The Rest Is Science - All The People You Don't Know

Episode Date: July 12, 2026

Do your friends actually like you? Does an acquaintance think you’re closer than you are? This week, Hannah Fry and Michael Stevens explore the surprising psychology of friendship, from familiar strangers and para-social relationships to the unsettling discovery that nearly half of friendships may not be mutual. Why are we so bad at judging who considers us a friend? Why do strangers often have a bigger impact on our lives than we realise? And why do your friends almost certainly have more friends than you do? Along the way, they uncover the science of social networks, loneliness, influence, popularity, and the famous friendship paradox, revealing how the hidden connections around us shape our health, happiness, and behaviour. A View From A Bridge - https://www.instagram.com/aview.fromabridge Letters Anonymous - https://www.lettersanonymous.com Are You Friends', Friend paper - https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0151588&type=printable ------------------- For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit ⁠⁠https://cancerresearchuk.org/restisscience ⁠⁠Cancer Research UK is a registered charity in England and Wales (1089464), Scotland (SC041666), the Isle of Man (1103) and Jersey (247). A company limited by guarantee. Registered company in England and Wales (4325234) and the Isle of Man (5713F). Registered address: 2 Redman Place, London, E20 1JQ. ------------------- Find The Rest Is Science all over the internet by ⁠⁠clicking here.⁠⁠ ------------------- Video Producer: Adam Thornton + Oli Oakley + Jack MeekAnimator: Sam BensonVideo & Social: Bex TyrrellAssistant Producer: Lucy LipscombeProducer: Simona RataSenior Producer: Lauren Armstrong-CarterHead Of Digital: Samuel OakleyExec Producer: Neil Fearn Learn more about your ad choices. Visit podcastchoices.com/adchoices

Welcome to The Rest of Science. I'm Hannah Fry. And I am Michael Stevens. Hannah, you and I have some friends, I'm sure. You've got friends? Some. Some? Yeah. I think I do, too.

Are the people out there listening to us, our friends? What is a friend? Sort of. Yeah. I want to talk about a lot of things today, including a 2015 study that looked at friendships, specifically whether you are your friend's friend. Yeah. Is it reciprocal?

This question had not been asked before, apparently. There had been a lot of studies and data sets about friends and social networks, but none looked at the reciprocity of them. Sure, you consider Jim your friend, but does Jim call you a friend when he thinks he's anonymously asked? And the results were not pleasant. Oh, Ben. Okay.

Yes. As it turns out, we as a species are really bad at judging whether someone is a mutual friend or not. And that's kind of scary. I did see something. Actually, yesterday, in fact, my partner was on Reddit. And there was this Reddit thread and they were talking about me wherever. And then someone on the Reddit thread said, oh, I'm friends with her in real life. Obviously, Reddit, so you don't know who anyone is.

Sure. And then the conversation continued. And then they said, oh, yeah, I go to parties with her. And that immediately raised a big old red flag for me because I haven't been to a party since about 2003. So if we are friends in real life, that's something that's got more longevity in it than I would consider. I think that that is a non-recipricated friendship. That is a perfect example of a non-recipricated friendship or a unilateral friendship. It's also probably an example of a influencer where you are the influencer and they see themselves as your friend, but maybe you don't see it the other way.

This is harsh. Whoever that person is, I'm sorry. Call me. Call me. I love you. Yeah. Give Hannah a call. We really appreciate you giving us a great anecdotal piece of evidence for this episode.

And we're going to talk about you the whole time. If you've got my number, which I doubt it. And we're also going to talk about many other things, including the friendship paradox, which is the established scientific fact that your friends have more friends than you do. And not only that, but your friends have more money than you do and are healthier than you are. All of that after the break. This episode is brought to you by Cancer Research, UK. Scientists have found that cancer risks usually increase with age and size, but some species, defy the odds. For example, deep sea Greenland sharks. They can grow over six meters long,

weigh more than a small car, and yet live for up to 400 years. Now, understanding how Greenland Sharks cellular repair and immune systems seem to have managed to keep them cancer-free for centuries, that could open up exciting research pathways. Essentially, over millions of years, evolution has been running the world's most successful cancer prevention trial. And sometimes breakthroughs can be found in unusual places. So by exploring the unexpected, Cancer Research UK scientists are uncovering new ways to tackle over 200 types of cancer.

Their work has helped to double survival in the UK over the last 50 years and continues to save and improve lives around the world. For more information about Cancer Research UK, their research and breakthroughs and how you can support them, visit cancerresearchuk.org slash the rest. is science. All right, so I want to start our discussion of friendships by talking about strangers. That's a good place to start.

It's like the opposite place to be. As it turns out, there are a lot of different kinds of strangers. And ever since the 70s, researchers have tried to create a taxonomy of strangerhood. First of all, there are complete strangers. These are people that you would not recognize, you've never met them. You don't know anything about them. But then there's this really rich group of what I call incomplete strangers. And my favorite Kant was identified by Stanley Milgram of all people, the guy who did the torture experiments.

He said, you know, we've got to talk about this kind of relationship humans have that's not a stranger and it's not an intimate friend. It's not an acquaintance either. It's a familiar stranger. What does that mean? So here's the definition of a familiar stranger. It is an individual you repeatedly observe, yet do not directly interact with. That comes from Paulus and Goodman out of Berkeley. Right.

So it's like when you're on holiday, there's the same family at the buffet every morning, and you spot them and you see them at the pool and you're like spy on them, but you've never spoken to them. Exactly. And in fact, there's a mutually understood behavior pattern between both of those groups. They see you too at the at the buffet and you both agree to ignore each other and that's totally healthy. It's very normal. It's there's no hostility involved there at all. You have agreed we are familiar strangers.

I recognize you, but I'm not going to say anything to you ever. This can be in your day to day life. It can be the person you see at the same train station every morning. And if they weren't there, you would notice. But you both have this agreement. that you're not going to talk to each other. One of my favorite descriptions of these kinds of people is from a clickhole article from 2020.

I'm going to send it to you because I also just love the picture of the guy. Hopefully we can show it on screen. So first of all, there's a picture of a guy who's bald with a goatee and big eyebrows and he's got a green like army vest over a green t-shirt. And the headline says, heartbreaking. This guy has no idea that he's so strange and memorable looking that ever. Everyone from his flight is using him as a landmark to figure out which baggage claim area is there. Amazing.

Amazing. I love it because we've all met these people. They were on your flight because there was something remarkable about their appearance that means you remember them. And later on, you go, oh, there's that guy with the Mohawk or the weird ears. This must be our baggage claim carousel because I know he was on our flight. And everyone has that same experience. They're all going, but here's the thing. Sometimes you're that person.

I fear, I genuinely fear being almost six foot tall and having red hair. Yep. I genuinely fear that for almost all of my life I have been that person. And now I wear really bright colors because I don't really care anymore. So I think I have become that person all the more. It's good. And embracing it and meditating on that fact is, I think, good for the soul. It's actually called the epiphany of the familiar stranger.

which is the realization that you are someone's familiar stranger, someone you have never met whose name you don't know, recognizes you and goes, oh, there's that guy. And that's true for all of us. It's true for all of us. It's related to the Dictionary of Obscure Sorrows coinage of the word saunder, which is the realization that all these people, those people on that train over there that you're not even on, they have rich, deep lives, full of concerns and ambitions, just as strongly as you. yourself have them, that were all individuals. And so to be someone's familiar stranger is a cool thing to think. I mean, I walk to work every day, and I think there must be people who were on their commute driving on the roads that see me crossing the street every other day or so.

And they go, oh, there's that guy. I mean, I'm not six foot tall with red hair, but I am like a bald guy with a big beard and big glasses, and they probably go, oh, there's that guy. I mean, you're cheating slightly because you're also a visor. So I think I'd probably notice if Vsource was on my commute. Yeah. Okay. If they're familiar with Vsauce,

then that's a whole other thing where they don't interact with me. They don't just observe me. They do know more facts about me. Their observation comes in a richer form through videos. They know of me, but I don't know of them. Anyway, the familiar stranger effect can be changed quite, suddenly. For example, obviously in the case of an emergency, we suddenly will interact with

familiar strangers and feel a bond to them. Also, if we find ourselves and our familiar strangers outside of our routine, so if I ran into the person that I always see at the pet food store, but I've never spoken to, never interacted with, if I ran into them in Rome, I'd be like, oh my gosh, you live in Colorado. And they would recognize me too. And we would suddenly feel so much closer. We would ask each other our names. What do you do?

And it would change the relationship. But while we're in our routine, we remain familiar strangers with a mutual agreement to ignore each other. I remember a story. It was in 2016. And there was someone who would order pizza, basically every single night, we'll just come in, get his pizza, kind of had a regular order. And, you know, the staff didn't hang out with him, but they knew who he was and they knew where

he lived, right, because he had this pizza ordered. Anyway, one night, the store manager was looking through the orders and was like, hang on a second, this guy hasn't placed an order for 11 days. There's something really strange going on here. So they decided to send a delivery drive around to the house to just check everything was all right. And they found, basically, he'd had a stroke and was, because he was living on his own, he had a stroke and he was, you know, genuinely in mortal danger. And these staff, just because he was a familiar stranger, you know, despite never having

sort of been emotionally connected to him before, managed to save his life. And that gorgeous story. You sort of care for your familiar strangers. There are a lot of stories like that. And I want to revisit that because familiar strangers. might not seem as important as our intimate connections and our close friends and family. And yet they play a pivotal role in our lives. By the way, I forgot to say there's a name for those remarkable familiar strangers that we all kind of recognize and go, oh, there's that guy.

Sometimes it's just, oh, there's that pink car. Like, it's always, it's always, you know, coming in around 9 a.m. parking in one of those spots. They're called by psychology researchers sociometric stars. Okay. They're a special class or kind of familiar stranger who stand out in a community or group and are recognized by an extremely high percentage of people. So sociometric is like by the metric of social status? That's right. Yeah. Yeah. They are recognized by and sort of familiar to their social group. even those that they don't interact with,

they're sociometric stars. So, Clickhole, you have described as sociometric star, kind of a weird-looking dude. It's a much nicer thing. All gingers of the world, I think, can call themselves that. Oh, for sure. For sure. So other people recognize them and make a mental note of it,

consciously or not. And then agree to ignore it and not, like, bring it up or say, oh, my gosh, your hair is red. I can't help but notice you. What's your name? I mean, some people do that. But this pervasive ignoring without hostility has another cool name. It's called civic inattention.

There's an agreement we have that when I'm on the train, I'm going to pretend like I don't even realize you're there. I'm not listening to your conversation. Even though I am, I pretend to be inattentive because that's the civic thing to do. There's a different kind of stranger besides the familiar stranger that's a little bit closer. And this type of relationship was first described by Karen L. Fingerman. Great name, by the way. We've got a few great names today. So she described what she called the consequential stranger.

The consequential stranger is someone that you don't mutually ignore, but you're not intimate. One of the key defining differences between your intimate friends and the consequential stranger is that there's basically no obligation. Okay, this might be someone like the person at the hardware store or the grocery store. You might know their name. You tell them about your day when you check out. They work there. But like you would never invite them to your birthday party. You're not going for a beer with them.

That's right. You would never give them a ride to the airport. And there's no expectation that that kind of obligation would ever come up in your relationship. So sometimes we call them acquaintances. But there are obviously different degrees of acquaintanceship. One kind that psychologists talk about a lot is the nodding relationship, which is a very fringe one where you'll just kind of nod at each other. Often it's a coworker that's in a completely different department or they share a building but work for a different company. And you recognize them and you got to do something so you nod, but you don't even talk.

The country road version of that is the one finger wave. Hand still on steering wheel, one finger wave. One finger wave. They do that out here where I am. By the way, it's like a whole thing. And my wife does most of the driving out here because I'm not used to driving on the right hand side of the car. But she always like talks about, oh, man, I need to get better at doing the wave because she

always misses it because she's just not used to doing it. Where am I, by the way? You might be wondering, I am off the grid in New Zealand visiting. I've told Hannah all about this. I don't want to docks myself. But basically, I married a woman who has a lot of family in a certain location and I am there right now. That sounds so mysterious.

I don't mean it to sound mysterious. No, it's great. You got your wife outside turning a hand crank just to give you power? No, I don't. I don't. The electrical power all comes from the sun. We've got solar panels on the roof. And so I am, I'm nervous.

It was sunny yesterday, but it's cloudy today. So I might be using up all the power just to do this. It was worth it. But yeah, that's what the fire is for. The fire gives you the light you need. It also gives you warmth. It's your clothes dry. It's how you cook.

And it makes sense that you are currently in winter. Yes, I am currently in winter, whereas you are currently in summer. Yeah, I would swap, frankly. This is disgustingly hot here. I do not envy you. I am so glad. I love escaping the Northern Hemisphere summer for this winter. Fingerman also fingered a different kind of relationship.

It's becoming a very finger-themed section. She's the one who coined the term, friendship. Okay. Not a friendship, but a fringe ship. So is this like somewhere between your intimate friends and your, what did you call them, consequential strangers? Yeah, consequential strangers are called consequential because as it turns out, after decades of study, it's really been established that the majority of what events change our lives come from these strangers. Obviously, my close family affects my life really directly. But when it comes to things like job opportunities, when it comes to things like finding flats to rent, finding a dog or a cat to adopt,

it's not usually my mother, who happens to know that there's an opening at some company, it's my neighbor's brother who had just visited last weekend, right? It's, it's, oh, my daughter's teacher has a cold college friend who's got a bunch of kittens. Is that, is that by virtue of just the fact that there's so many more of them? I mean, absolutely. If you're thinking of like an onion here, right? Like, you're in the center. Your immediate friends and family are surrounding you.

And as you go sort of further out through friendship, consequential strangers, familiar strangers and out to complete strangers, it's like the number just gets progressively larger and larger and larger. Yeah, the number gets larger. And so the diversity increases. And it also makes sense that, you know, we would self-select intimate friends that are more similar to us. But when it comes to a life-changing opportunity, it's going to come from outside of our routine, which means it's going to come from someone we haven't self-selected to have as a really close friend. The decision that you made to really change your life came from a consequential stranger.

And as social media grows, there's yet another kind that was named by, hidden nori to meeta the intimate stranger this is a person that we have anonymous contact with usually through the internet that we yet share quite intimate details with and this is just a word i don't think there's been a whole lot of research into differentiating the intimate stranger from the consequential stranger except for the fact that the intimate stranger needs to be an anonymous we don't even share names. You might only know their avatar or their username. But we do know that people often feel very comfortable sharing intimate details with strangers. There's a sort of safety to it almost because you don't feel as though, I don't know, like the stuff that you tell them is going to come back

to bite you. If they're unconnected from your life, I think there's something that's a little bit freeing potentially about that. That's right. It's freeing. It's also freeing to know that because they don't know the people involved and they haven't heard it before, you can kind of tell it fresh and you can understand yourself better by talking. It's like a therapist, except they don't even have a history. You know, it's like your first day with a therapist. You're like, okay, I can kind of like look at myself from outside because you're so outside. And there's a, there's a bit of a hump. It's been discovered when it comes to how easily we will share intimate details with strangers. They call this the stranger on the train phenomenon, by the way, the fact that people are

so open with those they really don't know. But that hump is that we have this civic and attention, this like, we're not going to talk, hump to get over. And so when researchers investigate how intimate strangers will be with them, it sounded kind of weird, but what I mean is sharing personal information. emotionally intimate. Yeah. Emotionally intimate. Yeah, they find that it's really hard to get it started. It's really hard to get a stranger to share a cab with you, even if you agree to pay the whole fare. But once you get them in, they'll start telling you about their divorce. They'll start telling you about how maybe they're never going to find love. And it's, it makes them feel better. But they just needed to get in the cab in the first place. And you needed to invite them in and convince them to get in in the first place. And then all this growth can occur. There's a really beautiful. YouTube channel that I really like, which is where they have a phone, like an old-fashioned sort of corded phone set up on a bridge. And the camera starts out with a person's face just framed,

they're holding the phone and that's kind of all you see. And they're telling a story that's incredibly emotionally intimate, incredibly personal about some trauma that they that they live through or, you know, the thing that they dislike the most about themselves, right? It's really, really revealing stuff. And as they're talking, the camera slowly pans away, and you realize that it's this incredibly long lens shot, that the actual camera, there's sort of, you know, nobody's really listening.

This person is essentially talking out to the open water. We feel freer to reveal the most, the innermost secrets that we have when we don't necessarily feel that we're like divulging it to someone where there'll be consequences. Okay, you got to share that link with me because I'm trying to remember there was also like a blog that would publish letters you could write anonymously

where you could apologize for something or admit something or discuss a regret that you would never say to anyone involved, but you needed to say to strangers. It wasn't post-secret. It was something else. I'm sure the commenters will know. This is called A View from a Brits.

Let me send it to you. It's absolutely beautiful. Ooh, thank you. I have one more question actually. About that idea of intimate strangers, that has to be reciprocal, right? It's not, this is a relationship between two people. It's not just someone divulging stuff about them into the ether. This intimate stranger friendship in inverted commas means the details are being shared both ways.

I don't think it has to be actually. I think that sometimes you just need someone to listen, and one can just be the anonymous listener, and the other can be the divulger. I'm thinking about some very oversharey influences here, basically. Ah, interesting. Well, yeah. So influencers, I think, can bring us into what I want to talk about next, which is the directionality of friendships and how it's not always as even as we think or would like.

Okay, well, that sounds like a perfect point for us to have a little break. And yeah, when we come back, we'll find out why you're not as popular as you think you are. This episode is brought to you by Cancer Research UK. What if your immune system could learn to recognise cancer cells? That's immunotherapy. One type is car T-cell therapy. T-cells are your body's watchmen, and doctors can now extract these and reprogram them to spot cancer.

They've started showing this real promise in treating cancers of the blood like leukemia. Because unlike most cancers, blood cancer cells, They float around separately, and that makes it easier for CART cells to seek them out and destroy them. And now, Cancer Research UK-funded scientists are designing CAR-T cells that can tackle solid tumors too, making them tougher so they can survive a more crowded and hostile cancer environment. Now, these approaches are experimental, but they do start to show where treatment might go next. And over the past 50 years, Cancer Research UK's pioneering work has helped to double cancer survival in the UK. I mean, this shows you how far research can take us.

For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit cancer research, UK.org, forward slash rest is science. Okay, welcome back, everybody. So we've been talking about strangers and the different kinds and the different sort of surprising relationships we can have to people we don't even know. And the fact that researchers are looking into this and have names for them. And, you know, what I said that we would come back to is the big so what? Hannah, you mentioned the guy who would always order a pizza regularly. And then when he stopped, they checked on him. Well, as it turns out, that kind of thing, beyond just job opportunities and life opportunities, are some of the most necessary things we get from strangers.

In fact, studies have been done ever since the 70s when Mark Granovetter first coined. the term weak ties to refer to people that were weak tied to. And they found that the more different types of relationships you have, the healthier you are. There's a correlation between your physical health and your longevity as well and the diversity of types of relationships you have. So it's not just important to have some really close friends. It's also important to have consequential strangers, familiar strangers, even intimate strangers in your life. I have some questions about the methodology of that particular study. I want to know how you're measuring health.

I want to know how you are, like over how long are they tracking people. I've got questions. Tell me more about your question. Like, are you suspicious of that result? I would say curious rather than suspicious. But mostly because it feels like it would be really hard to measure concretely. Everything I'm sharing today, I researched years up to months ago for a B-Soss episode. And I'm giving everyone a little introductory taste.

And I even remember writing this into a script draft that they took people and injected them with the common cold. And then they saw if the outcome would correlate with the variety of social ties that they had. Not the variety of the people themselves, but the variety of types of relationships, consequential, familiar, intimate, those kinds of things. So, yeah, you've got it right in front of you. No, right? So exactly as you're describing. And you would think it wouldn't make a difference, right?

So you take everybody, you map their social networks, you put them into quarantine, and then just before they leave quarantine, you squirt. some common cold up their noses, right? And it's like, why would it make a difference? They've got squirted up their noses. Surely they've all got the cold. But in this paper, people who had low social network diversity, so essentially only one to three types of social ties, were four times as likely to develop a full-blown cold compared to people who had highly diverse networks of like six or more ties. So people who are essentially out there in the world running around, the entire time, talking to people, mixing with people, were physically less likely to end up

getting sick despite having the same exposure as people who just sort of sat around at home, which is wild. It doesn't mean that you have a better outcome if you love your mother more. It means you have a better outcome if you have more different types of relationships. If you're out there in the world. That's right. Sociology and Anthropology Department at Illinois State University has been looking into this, especially Susan Sprecher. And she's found that having a more diverse social network that includes intimate others and family, close friends, casual friends, and weak ties acquaintances and other peripheral ties is associated with good health and well-being.

Indeed, this article says weak ties can give us a real mental health boost. A 2014 study indicated that people with wider connections of weak ties tend to be healthy. So not just a variety of different strength of ties, but also the diversity and size of those ties. First of all, I get how it would make you feel more connected to the world. In fact, one famous way of describing consequential strangers versus intimates is to say that intimates anchor us at home. Consequential strangers anchor us in the world. So the person at the hardware store who always checks you out, checks you out. Like, ooh, you're looking good.

I think that would also be a very consequential stranger. I mean, that would be. It's true. The people you fancy on the bus. Yeah, those people that we have very few obligations to and yet recognize and interact with anchor us in the larger world and make us feel like we belong, that we would be missed. Obviously, my mother, my wife and my daughter make me feel like I would be missed. but there's an almost unconscious way in which the people we see every day, the coworker whose name we don't really know, but we have a nodding relationship with, all of those contribute to our emotional and potentially even our physical well-being. Now, I can see like one strong explanation for the correlation could be that if someone has a large variety of types of social relationships, then they probably are also interacting. with more people, which means their immune system is getting exposure to a lot more pathogens.

Whereas someone who has a close-knit group of just intimate friends but doesn't really get out, they're not exposed to as many pathogens for their immune system to then recognize and be prepared for. This is another paper that came out later in 2019, which essentially says, right, with the social, with the cognitive social species, right? We are happiest when we are out among others when we're socialising. And the idea is that our immune system treats social isolation as like an active physical threat. And so ramps up inflammatory responses and then suppresses antiviral immunity. So basically, we don't like being on our own and your body is physically happier and more capable of handling actual threats when you're out in the world around.

people. Exactly. I need to leave my home office immediately, Michael. This is, it's freaking me out. Maybe, maybe. I want to, I want to emphasize that what it means to be lonely is subjective. And it's important that you don't feel lonely. It doesn't mean that you have to be an extrovert who's out among people all the time. For different people, what it means to have a lot of relationships can change. But I do know that when it comes to cognitive health late in life, so things like the onset of dementia, we know that one of the best predictors of a quick decline is whether the person says they feel lonely. Now, there are people who do really well and by all accounts, externally, are lonely. Like, they rarely see other people. And yet, as long as they don't say they

feel lonely. Like they feel fine. The amount of social interaction they're getting is fine for them. They have a better outcome. But as soon as you feel that it's not meeting what your needs are socially, that's when there can be trouble. Got you. Got you. There's a gap that you're yearning for. So if you're someone out there who loves bed rotting and you just stare at your phone all day and never leave, that's that's probably not good, okay? To be fair. However, if it doesn't bother you that much, it's better than if it does bother you a lot, is what I'm saying.

But all the same. Please enjoy this YouTube presentation. That's right. And we will keep pumping out a couple hours of this a week for your lonely pleasure. Look, all we're saying is, look, I doomscroll as much as anybody else. But if you're going to doomscroll,

you may as well doomscroll on stuff that's actually enriching your brain, which is what this is. And that's a great transition into the next kind of relationship I want to look at, which is a unilateral one. These exist and have existed for all of human history. Unilateral means the friendship, the relationship goes one way. Oh, yeah.

Hannah's my friend. But then if you ask Hannah, she goes, I don't really know him. Okay. That is in contrast to a reciprocal friendship where both people independently say that the other is a friend. And consider each other friends to the same degree. Obviously, this can get us into discussions of influencers where a lot of people who follow the influencer might have a parasycial relationship with that influencer where they feel like the influencer is their friend is closer to them than in reality they are. And certainly it feels closer than the influencer themselves feel to that person. They probably don't even know that person.

So this brings us to the 2015 study out of MIT that looked at a number of different data sets, a number of different data sets involving social networks where groups of college students or coworkers or community members were asked, here's a list of everyone that's around you. I want you to rate them on a scale of zero to five with zero being, I've never heard of that person, five being they are one of my closest friends. where would you rank them? And this kind of study had been done, you know, for decades to look at how social networks build in real life and what it means to be popular, how influence spreads. But what hadn't really been looked at was the unilateralness. How often is it that a person says, oh, yeah, Sarah is my friend, but Sarah doesn't think that person is her friend. And as it turns out, it's really, really common. So I'll tell you what they found. They found that in the friends and family data set, which you'll have to look up what all these data sets are when they were made and how many people they involved. Okay, they found that in the friends and family data set, only 45% of reported friendships were reciprocal. So less than half the time did two people agree independently that they were friends? In the reality mining data set, only 34% were reciprocal. In the social evolution data set, 35%.

In Europe, those are all from America, by the way, the ones I just said. This one, the strongest ties data set from Europe, 49% were reciprocal. And then the personality survey, which is a Middle Eastern survey, only found that 53% of described friendships were reciprocal. And this was really shocking. And it's been found since that, yes, indeed, people are really bad at, I. either evaluating the reciprocity of a friendship or they're just bad at reporting it. One of the most common reasons is that non-recipical friendships the researchers have found are generally aspirational, meaning a person wants to be friends with a higher status individual. Yeah.

But those higher status individuals where status can mean anything from from wealth to popularity to perceived coolness, those people have greater choice. they've got their own focus. Yeah. Can I just ask you, just remind me, wait, how do they do it? So it's a score between zero and five and you have a full list of names and you put a number against everybody

or you limited in the number of people you can score? You're limited to scoring people that are on the provided list and everyone on the list is asked about everyone on the list. Right. Oh, wow, that's rough. Zero to five is only true of the friends and family data set. I don't, haven't looked at the others, but I know that the personality survey was zero to seven.

But it's not like, It's not like someone saying, okay, give me your top 10 friends and then popular people just sort of run out of places to put friends down. No. No, I see what you're asking. No, it really was you have to score everybody on this list. How close are they to you? Would you consider them a three, which is just like a friend or a really good friend or one of your best? Or are they an acquaintance or do you not know them at all? Oh, that's so brutal. Here's the thing. When you look at the graphs, we can put the page. I can share it with you too, Hannah. When you look at the graphs they've built where a node is a person and a line is a connection, you'll also see that there are essentially clicks where a lot of people all consider each other mutual friends. But the connections between those clicks are usually made of unilateral connections where someone in one click says a person in another click is their friend, but it doesn't go the other way. So here's the paper coming at you. I have to say, as somebody, who was, like, I really struggled at school. I really, really struggled at school with friendships. I was so nerdy.

I definitely would have been one of the people who had only unilateral friendships, who was sort of like, oh, I think this person's my friend, this person is my friend, this person is my friend. And then they would never have written me down. Like, I was the kid who was eating lunch in the bathroom. You know what I mean? Oh, Hannah. I'm so sorry.

Was it because of your red hair? I think it was a whole manner of things, Michael, a whole manner of things. But look how much you've grown. But look, look at that. Now people claim to know me on Reddit. Oh, that's true. Yeah. So the researchers in this paper, they didn't just look at reciprocity and how frequent it is in friendships.

They also looked at the way influence happens. And they found quite surprisingly, because a lot of these data sets have been followed over time and different experiments have been done on the same subject pool. And sometimes what's done is studies that use things like the buddy system to see how people can help each other. They found that when it comes to influencing someone else's behavior, like getting someone to become more physically active, mutual friends do a really good job of lifting each other up. A mutual friend is when both people independently say that the other is their friend. But surprisingly, they found that if someone else calls me their friend, that also, but I don't call them a friend, that also influences me. Their behavior is correlated with a change in my behavior. Just as though we were mutual friends. If someone admires you and you spend time around them physically, so it's not like a kind of, you're not strangers.

That's right. But I don't admire them. I don't. consider them close. Yeah. They nonetheless influence me a statistically significant amount. And yet, if the inverse relationship happens where I consider someone a friend, but unbeknownst to me, they don't really think about me very much, in that case, they don't influence me actually as off as much as you would think. Why? That feels like almost the wrong way around. It sounds the wrong way around because we call that third kind of relationship and influencer relationship. I'm follower, the followee should be influencing me, but they just have not found that to be the case, at least in real life. On social media, it could be different. But I think that this does

raise a question that we need more research on, which is to what extent are the influencers actually the influenced? Because I can tell you that, you know, you and I here on this podcast were influencers, right? But yet the amount of time we spend as a team discussing comments and how we should title things and what topics we should choose is gargantuan. Okay? Maybe we are the influenced.

We are the influenced by you, our listeners and viewers. What you like changes what we do. Exactly. And all of the subscribers, all of the followers, all the listeners out there, they're the true influencers. And they have an extremely powerful well. that amplifies their influence. It's called the algorithm. The algorithm tells us, hey, this is what they want to watch. You can't just do whatever you want and they'll watch it. This isn't the 1990s with, you know, cable television and whatever's on is on. They're going to choose and we're going to let them choose and then we're going to learn what they like to choose and give them more of it. And so we, the influencers, are much more influenced by the audience than possibly even the other way around. That doesn't mean there aren't exceptions, obviously.

There are clearly, especially young people who follow influencers and really idolize those people and change their behavior. And yet, the influencer doesn't even know they exist. But by and large, across the human population, we just aren't seeing that influencers actually have the behavior changing effect that we think they do. That's amazing. I have an example of an exception. It's one of my favourite ever stories. Okay, tell me. Which is about a tile-making company in Hungary,

and it was having to downsize. But the real problem was that there were all of these incredibly vicious rumors that were flying around the entire company. So it just so happened that they knew this very famous Hungarian network scientist called Barabashi. And so he suggested conducting this mapping, right? Go in, let's map this network of influence. Essentially, I mean, there was this whole questionnaire,

but essentially the key question was, give me the name of one person you would go to for advice or information. So they asked every single person in the company there. And they mapped the network that resulted. And almost everybody had almost no one. But far and away, the most influential person in this entire company was this entry-level employee. It turns out this was the safety officer for the company. So what he was doing was going around to all of these different offices.

And apparently, just bringing all the gossip with them as he went. So then they recognised how powerful it was to have somebody like that. So they just sort of gave him a pay rise and then used him to kind of feed out all the secrets that they wanted throughout the company. Oh, yeah. I mean, social influence definitely exists. But the extent to which friendship is part of it. And whether that friendship is reciprocal is still very much up for debate. I think this safety officer had a lot of arrows pointing to him, but he may have also known all of those people and also counted them as friends. True, very true. I think that these ideas are all in my mind still being formed and research is still being done on it.

But I think that obviously influencers can, you know, let us know about things. But whether we take an action on them, I think when you think about it, it often also depends on what the community is saying and how they're responding. It's not just the influencers video alone. It's also the comments. And those comments are coming from people that I am sort of forming a trust relationship with momentarily. And they don't even know I'm doing it. So it's unilateral. I'm kind of counting them as a friend temporarily.

And yet they don't even know I'm doing this. They don't know who I am. It's those comments and the reaction the community has that lets me know if this influencer is going to push or pull me or if I'm just going to make fun of them as well. The last thing I want to talk about is the scientific fact that your friends have more friends than you do. Think for yourself, Michael. Look, look, there are, obviously there are exceptions, but as a general rule, it's known as the friendship paradox. And it mathematically must be true. So long as people have friends and they don't all have the same number of friends, this will always be true.

The reason it's true is that people who have a lot of friends, people who are really popular, wind up getting overcounted. They're sampled a lot more when you ask any random person, who are you friends with? So if I'm friends with only two people, and one of them is kind of like a special friendship, and this person only has one other friend and it's me, okay, there's that.

But then I might have my second friend, and it's Jim, a guy with 99 friends. Of course I'm friends with Jim. He's got 99 friends. We're all friends with Jim. Well, now when you look at it, I've got two friends, but my friends, on average, have 50 friends because those really popular, socially central people throw it all off. And this can lead to a lot of illusory perceptions we have of our own popularity.

Because as a rule, unless you are one of the most popular people or the most popular person, on average, your friends will have more friends than you do. It holds true. You get the same phenomenon on social media. like the people you follow have more followers than you. Exactly. And the reality is it's because you follow, you know, Mr. Beast. I'm just making assumptions about who you're following, Michael, but you know, has a hundred million followers or whatever it might be.

And, and therefore, I mean, exactly the same example that you laid out, but just sort of scaled up to the size of a population. Yeah. And so I think it's a good thing to keep in mind if you ever feel like you're trying to keep up with the Joneses. be like, how come it feels like everyone else has more friends than I do? They do, but it's mathematically the case that everyone feels that way. But that's a topological fact. There are other things associated with being popular and with having a lot of friends that also can be described by the

friendship paradox. For example, your friends also tend to be wealthier than you. Because wealthier people, they tend to statistically have more friends, have more interactions with more people. Therefore, the same effect happens for the same reason. There are people with a lot of money and a lot of friends who throw off those averages and make it the case that your friends, on average, have more money than you, that they are healthier than you because healthy people are out and about. They're forming connections. They have a lot of friendships.

The question I have that's still open, I haven't found research that's recent. on this. But this also leads to why young people overestimate the number of risky behaviors their peers participate in because there are certain things like going to parties, drinking, smoking that are more prevalent with people who have more friends. Therefore, when you look at your friend group, you go, wow, the people that I know and the people that I know of definitely drink more than I do. And everyone feels that way. And it's not just, We don't have to just look at the psychology behind it of, oh, well, everyone overestimates how much their peers drink because it makes them feel better. We can just look statistically at how it's going to happen that when you go to parties, you see people who go to more parties.

And so that becomes the sample that you're looking at. But this has become something that researchers have noticed for real. It's not just a, well, in my armchair, I think this makes sense. These studies are all a bit older. And I think that in recent years, we've seen that young people especially are drinking less, they're being violent less, they're having premarital sex less. But in 2005, it was found amongst middle school students that each additional friendship accounted for a 5% increase in the probability that the student smoked. And a 2013 study found that being named as a friend by five additional others accounted for a 30% increase in the likelihood that that middle schooler had tried alcohol. Here's the thing, Michael. I can hear you're reading this and you're saying, no, look, the friendship paradox demonstrates that you have an incorrect perception or a warped perception of how important these individuals are across the entire population. Sure, I appreciate that's what you're saying. But all I'm hearing is, you get more friends if you go to parties and you get more friends if you drink and smoke. And maybe that was the mistake that I've been making since 2003. Maybe I should be at parties more.

Exactly. If you'd gone to more parties, then you would have probably partaken in more of these activities. I'd have actual friends. Redditor, hit me up, okay? And so anyway, this kind of explains why especially young people tend to overestimate the behaviors of their peers when it comes to things like drinking and smoking. But I'm wondering if it's different today. I think there might be other traits that correlate with popularity today. For example, maybe your ability to communicate and be effective on social media. It might lead to a feeling of, well, everyone else is so much better at social media than me. And that's because the ones that you see are the ones who are good at it and they wind up having more connections.

And you are more likely to know of them and be a friend or follower of theirs. I also wonder about gyms being the new party places, you know. Yeah. Jim bunnies have a lot of friends because they meet them in the gym. Yeah, exactly. And so I'm quoting studies that are more than 10, 20 years old. Yeah. And I wasn't able to find much about how teens especially evaluate the frequency of certain behaviors of their peers.

So I don't know how this works today. But I do think that the math will still hold that whatever other traits coincide with popularity will also be overestimated by the rest of the population as being prevalent. One of the things about the friendship paradox that I've always thought is that it's sort of an artifact of the idea that like means, you know, averages using a mean, is not a useful way to think about stuff, right? That's sort of one of the things I think about it. There's network effects. There's all of that. Sure. But one of the key things is that you're taking a distribution of individuals, some with very large numbers that are overrepresented, sure. But then when you take

the average, it's just the whole, excuse the average. And the thing I like to think about is that you have an above average number of arms, Michael. So do I. In fact, limbs in general, right? Or like the average person has slightly less than one boob, you know? It's like actually when you use means, Sometimes they don't make any sense. You could apply this this way, which is that your friends have less arms than you, on average. Because you probably statistically have two arms. And yet, if we fan out to all the people you know, there will be people who have fewer than two arms, and they'll drag that average down. So your friends have fewer arms than you do, statistically.

On average, yeah. On average. And by the way, that also brings up. the enemy paradox, which is the same thing, which is that your enemies have more enemies than you do. That one feels better. Yeah, exactly. So it just depends on what data you want to meditate on how well you feel. That also sort of makes more intuitive sense, I think, because of course, my enemies are

absolute arseholes and everyone hates them, not just me. Yeah, see, exactly, exactly. It's just math. So keep this in mind. When you compare yourself to other people, you're comparing you. yourself to a group that isn't an arbitrary sample of the population. It is weighted towards those that you will be aware of. It's weighted full of people who are more connected and popular than the average person. Therefore, it's not a fair comparison. I don't know, that actually

doesn't make me feel that much better. It just makes me remember that there are people who are doing much better at forming friendships and being popular than me. Look, it would have been, it would have been little comfort to me in the bathroom stall of Presdale School in about 1998, you know, as I tried to eat my lunch. That's right. It doesn't really work. You know, Mom, I'm feeling bad about myself. Well, just remember that a few people are amazing and they're so much better than you, that

they throw off the average. But in general, a typical person chosen at random could be worse than you. Do you feel better now, Michael? Look, our job here is not to make anyone feel better. It's to expand your minds, tickle and tease you with the absolute best of what science and psychology and mathematics and philosophy have to offer. And I feel like we've done that, you know? Exactly. What we have to offer is reality and humility.

And I am really glad to hand that out. I think the most magical thought that has happened in my mind during all of this is just that reflection on the fact that, I am someone else's familiar stranger. I'm part of someone's life, and I don't know it. And everyone is. And we all are. All of you out there listening are a part of our lives. And you might actually be the true influencer here.

So thank you for being who you are. This is very true. You can continue to influence us by emailing the rest of science at gollhanger.com or by leaving a comment here wherever you're getting this podcast. Exactly. See, look at that. They can email us, but I can't email them. No, no.

This is not a reciprocal relationship in the wrong direction. How the tables have turned, Hannah. How they have turned. We appreciate you guys. Have a good day and we'll see you later. See you next time.