[MUSIC] Hi, welcome back. We're going to be talking now a little bit about why it is that popularity is so important. How come this is something that is affecting us so much when we're young? And how come it's something we seem to kind of gravitate towards for the rest of our lives? Well, let's talk about that a little bit. One thing I'm going to point out is the idea that this has become really explicit. Have you ever noticed recently if you're on the web, there's a lot of information about what's trending? Whether you're on Twitter, or whether you're just even looking at a news story or anything you see. You'll sometimes see these graphics that talk about how many times has a story been Tweeted. Or how many people have liked it on Facebook or how many comments are there? And often that's right at the top of the story. In fact, even after you're done reading the story there's maybe those icons again. Encouraging you like, you should Tweet about it, you should like it on Facebook. Why is that happening? We've kind of almost grown accustomed to it. I think one of the reasons why this is happening is because it's based on this fundamental premise. That if we see that a lot of people are really interested in something, we will think somehow it's good, it's important. We want to do what everyone else is doing, even if we resist that idea and we think, no, no, I'm an individual, I don't just conform. Still, we're kind of a bit influenced by that. We think well, if that's something that 3,000 other people have liked, then it must be something really important that I need to look at. It's the same thing when you watch a commercial and they say this is the number one movie at the box office. They're really trying to pull on the idea that it's popular and therefore that means it's good. But why does that work so well? Why do we even care about the fact that everyone else is doing it? I mean, I want to read the news stories that I think are of interest to me. And I don't think my interests are going to be the same as 10,000 other people that read the same news story. So why would I automatically think that that's important? It turns out that a lot of this might have to do with the way that we developed as a species. And the way that we can think about that is we took a step way, way, way back and thought about this from an evolutionary perspective. So, let's go back to the world of, of cavemen and cavewomen. And really thought about what life was like at that time because that's how we develop the brains we have today. Even though that's a long time ago, that's not very long ago from the perspective of our biological development. So there are lots of ways that what happened back then is still influencing us today and it's still influencing how our brains work. So, have you ever noticed how if you yawn then other people around you will yawn. Yawns are kind of contagious. Or have you ever heard that when women live together in close quarters or spend a lot of time together their menstrual cycles will start to synchronize? That all has to do with the same idea here. It's the sense that, when we were cave people, a long time ago, we quickly learned that we're going to do a lot better if we live together. And if we kind of pay attention to signals from each other. So if you think about it, if you went on your own, well, you would have a hard time getting food, right? And if you got food and you killed something like a giant wilder beast or whatever. You're not going to be able to eat all of that all by yourself. So it's really inefficient. And if you try to save the rest of it, it's going to spoil and you're going to get sick and die, and evolutionarily you're going to be weeded out. So we really learn that when it comes to food, same with safety, protecting one another. Or when it comes to other ways of coordinating activities like when should we all go to sleep? That way we can all go to the next part of, we're a nomadic group, so that helps us get to the next part of where we're trying to move to. It would be good if that was all synchronized. And we were in a herd and we learned to be a herd. And the more you stay in the herd, the more you sleep when everyone sleeps. That way, we can all work together and move together at the same time. The more that everyone stops to give birth or to conceive new babies. That should all happen at the same time. We should all eat together, we should all protect each other. If you are leaving that herd, then those things will be threatened. You won't get food, you won't be safe, you won't stop at the same times as other, and you might get kicked out. You might be alone, you might be unsafe. And that's not good for you. The people that did that, they were weeded out through natural selection. We are all the people that survived by learning to pay attention to what the herd has to say. It turns out that that has had a really cool indelible effect on how our brains are put together. But we just recently discovered this in ways that we kind of didn't even expect. So, there have been a lot of researchers that have been interested in understanding how the brain works. And in particular, there have been a lot of people that have looked at how the brain kind of lights up in an FMRI, let's say, when we experience pain. So what I mean by that is there have been a lot of studies where they have asked people to lay down in FMRIs. They're kind of laying there and they show them a screen over their head. And they give them an opportunity to experience some types of stimuli. Now in some cases, those might be real life stimuli. So while their hand is sticking out of the FMRI, they might get a little prick or some sort of a painful stimulus. And when that happens, the FMRI would allow them to see what areas of the brain are kind of lighting up. And what we learned was very reliably for a very long time we've seen in research. That there are particular areas that tell us that we're experiencing pain and there areas that tell us it's time to start regulating this pain and doing something about it. Now, the parts of our brain that signal pain, it's really important because the pain is our ways of. It's the brain's way of telling us, something very serious is happening you need to do something about it. This is going to threaten your survival. So pain is kind of the most powerful signal that our brains can give us. To tell us that, if we don't do something soon, we may die or our species may be in trouble. Well an interesting thing happens. So, there were some researchers, including Naomi Eisenberger, from UCLA. Who decided to do some studies looking at people in the FMRI machine in the magnet. And they asked them to instead of getting real pain, they asked them to participate in some interactions where they were getting excluded by others. And the way that this worked was, sometimes there were real people that folks were communicating with while they were in the magnet. And sometimes they were just pretend. But either way, the experimenters put it together so the person in the FMRI magnet thought that they were being excluded, and that others were choosing not to interact with them. So in a way it was kind of like they were getting a signal saying you're getting kicked out of the herd. You're not part of the group anymore you're getting excluded. It turns out they were very surprised to find that when people got the signal to say that they were getting excluded. The parts of their brain that lit up were the parts of the brain that light up when we experience real physical pain. And this kind of led to the idea that there might be something called social pain. We experience social exclusion in the exact same way that we experience physical pain. In fact, there's even a research to say that if you take a Tylenol, then that helps your social pain go down. Just like it helps your physical pain go down. So maybe this is why even the way that we say it in English our language tends to mirror the idea of pain. We talk about heartbreak or homesickness. It's the idea that we experience physical symptoms from a social rejection experience. So it kind of suggests that there's some way that the lack of popularity makes us experience pain. And our brain is telling us, with its most powerful signal, you need to do something about this. Don't get kicked out of the herd. Make sure that you are safe. It turns out that there's some other research, also, that has to do with our DNA. That's found that this is even more powerful than we even realized. But before we talk about that, I just have to tell you briefly about something that's really new and it's the idea of epigenetics. Epigenetics is really the sense that while we all have our DNA and every single cell in our bodies has DNA in it's nucleus. That DNA, not every gene is turned on. Some genes turn on later and some genes never turn on. But what we've recently learned in epigenetics is that sometimes what makes those cells turn on certain DNA is something that happens in our environment. So, believe it or not, someone could walk in the room, they could say hello to you, or they could say something not pleasant to you, that kind of rejects you. And that will actually affect what happens in your own cells. And, the reason why this is important is because, as you probably know, many of our cells are dying every second. And new cells are growing every second. So if an experience happens to you now, the cells that will start growing two seconds from now. Are going to start relying on the DNA that was activated by what happened to you before. In fact it's been suggested that every six months or so we are the person that is reactive to what happened to us and those prior cells about six months ago. So we are constantly new, renewed people that are living through epigenetics based on what happened to us months before. It turns out, our social experiences have an incredibly important impact on that DNA. So for the same reasons we talked about before, with hurting, and with our evolutionary legacy. We've learned that if something happens to us that makes us feel rejected then our bodies turn on specific DNA. And the DNA they turn on has to do with our physical health. So again, let's think again about cave people. If you were a person that was living back in those times One of the things that happen when you lived with others, is you found that you got a lot of colds. And the reason why is because viruses spread from human to human. So as long as you're interacting with other people, your DNA is activated to develop immunity to viruses. And all of the genes that help us to resist viruses, are upregulateing, in other words, they are kind of turned on. If you were part of a herd, there was much less of a chance that a dinosaur was going to come and eat your arm off. Therefore, you wouldn't have to have all of the inflammatory types of responses in your body, to quick heal that bleeding limb. And keep you to survive. You wouldn't need that kind of pro-inflammatory protection as much. Well, what happens is the minute we get rejected by others, we actually find that the genes that help us resist viruses become down-regulated. In fact, you can take a blood test 40 minutes later and find that you can see the signs of that so quickly. Meanwhile, the inflammatory responses all up-regulate. So, of course, if something happens to you for one minute today, that doesn't mean you're going to have an inflammatory disease necessarily. But if you experience chronic rejection, over so much time you experience ways of feeling that you're not part of the herd. You are not someone that is accepted and popular, than over time your cells will continually develop this up-regulated inflammatory response. So it turns out that popularity is actually changing the way that our DNA expresses. This has major implications for health. And it turns out that there's a way that that has a feedback loop into our brains and it even changes our mood and our experiences too. And we'll talk about more of that later. So in summary it's important to remember that one of the reasons why we seem to care so much about popularity. Is that our species, thought about being in the herd as something we needed for safety. And the minute that we loose popularity, our body is preparing us for what will happen when we're kicked out of the herd. And our brain is telling us with its most powerful signal you are needing to do something to fix this. Go back to others. Do what you can, and be part of the group. And, that's really important. Our DNA is changing. This is all very adaptive. But, unfortunately it's not really helpful for us, today, in the millennium that we live in, now. You can go out for a fun walk on your own and not get eaten by a dinosaur. So unfortunately our bodies are helping us in a way that would have been useful millions of years ago. But it's not necessarily helpful in today's society. And that's some of the reasons why popularity plays such a huge role today. But it has affects on us that aren't necessarily what we would have wished for.