarily sound like a mechanism
Speaker 1: that would result in more like hugs and cooperation. That
Speaker 1: seems like a bit of a cutthroat thing. You know,
Speaker 1: if you are faster and better able to get away
Speaker 1: from the predators, are better able to secure the food,
Speaker 1: then you're the one who gets to reproduce and you're
Speaker 1: the one who, you know, gets to pass your genes
Speaker 1: to the next generation. But when when look out in
Speaker 1: nature we see tons of cooperation. So you know, for example,
Speaker 1: honey bees, if you walk up to a honeybee nest okay,
Speaker 1: and you disturb the nest, do not recommend a honey
Speaker 1: bee will come out and they'll sting you. And they've
Speaker 1: got these barbed stingers that get stuck in your skin,
Speaker 1: and so the stinger will stay behind and the venom
Speaker 1: gland and like the insides of the honey bee will
Speaker 1: get pulled out of the bee. The bee will get
Speaker 1: disemboweled and will die to protect its hive mates. And
Speaker 1: so that bee is giving its life to protect the
Speaker 1: rest of the hive. And we see ants that are
Speaker 1: willing to, for example, like plug the whole of a
Speaker 1: nest overnight, even though the temperature is going to kill
Speaker 1: them overnight. They give their lives to like protect the
Speaker 1: temperature for the rest of their hivemates. And we see
Speaker 1: just loads of examples of animals dying for you know,
Speaker 1: their buddies, and you know, why does that happen?
Speaker 3: And so this is a great analogy, for example, to
Speaker 3: like soldiers dying in a war. Right, they're not going
Speaker 3: to be around to experience the benefits of victory, and
Speaker 3: yet they give up their lives. But then it's always
Speaker 3: easier to understand these things in terms of like ants
Speaker 3: and bees because you can actually do experiments on them ethically. Right, Yes,
Speaker 3: so what do we know about why honey bees act altruistically?
Speaker 3: Is it because they have like more sophisticated genetic relationships
Speaker 3: among themselves and with their queens or what's the story?
Speaker 1: Yes, absolutely so that is part of it. But first
Speaker 1: I want to dig down a little bit more and
Speaker 1: clarify what level we think evolution is happening at. Evolution
Speaker 1: at the end of the day, is just changes in
Speaker 1: gene frequencies over time. So when we were talking about
Speaker 1: natural selection happening for fastness, like being able to run
Speaker 1: away from the predators, evolution happening there, you'd end up
Speaker 1: with a higher frequency of the types of genes that
Speaker 1: are associated with moving quickly. So over time, the versions
Speaker 1: of the genes for slow individuals go away and you
Speaker 1: get more of the versions of the genes for fast individuals.
Speaker 1: Does that make sense?
Speaker 3: It does make sense, But it sounds like you're choosing
Speaker 3: this set of words gene frequencies changing over time through
Speaker 3: natural selection very specifically, maybe in contrast to something you
Speaker 3: imagine is in the minds of the listeners or a
Speaker 3: general misunderstanding of evolution. What are you contrasting this with, Well.
Speaker 1: So I'm eventually going to make the point that individuals
Speaker 1: are the ones who are carrying these genes around, and
Speaker 1: selection is going to be happening at the level of
Speaker 1: individuals and not the level of groups.
Speaker 3: I see. So it's not like evolution is this like
Speaker 3: mastermind guiding some species towards some predetermined goal or something.
Speaker 3: It's just a bunch of individuals changing over time.
Speaker 1: Yeah, it's a frequency of genes that are found in
Speaker 1: a population, and those genes are carried by individuals that
Speaker 1: some of which will die and some of which will not.
Speaker 1: All right, yeah, okay, so individuals are carrying around these genes.
Speaker 1: And then in the nineteen sixties there was this guy,
Speaker 1: when Edwards, who was arguing that selection might be happening
Speaker 1: at the level of like groups, or maybe even at
Speaker 1: the level of species, and this idea kind of makes sense. So, like,
Speaker 1: you know, you look around and there's for example, maybe
Speaker 1: rodents having two babies each, and you might say, oh, okay,
Speaker 1: two babies, that's not a lot of babies. Maybe what
Speaker 1: they're doing is they're trying to not eat all of
Speaker 1: the seeds. They're trying to make sure that they don't
Speaker 1: over exploit the seeds for the good of the species.
Speaker 1: They want to make sure that they're able to survive
Speaker 1: for many generations.
Speaker 3: What considerate and well organized rote.
Speaker 1: Yes, yes, you know, maybe we should take some lessons
Speaker 1: from their behavior, but unfortunately it turns out that we
Speaker 1: don't actually usually see group selection being a good explanation
Speaker 1: for what animals are doing in the wild. So imagine
Speaker 1: you did have like a population of individuals who were
Speaker 1: very responsible rodents and were limiting themselves to two babies
Speaker 1: each because they didn't want to over exploit the seeds.
Speaker 1: And then you had a mutation in a gene, and
Speaker 1: a selfish gene popped up. Okay, and those parents six babies.
Speaker 1: The jerk rats had six babies, and there's all these
Speaker 1: extra seeds because everybody else is being responsible, and so
Speaker 1: all of their babies survive. And they also got the
Speaker 1: jerk gene, and so they have six babies too.
Speaker 3: Dominion of the jerk rats.
Speaker 1: Dominion of the jerk rats exactly. So over time, that
Speaker 1: selfish gene is going to pass through the population. You're
Speaker 1: going to end up with a lot more of this
Speaker 1: jerk gene.
Speaker 3: So does this argue against when Edward's idea of evolution
Speaker 3: at the population level.
Speaker 1: Yes, it does. And so just about whenever we look
Speaker 1: when we go out into nature, we see that animals
Speaker 1: are trying to have as many babies as they can,
Speaker 1: maybe not in a particular season, but across their entire lifetime.
Speaker 1: We don't see much evidence of individuals sort of doing
Speaker 1: things for the good of the species. Most of the
Speaker 1: evidence we find is that they're doing it for the
Speaker 1: good of themselves. And we think that's because selfish strategies
Speaker 1: could easily invade populations where everyone's you know, trying to
Speaker 1: do things for the good of the species. That's just
Speaker 1: a strategy that's very easy to invade by more selfish behaviors.
Speaker 3: This is a cool test because the cooperative strategy is
Speaker 3: actually more successful. Right, if nobody's a jerk, everybody does better.
Speaker 3: It's sort of a prisoner's dilemma situation. But if everybody
Speaker 3: else is cooperating and you're the jerk, then you individually
Speaker 3: win out and then your babies dominate the future. Yes,
Speaker 3: and so if you were operating at a population level,
Speaker 3: you would definitely choose no jerks.
Speaker 5: Yeah.
Speaker 2: Yeah.
Speaker 1: If selection was acting at the level of the group,
Speaker 1: then maybe that would be better for everybody, but we
Speaker 1: don't see evidence of that happening. And additionally, like even
Speaker 1: if you could get a group of individuals to be
Speaker 1: like super nice and everybody cooperates, usually we see migration
Speaker 1: between groups because they don't usually exist completely in isolation.
Speaker 1: So if you had a jerk group, you know, a
Speaker 1: little north of you, some jerks might move south and
Speaker 1: invade your population. And since you've left all these resources unexploited,
Speaker 1: they're going to come in and sort of mess everything
Speaker 1: up for everybody else.
Speaker 3: Those northern jerks.
Speaker 1: Every time time I know, I'm looking at you, Canada,
Speaker 1: I'm just kidding. Canadians are way nicer. We should have
Speaker 1: done it in reverse.
Speaker 3: Oh, now you're offending the Mexicans.
Speaker 1: Oh no, no, no, I meant it's the Americans ruining
Speaker 1: things for the Canadians, is what I was saying. No, no, no, no,
Speaker 1: don't get me wrong. Okay, So there are some arguments
Speaker 1: still that there could be some situations where it makes
Speaker 1: sense to think about selection from a group or a
Speaker 1: species level, But I think in general, we think that
Speaker 1: most of the time selection is happening at the level
Speaker 1: of the individual and that you can, you know, get
Speaker 1: away with not thinking about group selection most of the time.
Speaker 3: And this is true for behavior and also for more
Speaker 3: like mechanical traits like cheetah's running fast and stuff.
Speaker 1: Yes, okay, okay, And actually I bought a recent animal
Speaker 1: behavior textbook because that's what I learned in like the
Speaker 1: early two thousands, and I was like, I just want
Speaker 1: to be one hundred percent chore that this is what
Speaker 1: everybody still says and it is.
Speaker 3: So then you're telling me that you can't choose behavior
Speaker 3: based at the population level, like hey, everybody be nice
Speaker 3: or everybody like to have go to parties or whatever.
Speaker 3: And so in that case, how do we get things
Speaker 3: like altruism or social behavior if natural selection acts only
Speaker 3: on individuals.
Speaker 1: That's the puzzle, right, Yeah, that is the puzzle. Okay.
Speaker 1: So we're going to talk about three or four different
Speaker 1: ways that we think you can get it by individual
Speaker 1: level selection. Oh all right, So the first way is
Speaker 1: what we call kin selection. This is an idea by
Speaker 1: William Hamilton. It was proposed in the sixties, and the
Speaker 1: idea is that you've got genes for particular traits, and
Speaker 1: you can get those genes passed from one generation to
Speaker 1: another by having your own babies directly, but you can
Speaker 1: also increase the frequency of those genes by doing things
Speaker 1: like helping out your brother, and so that indirectly increases
Speaker 1: your fitness because you probably share about fifty percent of
Speaker 1: your genes by descent because you come from the same parents.
Speaker 1: And you know, for example, if you're a diploid organism,
Speaker 1: so humans are diploid organisms, that means we have two chromosomes.
Speaker 1: We got fifty percent of our genes from our mom,
Speaker 1: fifty percent of our genes from our dad, and just
Speaker 1: by random chance, you and a sibling probably share about
Speaker 1: fifty percent of the versions of the genes that you
Speaker 1: have in your body. Does that make sense?
Speaker 3: Yes, So basically, I have a big nose. My brother
Speaker 3: is a big nose. If I help my brother's kids,
Speaker 3: then I'm increasing the big nose fraction of future generation.
Speaker 3: So I'm not really being altruistic by helping people who
Speaker 3: are not my direct offspring.
Speaker 1: As long as they're related to you. Yeah, yes, right right, yeah,
Speaker 1: as long as they're related.
Speaker 3: That's why it's called kin selection.
Speaker 1: I guess, yes, exactly right, and so are there's some
Speaker 1: predictions that come from this. You should care about how
Speaker 1: closely related people are to you, and so for example,
Speaker 1: you should be more likely to help a brother or
Speaker 1: a sister, and you should be, you know, sort of
Speaker 1: willing to help like a half sibling or a cousin.
Speaker 3: Depends how big their nose is.
Speaker 1: Actually that's maybe, that's right. Depends on the gene. But
Speaker 1: you know, for example, if you imagine that there is
Speaker 1: a gene out there for altruism, and that gene does
Speaker 1: make you more likely to help out other members of
Speaker 1: your family, then you can imagine that that gene would
Speaker 1: pass through a population if family members are helping each other.
Speaker 1: And so there's this fameless quote by a scientist named
Speaker 1: JBS Haldane and he was asked, would you save a
Speaker 1: drowning brother if it risked your own life? And he
Speaker 1: said no, but I would save two brothers or eight
Speaker 1: cousins because.
Speaker 3: And mathematically that checks out.
Speaker 1: That's right, that's right. And so whether or not you
Speaker 1: should engage in a behavior that helps out your family
Speaker 1: members to some extent depends on how closely related they
Speaker 1: are to you. How much the cost would be to
Speaker 1: yourself and how much they would benefit. And so you
Speaker 1: should expect to see altruistic behaviors arising a mon closely
Speaker 1: related individuals if it's going to result in, for example,
Speaker 1: your siblings having more kids that are going to carry
Speaker 1: some of the genes that you would find in yourself.
Speaker 1: And so maybe you're not having as many kids personally,
Speaker 1: but if your siblings are having loads of additional kids,
Speaker 1: then your genes are still getting out there, and so indirectly,
Speaker 1: your fitness is doing great, and so maybe we see
Speaker 1: altruism happening because selfishly, that still helps your genes pass
Speaker 1: through the environment.
Speaker 3: All right, So just to make sure I understand, we
Speaker 3: started out wondering why would anybody die for other members
Speaker 3: of the population, And this seems like to me a
Speaker 3: partial answer, because it doesn't suggest you would die for
Speaker 3: any member of the population, but it tells you that
Speaker 3: you might sacrifice yourself for people you're related to who
Speaker 3: are not directly your offspring. Yes, exactly, And that to
Speaker 3: me described as sort of like limited local altruism that
Speaker 3: like falls off with the size of the nose of
Speaker 3: people in your family. But then you added this twist
Speaker 3: about a gene for altruism itself, right, because this doesn't
Speaker 3: require a gene for altruism. You just support people who
Speaker 3: have enough genes that overlap with you.
Speaker 1: Yes, but you could imagine that a gene for altruism
Speaker 1: would be how you get this trait to pass from
Speaker 1: family member to family member to family member.
Speaker 3: Oh, I see, yeah, The gene for altruism helps you
Speaker 3: recognize that this is beneficial.
Speaker 1: It helps make sure that the trait passes in families
Speaker 1: and is maintained.
Speaker 3: I see, all right.
Speaker 1: And we have some examples of this. So, for example,
Speaker 1: there are these squirrels that you find in California building's
Speaker 1: ground squirrels, and the females tend to stay in the
Speaker 1: areas where they were born, whereas the males tend to
Speaker 1: go away. And so if you're a female, your sisters
Speaker 1: are likely to be nearby, your aunts are likely to
Speaker 1: be nearby. And what they find is that the females
Speaker 1: are more likely to call when there's a predator around.
Speaker 1: And so when a predator's around, they call, and then
Speaker 1: their sisters and their aunts, maybe their mom and even
Speaker 1: their kids go and hide in their burrows. But when
Speaker 1: you call, you also increase the probability that the coyote
Speaker 1: goes after you because you've drawn its attention. So it's
Speaker 1: a risky behavior that has a cost. But they've also
Speaker 1: found that females will call even if none of their
Speaker 1: own kids are around, so it's not just a direct
Speaker 1: fitness thing. They will call to help their aunts get
Speaker 1: out of the way or some or their sisters get
Speaker 1: out of the way. So it looks like they're also
Speaker 1: willing to take a cost to get an indirect fitness benefit,
Speaker 1: so to help their sisters and stuff.
Speaker 3: So females without any kids of their own still raise
Speaker 3: the alarm, putting themselves at risk even though they have
Speaker 3: no offspring. That's fascinating. Are squirrels smart enough to do
Speaker 3: this calculation of the little jbs haldines adding up like
Speaker 3: you know, fractions and cousins and stuff.
Speaker 1: Yeah, that's a great question. So I think they really
Speaker 1: just need to know, like, Okay, I was raised with uh,
Speaker 1: so you know, for example, they were raised in a
Speaker 1: nest with their sisters, and so they don't necessarily have
Speaker 1: to be like, all right, I've got three sisters out here,
Speaker 1: I'm fifty percent related to all of them. So that's
Speaker 1: point five plus point five plus point five, that's one
Speaker 1: point five. So that's more than just me. So you know,
Speaker 1: they don't necessarily have to do those calculations. They just
Speaker 1: have to, like, you know, have some affiliative feeling for
Speaker 1: the individuals that they were raised in a nest with
Speaker 1: and be willing to call. And so maybe the genes
Speaker 1: that are being passed aren't necessarily like altruism genes. They're
Speaker 1: just genes for you know, having like a nice feeling
Speaker 1: about the people that you were raised in a nest
Speaker 1: or you know, the squirrels you were raised in a
Speaker 1: nest with and being willing to call if you think
Speaker 1: that they're in danger.
Speaker 3: Or does it work even if it's more instinctive, like
Speaker 3: if every female squirrel responds to a predator with a call,
Speaker 3: than in general that increases the fitness and the whole population,
Speaker 3: including their own, and then that gene tends to survive.
Speaker 1: Is that a reasonable argument, Well, there is evidence that
Speaker 1: females are less likely to call if they are surrounded
Speaker 1: by females they are not related to. Oh wow, so
Speaker 1: they will withhold calling when they're not around family members.
Speaker 3: So it's really context dependent. They are doing fractions in
Speaker 3: their head. When deciding whether to save your.
Speaker 1: Life, they are at least deciding are there people who
Speaker 1: were at the last family reunion or not?
Speaker 3: What did they bring to the pot luck?
Speaker 1: That's right, that's right. And if you didn't bring enough,
Speaker 1: I'm not gonna call that coyote, can have you for dinner.
Speaker 3: I know that akon casserole didn't pass muster, and so
Speaker 3: I'm sorry.
Speaker 1: Okay, let's take a break, and when we get back,
Speaker 1: we're going to return to the honey bees and the
Speaker 1: insects that Daniel asked about like fifteen minutes ago. And
Speaker 1: I was like, oh, get right back to it, and
Speaker 1: then I didn't.
Speaker 3: All right, we're back, and we're answering a question from
Speaker 3: a listener about how behaviors can evolve and a broader
Speaker 3: question about altruism in evolution. So tell me about insects.
Speaker 3: Why do bees give up their lives for their fellow bees?
Speaker 1: Yeah, so, in particular, we're talking about hymenopteran insects, and
Speaker 1: hymenoptrans are like the bees and the ants and stuff
Speaker 1: like that, and the wasps and these have some of
Speaker 1: the most amazing examples of hymenopterans. Oh yeah, you'd ask that.
Speaker 3: Well, it's just it has an interesting prefix.
Speaker 1: So hymen is Greek for membrane and turin is wing,
Speaker 1: and so they have wing membranes.
Speaker 3: Got it. Okay, Yeah, so membrane. That's a great answer.
Speaker 1: Yeah, thanks. Okay. So they have a really interesting sort
Speaker 1: of system for determining whether or not they end up
Speaker 1: being males or females. And we talked about this a
Speaker 1: little bit in the Listener Questions episode. But briefly, males
Speaker 1: are haploid, which means they only get one set of
Speaker 1: genetic information, so they develop from unfertilized eggs. So females
Speaker 1: will not mate with males, they'll just lay an egg.
Speaker 1: It will have one set of chromosomes instead of two,
Speaker 1: whereas females will get two sets of chromosomes. And so
Speaker 1: when a daughter is born, she gets one hundred percent
Speaker 1: of the info from dad because you only had one
Speaker 1: set of chromosomes to give. So all of the sisters
Speaker 1: they're going to get the same chromosome from Dad, So
Speaker 1: that chromosome's one hundred percent the same the chromosome they
Speaker 1: get from mom. They're going to have a like fifty
Speaker 1: percent chance of having the same information if you're comparing
Speaker 1: between two sisters. So if you look at two sisters,
Speaker 1: seventy five percent of their genetic information is going to
Speaker 1: be the same.
Speaker 3: Whereas between me and my brothers and humans it's only
Speaker 3: fifty percent.
Speaker 1: That's right, I see. And if you compare the mom
Speaker 1: to her daughters, they're only fifty percent similar. And so
Speaker 1: the daughters are like super hyper similar to each other.
Speaker 3: They're more like clones than our sisters.
Speaker 1: Yeah, yeah, they're much closer. And so you find that
Speaker 1: they're willing to help their mom produce a bunch of
Speaker 1: additional sisters because they're producing more individuals that are very
Speaker 1: similar to each other, and they are quite willing to
Speaker 1: give up their lives to protect each other because they
Speaker 1: are very genetically similar. And so we think that that's
Speaker 1: why you tend to see these amazing examples of animals
Speaker 1: being willing to give up their lives to protect each
Speaker 1: other because in these systems, at least the sisters tend
Speaker 1: to be very genetically similar. So kin selection seems to
Speaker 1: be able to particularly work well in these systems.
Speaker 3: It's fascinating that behavior seems to follow these relationships. You
Speaker 3: know that people who are more closely aligned tend to
Speaker 3: act in a way that benefits people who are more
Speaker 3: related to them. And isn't it because selection at the
Speaker 3: level of individuals, when individuals have these complex overlaps, tends
Speaker 3: to benefit behaviors that leads to the selection of those
Speaker 3: genes that led to those behaviors. Is that right?
Speaker 1: When you are closely related to individuals, you might be
Speaker 1: more likely to see a benefit to any genes associated
Speaker 1: with behaviors for cooperation.
Speaker 3: But you have to see the benefit. I guess that's
Speaker 3: my question, you know, because like we were talking earlier
Speaker 3: about like the squirrels knowing whether their people are related,
Speaker 3: But in the case of like a bee, like a
Speaker 3: bee isn't aware that they're related in some way? Isn't
Speaker 3: it just that their behavior benefits people who are more
Speaker 3: closely related to them without them being aware of their
Speaker 3: like sisterly relationship? I mean, are bees feeling a sisterly
Speaker 3: bond with their clone sisters?
Speaker 1: I see? Okay, So I think ants are able to
Speaker 1: tell the difference between nestmates and not nestmates based on
Speaker 1: their chemical smell. I wouldn't be surprised if bees could
Speaker 1: do something similar. There are social trematodes We talked about
Speaker 1: this in a prior episode, Living in the go nedes
Speaker 1: of snails that are able to tell the difference between
Speaker 1: members of the same species that are a different genotype
Speaker 1: that are trying to invade and take over the snail.
Speaker 1: And so I think even for species that we think
Speaker 1: of as like you know, quite quote unquote lower, they
Speaker 1: are able to tell even within the same species, you know,
Speaker 1: are you my family or not? Which is kind of amazing.
Speaker 1: But I think there are a lot of techniques for telling,
Speaker 1: even in a hive, are you in my family or
Speaker 1: are you not in my family?
Speaker 3: Yeah? I see, And that makes sense because if you
Speaker 3: can do that, then you can act differently based on
Speaker 3: that information. And that also will help propagate your genes
Speaker 3: if you help people who have your genes more than
Speaker 3: you help people who don't have your genes. Yes, yeah,
Speaker 3: that makes sense.
Speaker 1: Yeah, I think being able to recognize family is a
Speaker 1: big part of how this stuff works.
Speaker 3: All right. Cool, So in the future when the aliens
Speaker 3: come and they create like an army of ten thousand
Speaker 3: Daniel clones, I will just like naturally help those guys
Speaker 3: out more than like all the Kelly clones, because I'll
Speaker 3: know that I'm more closely related to the damn clones,
Speaker 3: and it's just nature. Kelly, don't be offended.
Speaker 1: Okay, okay, but let's move on to mechanism too, which
Speaker 1: is mutualism, which is there are some instances where there
Speaker 1: is mutual benefit to working together and you both get
Speaker 1: higher fitness by cooperating. And so, for example, although I
Speaker 1: was going to say, you know, we both have this
Speaker 1: great fitness together, but I don't think it's going to
Speaker 1: help either of our reproductions. So maybe that's not going
Speaker 1: to work. You help the Daniel clones, I understand. So
Speaker 1: all right, So here here's an example in paper wasps.
Speaker 1: You may have seen like these giant wasp nests that
Speaker 1: kind of look like they're made of paper, Like you know,
Speaker 1: they're literally using their mouth parts to sort of scrape
Speaker 1: parts off of trees or parts off of your furniture,
Speaker 1: and then they make these giant nests. They're made by
Speaker 1: several females, and some of those females, up to thirty
Speaker 1: five percent are actually not related. And so why would
Speaker 1: they be helping to make these giant nests if they're
Speaker 1: not related, Because only one of the females in that
Speaker 1: nest is laying the eggs, and everybody else is subordinating
Speaker 1: themselves and choosing to not lay eggs. Yeah, and so
Speaker 1: why would they do that, Well, it turns out that
Speaker 1: at some point the dominant female will die and one
Speaker 1: of the subordinate females will get the chance to take
Speaker 1: over that giant nest when she dies. And the giant
Speaker 1: nests have a much better chance of surviving like a
Speaker 1: predator attack than teeny tiny nests that are made by
Speaker 1: solitary females. So there are nests like that are made
Speaker 1: by solitary females who try to go it alone. And
Speaker 1: so there are some females who will say, all right,
Speaker 1: you know what, I'm not related to you, but I
Speaker 1: am going to help you out in the hope that
Speaker 1: maybe one day I'm going to get to take over
Speaker 1: this giant kingdom and my turn will come. And so
Speaker 1: I'm going to cooperate now in the hope that later
Speaker 1: I'm going to get to take this over. And so
Speaker 1: it's like a delayed benefit with it. This is called
Speaker 1: postponed coordination. And actually this idea of like territorial inheritance,
Speaker 1: where if I help you now, I might get to
Speaker 1: take over this amazing territory later is a pretty common
Speaker 1: thing that we see in like birds and insects and
Speaker 1: lots of other lots of other species.
Speaker 3: Okay, so then my question here is it makes sense
Speaker 3: to cooperate. Everybody benefits. But what about the prisoner's dilima
Speaker 3: example we talked about earlier. Why aren't there jerk wasps
Speaker 3: who come and wait for you to build your nice
Speaker 3: nest and then say, oh, wouldn't it be a tragedy
Speaker 3: if something were to happen to your paper wasp nest
Speaker 3: and you know, kill everybody and take it over.
Speaker 1: Ah. Yeah, So usually the individuals who are helping are
Speaker 1: weaker and couldn't be the dominant individual for whatever reason.
Speaker 1: And so, for example, if you are one of the
Speaker 1: thirty five percent of individuals who are not genetically related
Speaker 1: to the dominant individual who's making the nest, you probably
Speaker 1: couldn't try to oust the dominant individual who's laying the eggs.
Speaker 1: You'd probably get slaughtered if you tried to do that.
Speaker 1: And so I think in a lot of cases you
Speaker 1: would be outnumbered, and you are kind of like waiting
Speaker 1: to get older, and in the meantime, you're probably also
Speaker 1: like learning how things are done. It's also like an apprenticeship,
Speaker 1: and so I think that if you could go it alone,
Speaker 1: maybe you would, but you're just sort of waiting for
Speaker 1: your chance.
Speaker 3: I see, all right, cool, so that makes.
Speaker 1: Sense, okay, And then option three is manipulation. So maybe
Speaker 1: it looks like cooperation, but you are just straight up
Speaker 1: being coerced. And you should go to our episode on
Speaker 1: interspecific brood parasitism where we talk about birds who take
Speaker 1: care of eggs that are not theirs because they were
Speaker 1: tricked into doing so.
Speaker 3: So definitely not altruism, right.
Speaker 1: Definitely, just you have straight up been duped. And so
Speaker 1: last let's talk about reciprocity. This used to be called
Speaker 1: reciprocal altruism, but we stop calling it that because altruism,
Speaker 1: in my mind, is when you do something nice with
Speaker 1: no anti a patient that you'll get paid back. But
Speaker 1: this is really like you're doing something nice because you
Speaker 1: expect to get paid back eventually.
Speaker 3: This is like a gift exchange.
Speaker 1: Yeah right, yeah, that doesn't really feel like ultruism, So
Speaker 1: we call it reciprocity. And my favorite example of reciprocity
Speaker 1: is vampire bats in Costa Rica. So the idea here
Speaker 1: is that you are doing something nice because you expect
Speaker 1: that you're going to interact with this individual over and
Speaker 1: over and over again. So you mentioned the prisoner's dilemma,
Speaker 1: and so the prisoner's dilemma is a game that is
Speaker 1: often used to think about these reciprocal interactions. And it
Speaker 1: doesn't work if you're only going to interact with somebody once.
Speaker 1: If you interact with someone once, you should probably dupe
Speaker 1: them to try to get, you know, the best outcome
Speaker 1: from the interaction for that one iteration. But if you're
Speaker 1: going to interact with someone over and over and over
Speaker 1: and over again, maybe it makes sense to cooperate and
Speaker 1: try to make it so that both of you are
Speaker 1: getting the best outcome from interacting over and over and
Speaker 1: over again.
Speaker 3: And I remember they did this experiment and they showed
Speaker 3: that like the best strategy for the prisoners to dumble
Speaker 3: is called like tit for tat. Basically, people are being
Speaker 3: nice to you, you're nice to them. People are not
Speaker 3: nice to you. You're not nice back.
Speaker 6: Right.
Speaker 1: Excelelrod is the one who's set up I think the
Speaker 1: games and people could submit different strategies and tit for
Speaker 1: tat one.
Speaker 3: Right, Okay, classic game theory. Cool stuff.
Speaker 1: All right, So with these vampire bats that live in
Speaker 1: Costa Rica, they go out for a blood meal at night.
Speaker 1: If they unfortunately don't get a blood meal, they can
Speaker 1: make it for one night, but if they don't get
Speaker 1: a blood meal for three nights in a row, they're
Speaker 1: probably gonna die. But if they get a blood meal
Speaker 1: and they could find an animal, they probably get more
Speaker 1: than enough blood and they could afford to share some.
Speaker 1: So helping out a roost meat so they live in roosts,
Speaker 1: isn't a big cost to you, but could be a
Speaker 1: big benefit to an individual who didn't get any food
Speaker 1: that night.
Speaker 3: How do they help them out? They're like, spit up
Speaker 3: some blood.
Speaker 1: Yeah, yeah, they puke in their mouth. Yeah, super gross.
Speaker 1: Puke up blood in their mouth?
Speaker 3: You very much?
Speaker 1: Yeah, well you know, yeah, well you wanted to do
Speaker 1: a podcast with an animal behavior person, this is what
Speaker 1: you get. So anyway, Okay, So they looked and they
Speaker 1: saw that bats that didn't manage to get a meal
Speaker 1: for the night, they weren't very likely to get fed
Speaker 1: by family members. So that's totally consistent with our kin
Speaker 1: selection discussion. But they were also really likely to get
Speaker 1: fed by roostmates. So there was a guy who went
Speaker 1: out and they collected a bunch of bats from the wild,
Speaker 1: brought them into the lab and then held onto some
Speaker 1: of the bats and made it so that they couldn't
Speaker 1: get food, and then they released them back into a
Speaker 1: room that had some individuals from the same roost and
Speaker 1: some individuals that were completely new to the bats, so
Speaker 1: they essentially had like friends and non friends, and the
Speaker 1: friends were much more likely to feed the bats when
Speaker 1: it went in asking for food and essentially was like,
Speaker 1: I'm hungry, and individuals that knew the bat were like, okay,
Speaker 1: I'll feed you bat, And so it does seem like
Speaker 1: having some familiarity with an individual and essentially like some
Speaker 1: anticipation that you'll see this individual again so they might
Speaker 1: be able to pay you back. Yeah, made you more
Speaker 1: likely to feed them. And individuals who were fed were
Speaker 1: then more likely to feed individuals later on in the experiment,
Speaker 1: And so it does look like other individuals expect you
Speaker 1: to ante up later if it's known that you were
Speaker 1: helped out, and if you see someone pretty often, then
Speaker 1: you feel like you can ask them for help. And
Speaker 1: so it does look like these bats have this reciprocal
Speaker 1: altruism system going on, where if you've got these iterated
Speaker 1: interactions where you know you're going to see them pretty often,
Speaker 1: you can ask them for help and expect to get
Speaker 1: help in return.
Speaker 3: I see, all right, So that's like another reason why
Speaker 3: what seems like altruistic behavior might benefit the individual, And
Speaker 3: that seems to be the common thread is that you're
Speaker 3: arguing that all of this behavior, which seems like it
Speaker 3: might have been selected at the group level, can sometimes
Speaker 3: be explained by evolution on the individual because in the end,
Speaker 3: all of this behavior really does come back to benefit
Speaker 3: the individual, and that's why it would.
Speaker 1: Be selected exactly. Yep, that's the perfect way. At bottom
Speaker 1: line it whenever we've seen examples of cooperation, we've been
Speaker 1: able to find explanations that can be explained by individual
Speaker 1: level selection, don't require group selection, and can be completely
Speaker 1: understood through the lens of natural selection.
Speaker 3: So everybody out there is selfish, you're.
Speaker 1: Saying, well, we do see a lot of selfish behavior
Speaker 1: in nature. We also, this is kind of interesting. We
Speaker 1: don't see a lot of examples of spite, which is
Speaker 1: where someone is willing, which is where someone is willing
Speaker 1: to accept a negative impact on themselves just to see
Speaker 1: something bad happen as someone else. But we do see
Speaker 1: humans do that. That's a unique thing.
Speaker 3: Now, this sounds like a Mary roach book spite. Spite
Speaker 3: examples of people hurting themselves just to get back at somebody.
Speaker 1: Else we know of at least one case. So like,
Speaker 1: there's been studies on monkeys in the lab, capuchin monkeys,
Speaker 1: I think, where if a capuchin monkey was observed getting
Speaker 1: too many of the most delicious snack, another monkey would
Speaker 1: take a less delicious snack as long as it meant
Speaker 1: the other monkey would get punished in some way like no, no,
Speaker 1: you've been getting too many good snacks. This is not cool.
Speaker 1: You're getting punished and I'm getting punished. I don't care,
Speaker 1: it's not cool. So other animals are capable of spite.
Speaker 3: I'm willing to have a less delicious snack as long
Speaker 3: as I get to see you suffer.
Speaker 1: That's right.
Speaker 3: Wow, that is cold cold.
Speaker 1: Yeah, So we don't see it as often as we
Speaker 1: see humans doing it, but we also see amazing examples
Speaker 1: of cooperation and social behavior in humans, which gets to
Speaker 1: Kurran's question, which we will get to after the break.
Speaker 3: All right, we're back when we're taking a long detour
Speaker 3: to answer this question, first giving you a background and
Speaker 3: how evolution works, and reminding you that there is no
Speaker 3: true altruism out there in the animal kingdom, and that
Speaker 3: in the end, it all benefits the individual and that's
Speaker 3: how evolution works. So tell us, Kelly, how does this
Speaker 3: help us understand the answer to Karen's question about human behavior?
Speaker 1: All right, Well, first of all, I'm hoping this wasn't
Speaker 1: too painful for Karen. They have professor parents, so hopefully
Speaker 1: they're accustomed to long winded answers and so they're not surprised.
Speaker 3: I'm afraid you might be making the wrong assumption there. Now.
Speaker 3: My daughter Hazel is like oversensitized to long answers. If
Speaker 3: she sends us when coming, she's like, I didn't ask
Speaker 3: for a college lecture.
Speaker 1: All right, well, I'll tell them that they can fast
Speaker 1: forward to forty minutes in and get right to the point. Okay,
Speaker 1: so let's hone in on mammals, and so you'll see
Speaker 1: I actually haven't quite gotten the answer. We're just getting
Speaker 1: to mammals. So all right, two thirds of mammals are
Speaker 1: actually living alone. So only of mammals are social. In
Speaker 1: other cases, they get together to mate and then they
Speaker 1: tend to split up, and the females will spend some
Speaker 1: time with the babies because mammals do lactation, which means
Speaker 1: the moms need to be around the babies for a
Speaker 1: while to feed them. But okay, so now, why did
Speaker 1: humans in particular evolve to be social? Yeaht hey, they're extraordinaries. Well,
Speaker 1: Daniel and I actually recorded an answer to the question
Speaker 1: that I just asked, but after I listened to our answer,
Speaker 1: I decided it's like not a super satisfying answer. So
Speaker 1: instead I reached out to an expert to get away
Speaker 1: better answer, and I'm having our amazing audio guy Matt,
Speaker 1: drop that much better answer in here. Doctor Nathan Lynz
Speaker 1: is a professor of biology at John Jay College, City
Speaker 1: University of New York, and he's the author of three
Speaker 1: books that touch on human evolution topics. We had him
Speaker 1: on the show on February twenty seventh, twenty tw to
Speaker 1: talk about the sexual evolution How five hundred million years
Speaker 1: of sex, gender, and mating shape modern relationships, which is
Speaker 1: a book you all should definitely check out, and you
Speaker 1: can also find more of his writing over at the
Speaker 1: Human Evolution Blog and today we're bringing him on to
Speaker 1: answer one of Karen's questions. And so, Nathan, welcome back
Speaker 1: on to the show.
Speaker 4: It's a pleasure. I love this podcast.
Speaker 1: Well, we love having you on the show. This is
Speaker 1: your third appearance now, which I think makes you tied
Speaker 1: with Scott Solomon for most regular appearances on the show.
Speaker 1: So that's awesome for us.
Speaker 4: The gauntlet has been thrown down.
Speaker 1: That's right, that's right. Yeah, So folks submit more human
Speaker 1: evolution questions and then we can you know, we can
Speaker 1: get Nathan on even more.
Speaker 3: So.
Speaker 1: Yeah, So why did humans evolve to be social? And
Speaker 1: a little bit of context here. We just spent forty
Speaker 1: minutes talking about social evolution and other animals. We've talked
Speaker 1: about kin selection, reciprocal altruism, and now we're talking about humans.
Speaker 1: Why do we cooperate and why? Why are we social?
Speaker 1: What do we know about this?
Speaker 4: Yeah?
Speaker 7: So, I mean humans, So mammals and then primates evolved
Speaker 7: to be very very social. Very few mammals live solitary lives.
Speaker 7: They live in communities, they live in families, and they
Speaker 7: interact with one another and they're obviously they're better off
Speaker 7: when they do. So humans have taken this to an
Speaker 7: incredible extreme. And the reason why is humans are the
Speaker 7: ultimate generalists, right, We're actually not particularly well evolved or
Speaker 7: suited for any particular habitat or lifestyle. Instead, we went
Speaker 7: the other way. We evolved to be adaptable and to
Speaker 7: live in a whole variety of ways.
Speaker 4: So, you know, there are animals.
Speaker 7: That can throw better, that can run faster, that can
Speaker 7: climb better, that can swim better. But we can run
Speaker 7: and climb and jump, and we could do it all,
Speaker 7: and we can eat a variety of diets. Think of
Speaker 7: how different world diets are around the world, you know,
Speaker 7: from chore lines and seafaring peoples to desert people to
Speaker 7: tundra to rainforest. So that that quality of being very
Speaker 7: general in our approach lends itself to division of labor
Speaker 7: where individuals do not have to all do.
Speaker 4: The same thing.
Speaker 7: Whereas most other animals they all do the same thing.
Speaker 7: They can do different things, and they can work together.
Speaker 7: But there's not like trades, you know, there aren't professions.
Speaker 7: They all basically do the same thing, and they basically
Speaker 7: all have to learn everything they need to know each generation. Right,
Speaker 7: they don't inherit a whole bunch of knowledge. They do
Speaker 7: learn from each other, but they don't intentionally teach anything.
Speaker 7: And that's what humans do is we have this huge
Speaker 7: toolkit of knowledge, of cultural knowledge that gets passed on
Speaker 7: each generation and then get specialized. So some individuals can
Speaker 7: do one thing. They can be homesteaders, you know, they
Speaker 7: can work with their hands. Other people are out hunting
Speaker 7: and they have great vision, whatever it is. There's lots
Speaker 7: of different ways that you can contribute to the group
Speaker 7: and be important and valuable, and therefore your genes are
Speaker 7: more likely to find success, not because you're good at
Speaker 7: this one specific thing, but because you're good at something.
Speaker 7: So we were all contributing in this wide variety of ways. Well,
Speaker 7: that creates a social network that is better the larger
Speaker 7: it gets, because then that's how you add more and
Speaker 7: more skills to the toolkit, is that any one person
Speaker 7: doesn't have to do it all. They only have to
Speaker 7: do one thing. And so our groups became highly intricate,
Speaker 7: highly cooperative, and also large reservoirs of knowledge.
Speaker 8: And the best support for this hypothesis is that the
Speaker 8: few examples we have of population declines where you get
Speaker 8: a bottleneck, they lose tons of skills. So we have
Speaker 8: societies like in Tasmania where we can tell from the
Speaker 8: fossils and the archaeology that they used to be able
Speaker 8: to do some things that they no longer can. I
Speaker 8: mean now they can, but when they were first kind
Speaker 8: of studied anthropologically, they had actually lost a lot of
Speaker 8: cultural knowledge when the population shrunk to a small size.
Speaker 4: So our large groups with intricate social structures.
Speaker 7: And division of labor, that created a society that was
Speaker 7: much better than just the sum of its parts. Right,
Speaker 7: we're not all doing the same thing, we're contributing to
Speaker 7: this larger group set.
Speaker 4: So that's why social evolution just really ran out of control.
Speaker 7: And in fact, it's what Dan Lieberman calls evolution in
Speaker 7: warp drive because you don't have to wait around for
Speaker 7: new genes or new alleles, you know, mutations to provide things.
Speaker 7: You can actually learn a new skill, teach it, and
Speaker 7: then boom, everyone has it. So it's really our sociality
Speaker 7: is key to our success.
Speaker 1: Why just us? Why don't more animals do this generalist
Speaker 1: thing that has clearly been so great for us?
Speaker 7: Well, to be honest, it's an unlikely scenario to play
Speaker 7: out because if you think about it. Selection generally operates
Speaker 7: on the level of the individual, right, so you don't
Speaker 7: get anything out of helping other people, for example, it
Speaker 7: doesn't unless it directly benefits you.
Speaker 4: It won't. Those genes won't persist.
Speaker 7: And in fact, I just finished a book not too
Speaker 7: long called The Accidental Homo Sapiens, and it talks about how,
Speaker 7: in many ways our particular trajectory was not destined for success.
Speaker 7: It's actually quite costly to be have these big, huge
Speaker 7: brains at the expense of our bodies. We use our
Speaker 7: brains instead of our bodies, and so our bodies actually
Speaker 7: aren't that great.
Speaker 4: I read a book about that.
Speaker 7: Because we rely on our on our brains so much,
Speaker 7: our bodies kind of aren't as heavily scrutinized by natural selection.
Speaker 1: That book is called Human Errors. Right, Yes, another great book.
Speaker 7: Thanks for the plug. It's available at fine stores near you.
Speaker 1: Yeah, don't miss those opportunities.
Speaker 7: But the best proof of the sort of futility of
Speaker 7: our approach is if you look at all of our
Speaker 7: close relatives. They all went extinct, right and everywhere, whether
Speaker 7: it's Homo erectus or you know, Homo habilists, and you know,
Speaker 7: total rid of fences. Think of all of the named species,
Speaker 7: those were all the smartest things that they were planet
Speaker 7: had ever seen, and they all went extinct, right, some
Speaker 7: of them because of direct interaction with us, but most
Speaker 7: of them probably not. You know, so this is not
Speaker 7: actually that successful a strategy. And our own species was
Speaker 7: kind of on the nice edge of extinction multiple.
Speaker 4: Times in our history.
Speaker 9: Right.
Speaker 7: We have a lot of population bottlenecks in our genetic history.
Speaker 4: So what that means is it's a great system.
Speaker 7: Once you get big enough and spread around far enough,
Speaker 7: then it's a great system. But until then, favoring the
Speaker 7: development of the brain over everything else was a recipe
Speaker 7: for extinction.
Speaker 1: How sure are we of this hypothesis? This seems like
Speaker 1: a hard thing. You know, studying behavior is tough because
Speaker 1: behavior rarely leaves fossils, Like, you know, what percent confidence
Speaker 1: would you put on this explanation for why we're social?
Speaker 4: I don't know. It's really hard to say. What we
Speaker 4: can do.
Speaker 7: The best way to test these is to look at
Speaker 7: animal correlates and to look at closely related species that
Speaker 7: have some key difference and kind of see how it
Speaker 7: plays out. And you know, for example, if you look
Speaker 7: at chimpanzees and bonobos. They're very closely related. They're sister species,
Speaker 7: separated by about a million and a half year of
Speaker 7: distinct evolution, and their sociality is very very different, and
Speaker 7: a very short amount of time they developed very different
Speaker 7: social structures. The bonobo seems to be a bit more
Speaker 7: cooperative and egalitarian and gregarious. You know, they still have
Speaker 7: some you know, competition and it can be ruthless, but
Speaker 7: in general they're more pro social than the chimpanzees, which
Speaker 7: are much more aggressive and hierarchical. But the common chipanzees
Speaker 7: are more successful if you use numbers as your outfit,
Speaker 7: so it's you know, our sociality, it was no guarantee
Speaker 7: of success. So we don't really know. A lot of
Speaker 7: social evolution.
Speaker 6: Is speculative, but you know, when these hypotheses attract a
Speaker 6: lot of attention and a lot of scrutiny, and you
Speaker 6: have a lot of scientists who, you know, would try
Speaker 6: to think of clever ways to test them.
Speaker 4: So all we can do is say that this explanation.
Speaker 7: Has so far held up and no a lot without
Speaker 7: a time machine, we don't really know for sure. As
Speaker 7: you said, behaviors don't fossilize, but archaeology does, and we
Speaker 7: have a lot of evidence of an intricately pro social ancestry.
Speaker 7: I mean, they're they're. My favorite fossil of all time
Speaker 7: is called the old Man from Demonissi. He's it's a
Speaker 7: fossil of a homoerectus from about two and a half
Speaker 7: million years ago. And this is an old man who
Speaker 7: lost all of his teeth and survived because we can
Speaker 7: tell by the healing of his bones that he survived
Speaker 7: for at least two years beyond having any teeth in
Speaker 7: his head. How does one survive before you know, soft
Speaker 7: cooked foods, you know, the only explanation is that somebody
Speaker 7: was chewing his food for him, someone was preparing his food,
Speaker 7: softening it. And why would you do this to this
Speaker 7: old man who was a burden to his group because
Speaker 7: he knew things.
Speaker 3: Or maybe he was really fun to have around.
Speaker 6: Yeah, he made him laugh, you know, But the point
Speaker 6: is he contributed, like and that's I think, as far
Speaker 6: as I know, the oldest evidence we have that that
Speaker 6: just being older, you know, was a value to the
Speaker 6: group because you old people know things, you know, they've been.
Speaker 7: Around longer, they teach things, and so when and by
Speaker 7: the way, that fossil does not stand alone. We have
Speaker 7: a lot of other examples of clearly individuals that had
Speaker 7: been helped by their group that by having all kinds
Speaker 7: of you know, injuries and deformities and yet continue to
Speaker 7: live for years on end, they couldn't have done that
Speaker 7: without help. So we've been caring for each other, taking
Speaker 7: care of each other, and also respecting each other's contributions.
Speaker 7: We've been doing that for a very, very long time,
Speaker 7: and I'm pretty convinced that that's that our sociality is
Speaker 7: the key the key aspect.
Speaker 3: What do you think is the sort of leading alternative hypothesis.
Speaker 7: Well, there's a lot of people still to this day
Speaker 7: who have a hard time accepting any benefits to the
Speaker 7: group that a particular you know, genetic trade, certain adaptation
Speaker 7: would have because if it doesn't directly benefit the individual
Speaker 7: and quickly, some biologists, many biologists, can't see a way
Speaker 7: that it would.
Speaker 3: Be selected for.
Speaker 7: I'm not convinced of that. I think that the tide
Speaker 7: is turning against the opponents of group selection. The reason
Speaker 7: why is it's not hard to imagine when you have
Speaker 7: multiple groups competing against each other that a cooperative group
Speaker 7: would outcompete a non cooperative.
Speaker 4: Or less cooperative group.
Speaker 7: And this is the work of Davis Loan Wilson, and
Speaker 7: he's been ringing this bell for fifty years. And the
Speaker 7: idea is that it's true that really competitive, kind of
Speaker 7: antisocial instincts can be rewarded within a group, rewarded meaning success.
Speaker 7: But when you have groups competing against each other, that
Speaker 7: actually becomes the more powerful selective force. And to be honest,
Speaker 7: Darwin mentioned this in the Descent of Man when he
Speaker 7: talked about if you look at any two human groups
Speaker 7: when they clash, the differences between them that determined which
Speaker 7: group is successful is never genetic, right, It's always has
Speaker 7: to do with something entirely non genetic, something social, something cultural,
Speaker 7: something technological. And if you can imagine that same competition
Speaker 7: playing out for millions of years, not just a few generations,
Speaker 7: but millions of years, what you would see emerging is
Speaker 7: very cooperative, pro social groups would tend to outcompete those
Speaker 7: that aren't.
Speaker 3: But isn't that social behavior somehow encoded in the gene
Speaker 3: so indirectly, it is still a genetic advantage.
Speaker 4: Right, It is?
Speaker 7: It is and so and that's why I think group
Speaker 7: selection is starting to experience this renaissance where people can
Speaker 7: recognize that if the genes make you more social than
Speaker 7: your whole group really is better. And if your group
Speaker 7: is competing against the less one than those genes would accumulate.
Speaker 7: You know, the jury still out on a lot of
Speaker 7: these a lot of these questions. But one thing I
Speaker 7: would point out is that competition and cooperation we think
Speaker 7: of them as opposites, but actually they involve all of
Speaker 7: the same skill sets, right, because to cooperate with someone
Speaker 7: requires the same things to compete against them, you have
Speaker 7: to understand them. You have to be able to predict
Speaker 7: their behavior, you have to be able to manipulate them.
Speaker 7: And whether that's good or bad, you know, depending on
Speaker 7: who it is. But you know, if you can kind
Speaker 7: of get someone to do what you want, you have
Speaker 7: to understand them. So it's like empathy, and I mean
Speaker 7: that is like emotional empathy, cognitive empathy. And when you
Speaker 7: have that ability, you can either work with them or
Speaker 7: work against them. So it's the same skill set. So
Speaker 7: what the difference is who do you identify as groups?
Speaker 7: So what makes you cooperative versus competitive is in group
Speaker 7: versus outgroup identification, which to me still proves the point
Speaker 7: that you had cooperative groups competing against each other. Cooperation
Speaker 7: and competition do exist together at the same time in
Speaker 7: the same individuals, and that's why you can have someone
Speaker 7: who's you know, extremely you know, generous and nice to
Speaker 7: his friends and absolutely ruthless to his enemies. I mean
Speaker 7: the classic caces that Nazi soldiers used to come home
Speaker 7: and kiss their children gently on the head, you know,
Speaker 7: Like we're all capable of both evil and pro social acts.
Speaker 7: Even on a dying we can switch, right, So, because
Speaker 7: I think it's the same parts of our brain. It's
Speaker 7: just whether or not we identify as pro social or
Speaker 7: anti is in group outgroup identification, which is depressing given
Speaker 7: the way the world is increasingly pitting us against each other.
Speaker 3: Agreed, fascinating. Do you think when we meet aliens we
Speaker 3: will discover the same sort of social structures there, and
Speaker 3: the same sort of you know, arguments apply.
Speaker 7: It's really hard to predict anything about how life outside
Speaker 7: of you know, the selective pressures of Earth, how that
Speaker 7: would evolve.
Speaker 3: But the arguments you've made are fairly general, right.
Speaker 4: Yeah, exactly.
Speaker 7: It's very hard to imagine how a very anti social
Speaker 7: species could ever evolve very far, and we see that
Speaker 7: in our own planet, right, So there are some creatures
Speaker 7: who have evolved to be very solitary as adults and
Speaker 7: are fairly hostile to one another. The orangutan is our
Speaker 7: closest relative that, at least among the males. They're just
Speaker 7: generally hostile. They kind of hate each other. So it's
Speaker 7: probably a dead end evolutionarily. It's hard to imagine getting
Speaker 7: much And you know, Tasmanian devils are sort of the
Speaker 7: same way that they pretty much hate one another.
Speaker 3: So we're not going to be visited by space orangutangs,
Speaker 3: that's your prediction.
Speaker 4: Yeah, I think.
Speaker 9: I think like if you if you watch Star Trek
Speaker 9: and and and you know Galaxy, you know all of these,
Speaker 9: it's hard to imagine the really nasty, anti ruthless ones
Speaker 9: ever becoming that successful.
Speaker 6: But I'm an optimist, so maybe that's where that's coming from.
Speaker 6: Is I just refuse to believe that evil's gonna win?
Speaker 4: But I don't know.
Speaker 1: I think that attitude is helpful to keep us all
Speaker 1: going personal.
Speaker 7: Yeah, but even if it's wrong, it's a youthful illusion, right, Yeah.
Speaker 1: I mean, you need something to get you up in
Speaker 1: the morning. And get you out of bed and keep
Speaker 1: you going personally. Maybe I'm speaking for myself now, but.
Speaker 7: Yeah, well, use useful illusions. That's a whole area of
Speaker 7: evolutionary thought as well. Useful illusions. I mean, free will
Speaker 7: is very likely a useful illusion.
Speaker 6: Even our sense of self as a as a as
Speaker 6: an identity is a useful consciousness, useful illusion.
Speaker 1: Yeah, well, we are getting into a whole new episode there,
Speaker 1: and we will have you back on to talk about
Speaker 1: that some other times. So thank you so much for
Speaker 1: answering that question, and we'll chat with you later. Okay,
Speaker 1: we're back to our regularly scheduled Daniel and Kelly programming.
Speaker 1: So Karen also wanted to know why do we go
Speaker 1: crazy if we're isolated and why doesn't that happen to
Speaker 1: other species like whales? And so the first thing I
Speaker 1: do when I have a question like why do we
Speaker 1: go crazy? Is first I want to ask do we
Speaker 1: go crazy? Let's make sure that there's evidence for that statement,
Speaker 1: and so you know, first of all, I'll note that
Speaker 1: some of us, there's a lot of variability and how
Speaker 1: our species responds to social isolation. Some of us really
Speaker 1: would rather be by ourselves. Yeah, yeah, but for some
Speaker 1: of us, loneliness is detrimental to our health. And so
Speaker 1: according to the Centers for Disease Control, social isolation and
Speaker 1: loneliness can increase a person's risk for heart disease and stroke,
Speaker 1: type two diabetes, depression and anxiety, suicidality and self harm, dementia,
Speaker 1: and earlier death. Yikes. Okay, so lots lots of things.
Speaker 1: And so why well, you know, we for species that
Speaker 1: are social, our brains are sort of hardwired to expect
Speaker 1: that level of connection. And so when we don't have
Speaker 1: that connection, when you want that connection, that can be stressful.
Speaker 1: And so there's evidence that people who are isolated, who
Speaker 1: are feeling isolated and feeling lonely, they have higher levels
Speaker 1: of stress hormones. So we have these like hormones that
Speaker 1: our body releases when we're stressed out and in acute stressors.
Speaker 1: So like you know, if you need to run out
Speaker 1: in front of a car to pull your dog out
Speaker 1: from you know, the path of the car, having a
Speaker 1: big release of stress hormones is good because you you know,
Speaker 1: you run out there quickly, you go back and your
Speaker 1: body then returns to normal. Like it helps you in
Speaker 1: that immediate moment. But if you have high levels of
Speaker 1: stress hormones all the time, that's bad for your body.
Speaker 1: It does things like mess with your immune system, and
Speaker 1: if your immune system is messed up, then when you
Speaker 1: get sick, you get sick worse. And it can do
Speaker 1: things like increase your risk of type two diabetes, and
Speaker 1: over time, it can make you sort of depressed and
Speaker 1: anxious and stuff like that. And so this can have
Speaker 1: negative impacts on our bodies, especially if you're feeling isolated
Speaker 1: for a really long time. So Karen is right, being
Speaker 1: isolated is definitely bad for your health, but it also
Speaker 1: is bad for other social animals as well. So any
Speaker 1: animal that's highly social does show evidence of being harmed,
Speaker 1: like physically by being isolated socially. And I don't know
Speaker 1: about whales in particular, because it's hard to do these
Speaker 1: kinds of studies on big animals like whales, But there
Speaker 1: are monkeys that have been in labs and we've infected
Speaker 1: them with viruses, and if they're socially isolated, they show
Speaker 1: similar things that you see in humans. They show high
Speaker 1: levels of stress hormones, their immune systems don't respond to
Speaker 1: the virus as well, and so you see more of
Speaker 1: the virus particles moving around in their body, and they're
Speaker 1: more likely to die from that viral infection. So very
Speaker 1: similar to what we were talking about in humans.
Speaker 3: That's a terrible experiment. Not only are you making the
Speaker 3: monkey sick, but then you make them be on their
Speaker 3: own and see if that makes it even worse.
Speaker 1: Yeah, I mean so, there's a really interesting book by
Speaker 1: Robert Sapolski called Why Zebras Don't Get Ulcers? And this
Speaker 1: was an example he used in that book. And so
Speaker 1: you know, monkeys are often used as a way of
Speaker 1: trying to understand diseases that humans get associated by having
Speaker 1: chronic stress, and that book is a really interesting look
Speaker 1: at how chronic stress can impact a lot of different
Speaker 1: aspects of our lives. But yes, I agree, that's a
Speaker 1: horrible experiment. Here's another horrible experiment. Harry Harlowe in the
Speaker 1: nineteen fifties in the nineteen sixties was living at a
Speaker 1: time where people were arguing that the main reason babies
Speaker 1: were attached to their moms is because they're a source
Speaker 1: of food, and that's it. They're a source of food.
Speaker 3: Is the wire monkey experiment?
Speaker 1: This does the wire monkey experiment? Oh, my God. And
Speaker 1: so so he was like, no, it's not just food.
Speaker 1: It's because there's like there's comfort and love and that
Speaker 1: and attachment and those things matter too. And so to
Speaker 1: show that, he took infant reesiss monkeys and he created
Speaker 1: two kinds of quote unquote moms. Both of them started
Speaker 1: from a wooden and wire frame, but one of them
Speaker 1: also had like a rubber or a foam support and
Speaker 1: then a terry cloth on top of it. And he
Speaker 1: alternated which one got a bottle, and so which got
Speaker 1: a bottle which quote unquote mom, Yeah, got a bottle.
Speaker 1: And so if like comfort didn't matter, the baby should
Speaker 1: just stick to the bottle wherever the bottle was. But
Speaker 1: it turned out if the bottle is on the wire mom,
Speaker 1: the baby will go over to the wire mom, drink
Speaker 1: its milk, and then immediately go back to the terry
Speaker 1: cloth mom for support. So clearly it's more than just
Speaker 1: where the bottle is. It wants to feel like the comfort.
Speaker 3: And there's something just so sad about how a terry
Speaker 3: cloth is a stand in for comfort, I know, if
Speaker 3: not even the presence of another monkey. It's like this
Speaker 3: thing is so desperate for love that a will find
Speaker 3: comfort in a towel.
Speaker 1: I know, I know. And then they also did experiments
Speaker 1: where he just kind of put it in a space
Speaker 1: like without any sort of comfort, and it would sort
Speaker 1: of stare at the wall and go in circles and
Speaker 1: just sort of freak out. And then if you would
Speaker 1: put it and it would hurt itself. And then if
Speaker 1: you put it in a room with other infant monkeys,
Speaker 1: eventually it would be totally confused about how to interact
Speaker 1: with them, and some of them stopped eating and would
Speaker 1: pass away. And I should start this episode with a
Speaker 1: disclaimer anyway, So he did a variety of experiments, and
Speaker 1: the monkeys that had just the terry cloth were in
Speaker 1: a much better shape, Like they would go out and
Speaker 1: explore the environment, and they would like explore the environment
Speaker 1: and then run back to the terry cloth mom if
Speaker 1: they got scared, and then they would go back out
Speaker 1: and explore again. And the one that didn't have a
Speaker 1: terry cloth mom in the cage at all would just
Speaker 1: kind of like sit in a corner, like huddled up,
Speaker 1: sucking its thumb, being totally upset. And so anyway, the
Speaker 1: point is, there are lots of other animals that really
Speaker 1: need love in social connection as well, and so humans
Speaker 1: we get totally messed up without it, but so do
Speaker 1: other animals also, and so any animal that it seems
Speaker 1: like any animal that's wired to need social connection who
Speaker 1: misses who doesn't have it, really suffers from that.
Speaker 3: This reminds me also of the sort of accidental terrible
Speaker 3: experiment of the like Eastern European orphanages, where there were
Speaker 3: a lot of kids that were sort of raised mechanically
Speaker 3: in cribs and left in their cribs like most of
Speaker 3: their childhood until there were seven, and then had difficulty
Speaker 3: forming attachments, right, So I.
Speaker 1: Think that was in Romania, Chowchescu outlawed birth control, and
Speaker 1: so you ended up with a bunch of babies all
Speaker 1: at once from a bunch of parents that were not
Speaker 1: quite ready to take care of them. And maybe it
Speaker 1: wasn't half, but a subset of those children were then
Speaker 1: given to foster families, and you could compare the outcomes,
Speaker 1: and the kiddos who ended up in foster families did
Speaker 1: a lot better. And so yes, there's a lot of
Speaker 1: evidence that even just getting hugs makes a huge difference. Okay,
Speaker 1: And then the last question was what would happen if
Speaker 1: a human lived its whole life without ever having contact
Speaker 1: with another human. This is so depressing. This is where
Speaker 1: we hope that Kelly is not going to cry here.
Speaker 1: So the answer is nothing good. So for ethical reasons,
Speaker 1: this is of course an experiment that we can't do.
Speaker 1: And any experiments that have happened, you know, quote unquote
Speaker 1: naturally have had like abuse layered on top of them,
Speaker 1: so it's not like a clean experiment essentially. So let's see.
Speaker 1: So there have been like quote unquote feral children that
Speaker 1: have been like found out in the wilds, that have
Speaker 1: been raised by animals. And in these cases, these children
Speaker 1: had to have been at least for a while raised
Speaker 1: with adults, because you know, they had to have been
Speaker 1: born to adults. They had to have been raised up
Speaker 1: until a point where they could you know, probably walk around.
Speaker 3: Wolves can't nurse an infant, for.
Speaker 1: Example, They're probably not going to nurse an infant, right
Speaker 1: and so one, there's a lot of evidence that some
Speaker 1: of these stories are actually just stories and didn't actually happen.
Speaker 1: There's also some evidence that some of these are cases
Speaker 1: of kids that hit age six or seven, their parents
Speaker 1: identified that the kiddo had a disability, and they decided
Speaker 1: they were just going to abandon the kid in the woods.
Speaker 1: And then the kid was found, you know, months or
Speaker 1: years later, and the kiddo had difficulty communicating, and it
Speaker 1: wasn't necessarily clear if that was the disability or if
Speaker 1: that was the time alone in the woods. And so
Speaker 1: humans are horrible is really what I conclude from the
Speaker 1: feral children examples. But in general, if there is a
Speaker 1: lesson from the federal children's stories, it appears to be
Speaker 1: that language is impacted. If there are any cases where
Speaker 1: children who could have developed language normally were released out
Speaker 1: into the wild, it seems that their language is impacted
Speaker 1: and some of their ability to exhibit social behaviors that
Speaker 1: we've come to expect from kids in society, things like
Speaker 1: eating with a fork and knowing which behaviors are acceptable
Speaker 1: when you're in private and which behaviors are acceptable when
Speaker 1: you are in public, like.
Speaker 3: Can you bring up poop at the dinner table? Only
Speaker 3: if they're biologists.
Speaker 1: There ex was Katrina Ferrell.
Speaker 3: I'm just saying behavior is surprisingly context.
Speaker 1: Depending it is it is okay. And then there are
Speaker 1: a handful of kids that you'd maybe call cases of
Speaker 1: isolation where they were kept in houses where they weren't
Speaker 1: really interacting with people. But again this is isolation layered
Speaker 1: with abuse, so it's not just isolation. So for example,
Speaker 1: in the nineteen seventies, there was a kid named Genie
Speaker 1: who for years was locked in a room by herself,
Speaker 1: was tied to a toilet, and was abused by her father,
Speaker 1: and eventually she was found and she had very few words.
Speaker 1: She was able to develop some words with a little
Speaker 1: bit of extra help, but she never was really able
Speaker 1: to develop grammar. And so grammar seems to be maybe
Speaker 1: something that we need to develop early if we're going
Speaker 1: to develop it at all, or it needs to be
Speaker 1: something that we hear a little bit when we're younger.
Speaker 1: And she also had some trouble with understanding what was
Speaker 1: societally acceptable, you know, again, like what is okay to
Speaker 1: do in public? What is not okay to do in public?
Speaker 1: You know, how close is it acceptable to be when
Speaker 1: you're interacting with someone, stuff like that In general, like
Speaker 1: I read through a couple cases before I felt like
Speaker 1: I wasn't going to be able to not cry. And
Speaker 1: it seemed like in general, language and meeting societal expectations
Speaker 1: were the things that tended to get impacted most strongly
Speaker 1: by these isolation things. But again, in all of these
Speaker 1: cases you also have like abuse layered in, so it's complicated.
Speaker 3: Isn't it amazing that you need like a license to
Speaker 3: drive a car but not to become a parent.
Speaker 1: Sometimes I do feel like it is amazing.
Speaker 3: Yeah, all right, So bottom line it for us, Kelly,
Speaker 3: what is the overall answer to Karen's question.
Speaker 1: My brain is so mired right now and all of
Speaker 1: the depressing stuff that we just talked about, I'm gonna
Speaker 1: try to lift it up a little bit. So our
Speaker 1: species does some absolutely amazing things socially, you know, so,
Speaker 1: like we share information with each other that has resulted
Speaker 1: in our ability to do things like create vaccines. Everybody
Speaker 1: knows how excited I am about vaccines that like save
Speaker 1: the lives of our children. We are able to share
Speaker 1: technologies that heat our homes and make it so we
Speaker 1: can live even in Virginia and love Virginia.
Speaker 3: And on that point, make jokes which can like bring
Speaker 3: light to the darkness and make people feel happy and
Speaker 3: together even if they're something Yeah exactly.
Speaker 1: And you know, these these horrible stories of isolation that
Speaker 1: I read about part of why they're so horrible is
Speaker 1: because they are really rare. And for example, I live
Speaker 1: in a place where there's incredible support for you know,
Speaker 1: for kiddos with disabilities, and there's just you know, incredible
Speaker 1: school system, and there's just incredible support in general. And
Speaker 1: so we are a species that in a lot of
Speaker 1: cases takes care of each other. I would love to
Speaker 1: see us make more progress there, but in general, you know,
Speaker 1: there's a lot to be excited about it.
Speaker 3: And so thanks to everybody out there who has a
Speaker 3: job where you're taking care of people you're not directly
Speaker 3: related to. Teachers and soldiers and firefighters and everybody out
Speaker 3: there who's helping make the world a little bit of
Speaker 3: a better place. Thank you all.
Speaker 8: Yeah.
Speaker 1: And one of the amazing things about our species is
Speaker 1: I think that maybe we are the only species where
Speaker 1: you really see altruism, where you'll see people make a
Speaker 1: huge donation or something too an organization anonymously, where they
Speaker 1: really don't expect to get anything in return. And so
Speaker 1: way to go humans. We're not perfect, but a lot
Speaker 1: of us do some good stuff.
Speaker 3: And for all of these examples of terrible parenting, there
Speaker 3: are millions and millions of people out there who just
Speaker 3: love their kiddos to smithereens right.
Speaker 1: Oh my gosh, yes, amen, all right.
Speaker 3: And we love all of you, and we love all
Speaker 3: of your questions and your curiosity and your desire to
Speaker 3: know everything we do and don't know about this amazing,
Speaker 3: beautiful and crazy universe.
Speaker 1: And thank you to Karin for sharing your question with us.
Speaker 1: I'm sorry it got so dark at the end there.
Speaker 1: We look forward to hearing what you thought of the answer.
Speaker 2: Hi, guys, thanks so much for answer my question. I
Speaker 2: don't mind the long winded answer, and I thought it
Speaker 2: was really interesting to take a tour of altruism throughout
Speaker 2: the animal kingdom. I also thought it was interesting that
Speaker 2: some animals will be promoting their genes by helping others
Speaker 2: who are closely related to that. Thanks so much. Bye.
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