- Let's talk about oxytocin. We hear about it as the love hormone, the affiliative hormone. Folks, it's a neuro hormone, so it's somewhere in between a neuromodulator and a hormone. Let's set all that aside, all the mechanistic stuff, and I'd love to know your knowledge about what changing levels of oxytocin does to perception, to behavior, humans.

- So yeah, oxytocin, we've been interested in it for a long time because, as you said, it seems to be a dial that can turn up or turn down certain aspects of social behavior and other aspects of mental and emotional function. It's important to point out that oxytocin and its sister neuro hormone, vasopressin, arginine vasopressin, which is sort of maybe a little more important in males than in females, and females, oxytocin's a little more important, but they're in both, and they've been around a long time.

They've actually, you know, there's a very early invertebrate evolution. In mammals, oxytocin has the primary role, right, of helping to build bonds between mom and baby, so oxytocin's released during childbirth, it's released when mom is nursing, and it seems that in humans and some other social, you know, really, really social creatures, it's now been co-opted to kind of have a similar kind of role in the relationships you have with other people who are not your offspring or your pairmate, right, 'cause oxytocin, for example, is released, you know, when you orgasm, and so, and that's, you know, thought to be why that sort of pillow talk afterward is, you know, like, it's more engaging, and, you know, people feel things at that time that they might have, that are different from what they would have felt before that.

- It fosters attachment. - Fosters attachment, that's a good way of putting it. So, oxytocin levels are hard to measure, right? You can measure it at a distance in the periphery, in the blood, but it's not exactly, like, one-to-one correlated with what's going on in the brain, and in general, we don't wanna put, like a, you know, a pump or a little thing in your brain that we could measure how much is in there.

So, we can look at, instead, what is often done is to look at what happens if you introduce oxytocin, more oxytocin than you normally have, like, into the brain. You can't inject it or anything like that, and the way that it's typically applied is to squirt it up your nose, or inhale it intranasally, so it then is taken up by the nerves that are in your sinuses and whatnot, and then goes into the brain.

That was what it was thought to, I think, that we were the first to show that that's actually how it works. We did all the work in monkeys, where it's, all these things are just sort of easier to do, and the behavior's a little bit less complex, so our readouts are, I think, a bit more straightforward.

In the human studies, there's a lot of, you know, it's controversial, 'cause there's a lot of, like, there's some crap studies, and there's just a lot of variability in the effects across studies, and I think some of that's just because you ask people to squirt it up their own noses, and so there's a lot of, that introduces variation in just how good they were at getting it in the right place.

With the monkeys, what we did instead is we used what's called a nebulizer or aerosolizer. Like, I had noticed when, like, my kid had, like, pneumonia, and I took him to the ER, they put this mask on him, and they, you know, they missed this albuterol, which opened up his airways.

Oh, we could do that with oxytocin, too, so that's what we did with the monkeys. It makes sure they get, like, a really good dose, and then we showed that that gets right into the brain. Okay, now that puts us in a position to ask questions of what does it do.

Well, one of the first things that oxytocin does is it relaxes you, so just overall, you know, you were talking about autonomic function. It's a relaxer. It's an anxiolytic, so it, and in monkeys, what that does is it reduces their vigilance to sort of any threats, so they're just a lot more chill, so that's sort of a primary thing, and then we've looked at how it affects their behavior in males and females separately, because as I said before, they sort of, first of all, males and females have different strategies and behaviors and the expression of where oxytocin receptors are in the brain, et cetera, and vasopressin receptors are a little bit different, and in male monkeys, it's super interesting, because, you know, we've been talking about how, you know, dominance, and they're really, like rhesus macaques have this really steep hierarchy, and one of the things we found right away is that you give oxytocin and it just flattens the hierarchy, so the dominant male monkeys become super chill and friendly, and the subordinate ones become a bit bolder, perhaps because, you know, when, if I dose, if I dosed my own, or I've dosed you with oxytocin, it'd change your behavior, which would change my behavior, so it reverberates across individuals, so it flattens the hierarchy.

They spend more time making eye contact. They pay more attention to the other individual, and we've shown that-- - It's Burning Man. - Yeah, it's true. - I've never been to Burning Man. - I've never either, but it's-- - This is what I hear. - No, I think that's the right point, and I'll circle back to that, because we also showed that in a task-based situation where a monkey can choose, we gave monkeys choices of whether they could give a reward to themselves, to another monkey, to a bottle that could collect reward, you know, in case they just like to see juice dripping out, and they would become more pro-social, so they're much more likely to give a reward to another monkey.

They're more altruistic, as we talked about earlier, so that's like, it looks like a real pro-social kind of thing, right, which I think is super interesting. In females, it's a little bit different. Females become kind of nicer to each other, and we see that greater eye contact, et cetera, but they become more aggressive toward males.

And we speculate, I think, it's a hypothesis, that because oxytocin is released when you've got an infant, basically, for females, males are a bigger threat then, because in many primate societies and other mammals, males sometimes can be infanticidal, because if they kill off a female's infant, then that will bring that female into receptivity for mating much more quickly, and so that's sort of the-- - Brutal.

- Evolutionary, yeah, it is brutal, the evolutionary rationale behind that. So that's kind of our supposition. The other thing that I thought is really interesting, as well, is we find a greater, or an increase in the synchronization of behavior. So when I do, you know this idea of mirroring, which has been talked about in business context for a long time, it's a real thing, and it's a marker of a good relationship, a strong relationship.

If you have good rapport with somebody, you tend to adopt similar movements and postures, and if you do those things-- - Shirts. - Shirts, exactly, we didn't coordinate here, but yeah. - You just happen to be a great dresser. - Ah, well, you know, same here. So when you have that, actually, if you do those things, if I subtly mirror you, and I'm in a job interview, I'm more likely to get the job, gonna get a higher salary, et cetera, all those sort of good things.

- Really? - So oxytocin turns up behavioral synchrony, and one of the things, this is like something I've been fascinated in for the last decade, and we and a lot of other people have been working on, is that this synchrony, the behavioral and neural level, physiological synchrony, is kind of, it's this black magic of social behavior.

It's the glue that allows us to live and work together. So the observation is that if you and I, we have a good rapport here, let's say, if we are measuring activity in our brains right now, we'd see that they were coming into alignment. So they might've been very disparate when I arrived here and you arrived here today, and as we've grown closer and we've discovered things that are similar about us, that the, you know, our mindsets and our emotional sets are more overlapping.

So we see this world more similarly, we feel more similarly about it, we're more likely to take similar decisions, and then that, the coolest thing is this reverberates down to your body. So if our brains begin to align, our hearts actually begin to beat together, you know, if we have different resting heart rates, we begin to breathe together and you start to move together, you start to look at the same things in the environment.

We've talked about attention. When you look at something, the same thing, you're getting the same data and that feedback loop, which I think now you can see that that is a way to coordinate behavior. And that is the essence of sort of, that's our secret sauce as a species, which is that we can collaborate and do things together.

And it seems to, like oxytocin, vasopressin are involved in this as a way of kind of turning up the dial on synchrony. It seemed to turn up the so-called social brain network. And then that synchrony is the glue, and it's a biomarker, a biological marker of a close relationship that predicts better communication, increased trust, better teamwork, you know, whether your marriage is gonna last.

I mean, the things that it predicts, you know, group decision-making, so we showed that in like in a business context, committees that are more in sync with each other, that their hearts are beating together, are more likely to reach the right decision in a really difficult problem than committees that are not.

The cool thing is that now that you have a biomarker, you can hack that, right, in the sense that now we can start looking at all those trust-building exercises or anything else that, you know, is supposed to turn things up, turn up the dial on teamwork or communication, and we have a readout.

And we could say, yeah, that's working. That's actually doing the thing. It's not BS, right? You should invest your time and energy in that rather than something else. And there's like, now we've been working through this list as well as others. There's a whole host of things that seem to actually turn up synchrony, and that's a shortcut to team chemistry.

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