FIVE TEENAGE GIRLS are sitting on the tube in London, late afternoon, freshly changed out of school uniforms. Three of them are whispering and hooting, their arms and legs splayed over seats and each other’s laps, as physically close to one another as possible. The remaining two sit across the aisle, one pulling the other’s hair into a long plait down her back. This amateur hair stylist picks up a thick bunch of her friend’s hair, parts it and inspects her scalp — they could be chimps in that moment, one picking the nits out of the other’s hair while David Attenborough narrates from the sidelines in head-to-toe khaki. I observe this behaviour with a quiet little grin and go back to my book (eye contact on public transport is strictly forbidden in all unwritten codes of appropriate social behaviour — besides which, teenage girls only usually speak to me in public if I’m wearing my 2013 One Direction World Tour T-shirt). But the tableau stays with me — partly because I remember being one of those young girls, physically attached to my friends as though they might simply float away if they weren’t secured. But partly, also, because I’ve been reading about evolutionary psychology and social grooming. Science says that we, like primates and hyenas and prairie voles, develop close relationships through physical contact. So when I see these lovely girls playing with each other’s hair, draped over one another as though they truly couldn’t bear to have the distance of an armrest between them, it occurs to me that they’re right in the middle of some social grooming. They’re bonding in the most primal way we know how: by touching one another. Teenage girls, as it happens, are the perfect example of how we’ve evolved as a species to foster and maintain friendships. They’re very fond of physical contact, they partake in a great volume of gossip and they like to choreograph synchronised dance routines at sleepover parties (more on that in a moment). They’re also perhaps at peak vulnerability when it comes to friendship formation.
Teenage girls evolved from primates, just like the rest of us, only they seem to need the validation of linking arms as they walk between classes more than anyone. Their incarnation of friendship is demonstrative — and heavy on the social grooming. Social grooming is a very popular way for animals of all kinds to make friends, actually. Primates spend inordinate amounts of time licking, nit picking and stroking one another — far more time than required simply for hygiene. Researchers have observed again and again that monkeys and chimps groom one another, both their family members and what we would call friends. There’s plenty of evidence in the animal kingdom that physical touch is an important foundation for kinship, and that certainly translates to human behaviour. Physical touch on our skin releases endorphins, those lovely feel-good rushes we also (allegedly) get from exercise. Touch also triggers the release of the chemical oxytocin, which is colloquially known as ‘the cuddle chemical’, ‘the love hormone’ or ‘the hug hormone’ for its intimacy inducing properties. Oxytocin tends to make us feel relaxed and comfortable, so much so that its production can even make us sleepy. It’s involved in our development of generosity, empathy and as you probably know, orgasm (that last one is less related to friendship, though please see my chapter on whether men and women can ever truly be friends). Oxytocin is a pleasure hormone and its release is linked to our neural reward and social memory systems, which explains why we tend to repeat whatever behaviour produced it. Researchers at the Max Planck Institute in Germany found that chimps who bonded with other chimps using social grooming had higher oxytocin levels than those who did not. It is reasonable to assume there’s a similar reaction in human bodies, and it points to our evolution as a species that enjoys physical touch. Some scientists even call the skin a ‘social organ’ because of how deeply and instantaneously affected we are by touch. Just think about the last time someone you love hugged you when you needed it (if you’re ‘not a hug person’, I can’t help you), or a colleague rested their hand on your shoulder in a gesture of support. It was lovely, no? It communicated things to you wordlessly, things that maybe couldn’t be articulated? Then think about the opposite sort of feeling you get when someone touches you without your consent or desire; how quick you are to feel repulsion and how powerfully it can move you to anger or fear. Our skin is a receptor for emotional communication in many ways, and humans absolutely use physical touch as a way to gauge someone else’s intentions — be they friendship or enmity.
Now, for chimps, social grooming has all sorts of important purposes. It sets the social hierarchy and establishes a power balance between peers because, for instance, chimps are more likely to share food with chimps who’ve groomed them before. Social grooming can be a really effective way to dispel tension after a fight or conflict between chimps, so it can actually affect their chances of survival. We have a lot in common with chimps (DNA, sense of humour, fondness for bananas), but we are also, in many ways, not chimp-like. Perhaps the most obvious way humans digress from chimp behaviour is spoken language. Humans have evolved to speak to one another, and that should go some way to reducing our reliance on physical touch to communicate all our feelings or intentions. We communicate with body language and spoken language, and we use both those things to establish camaraderie. In his book Grooming, Gossip and the Evolution of Language, eminent British anthropologist and evolutionary psychologist Robin Dunbar argues that because language is so important to us, gossip has in some ways replaced grooming as a bonding agent between humans.
We gossip strategically, too, to get close to people who are viable or desirable companions for us. We’re a sophisticated species, what can I say? And that is perhaps why you won’t see as many people at work or school licking their fingers and straightening out someone else’s eyebrow hair. It is also why mothers tend to do exactly that kind of thing to their kids: because grooming is our most primitive gesture of love.
And so, let’s go back to those teenage girls as an example here. The whole ecosystem of adolescence is, for better or worse, built on gossip. Young people trade secrets, spread rumours, tarnish reputations and establish a social hierarchy in whispered or texted exchanges. Do you remember high school? It’s all about trading gossip for social status. Gossip is a vital, and fascinating, form of human currency, used to build people up, tear people down, bring people together and push them apart. There is no faster way to bond with someone new than to share a hatred for a third party or, even better, have something salacious to divulge about them. I have no idea what those girls on the tube were whispering about that day, it could have been anything. But I have been a teenage girl and I remember only too vividly how much your survival at school depended on your gossip capital.
The power of gossip extends into adulthood too, of course; secrets and rumours are equally destructive and unifying in college, university and the office. There’s nothing better than office gossip! Oh, boy. I’ve known entire workplace friendships that exist on nothing else. Adults are just as culpable when it comes to gossiping. But it’s not always sinister. Sometimes, yeah, telling a secret that is not yours to tell can damage another person and certainly spreading lies is dangerous. But simply exchanging social information with someone can be incredibly bonding. Think how great it is to be the one with the goss, how much fun it is to be the one hearing it and how close you feel after the exchange. Gossip doesn’t have to be cruel; it can also just be the exchange of information to do with what someone is doing or wearing, who someone is dating, marrying or shagging, where someone has been seen, employed or propositioned. We build alliances with gossip in a delicate, sometimes ominous way that probably does mirror the way primates use grooming.
It’s not all about gossip, though. I’d go as far as to say any verbal exchange could emulate the evolutionary significance of touch. Kind words, commiserations, whispers of support and whoops of delight are all ways we communicate our intentions of friendship. They affect us in much the same way stroking and petting might calm or endear an animal. And, of course, you can put vast, aching distance between you and another human being in the space of a coolly uttered phrase.
Language is, obviously, an enormous part of our communication as humans. But it ain’t everything. We know now that social grooming is an effective way of forming friendship ties between people, but you know what else is? Dancing. Singing. Anything done in sync with other human beings. If there’s alcohol involved, all the better. There’s something magical about moving and making noise with other people — and it doesn’t matter whether you have the correct pitch or any sense of rhythm at all. It couldn’t matter less, really, whether you’re singing the right lyrics to the Venga Boys or dancing the Macarena technically correctly. The point is that moving in relative unison with other human beings, in close proximity and usually with joy, triggers our endorphin system in the same way as physically touching one another does. If you imagine that each person is wrapped in a string of figurative fairy lights, activities like dancing and singing light them right up. That’s why we dance at weddings, birthday parties and celebrations: not just because it’s tradition and not just because it’s good fun. It’s because these are occasions when we ask for spontaneous friendship between newly introduced strangers and we reinforce the closeness of our existing connections. To return to the teenage girls for a moment, this is precisely why One Direction or Ariana Grande fans are so united as a fan base and so desperate to go to concerts; these are the venues of their social bonding. Shouting lewd or loving things in the general direction of Harry Styles, along with 30,000 other people who agree, creates the most joyous sense of belonging. Strangers become friends, friends become closer. Concerts are friendship festivals with a good soundtrack — teenagers know that better than anyone.
When I was growing up, the single most popular activity at sleepover parties and school camps was spontaneous, earnest choreography. I played Lou Bega in a deeply inappropriate public dance performance of Mambo No. 5 when I was in my first year of high school, and I can still picture the consternation with which we choreographed that dance. There was one girl who was a trained dancer, so she took the lead with choreography and we all threw in a move or two. Presumably my casting as the male singer had something to do with my strong masculine presence at the time (despite my girlish curls, I was always getting cast as men). The act of learning, rehearsing and then performing that ridiculous dance was powerfully bonding for that group of girls. It brought us close to each other, in a way that other getting-to-know-you activities organised by teachers simply didn’t. It set us apart from the other girls in our year, secured our positions in a group of people we were tentatively beginning to call friends. It was not the first time, nor the last, that I used synchronised dance (clumsy, melodramatic, oddly sexual) as a way of bonding with other teenage girls. We did it all the time, and it didn’t even matter whether we ultimately had an audience. This wasn’t about wanting to be seen by outsiders, it was about wanting to be seen by each other. Twelve was probably the age at which this sort of boogie ritual was most popular, and there obviously wasn’t any alcohol involved. Give it a few years and that heady, dreamy state of intoxication only exacerbated a) the need to dance, even if it involved a minimalist approach like gentle swaying or raising your arms in the air and b) the feeling of closeness with your drinking/grooving companions. The disgusting beer I sampled from my stepbrother’s mini fridge circa 14 years old inspired me to sing loudly, dance emphatically and bond with my fellow under-agers in a way we simply wouldn’t have done without the 4.9 per cent alcohol content. That was, of course, just the beginning. As I got older and hit my twenties, drinking, dancing and yelling lyrics at each other in public places became a deeply important social ritual. Of course, for all time, alcohol has facilitated romantic and sexual dalliances. But to me, the more interesting thing is how it initiates and strengthens friendship (or, let’s be honest, has the capacity to destroy it — many a fight goes down on the d-floor).
Perhaps this is why we form so many significant friendships in our teenage years and early adulthood: because it’s probably the most concentrated period of drinking, dancing and singing along to Elton John/The Killers/Destiny’s Child in our lives. It’s also the time, I think, that we naturally have the greatest number of friends. If I could draw the general patterns of my friendships over my life so far on a graph, it’d start off tentatively with my childhood friends, dip when I became inseparable from my first best friend, increase moderately through primary school, jump slightly at high school, spike at university then, happily, settle down a little as I found my true friends in my late-twenties, with little peaks for new work friends along the way. We tend to collect a lot of friends when we’re entering adulthood because we’re still working out who we are and what we want from our companions in life. Having spoken to so many people my age about friendship, I notice a definite trend of shedding friends as we head into our thirties. By this age, our barometers for friendship quality have improved and we’re really starting to fill our lives with things like career goals, romance, marriage, family and financial responsibility, so we tend to close ranks a little as the available slots for friends in our lives become more precious. It is tempting, at different times in our lives and as we establish our own identities, to pick up as many friends as possible. But as we become adults, that ambition for popularity wanes a little and we’re able to make smarter friendship decisions. Then we start arranging friends into a hierarchy, determined by how close we are and how much we value them.
Pleasingly, we can use maths and evolutionary science to work out both the maximum number of friends we should have in our social circles, and how many might be in each league.
Researching friendship in any sort of academic sense will inevitably lead you to the office of evolutionary psychologist Dr Robin Dunbar at Oxford University in the United Kingdom, whose book on gossip as evolutionary strategy we’ve already mentioned. Dunbar is what you’d call the authority on friendship studies. He began his academic career studying evolution but ended up brain-deep in the theory of friendship when he started applying what he’d learnt about primates to human beings. He invented something he rather modestly called ‘Dunbar’s Number’, which is the maximum number of friends and acquaintances one person can realistically keep within their social network. He arrived at the number in the ’80s, when the Machiavellian Intelligence Hypothesis — now known as the Social Brain Hypothesis — had just become popular in anthropological circles. The hypothesis suggested that primates have large brains because they live in socially complex societies, meaning you could theoretically tell the size of a primate’s social group by the size of their brain. Building on this idea, Dunbar did some fancy maths (using the ratio of neocortical volume to total brain volume in the human brain) and arrived at a number. A number that should, according to Dunbar’s hypothesis, be the size of a human’s social group. That number was 150. We have what Dunbar calls ‘cognitive constraints’ that prevent us from maintaining meaningful relationships with any more people than that. That is to say, there are limits to the amount of information our brains can process and retain, which means we are restricted when it comes to the number of people we can assimilate into our social network. It’s directly correlated to the size of our neocortex, which is the most recently evolved part of the cerebral cortex that concerns hearing and sight in mammals. Our brains are simply not capable of having infinite friendships — we have to stop somewhere and evolutionary psychology says that’s at the 150 mark.
Within that 150, there are several groups of friends with whom we have varying levels of intimacy: we typically have five very close friends, 10 close friends, 35 friends and 100 acquaintances. There’s a secret inner layer of 1.5, which is usually your romantic partner (they take so much time and love, they’re worth 1.5 humans — which you’re welcome to tell them, but do credit me for the romance of it). It’s as though we’re given a quota of intimacy that our brains can handle, and we’ve learnt to distribute that intimacy among the people in our lives according to how much we care about them. The way we allocate that intimacy has a lot to do with the sort of people we are. Introverts are more likely to have a smaller group of intense friendships, where extroverts might have a larger group of shallower connections. We might spend a lot of intense time with a few people, a lot of quality time with a couple of people, occasional time with a lot of people, or any variation of the time-to-intimacy ratio. This is what Dunbar would call our ‘social fingerprint’; our own unique pattern of friendship distribution. We may all have this evolutionarily determined group of 150 friends, but the way we treat them is entirely over to us.
Now if, like me, you can’t quite conceive of such an exact friendship system without seeing it applied to your own life, grab a pencil. Map out your own social network by drawing a small circle with your favourite five people in it, surrounded by concentric circles containing your 10, your 35 and finally, your 100. You may include family members, if you wish. Start with the people you’re most likely to call in an emergency or emotional crisis, then fan out until you reach the people whose existence you mainly acknowledge via Facebook on their birthday. You should end up with a scribbly diagram of roughly 150 names in layered circles. We say 150, but it could range from 100 to 200, depending on how open to socialising you are.
When I met with Dunbar, having travelled by train from London to Oxford with a copy of his book How Many Friends Does One Person Need? in my backpack, I told him I couldn’t resist making my own friendship map using Dunbar’s Number.
‘I sat down with a pencil and tried to map out my friends in circles,’ I say, rather proudly.
‘What, both of them?’ Dunbar says in reply, attempting what I can only assume is just one of the friendship-themed jokes he keeps up his sleeve for occasions such as this. We chuckle.
‘Am I mad or can you actually feel the cognitive constraint when you’re doing it?’ I say. And I stand by that — arranging the people in your life into categories of closeness is quite difficult. The most important friendships, the ones you can count on one hand, are easy. I jotted mine down fairly quickly. But it gets harder the further you get from that first layer of intimacy. By the time I got to the final 100 people in my social network, I was struggling to list names and I could have sworn I could feel that strain in my brain. I have an active imagination; I was envisaging those cognitive constraints. I did actually cave and have a cheeky look at my Facebook friends list to remind myself who I might count as an acquaintance. At the end of all that, I did, rather pleasingly, arrive at around 150. Beyond that, I couldn’t think of anyone else I’d comfortably call a friend or acquaintance.
Dunbar tells me the outer limit of our memory is 1,500. That’s the maximum number of names we should be able to put to faces. If you were shown photographs of people you’ve encountered in your life, you should be able to identify 1,500 of them. But facial recognition is hardly a basis for friendship and 1,500 is much bigger than our natural social networks, regardless of how many followers we have on Instagram. What keeps us down at that 150 mark for real connection is partly the cognitive constraint of memory, partly our willingness to invest time in a particular relationship. In what world could you possibly maintain more friendships and acquaintances than that? The quality of a friendship is directly related to how often you see or speak to someone. Friendships are not like relationships with family members, whom you can ignore from time to time because you know you have a biological contract to love one another. They require temporal and emotional commitment, or they simply disintegrate. If you’re not diligent with friends, they drift out of those inner layers of intimacy and end up in that rather cold group of people you once knew.
Sitting in a plump burgundy armchair across from Dunbar, I sigh as I picture the people I used to know spilling out of the acquaintance circle like lemmings over a cliff. It’s a funny thing, the way some friends come into your life and then later vanish from it. There are so many reasons people come and go or move between those layers of intimacy, I almost want to do a second drawing of all the people who no longer belong in my 150 (seems a little bleak, though). As you’ll find out if you try and make your own social network map, it’s a strangely exposing thing to do. The make up of our social circles is a deeply personal thing; you’re literally counting out the people who matter to you. And who are we, really, but a reflection of all the people who sit in those circles?
Dunbar explains to me that the line-up of 5 — 10 — 35 — 100 friends and acquaintances seems to be human nature — whether we’re talking about my personal friends list, or the composition of Indigenous tribes around the world. The humbling reality is that we may live in a hyper-modern world with infinite technological possibilities for connection, but we’re still beholden to our neocortex for the size of our social network. The closer we have to work or live with other human beings, the more likely it is we will reach that number; that’s why nomadic tribes or subsistence villages almost inevitably reach a population of between 100 and 250. Dunbar says it’s ‘almost spooky’ how often the number 150, or thereabouts, pops up. For your reference, 150 is the size of a clan within the world’s remaining hunter-gatherer societies. It’s the size of a Neolithic farming village, a Roman army and a self-governing commune of the Anabaptist sect, the Hutterites. It’s the number of academics typically found in a specialisation at a university. It’s the smallest self-sufficient military unit in any Western armed force. It’s the total number of people Brits send Christmas cards to each year, according to a study Dunbar did in the ’90s. And it’s become the standard number of employees some firms around the world will house in one office, before they build another one (the firm W.L. Gore & Associates was the first business to explicitly use Dunbar’s Number to determine the size of their individual branches). Dunbar’s Number — 150 — is a magic formula for meaningful interaction, whether we’re talking about personal companionship, military strategy or an office population. It seems to be the limit of people we can meaningfully interact with, in any context.
If we’re talking about the number 150 in a friendship context, each of those layers within that number — the 1.5, the 5, the 10, the 35, the 100 — require different levels of intimacy. Obviously, we start with the ‘significant other’ and circle outwards until we reach people we don’t see that often. The people in each of these layers serve different purposes, too: the closest 5 (or 6.5, if you count your romantic partner) are the people you rely on for primary support. They’re the ones you’d ask if you needed to borrow cash or cry on someone’s shoulder; your first line of emotional defence. Once you ripple out to include the next 10, bringing us to a total of 15, that’s more what your social network looks like. It’s called the ‘Sympathy Group’ in your social circle. These are the people you actively seek to hang out with, the people you’d want to see on your birthday. They’re people whose deaths would devastate you. Imagine the sort of mourning you might do if someone died, and you get a pretty clear idea of how much they mean to you now. The Sympathy Group might include friends and family. They’re your people, your important people. The next layer out (made up of 35, which brings us to 50) is . . . well, Dunbar’s not entirely sure, to be honest. The field of evolutionary psychology hasn’t exactly decided what purpose that layer serves — maybe the exchange of slightly more distant intimacies, maybe meeting at the school gate picking up the kids or looking after each other’s children. Maybe they’d get an invitation if you had a particularly big wedding; maybe you’d pay your respects at their funeral. They’re a pleasant lot wedged in between your closest buddies and your acquaintances, on the outer limits of what you might definitively call friends before you get to acquaintance territory.
That final layer (made up of 100, bringing us up to the total of 150) is made up of what we call weak ties. This is usually 75 per cent acquaintances, 25 per cent extended family. The people here are largely useful for information; they form your idea of what’s going on in the world. They’re sources of gossip, the people you like to casually check in on via social media, subjects of salacious interest more than an actual emotional connection. It’s satisfying to know what these people are up to — Did they just get engaged? Where did they get married? Are their kids cute? Who got divorced? Who nailed their dream job? — but there’s not a lot going on between you otherwise. You might actually see them in person once a year, if that, and that’s not really enough to sustain a proper friendship (unless, as we’ll cover later, you’re communicating and swapping secrets online regularly). If you bumped into anyone from the outer limits of your social circle, or happened to be in a foreign city at the same time, you’d probably get a drink and catch up. But there’s probably minimal concerted effort to see each other otherwise.
In his research, Dunbar has analysed a lot of Facebook and Twitter data, looking for evidence of this 150 breakdown. He says it’s all there: if you look at the number of people we communicate with very frequently and span out to the ones we barely interact with, you get roughly the same groupings we’ve been working with so far. We can afford to take our number of acquaintances out to 500 on social media, to include all sorts of transactional friendships like the people we work with, the barista who makes us coffee, the guy we always see on the commute to work, the friend we inexplicably made at that music festival in Berlin one time and never spoke to again. This is casual beer in extenuating circumstances territory, even more so than the people who make it into your 150. If anything, their primary purpose is to prop up our egos, assuring us that we have successfully collected hundreds of people in our lifetimes with whom we have affinity. It’s nice to have a lot of friends — that’s why we prize popularity so highly in our list of desired attributes. The emotional quality of these friendships may be low, but gazing at the number of your Facebook ‘friends’ gives you a pleasant little jolt to the ego. We shouldn’t go as far as to define ourselves or our social value by the number of friends we have; we’re more sophisticated and friendship is more complex than that. But, evolutionarily speaking, that may actually have been why people made friends in the first place.
Scientists and psychologists are, shall we say, perplexed by the very notion of friendship. It doesn’t, at first glance, have an obvious evolutionary purpose. We know a lot about finding kin in the early days of humanity, and how we were motivated to reproduce. We know comparatively little about why we might have sought out connections with non-kin. The prevailing theory is that popularity might protect you in crises or danger. Strategically, the more you can rely on the loyalty and protection of people when you need them, the safer you’ll be. In the early days of human existence, this might have been the people we could count on to defend us in a fight between or within tribes, or even in a showdown with a predator like a tiger. There would have been a contract of loyalty between pairs and groups of people that ensured you would have their back if it was needed and vice versa. For men, that would most likely have been a guarantee of physical back-up. For women, especially when they found themselves trying to make alliances in their partner’s family, it was more of an emotional or social back-up system. This sort of set-up is outlined in a theory called ‘reciprocal altruism’, whereby it’s understood between friends that they will exchange favours. You help me and I’ll help you, that kind of mentality. Evolutionary psychologists thought that was the evolutionary motive for friendship: purely an exchange system between human beings trying to assure their own survival. But that theory is limited and a bit grim, really, and it only accounts for certain types of friendships — the ones where we truly count favours and expect to get out what we put in. Researchers have realised that modern friendship is more complex (and lovelier) than that. Reciprocal altruism can only go so far; after a certain point in a friendship, it becomes irrelevant how many favours one person does for the other. In fact, in a genuine, loving friendship, it’s nice to deliberately lose track of who owes whom what. It’s less materialistic or pedantic than that (in fact, if you have a mate who insists on counting pennies or gestures of friendship between you, I’d suggest reevaluating the friendship).
That brings us to something called The Alliance Hypothesis, as outlined by Peter DeScioli and Robert Kurzban. According to them, friendship is, in part, caused by ‘cognitive mechanisms designed to assemble support groups for potential conflicts’. That’s the physical, moral, social or emotional back-up we can expect to get in fights. Conflicts between people tend to be resolved by counting who or what principle has the most supporters. So it’s logical that having more friends on whom you can rely for a vote of confidence in those situations makes you more powerful. The more friends you can rally to a particular cause, the more valuable you are. In this way, friendship works less like an exchange of altruism and more like alliance politics. Perhaps that’s where friendship began: in the desire to have the most support in times of conflict. Strategically and, in our most primal states, for survival, it makes sense. Now that we are more self-sufficient for survival (or more dependent on things like currency, economics, access and proximity to food, water and shelter, defence, emergency services and medical aid for survival), we have the luxury of defining our friendships by other things: kindness, familiarity, sense of humour, that often inexplicable feeling of just being fond of someone. Sometimes, these days, we choose friends quite against our survival instinct; people who nudge us to smoke or drink or binge eat or escape our responsibilities. We can build our networks of allies however we wish. It’s a modern indulgence, to compile our social circles based on loyalty as much as a sense of fun. That explains why you’ve got your old reliable friends who would do anything for you, as well as those low-key useless ones who make you laugh. But, to me, whatever the friendship is based on, it’s got to have an unspoken level of alliance; the sense that you are in something together.
In an experiment published by William Austin in the Personality and Social Psychology Bulletin in 1980, pairs of people were given a joint task to complete in return for a reward. Some of the pairs were strangers, others were friends. The participants were told their reward for completing the task together would be divided by contribution. That is, the person in each pair who contributed more would get a greater share of the reward. If you were in it for the reward, it would make sense for you to tally up your contribution as you went along so it would be clear what you’d done and what your partner had done. The pairs made up of strangers tended to use different coloured pens so they could clearly see who came up with what. The pairs made up of friends made no such effort to monitor contributions; they were happy to let that go and share whatever prize they were given. I think this is lovely. It’s the unspoken alliance I am talking about; the sense that you’re in this friendship together and happy to share whatever goodness comes your way, regardless of what you get out of it in return. This little scenario happens again and again between good friends: when the bill comes at the end of dinner, when it comes to giving birthday presents, how much time you spend talking about one person’s life, how much emotional support each person needs and receives. There’s this lovely sense of longevity implied in the decision not to count favours, like you know that you’ll always be in each other’s lives and it will ultimately balance out.
The teenage girls I saw on the tube that day are right at the beginning of all that. They are, in some ways, wiser than we tend to give teenagers credit for being. They’ve been through that excruciating, tender stage of childhood where you learn what it is to have friends and, in the playground, what it is not to. They’ve sampled loneliness, they’ve known self-doubt, they’ve compared themselves to people who seem more popular and wondered why they don’t look or sound like them. They’re smack-bang in the middle of that delicate phase where they’re trying to work out how much space to take up in the world, how much they’re allowed, how much they’ve earned. And most importantly, they’re choosing their allies for the long lives that stretch before them. Some of those friendships will last the distance, others will falter and fall apart. It’s all about learning who they are and who they want by their side through all the angst that’s yet to come. Of course, ideally, we make new friends throughout the later decades of our lives, too. I hope I’ll always be open to the idea of a new friend. But at their age, they’re in a more precarious position. Physically, their frontal lobes have not fully developed yet so they don’t have an adult mental or emotional capacity to necessarily make the best decisions for themselves. And yet, at what time in our lives other than adolescence do we spend as much energy ferociously trying to get to know ourselves? Making friends at that stage is like compiling elements of your soul; you are who you choose to hang out with and you’re going to make both wonderful and terrible selections. I wish every teenager the wisdom to start working out what they stand for, the strength to stick to it, and the humility to evolve. When it comes to friendship, we’re using all our faculties: our hearts, our brains, our egos and our bodies. We’re using language, both verbal and physical. We’re using social lubricants, like alcohol and music. We are social animals and our very instinct to survive compels us to make friends. There is scarcely anything more important in those girls’ lives than the friendships they have and will have, and I hope that in time, like me, they’ll realise that.