Now um it's my great pleasure to introduce tonight's speaker, Professor Robin May, who's our current professor of physic. He's also professor of infectious diseases at the University of Birmingham and the interim chief scientist at the UK Health Security Agency. Tonight is the fifth in a series of emotions. Why do we love? And I think without further ado, I'll just let you get on with it.

Thank you very much, Cisty. So tonight uh we have an upbeat topic. Those of you who've been to some of these before, um, you know, we've covered some really depressing things like hate and fear and all these kinds of things. Tonight is all good news, more or less. Um, it's all about love. Um and uh we are gonna consider, I hope, uh what love means, why it works, why it sometimes doesn't work, and maybe what we can do about it um going forwards. And uh so before I kick off, let me just take a quick show of hands. Who's it who's their first time here at Gresham? Excellent. Very pleased to meet you. Um and go on, just in case I'm lucky. Anyone here on a first date? Oh, that's disappointing. I was hoping to have a live example. I did, I did have at one of my earlier lectures, I had someone here on a second date, and they've chosen possibly the most depressing topic to come to. So I'm if you're listening online, I hope you made it. Um right, so tonight we're gonna talk about love. Um and I think before we start talking about love, we need to think about what do we actually mean by love? Because this is a word that we use all the time, right? So many of us will have used it today. Um, you know, if I think about most of us, hopefully, uh, love our partners, our wives, husbands, whatever. Uh, we love our children, hopefully. We often love our pets. We also love all sorts of other things. I love asparagus and I love aggression lectures, for example, but it's a different sort of love, right? Uh, hopefully. Um, and in all of these contexts, we use that word uh to mean different things. So when I say I love asparagus, I don't actually mean I have romantic relations with asparagus. What I mean is it is something that I really like eating or I enjoy listening to in the case of a lecture or whatever. If we talk about love in kind of filial terms, I love my siblings or I love my children, we mean something much more intense than loving asparagus, hopefully. Uh, but something that is still different to the love we express when we talk about a romantic partner. And so there's this kind of Venn diagram. And tonight we are focused primarily on uh love in the context of romance, of partner romance. But I think it's important to consider the fact that these are all different elements on the same uh kind of scale. Uh, and in fact, there's a quote I really love uh from this poet to Sharey about uh loves having the kind of many faces like waves of an ocean. And I think that's quite a good analogy. You know, we all know what a wave looks like, even though waves are all quite different. Um, and I think love is kind of like that. And so we're thinking about love and we're focused primarily on romantic love. So for those of you who are kind of tuning in to hear about loving asparagus, uh time to tune out now. The rest of us will stick with it and talk about romance. So when we're talking about romance, what we're really talking about is this idea of uh deep individual one-on-one relations. And clearly, one of the interesting things about romantic love is it is very different for all of us, right? There are people out there who fall in love with one person for their entire life, and that's it. There are people who fall in and out of love like it's changing days of the week. There are people who love multiple people or individual people and all sorts of uh variations. And that I think in its own right is fascinating. So it's quite tricky to think about things that are common to all of those settings. Um, but there are a few, and uh, we'll start off with a bit of classical art here. So this is uh Renoir with his uh lovers uh portrait, and what you see here um in uh kind of impressionist style is the first symptom of love, which is this idea of infatuation. I have to say, in this particular picture, he looks pretty infatuated. She doesn't look quite so convinced, does she? Um she's also a slightly worrying colour, I think. Uh, but never mind. That notwithstanding, he is clearly infatuated. And he is demonstrating a classical hallmark of romantic love. Uh deep focus, hyper intensity, it's often referred to, a deep focus on one thing, often to the exclusion of other things. So, people, many of you in this room, may have had that experience when you have eyes for only one person, despite the fact the room is full. Um, and you know, I well remember being a teenager and you'd all go to a party, you think, what happened to Fred? Fred appears to be lost, you know, somewhere in the corner to the rest of us, because they've become hyper-intensely focused on one individual. It's also demonstrating, I think, this idea of infatuation, which is a classical hallmark of early romantic love. The idea that you become obsessed with an individual, uh, often beyond what is reasonably logically explicable. Okay. Um, and so one of the ways that uh psychologists define love is when people do things that are uh beyond their normal behavior in order to spend time with a particular individual. And many of us will have experienced that. Uh, I don't know, the idea of walking for hours to go and see your partner or do some kind of elaborate public transport arrangement when you were 16 to see a girlfriend or boyfriend who you then broke up with three days later. Um, this idea of going beyond the measures you would take for any other relationship in order to spend time or to see this person. And often it may, of course, not even be to physically see them, telephone calls, zoom calls, whatever those kind of things. So this idea of infatuation and obsession uh is part of the kind of normal romantic process. There are also very, very interesting physiological consequences of falling in love. And if you think back, um perhaps many of you in the room are passionately in love right at the moment. And for those of us who are a bit longer in the tooth and maybe our early passionate romance is not quite still with us, uh, we can still hopefully remember those times of an early relationship where you had strong physiological consequences. So, for example, you might break out in the sweat. You know, you're about to go and see it's date number two, you're about to go and call on the prospective girlfriend, boyfriend, whatever, um, and you're like, oh, my hands are a bit clammy. You know, that's the last thing he or she's gonna feel. You're kind of frantically trying to get rid of the sweat. Uh you're sweaty. Uh the one, of course, that everyone talks about is your cardiovascular effect, right? Your heart rate picks up, your blood pressure rises. Often before you've even seen them, right? Your cot, the concept of I'm going to see them makes your heart skip a beat, as musicians and poets uh talk about. Um, and that is a physiological consequence. It is not under our control, right? I'm sure many of us have had that experience where you're, you know, you're trying to act cool on your first date, and actually your heart is racing and you're sweaty and all these kinds of things. You can't control that. It's happening without your uh your mental process deliberately constraining it. And third part about all this is of course, often we exhibit this, we exhibit anxiety. We're very nervous. And actually, one of the hallmarks earlier on in romance is uh a real roller coaster of this anxiety. Uh, people become very, very anxious, you know, and then you're in the date and you're much more relaxed. And then as soon as your date is finished, you're anxious again. Like, are they with somebody else? Do they actually like me? Will I see them again? Um, and so this kind of roller coaster of emotion is very characteristic and it changes over the course of a romantic uh relationship. So, to a first approximation, romance is essentially all in the brain, it's all about the brain doing things, many things that it does without us really having any control over there. It happens spontaneously. It's interesting because it happens spontaneously, but not all of a sudden. So, for most, I mean there are cases where people genuinely bolt from the blue, you know, Cupid's arrow, and that's it. I think for most of us, that's not quite how it works. Most of us don't see somebody on the bus and that's it, you know, you're committed forever. Um, but uh within a relatively short period of time, you might see somebody on the bus, you start chatting, and actually within hours, days, you you enter this state of being very, very passionately attracted to them. Um, and then over time that process changes. And so there is something happening in your brain that is not entirely under your control, that develops relatively slowly, uh, but you can do very little about. And one of the interesting things I think about this is that we think of romance as being very much uh a personal thing. We have strong feelings for somebody, etc. But actually, it's deeply hardwired inside the brain. And in particular, uh, it involves a very ancestral part of the brain called the hypothalamic pituitary adrenal axis, which is quite a mouthful HPA axis. And this is a very well-established uh kind of hormonal uh neurological response pathway that we have to control primarily stressful situations. So the hypothalamus and pituitary are up here in the brain system. You can see the arrow up here, they're right in the depth of the brain. Um and they are to do with controlling your immediate reactive stress responses. And they signal to the adrenal glands on the kidneys to regulate hormonal release to primarily regulate your immediate response to stressful situations. So uh, for example, uh, you know, big scary predator, uh, burglar breaking in, all these kind of things involves the HPA axis. But so does romance. And we know that when people uh start to enter this period of intense romantic attraction, the HPA axis becomes very active and you start to produce a large number of hormones that we also see uh during stress situations. And so this explains, in some ways, many of the effects we see during romantic uh love. So, for instance, I mentioned earlier this idea of hyper attention, hyper-vigilance. You've only got eyes for one person. If you think about it, that's also the process that happens if you're sound asleep in the night and there's a sudden bang, you're immediately bolt upright in bed, you're hyper-focused, right? What was that noise? Was it the cat? Was it a burglar? Because your entire body is tuned to this one event. And so, in some senses, the response we have to a romantic partner is like the response we have to an acute stressor. And similarly to that, we therefore also see that during early phase romantic love, we get a big increase in many of the hallmarks of stress, in particular, this molecule you see up here called cortisol. So, cortisol is a stress-responsive signal that the body uses in response to a whole variety of stresses. If you measure cortisol in people who have recently started uh seeing somebody romantically, what you see is that it fluctuates wildly, much more than in those of us who are in slightly more boring romantic relationships. Um, it goes up and down wildly because it's correlating with this idea of anxiety and then reassurance. And so, for instance, you know, immediately before a date, your cortisol flies through the roof because you're thinking, I'm gonna turn up and they don't like me, I don't like them, or it's all gonna be awkward. In the moment when everything is going smoothly and you're romantically intertwined, your cortisol drops, you're very, very calm because this is all going to go well, and then of course it finishes and off you go again with the high cortisol. So you have these cycles of uh stress. And if you think back to it, actually, this kind of idea of early romance is quite stressful, right? That often has consequences that we associate with other long-term sort of stress disorders. So, for instance, people often lose appetite during early romance, as they do when they're depressed. Um, they often uh neglect themselves or others or friendships. Um, they do things that are maybe not very wise, like, you know, for instance, skip school to go and see a new partner, um, because they are responding as if they're in this acute stressed phase rather than in a much more logical, rational thing. So for those of you who are about to embark on new romance, be warned, it's a very dangerous process. Um the other thing, the other thing that happens in the brain, which is very interesting during this romantic process, is that it needs to compensate for some of the things you do during romance, which are, in other contexts, a very bad idea. Um, and so what we see during uh early romance is a change in activity in this area here called the amygdala. And those of you who've followed some of these earlier lectures in this series, we've talked about the amygdala before. This is a part of the brain that is all to do with regulating fear. So when that bang in the middle of the night happens, I just mentioned, your amygdala lights up. It's driving that fear response. It is a very ancestral part of the brain that is there to protect you, essentially. It lights up and it coordinates rapid responses in response to something that might be a danger. It does that kind of almost unknowingly. So for instance, if I was to suddenly kind of leap at these people in the front row with an axe, I won't do that, I promise, but if I was to leap at you with an axe, your amygdala would signal a response to retreat, to run away, to defend yourself before you have consciously processed what I'm doing. And for this reason, I'm sure we've had all this experience, many of you, something will happen like uh a car will backfire and you're like, and then you'll realize slightly slower, oh, it's just a car backfiring and you'll recover. The reason you do that is because your ear has heard the sound of the backfire, it's recognized as a stress and sent it to the amygdala, which has responded instantly with the stress response before your higher brain functions have kicked in and gone, of course, it's not a gunshot, it's a it's a car backfiring and allow you to recover. That is a really important emotion to protect us from scary things that might eat us or kill us or do other stuff. It's pretty rubbish during romantic relationships. Because if you think about it, we do a whole bunch of things uh during early romance, which are maybe not so wise. Like maybe I'll take a quick straw pole here, maybe I'll pick on these poor people in the front here. So I'll pick on you, so uh early on in romance, what might you do if you've just met a new kind of partner? Keep it clean, we're before the watershed.

Physically.

Yeah, that I'll do physically was fine. Yeah, yeah. And how about with them when you meet them? Yeah. So you're meeting someone for the first date. Do you shake hands?

Oh, yeah. Say hi. Yep, say hi.

Yeah, and if it's going well, say second or third date. I'm gonna talk to this gentleman. Maybe a kiss. There we go. That's one thing you might do, right? Some of us at least might kiss somebody. You might also do this, lady. What might you do?

Uh impress them.

Impress them, yeah, exactly. And if you've kind of been with him for a little while, you might give them a hug, put your arms around them, those kind of things. We do lots of things early on, and actually later on in a relationship, which are tactile, right? You might hold hands, date number one. You might put your arm around each other, you might give them a hug, you might cuddle up on the setting, you might indeed give them a kiss. If you think about those activities, they're actually quite risky, right? Um, especially if you're female, for example, if you're a heterosexual female and your new found potential partner is a large male, evolutionarily speaking, you are putting yourself in considerable jeopardy, right? You are putting yourself alone often with a physically more powerful individual who you don't know very well. Um, and then you are limiting your ability to escape from that individual. You're allowing them to hold your hand, you're cuddling up close. And if you think about when you go in for a kiss, I'm not going to be too graphic here, but you you know, you lean in for a kiss, you are exposing the most vulnerable part of your body, particularly your neck, to somebody who's got teeth and you know, and fingernails and stuff. It's pretty risky, right? Um, and under normal circumstances, I'm pretty sure if I was to lean, I would probably say if I was to lean in for a kiss on any of you in the audience, you would respond quite rightly in a in a kind of you know, responsive fear response. You would run away, you would beat me around the face, whatever, do lots of things which are defending yourself. You're not gonna get very far in your romantic relationship if you do that. And so what you need is a way to turn off that response, and that is what your amygdala does. So normally your amygdala will be firing like crazy when someone comes in for a kiss, but your romantic engagement overrides that. And what we see in people in early romance is a downturn in the activity of the amygdala, deliberately to stop them responding in a fearful way to what would otherwise be a fearful act. That is really useful if you are going to form a relationship with somebody. Of course, is not so useful if that person is inappropriate, if there's a risk there, or indeed uh just in terms of your overall judgment. So by turning down the activity of the amygdala, you're also in some ways reducing your ability to make rational decisions about fearful acts. Um, and this is related to something we'll touch on towards the end of the lecture, this idea of damaging relationships. The fact that your brain is essentially telling you, don't worry about this, even if maybe it should be a bit more worried about this, which is an interesting and kind of challenging dimension, I think, of relationships. Okay, so that's what's happening in your brain. You're in your new relationship, there's all this kind of physiological stuff happening. One of the interesting things I think about the physiological part is because it's an so-called autonomic response, it's out of your control, has all sorts of interesting correlations. And one that I think we don't often think about is that the autonomic response that regulates things like blood pressure and sweating also regulates your gut axis. Um, and so one of the things that happens during early romance is you'll change your peristaltic movements, or the rate at which your gut is contracting and moving food. And this is one of the reasons that we have that symptom that people often talk about butterflies in your stomach, right? Early on. Um, you're about to go and see someone, you think, well, I've got real butterfly, I can't possibly eat anything. That's partly because you're nervous. It's also partly because your autonomic nervous system is telling your gut to go wild and you don't feel like eating because your peristaltic movements have gone all over the place. And it's also, for some unfortunate individuals, the reason why they get a bit of diarrhea when they're about to see a new date, which is not an ideal combination. Um, so uh so these are all things that are kind of happening in the brain. There is an interesting point here though that I think many of us will experience, which is this doesn't last forever, right? Most of us, even those of us in very happy, long-lasting relationships, don't spend every day of our lives clammy-handed, high blood pressure, counting down the minutes until we see our partner. There is a transition in a relationship from early relationship to later, which somehow shifts that. And at face value, that's a bit weird, right? The person is the same, you're the same. Um, uh, why have we changed that kind of uh uh that kind of relationship, that kind of experience? What's quite interesting is that it's surprisingly consistent between people. So for most people, their romance starts out with this phase here, okay? So you are infatuated, you are making over sometimes this, as we see here, this kind of inequality, one of these more infatuation than the other, you need to do a bit of hard work to convince them. But you go through this process of infatuation. If you're lucky, that infatuation becomes reciprocated, and you go through a period of intense, one-on-one, usually, although not exclusively, one-on-one eyes only for each other relationship. This period in which is typically characterized by lots of physical contact, kissing, cuddling, whatever, um, lots of obsession with each other. Can I see that person tomorrow? Can I say, oh, I haven't seen her for three hours? Help. Um, this kind of idea of very, very uh illogical obsession. And then it dwindles, and it dwindles for most people between 12 to 18 months in. So if anyone's on a if anyone's on month 18 of a new relationship, good luck. This is your moment. Um it's about 12 to 18 months. Uh for most people, the average time for this period to last is about 12 to 18 months. For some people, it goes on for about three years, uh, which is either lucky or unlucky, depending on your definition. Very, very few people still experience that beyond three years. Uh, a small number do. Um, and actually, psychologists are very interested in these people who have what they call prolonged love. Um, and so there's been some interesting studies looking at people, for instance, who still claim to have this kind of clammy, hands, passionate 10 years into a relationship about what it is that's different about those people to the rest of us. But for most of us, by certainly by year three of a relationship, you're not having the same level. And the hallmark of that is that idea of infatuation, which has gone. Most people in the first 12 months of a relationship can tell you when did I last see them? How long do I next see them, sometimes to the minute. Um, and they are very obsessed by that. For instance, you know, month nine of a relationship, you're going to go and see your new girlfriend, boyfriend, whatever, and then the flight is cancelled, you're pretty devastated. By year nine of a relationship, most people get over that and they're like, that's a bit inconvenient, but I'll book a new flight and see you a day later. And that shift between obsessive focus and a much more kind of sustainable thing is the kind of hallmark of the transition of the relationship. At that point, between 18 months and three years in for most of us, is crunch moment. Either that's it, you realize that you're infatuated, it's not the person you want to be with forever, and it all breaks up. And for that reason, many relationships crumble at a bit about a year and a half to three years in duration, or you enter the phase that many of us are lucky to be in, this idea of long-term stable romantic love. Really important, but physiologically different. Okay. That long-term relationship is marked not so much by elevated blood pressure and clammy hands, but by feelings of comfort, of mutual support. If you ask people who are in relationships that are long within three years, they tend to value things like companionship, shared interests, um, uh reciprocal uh welfare. So the idea that I'm poorly, they're looking after me, vice versa, those kind of things. If you ask someone who's three months into a relationship, they don't talk about that at all. They talk about, you know, oh, they make my heart skip a beat. I love spending time, they're a great kisser, whatever it is. Um they're different, they're qualitatively different. Um that is quite an interesting process in terms of mapping out the way the kind of brain changes. And one of the things that uh is there's quite a lot of focus on at the moment is how this then changes in light of changes in your brain as you age, and particularly a big focus at the moment around uh people who are older, for example, uh who might have neurodegenerative conditions, dementia, et cetera, et cetera, where often brain patterns change, and and very sadly for them, this is one of the things which is often Affected. And you you quite often hear of couples where one couple has dementia and the other person says, I feel they no longer love me. Or uh or sometimes actually you can have uh unusual behaviors where people fixate on somebody else, and that can be very, very distressing. You know, you've lived with someone for 40 years and suddenly they're falling in love with a neighbour. Um, uh so these kind of uh transitions are something that I think there's a lot of interest in at the moment. Okay, so love is physiological, it changes over time, uh, but there is a really big question here, which is still essentially unanswered, which is why does it exist in the first place? And if you think about this from an evolutionary biology perspective, it makes absolutely no sense at all, right? If you look out there in the world, the vast majority of animals, as far as we know, difficult to tell, but the vast majority of animals don't fall in love. Okay, if I go into my garden, I don't genuinely think that that butterfly is falling in love with that other butterfly there. I think that tomorrow, you know, they will part ways. It's a transient process at best, and it probably doesn't last for most animals. A few non-human animals do show long-term stable relationships, but most do not, okay? So patiently you don't need to fall in love to reproduce, and reproduction is essentially the currency of evolution, right? A successful species is one that reproduces. In fact, you could argue that love is counterproductive for evolutionary success, because it at face value, somebody who falls in love with one person for the rest of their life is probably going to have less reproductive success than somebody who plays fast and loose between lots of partners over a period of time, right? And we can all think of examples of that. And so you might expect over evolutionary time that people who fall in love should have been selected against, and the world should be full of sort of Lotharios who kind of skip from person to person very swiftly to reproduce maximum. But it's patently not, at least not for humans. Most humans, there are some exceptions, most humans don't behave like that. And so, why therefore does love exist at all? And when faced with an evolutionary problem, uh clearly the first base that one should always go to is to uh the father of all evolutionary problems, uh Charles Darwin. Disappointingly, on this particular question, Darwin didn't have much to say. In fact, the only, or the perhaps the most famous quote that Darwin had on love is not really related to this kind of love at all. He talks about the love for all living creatures, which is not quite what we're talking about today. I also, much as I love Darwin, I have to dispute, I'm not sure this is entirely correct. Um, if you walk down the meat aisle of your average supermarket, I would question whether most people have love for all living creatures, unless you mean love for them when they turn into a fillet steak. Uh, but nonetheless, um, he doesn't talk much about kind of romantic love in any of his books. Interestingly, as a bit of a side, he did talk about it a bit in his personal diaries, and I love this, and I will do a quick digression because it's just so much fun. So, in his diaries, um, particularly in 1838, young Darwin was musing on love or at least on marriage. Um, and like all good students at the time, as we tell our students now, if you're faced with a difficult decision, you write a list of pros and a list of cons and you work out what you're gonna do. And that is what Darwin did. Um, so he, as you can see here in his diary, this question of to marry or not to marry. And indeed, he puts it in the middle, this is the question. Um, and he lists here, it's difficult to read his writer's list here, all the pros and the cons about marriage. There's some of them I really like. Um, not sure if you can read this on the on the part up here. Marriage, one of the things it says is uh a wife would be a constant companion, brackets better than a dog, anyhow. Um uh I leave you to be the judge of that. Um, and uh one of the things I particularly like, as I guess the young man on the brink of, you know, the world is in front of him, and he says, uh, if I don't marry, I can travel. Yippee. If I do marry, I love this. If I do marry, I'm going to have to work for money. Disappointing. Uh bearing in mind this person comes from a relatively wealthy family. So presumably there was no need to actually work for money if it was just him. But if he's going to support a wife and kids, he needs to go out and work. So he's a bit, you know, mmm, about this, not entirely sure about this. Um, uh, but in the end, he comes down well and truly on the side of marriage. And he does it for an interesting reason, actually. He says, it is intolerable to think of spending one's life alone like a neuter bee and like a worker bee, just working with. No, no, no, it won't do. I this bit which does not wear well over time, but never mind, stick with me. Um, a nice soft wife, never mind, uh, on a sofa with a good fire. And so, what's quite interesting about this, I think, is that Darwin is highlighting here not the first bit that we've been talking about, right? He's not talking about the passionate embrace of romance, the kissing or any of this kind of stuff. He's talking about that later phase, this idea of companionship and support, which is quite telling, I think, and quite interesting, and of course, symptomatic of the time. So, Darwin doesn't really have the answer uh to romance, but but it has it is something that people have thought about intensely for the 150 plus years uh since then. Um, and ultimately, I think we have no real answer, but ultimately, psychologists generally come in together with the idea that this, although this is not directly related to producing lots and lots and lots of babies, because actually romance might not be helpful for that, it is about reproductive success in the long game. And it's probably like that for a number of reasons. One reason is that in humans, as in some other animals, but many not, we have this process of so-called concealed ovulation. So, in many animals, if you think about it, it is very apparent, especially if you're an animal of the same species, when the female of the species is ready to conceive. Okay, so if you think about baboons, baboons have this pink bottom. The pink bottom becomes very extended, very large when they're when they're ready to receive, when they're ovulating, when they're ready to reproduce. It's a visible signal of fertility. That is generally the norm in many animals. They have a very visible system. It may be physically visible, it may be, for example, like dogs, so female dog that's on heat. Uh, you can't physically see it, but they release uh you know odors that are immensely attractive to male dogs in the vicinity. There are ways to signal it. Humans don't do that. We have evolved this idea of concealed ovulation. You can't tell whether a woman is receptive, pregnant, etc. early on. Um, you don't know whether she's able to conceive or not. And so one of the ideas for that is that as a female, it's a way of keeping partner interest, even if actually that's not true. So, for example, the last thing you want, if you think back evolutionarily, is for some guy to come along, impregnate you, and disappear forever. You want is to be around, to provide food, to provide support, to protect against predators, all those kind of things. And so concealed ovulation is a way of doing that. It requires a longer commitment from a partner because they have to hang around with it and know if you're ovulating or not. And so the idea is that romance is a way to achieve that. If they stay interested for longer, it's a way to keep the partner around for longer. That's one idea. A second idea, which I uh particularly like is that early romance, as we've been talking about, is characterized by the suspension of logic, right? So the amygdala shuts down more, we're not fearful of stuff we should be afraid of. We become obsessively interested even if it's not in our interests. Um, and this idea of uh suspending rationality, and one idea that's been put forward by evolutionary psychologists is that this is a prerequisite to having children. And those of us who have children may agree with that. Yeah, you don't rationally have children because they cost you a lot of money, a lot of effort, they're very stressful. Um, there are lots of reasons why, on an individual basis, it's a bad idea to have children. Um, and and so one idea is that romantic love helps suspend that otherwise logical decision long enough for you to have children, by which point it's too late you've got them, and your rationality kicks back in at 3 a.m. and you think, oh gosh. Um but that idea of suspending rationality is part of it. So those are two ideas. But perhaps the dominant idea around why we hate romance is based on this idea of attachment theory. An attachment theory essentially says human children are extremely vulnerable for an extremely long period of time. So there's quite a lot of data, for example, from um uh underdeveloped societies, cultures, uh, where about how old a child has to be to survive on its own. And generally, it varies obviously as you'd imagine in different parts of the world, but generally speaking, there are not any good records of children surviving alone with no support under the age of about seven or eight. Okay. Um so there are quite good cases of, for example, individual children in uh the Amazon who have become detached from their tribe surviving on berries and nuts and things long enough uh to reach adulthood from the age of about seven or eight, but before that age, not really. So we are dependent on care for a number of years. If you're going to have that as your mode of growing up, you need to have other individuals, adult individuals who will look after you, right? So you need to engender that. So as a baby, you need to somehow bond with usually your parents or other adults so that they will look after you. So you need them to invest in you. Okay, and this is one of the reasons why all of us, even those people without children, react very strongly to things like the sound of an infant crying or the sight of their eyes or people cry, you know, just generally crying. We are very responsive because we are programmed to care for small children. And actually, as they get bigger, you get less and less bothered. You know, teenagers crying don't bother us as much as uh three-year-olds, for instance. This is the idea of attachment theory. So we are attached to small things because they require that to reach survival. And and one of the ideas around uh romantic love between adults is that it is a sort of inevitable consequence of attachment theory. We are programmed to bond very tightly to small children. And the idea is that when you uh interact romantically with an adult, you are using exactly the same set of skills. And if you think about that, in one hand it's slightly creepy, um, but if you think about it very analytically, there are many, many similarities, right? So when a baby comes, the first thing that people do with babies is pick them up, couple of them, lots of physical contact, right? Which you also do with a new partner if you're lucky. Um, we kiss babies all the time. And and you know, and we kiss partners quite a lot, most cultures. Um one of the most interesting things I think has been quite an interesting analysis of our use of language, which is distressingly similar when we talk to babies and when we talk to new partners. And so, for example, the use of what's called baby talk is common in both settings. So with a baby, we might say, Oh, but a koochie koochie koo, or you know, oh, and you're such a cutie pie. Most of us don't use that completely in the same way with partners, but we do often use things like pet names. Um, uh, you're, you know, you make kind of cooing noises, and it's all quite embarrassing when you think about it in the light of day. But it's true, right? I think I can see lots of nodding in the audience. We do things that actually you wouldn't do with other adults. You wouldn't, you know, call your boss my cutie pie, um, hopefully. Uh but but you might well call your new partner that. Um, and you might call a baby the same thing. And so there's kind of a lot of similarities there. So that similarity between how we deal with babies and how we deal with romantic partners turns out to be mirrored also in our brains. And so there's been a very interesting study when MRI study looking at areas of the brain that are activated during maternal love, so the love of a mother for the child, and romantic love, the same person looking at their romantic partner. Um, and there are areas that are different, but there are actually quite a lot of overlapping areas that are triggered in the same way in both. And so that's relatively good support, I would say, for this idea that they're not completely the same, but there is a conserved set of neurological pathways that are to do with love for a child and love for a partner, which is actually intuitively something we kind of experience. They're not the same, but they are related. What turns out to be very interesting about this is if you look at those brain areas that light up during this process of um both maternal and romantic love, they are areas of the brain that are very high in receptors for two uh hormones in particular: vasopressin, which is this one over here, and oxytocin over here on this side. Those areas of the brain are highly responsive to those particular hormones. And why is that interesting? That's interesting because these hormones are particularly associated with the process of having children. In particular, we know that oxytocin, about which we know more, I guess. Oxytocin has a really key role in the process of uh of women giving birth and looking after very, very young babies. So, for example, oxytocin levels rise very dramatically during contraction. So when you're giving birth, the physical contractions drive oxytocin uh production. They are critical for lactation and they respond strongly to lactation. So oxytocin is what helps signal the first milk fall when you're going to breastfeed. And if you're breastfeeding, the physical act of feeding releases more oxytocin in your brain. Um, and actually, it's one of the interesting things there's been interesting studies about people with eating things like smelling babies' heads, uh, which can trigger a release of oxytocin. So this appears to be a hormone that is signalling this is a baby and he's looking after, I need to bomb with it. And because of that, there's been a lot of studies on this uh hormone, and in fact, it's remarkably powerful in some animals. So, for instance, if you remove oxytocin from mice genetically, those mice will conceive pups no problem at all, they'll give birth, pups no problem at all, and then they will completely neglect them. They will not feed those pups and the pups will die. Um, so oxytocin is really critical in mice for the maternal care of their pups. In sheep, uh, so people might be familiar with that you have sheep, uh, bond with their lambs, and often it's a problem with yeah, for farmers, if your if your ew has died, getting another ew to accept this lamb can be difficult because they have bonded tightly with their own lamb, not so much with other lambs. If you inject a sheep with oxytocin, whilst you present a foreign lamb to it, it will bond immediately and it will take that lamb as if it's its own. Uh so there's a strong role for this hormone in bonding uh mothers with their children or indeed uh you know other animals with their with their offspring. Why am I telling you this in a lecture about romantic lab? Well, it turns out that this is also related, we think, to the process that happens during romance, at least in some animals. Um and this, let me introduce this very key animal here. This is the prairie vole, um, uh small rodent in North America, and people have spent a lot of time studying prairie voles. I think it's one of the things that, you know, for people who are perhaps not biologists, the idea that there's a romance lab focused on prairie voles is slightly weird. Um, but it's incredibly telling. Why are we interested in prairie voles? We're interested in prairie voles because these, very unusually for rodents, pair for life. In fact, it's really quite sad. So not only do they pair for life, but if Mrs. Prairie Vole dies, Mr. Prairie Vole doesn't marry again. He stays on his own and pies away, um, uh, which is which is quite sad, uh, a very Shakespearean, um, but quite interesting and very unusual. Other vole species don't do this. So uh, so for example, our European vole down here, or indeed the montane vole, which is the closest related species in North America to the prairie vole. They, you know, love them and leave them. They have lots of relationships. Uh, if Mrs. Vole dies, bad luck, there's another Mrs. Vole coming around the corner. Um, uh, they are fast and loose voles. These are very closely genetically related species, and so that allows you to say, well, what is it therefore that's different? What is it that's driven this apparent romantic commitment of the prairie vole versus the kind of you know, um love them and leave them approach of the other voles? Um, and it turns out that one of the strongest differences is this molecule oxytocin. All of them have oxytocin, but the receptor density in the brain for oxytocin is much, much higher in the prairie vole than in these other species. And what is particularly interesting is it is highly enriched, specifically in the area of the brain that we know from other studies to be associated with addiction. They have a lot of oxytocin in the addiction area, the area that drives reward. So it's this area of the brain that lights up, for example, when a prairie vole eats, it's the area of the brain that says, good stuff, keep eating, good for you. Um, and so the oxytocin receptor is there in this part of the brain that's do it that's driving uh reward. Um you can manipulate that in prairie rolls. So if you increase the amount of oxytocin they have, then they spend more time doing what's called huddling, it's quite what you see here. This idea of just bonding with each other, it's the equivalent of kind of cuddling up in front of a Friday night film on the safer, I think. Um if you uh inject prairie rolls, it's a bit unfortunate, inject prairie rolls at oxytocin and then present them with a new partner, they will bond with that partner and mate for life. Um, and depressingly, if you remove oxytocin, they fall out of love and divorce, um, uh, which is all which is all quite telling, really. So there is this idea that oxytocin is therefore driving this kind of romantic behavior, the prairie vole. There is a caveat, you can completely remove oxytocin genetically from prairie voles, and they will still form partnerships and mate. So it's not completely required, but it does seem to modulate their kind of romantic behaviour. So, prairie vole's romance all about oxytocin. We have oxytocin, uh, therefore, clearly, this must be the answer to all human romance, and understandably, people have spent a lot of time uh investigating this. And there have been some fabulous studies which I really like. Um, uh, all of which essentially say this is not the whole story in humans, which is maybe kind of reassuring for those of us who like to think we're not complete robots. Um, so there's been a great study uh which I really like of uh a few years ago, where people were exposed either to oxytocin or a placebo, so uh they didn't know which they got. And then they were introduced to new people online uh via Zoom or Teams or something. Um and then after that, they were asked, uh, you know, when you would you like to see this person again? Um uh they asked specific questions, would you like to see them again? Did you want to find out more about their life after this introduction? And would you like to take them on a date? Um, and what turns out to be very interesting is that people exposed to oxytocin did want to see them again and they did want to hear more about them, but they were no more likely to want to take them on a date. And interestingly, they were equally interested in partners of both sexes, regardless of whether they were heterosexual, homosexual, or anything else. And so there was no sign that oxytocin was driving romantic interest in these other people, it was just driving interest generally. They were interested in people in a to a higher degree when they're exposed to oxytocin. So that's one study. Um, and then this is this is possibly my favorite one. Um, there was a great study where people were again exposed to oxytocin or not, uh, or a placebo, um, and then introduced to uh people who were picked to be either of the opposite sex if they were heterosexual or of the same sex if they're homosexual, so potential partners, right? And then, unbeknown to the participants in this study, they were filmed and their distance was measured, how close they were to the person they'd met. Uh, with the theory being if oxytocin encourages romantic association, they will stand closer to each other than if they did not have a city oxytocin. And in fact, uh the reality was precisely the opposite. So you give people oxytocin, they stand slightly further. Only 15 centimeters. There's not a really big difference, um, but enough of a difference to be statistically significant that people exposed to oxygen, rather than bonding closer, just keep a bit more distance. And more recently, an interesting study looking at people's uh relative attraction to strangers, a kind of yoinder for biologists approach, um, looking at whether people think, yes, this person's attractive or not on a random set of photos, and exposing people to elkistocin before that test, on average decreases their attractiveness rating of other people. So a whiff of oxytocin is less likely to make you go on a date rather than more likely. So that all sounds kind of counterintuitive, unless you think of oxygen not as being an initiator of a romance, but a perpetuator of it, in which case this all makes perfect sense. So maybe the role of oxytocin is not to say time to find a new partner, but rather the opposite, time to stick with your partner and stay close to them because this is a long-standing relationship. Hence the prairie role and its very long uh association of romance and indeed possibly humans. So the idea is that oxytocin is actually driving us to stay true to our partners in romantic relationship because that's their best outcome for our stable uh kind of you know offspring potential. I think there's a lot to like in that biological um argument. It clearly has not filtered through, I should point out, uh, to the cosmetic industry. Because if you go online, you can buy a vast array of perfumes laced with oxygen at a very considerable expense. Um, most of which advertise like this one up here, uh, about I love this one, but yeah, irresistible scent enhances seduction. Look out, people. Um, unfortunately, no scientific basis. In fact, the opposite, but I guess it doesn't sell perfumes today. Great perfume for keeping your husband at home. Um, uh, so, but you know, so for those of you who are in a stable relationship and a bit worried about the partner, maybe you should invest. Uh, for those of you who are looking for a new date, I would not go down that way. Okay, so let's finally think a little bit then about this idea about uh love and the brain uh kind of effect of it and this concept of addiction. We mentioned earlier that the the areas of the brain, the prairie vole that are activated are ones that are all about uh reward and addiction. And actually, that is alarmingly similar in humans too. In fact, many musicians, of course, have talked about us being addicted to love. And it turns out that is not entirely inaccurate. So if you look at the activity of the brain during early romantic love, we've talked about the HPA axis and this downregulation of the amygdala. But one of the other areas of the brain that is strongly activated during uh romantic love is this uh area called the ventral tegmental area in the brainstem, which you can see here, the VTA. This is an interesting area of the brain because it is incredibly evolutionary ancient. So lots of organisms have this going back a long time in evolution. It's thought to be a very early part of the brain as opposed to the higher cortex areas that have evolved much later and give us kind of higher order capacity to think. This area, the VTA, is particularly involved in uh reward craving motivation. So it's an area of the brain that, for example, lights up when you're hungry, it makes you seek food. It is rewarding us when we do something that is good for our survival. Okay. And it lights up also during romantic love. And that is quite interesting because it leaves this idea that during romantic love, you are stimulating a part of the brain associated with a reward that can go wrong sometimes. And so this part of the brain and this complex set of hormones that we talked about, so vasopressin, oxtocin, and this stress hormone cortisol, are all also produced during generally negative addictions. So opiate addiction, for example, also addictions to behaviors, repetitive behaviors, these kind of things. People who suffer from addiction show very similar patterns to people who are in early romantic love. Their VTA lights up in the brain, they're producing this panoply of hormones in a similar sort of way. Leading this idea that in many ways early romance is an addiction. You're becoming addicted to a person that has evolved for good reasons. Early on, you need an inverted commas that addiction because you need to be demonstrating your suitability as a partner. You need to be going the extra mile to see them on Friday night. You need to be buying them flowers, you need to be doing all these kinds of things to demonstrate you are committed, like an addiction. Longer term, of course, it can be quite damaging, just like all addictions. And in particular, it can be very damaging, of course, in relationships where there is a big power dynamic going on, abusive relationships, places where you are addicted for all the wrong reasons to all an inappropriate person. Damaging addictive relationships are a huge burden on society and of course on individuals. And so there's a lot of interest in whether we can do anything to resolve those beyond the normal kind of social measures. And there's an interest in whether biologically we could potentially intervene or help people intervene for themselves to escape from addictive relationships. And the sort of kind of good news and bad news here, I think. There is quite a lot of evidence that that addictive relationship, romantic relationship, can be treated in the same way with same psychotherapies that we use for other sorts of addictions. In particular, cognitive behavioral therapy that's used with relative success in many other addictions shows some signs of promise in treating, for want of a better word, people who are stuck in abusive relationships, or indeed people who still have addictive, obsessive thoughts about partners who might have dumped them long ago, for example, or might have died. This idea of treating people's persistent addiction in a way that is unhelpful, but in the same way that we might treat an addiction for uh, you know, drugs or alcohol or something else. There's obviously a lot of interest, uh, not least from people who are stuck in these situations, about whether whether you might be able to kind of pop a pill and solve the problem. Unfortunately, the news there is less good. There is a bit of evidence that you can intervene in the dopamine cascade. So this is part of the brain's cascade for reward with drugs like naltrexone, which you can see up here, uh, that are used to treat dopamine deficiencies in in some patients. Um, there's an idea that you could intervene that those do dampen your reward circuits. So, in some senses, they may help with the addiction, but no real data they will help in this particular case. So I would definitely caution against that. Um, and one of the areas where uh there's been quite a lot of interest, but it kind of cuts both ways, is this idea of um uh selective serotonin reuptake inhibitors, SSRI. So this is like Prozac, for example, very widely used for uh you know treatment of depression and other uh neural disorders. They show quite good prowess in treating obsession, anxiety, some of those things we talked about early on in romance, these kind of behaviors associated uh with romance. Uh no evidence they specifically address the idea of being locked in abusive relationships. And of course, the big downside to these is they usually also really mess with your libido, which is not ideal if you're trying to intervene in a romantic uh relationship. So I think the prospects of a kind of drug to deal with damaging relationships, pretty slender. The prospects of psychotherapy helping may be much better. So on that slightly negative note, um, let me just draw to a close, but with one last parting thought. I we've spent quite a lot of this evening talking about all the kind of slightly downsides. I'm not sure that we want to go away thinking kind of romance is all about horrible addiction and sweaty palms and you know things going horribly wrong. There is an upside to romance. And the upside is uh if you're in a romantic relationship, you're gonna live longer on average. Um uh we can't really measure romance, it's quite difficult to measure uh objectively, but as a proxy measure, you can marry, you can measure marriage, assuming hopefully that most people who get married were at least one point romantically involved with each other. Um, and it turns out that if you get married, your chance of survival is just way better than people who don't get married. On all sorts of measures, you're less likely to die of a heart attack, uh, you do better on cancer prognosis, your blood pressure is better, all these kind of things. So there is some good news here that um if you are questioning whether you should embark on any kind of romantic liaison, this is the moment I would suggest go for it, give it a whirl, um, have a little bit of romance and hopefully live a lot longer. Thank you very much.