Freakonomics Radio - 299. "How Much Brain Damage Do I Have?"

Episode Date: September 7, 2017

John Urschel was the only player in the N.F.L. simultaneously getting a math Ph.D. at M.I.T. But after a new study came out linking football to brain damage, he abruptly retired. Here's the inside story — and a look at how we make decisions in the face of risk versus uncertainty.

Why is it the case that we have billionaires? Why should they exist? The economist Andrew Lowe is a finance professor at MIT. That's a very strange concept for an economist because we usually think that markets are reasonably competitive. And if it's reasonably competitive, then no one person should be able to make billions and billions of dollars. That is an interesting idea, isn't it? You could imagine market failures producing billionaires, like monopolies or cronyism. But yeah, if markets are reasonably competitive, why do we have billionaires? Andrew Lowe is not the first economist to consider this riddle. In fact, if you went back 100 years, an economist named Frank Knight had a notion.

And he came up with that notion to try to explain the difference between ordinary businesses that would make a reasonable living versus these incredible captains of industry, the Andrew Mellons, and at that time, just the incredible wealth that was generated by a relatively small number of entrepreneurs. These are people that in today's dollars would be multi-billionaires. Now, we all know the conventional wisdom that the big rewards in life go to the people willing to take big risks, right? Frank Knight saw it a bit differently. He realized that the way you make a huge amount of money is not to take on risk. And the reason is because risk, by his definition, is the kind of randomness that you can quantify. And if you can quantify it, so can everybody else. You can't really outsmart other people because they can calculate just as well as you can. So using probability and statistics, you can calculate risk. And because the odds of a given risk can be calculated, that risk can also be priced. Exactly. Yeah. A good example is the insurance industry. So risk is the stuff of actuarial tables. Taking on risk might make you a good living,

but it wouldn't have made you a multi-billionaire. To do that, Frank Knight argued, you had to take on something else entirely. Uncertainty. If you take on uncertainty, for example, if you create an entirely new industry that didn't exist before, there's no way to calculate what the odds are. So when Bill Gates started up Microsoft, we didn't have a huge there's no way to calculate what the odds are. So when Bill Gates started up Microsoft, we didn't have a huge PC and software industry. He created that. And so he couldn't sit down and calculate what the odds are. And so Knight came up with this idea that the way you really make money, that the way innovation really occurs in the economy is through taking on uncertainty, not taking on risk.

Okay, is that clear? Does the distinction between risk and uncertainty make sense to you? Maybe we could use an example. So the difference was highlighted in a really neat experiment that was done in the 1960s by an economist by the name of Daniel Ellsberg. And, you know, most people remember Ellsberg not because of his economics, but because he was the fellow who released the Pentagon Papers in the 1970s. Detailing secret Washington events,

events behind President Johnson's decision to wage secret war against Vietnam in early 1960s. Daniel Ellsberg, an MIT senior research associate, surrendered to federal authorities in Boston. To begin with, how did you get the papers? Well, I can't discuss. But before he did that, he actually did some really pioneering work in economics. And the experiment goes like this. Imagine if I have an urn, and in this urn, I've got 100 balls.

And 50 of the balls are colored red, and 50 of them are colored black. And you and I are going to play a game where you pick a color, red or black, don't tell me what it is, but write it down on a piece of paper, and then I'm going to draw a ball out of this urn. And if the color of the ball that I draw is the color you wrote down, I'm going to pay you $10,000. And if it's not, I'm going to pay you nothing. Now the question is, how much would you be willing to pay to play that game? And when most people think about the odds, they come up with an answer of about $5,000, because that's the expected value. That's the probability of getting the ball of your color

multiplied by the odds of winning. that's an example of risk. You know what the odds are. But now, suppose I change the game slightly and I have another urn, and in this urn I've got 100 balls, but I'm not going to tell you what the proportion of red or black is. It could be 100% black. It could be 100% red or 50-50, 75-25, and so on. And so now the question is, if we play the exact same game where you write down the color of your choice and I pick a ball from this second urn, what would you pay to play this game with me? In this case, most people would pay much, much less than $5,000. And this is an example of uncertainty. You don't know the odds, and so therefore you're much less likely to want to play.

And that, in a nutshell, is the difference between risk and uncertainty. And the fact that risk allows us to make these inferences, while uncertainty doesn't, means that from an evolutionary perspective, you know, our brains are going to start telling us, red alert, stay away from that kind of an uncertain environment. Because from an evolutionary perspective, we actually need to know what's out there, because what you don't know can kill you. How much brain damage do I have? The question is, would the risk be acceptable?

I don't know, and it's extremely hard to know. Today on Freakonomics Radio, risk versus uncertainty in the real world, but a part of the real world that most of us will never get near. In football, I just love running around and hitting people Radio, the podcast that explores the hidden side of everything. Here's your host, Stephen Dubner. The National Football League begins its new season this week. Football is far more than just the biggest sport in America. It's part of our calendar, part of our social fabric. Even during the offseason, it makes big news. Among the three biggest stories this offseason, the New England Patriots quarterback Tom Brady, arguably the best quarterback in history, turned 40 and is still amazingly good.

The quarterback Colin Kaepernick, meanwhile, has no team. In part, it is suspected because he is chosen to not stand during the national anthem. It is Kaepernick's protest against what he calls, quote, a country that oppresses Black people and people of color. A third big story this summer, a Baltimore Ravens offensive lineman named John Urschel, entering the prime of his career, abruptly retired at age 26. I told the Ravens, then the Ravens announced it. And then all of a sudden, you know, I was, so this was a very naive thing of me. I was really hoping to just go out quietly. Nice and quiet, like a thief in the night. No one pay attention to me. There's no story here.

There's nothing going on. That is naive. And I think on July 27th, I had a lot of phone calls, certainly in the hundreds of phone calls. And this was frankly a nightmare for me. I don't really relish being the center of attention. And I mean, and I'm trending on Twitter and people are writing. And people are kind of making guesses as to my motivations. Why did a relatively obscure player suddenly turn into such a big story? That's pretty simple. He quit football just two days after the publication of a study that assembled the most compelling evidence to date on the relationship between football and brain damage. And John Urschel has a particularly compelling

brain. He has bachelor's and master's degrees in math from Penn State, where he also taught math while playing college football. He's published papers in major journals like On the Maximal Error of Spectral Approximation of Graph Bisection, which appeared in linear and multilinear algebra. Also, he's been working toward a PhD in math at MIT. Yes, for the majority of my NFL career, actually. And so how did that work out? Just like, when did you do what as a doctoral candidate around the football season? Well, I was a, I shouldn't say was, I am a full-time PhD student at MIT and I was full-time the entire time. So there wasn't really any working around to be done. But obviously during the

football season, you're not attending classes. I assume. I mean, that's not possible, right? Football is very full-time job. Yes. Yes, of course. This is a natural question. And I guess since I'm retired, I'm allowed to say I was full-time, full-time. So for example, last fall, I took courses at MIT. During football season? Yes. last fall, I took courses at MIT. During football season? Yes. Via correspondence, I took courses which I thought were very manageable in season, areas that I was more or less familiar with previously, classes which had a textbook and which the professor followed the textbook and I would just do the assignments and then just send them in. So you say that you can tell me now that you're retired.

Am I to gather then that you didn't tell the Ravens that you were actually full-time at MIT during the football season? I did not tell anyone this. Well, except MIT, obviously. MIT was very much up to speed on that. But I don't think an NFL team would be extremely happy to hear that I'm working towards my PhD also in the fall. And how did a standard day work out?

Yeah, I mean, that's a natural question. So my schedule, to put the MIT things in perspective, what I would do is I would play the game on Sunday. And then from Sunday, suppose it's a home game, one o'clock kickoff, I get home around five, perhaps 530. And from Sunday, 5.30 p.m. until Tuesday, say 11 a.m. when I have to go into the Ravens, all I am doing is MIT coursework and math. That is all I am doing. So MIT accepted me as a PhD student, but they don't have part-time PhD students. So if I have to finish in four years, maybe five, well, this is just completely infeasible if I'm only working on the PhD half a year. Gotcha. You said that it would have been hard to do your coursework during

the later part of the week. That's because the intensity of the football week is building and you're getting more in your brain in terms of game plans and the opponent and so on? Yes. Your focus is very much on your opponent. Wednesday and Thursday in the NFL are their full eight-hour, seven to four days or eight to five days. And you're very tired at the end. You have to watch film of practice. You have to watch film of your opponent. And even, you know, Friday, Saturday, you're really preparing for the opponent. You're really getting your mind right for those things. Was the reason that you didn't do work later in the week because you would have felt it was kind

of cheating your team, the Ravens, and maybe the fans in the week? Yes, of course. Very much so. As we spoke, Urschel was planning to move from Baltimore to Boston with his fiancée. My fiancée's name is Louisa Thomas. She is a historical nonfiction author. The two of them will soon be three. Yes, yes. I'm expecting a baby girl. Her name is going to be Joanna. We were speaking in August.

In previous years, Urschel would have spent August training for the NFL season, or before that, college or high school football season. This time, he was on vacation, along with the rest of America. I actually didn't even know that August was like the vacation month. So this is news to me. He and his fiancée were in St. Louis for a chess vacation. Yes, chess vacation. Chess is a fairly new but serious passion of Urschel's. St. Louis is the site of the Sinkfield Cup.

It's like an elite chess tournament, and it's been very enjoyable for me. He's not nearly good enough yet to compete in this kind of tourney. He was there as a spectator. You can go up and watch them play. You can go into separate places and watch commentary. And certainly you can grab a beer and, you know, chat with your friends about the game. So John Urschel is just another 26-year-old chess-spectating former NFL lineman getting a Ph.D. in math at MIT. How'd that happen?

I grew up in Buffalo, New York. I grew up with my mother. My father left when I was three, though I have a good relationship with him. And he's a good guy. He was a surgeon, ultimately, yes? He was a good relationship with him. And he's a good guy. He was a surgeon ultimately, yes? He was a thoracic surgeon. He was the chief of surgery at the Harvard Hospital in Boston, Beth Israel, before he retired. And he had played college football, I believe, yes?

That is correct. He played college ball at the University of Alberta, initially as an offensive lineman, and then he moved to linebacker. And your mom then, I understand, became a lawyer? Yes, that is correct. And what were you into and not into as a kid? As a kid, I was very much into puzzles, math puzzles, any sort of puzzles, really. I was quite into horror movies. Now, what about sports as a kid?

I believe when I was younger, I think my mom put me in, like, indoor soccer. My mom was not quite in favor of me playing football, actually ever, now that I think about it. But my father was in favor of it. In high school, Urschel was a good enough player and student to be recruited by, among others, Stanford, Princeton, and Cornell. I visit Cornell, and they show me the best time of my life and I almost commit to Cornell on the spot, which those familiar with like football recruiting and, you know, how those things go, that works. Can you give us some details on what was so great about this visit?

No, but it was a very, it was a very... Did it involve alcohol or other, you know, generally forbidden substances? So as my story was going, it was a very enjoyable time. You know, tons of trips to church and Bible study. It was the best. One that I will never forget and I still have not forgotten. Urschel's dream school, and one of his mom's dream schools too, was Stanford. But after showing interest in Urschel, they disappeared.

And so Penn State offers me very late. So I make a visit to Penn State. I commit on the spot. And I just fell in love with the people. And also it was my best option. I go home. And the Monday after the weekend of my official visit to Penn State, who calls me? Jim Harbaugh.

Harbaugh was at the time the head coach at Stanford. He also happens to be the brother of John Harbaugh, who would become Urschel's head coach in the NFL. And he says, listen, I'm so sorry. We've dropped the ball on recruiting you. The person who was recruiting you quit suddenly. And so they had to get things in order. And he called me that Monday and offered me a scholarship on the spot and offered for me to fly out that weekend to go look at the school. And I remember because my mother was in the car with me, I had to tell him that, you know, I'm sorry, I just committed to Penn State this previous weekend.

Penn State wasn't expecting all that much from Urschel. I was the 26th out of 27 people they got for their class. I'm also undersized. I'm only about 265 at the time. And I just put my head down and I worked hard. I worked hard in the weight room. I worked extremely hard to try to improve my technique as an offensive lineman. I always like to say that my math talent came fairly easily. My football talent, very much less so. It was a lot of hard work, a lot of long hours. Urschel had an outstanding college career, winning athletic and academic awards.

Yes. So it started to become apparent to me that I'd have a chance to play in the NFL. And did you have any reservations? Was there ever a point where you said, you know, I'm thinking about a Ph.D. in math and you know what? I love football and I'm good at it, but I think I'll pass on that and just go straight into academia. Was that ever a thought or were you yourself pretty pro-NFL? It didn't even cross my mind. I was 100% pro-NFL. I mean, just the dream of playing the sport I love at the highest level. This was a no-brainer. And in hindsight, it would still be a no-brainer. Urschel was not a superstar with the Ravens, but to be fair, very few offensive linemen are. They do the dirty work that most fans don't pay that much attention to. But he had an absolute blast.

So the thing I really love about playing offensive line is it's a very physical, sort of visceral position. position because every play I'm fighting with a defensive lineman or a linebacker where they are trying to get through me to physically tackle someone and I am doing everything I can to stop them, whether in somewhat of a passive fashion or an extremely active one. In his second year during a preseason practice, Urschel got a concussion. Yes. I believe I was playing left guard. I pulled right to trap out the defensive end or outside linebacker. And I got a little bit more than I bargained for. And I was knocked unconscious. What was the treatment like for you then? I was, I walked off the field. Note that the Ravens did try to cart me off the field, but you know, I was being my stupid self. So I walked off the field. They, you know, they checked me for a concussion. They diagnosed me with a concussion

and I was in concussion protocol for perhaps two weeks, I believe. I had some trouble passing this so-called impact test. And I just wasn't quite feeling well nor feeling myself. And what did you notice about your brain during this concussion recovery period? It was tough for me to do like high-level math. I really tried to. I really wanted to because there was actually a paper to do like high level math. I really tried to, I really wanted to, because there was actually a paper that I had been working on that I was really proud of because it was going to be my first like big solo authored math paper. And I just wanted to like keep working

on it to finish it. And I really couldn't because, you know, I had really hard times like thinking through things and visualizing things. I mean, thankfully, I got the paper done and I was really happy to, you know, have it accepted. So it all ended well, but at the time I was frustrated. A few months before Urschel's concussion, a promising young linebacker for the San Francisco 49ers named Chris Borland announced he was quitting the NFL. He was concerned about long-term brain damage. Urschel, who was friends with Borland, responded by writing an essay for the Players' Tribune called Why I Still Play Football. Playing a hitting position in the NFL, Urschel wrote, can't possibly help your long-term mental health. However, it's also true that how bad such a pursuit is for you is something that I believe no one really knows for sure right now. From an evolutionary perspective, we actually

need to know what's out there. With that said, Urschel wrote, why take the risk? Because what you don't know can kill you. Objectively, I shouldn't take the risk, Urschel went on. I have a bright career ahead of me in mathematics, but I play because I love the game. I love hitting people. And then, a few months later, Urschel got the concussion that left him unable to do high-level math. Did you think about retiring or quitting football right then? Actually, I didn't. I didn't actually think about it at all. I just wanted to keep playing football. I loved the game, and I was very much focused on

being the best offensive lineman in the NFL, I could be. Coming up on Freakonomics Radio, what finally changed John Urschel's mind? It's clear that there's a link and that there's a problem in football. It's not what any of us wanted to hear. How did his head coach take the news that he was quitting? He even called me recently to, you know, check in on me and see how things are going at MIT. And how sympathetic has the NFL been, historically, on the issue of brain health? I think as far as the NFL goes, they're bullies. Even if you don't follow football at all, you know, their brain tissue examined for a degenerative brain disease. That's when things started getting pretty icky.

That's Alan Schwartz. And I'm a journalist and author based in New York. The brain disease is called CTE, or chronic traumatic encephalopathy. It's characterized by a deposition of a protein called tau, and that accumulates in nerve cells and other cells throughout the brain. Anne McKee is a neuropathologist who directs the CTE Center at Boston University School of Medicine. So it starts as very focal problems or abnormalities, but then over the decades becomes a devastating neurological condition. It causes memory loss, cognitive changes, behavioral changes like aggression,

impulsivity, depression, and it can be very disabling with time. Alan Schwartz wrote 130 articles for the New York Times about concussions or brain trauma in sports, primarily football. There were two reasons why this blew up in football's face or in the NFL's face. One is players started dying and were found to have the brain disease. And then the NFL put up such a fuss saying, oh, there's nothing happening here. We have our scientists who have shown. I mean, they played the perfect villain. We had something that resembled the tobacco industry. Former players were dying young, sometimes by suicide.

Older players were completely losing their faculties. And occasionally a current player would quit the game young, afraid of long-term brain damage. I think as far as the NFL goes, they're bullies. And they have been able to quash every public relations problem in their history. Whether it's domestic violence recently, whether it's steroids, whether it's the strikes and lockouts, I mean, there are games to be played on Sunday, and everyone forgets by then. But this is the one public relations crisis that they have lost. Well, my feelings about the sport have definitely evolved. The brain researcher Anne McKee again.

I was born and raised right outside of Green Bay, Wisconsin, and my brothers played football. In fact, I was an absolutely enormous Packer fan. And because I think I was raised in such a football-centric community, I have always had a terrific admiration for football players. Then she began to study the brains of deceased players. At one point, I could compartmentalize. I could still enjoy the games. I could watch them on Sunday on the television. But at this point, I can no longer dissociate what I'm seeing under

the microscope. And after listening to hundreds and hundreds of stories of really just profound tragedy, I can't look at the game anymore without just sort of imagining what might happen to some of those players. One challenge in brain research is that a lot of it can only be done post-mortem. So I think being able to detect changes in the brains of living athletes, looking at structural changes after playing seasons, and also being able to detect CTE is going to be absolutely a game changer, pardon the pun, in research going forward. But for now, researchers like McKee work with brains donated by the families of people who have died. I run a number of different brain banks. I have the Framingham Heart Study Brain Bank.

We have the Alzheimer's Brain Bank. We have an ALS Brain Bank. We have PTSD. And we see very few, you know, the incidence of CTE in those other brain banks is extremely low. But then in this brain bank, where the criteria for inclusion was participation in football, and that was the only criteria, we see a very high percentage of CTE. So it's impossible for me to dissociate the risk of playing football from the risk of

CTE. It's been nearly 10 years since McKee began finding evidence of CTE in the brains of deceased football players. Sometimes she'll meet with family members after she's done the analysis. The memory of one such visitor has stuck with her. Her father had died, and she came to the lab and wanted to look at the slides. And she was, you know, an adult. She was 30s or 40s. And I remember she looked at the brain, and I explained it to her, and she seemed fine with it.

And then a bit later, I saw her really crouched in a corner and sobbing. And I was wondering why, you know, had I upset her? Had I had too much information, you know, with the brain autopsy? And it wasn't that at all. It was actually, she was so overwhelmed because she suddenly realized that her father had loved her, that his behavior of not remembering her birthday or not remembering details of her life or seeming sort of distant was actually part of his illness and not part of a dad who didn't care.

Women are the heroes of all of this, in my opinion. Alan Schwartz again. They were the ones who really stood up to the NFL. It was Sylvia Mackey, the wife of John Mackey, who wrote to Commissioner Paul Tagliabue to say that her husband had early dementia and she knew a lot of wives dealing with their husbands and former players, and appealing to the NFL to help, which started a charity for families. Linda Sanchez was the congressperson most involved in all of this and most caring. And Gay Culverhouse, the former president of the Tampa Bay Buccaneers, is the only NFL executive to come out and speak out about the issue of brain trauma among former players. Happens to be a woman.

Culverhouse is no longer the only such executive, but she was the first. Dr. Anne McKee, the neuropathologist, these women are all football fans. They like football. They don't want to destroy football. But I think they wanted to introduce some sanity and some realism about all of this and to demand from the over-testosteroned men who said, you know, shut up, say, you know what, I'm not going to shut up. Ann McKee's latest study, co-authored with more than two dozen fellow researchers,

was published in the Journal of the American Medical Association in July, just as John Urschel was getting ready to play his fourth season in the NFL. That is correct. The fourth season, by the way, is typically the last season an NFL player is bound by his rookie contract, which can mean an even bigger payday the next year. Money just like showering, allegedly. So what did you see as your financial future within football? Did you think about, you know? I don't know. I didn't think about it.

I didn't really think about it that much. I don't really spend money that much. And I'm quite happy with my bank account. There's nothing I really want to spend money on. I buy books on occasion, like chess books, math books. That's about it. This new study was unprecedented in scope. This is the largest case series by far of American football players. It included brains donated from 202 deceased former players across all levels of the game. 111 of them had played in the NFL. And we did this very rigorous neuropathologic examination. We had defined criteria to make the diagnosis, and we had a team of four neuropathologists who looked at the cases. What did McKee and her colleagues find?

And so ultimately we found that I believe the overall was 87% of the football players in the series had CTE, and that included 99% of former NFL players. Here's my thing about this study, and this is something that bothers me. The big headline is like 99% of NFL brains they looked at had CTE. I think it was 99%, right? Yeah, more than that, 110 out of 111. Well, especially to NFL players that asked me my opinions about it, I said, listen, this number, do not look at this 99% chance that I have CTE, because that is far from what this is saying. Yeah, I don't think we're at the point where we can talk about a definitive risk estimate for an NFL player. I do think the 99%, although we have said in every interview, and we've said it very

clearly in that paper, that number became larger than life. But that wasn't because of the authors of the scientific manuscript. Because, frankly, there's a strong, strong case of self-selection bias there, and that cannot be ignored. In other words, the brains that are being donated to this bank were from families or players who suspected that they had CTE or something close to that. Is that what you're talking about? Yes. I mean, I can't say that, you know, I know for certain that it's self-selection bias,

but my instincts tell me it's extremely, extremely likely that it is. It's not a general population of all people in the community or all football players in the community. If we had those population studies, I'm sure the risk would be lower. However, the question is, would the risk be acceptable? And in my opinion, this study says no, it would not be acceptable. I assume the timing of the study and your decision were not coincidental? No, I don't think it was necessarily coincidental, but I don't think it was necessarily directly causal. The best, the easiest way I can explain it is that it was causal in one respect, but not in the way that most people think it was. The way that it was causal is that

it really reopened a dialogue between myself, well, within, you know, talking to myself and also between myself and my fiance. It really opened a dialogue that I had not opened in an extremely long time. And why was that? Did you, I mean, can I psychoanalyze you for one second? Yes, of course. Feel free. Was it because you loved playing football so much that you didn't even know the rational part of your brain that maybe contained the mathematical abilities in your brain? Just you were able to override that or quiet it down so that you could keep doing what you wanted to do? Yes. Yeah. I think that's a good way to put it.

So this thing comes out, and obviously it's not 99%. Like, it's 99% in the study, but it's like, for me, is my chance is 99%? I highly, highly doubt it. Is it 0%? I highly, highly doubt it. But the biggest thing it did was it made me say, well, okay, I should actually probably think about this again. Not like, okay, this new evidence is extremely overwhelming to change my opinion. in a very real way that, quite frankly, I was more or less aware of, but attempting to ignore to a degree. And in the back of my head, I had already been having these thoughts to some degree

about my longevity and how long I wanted to play because the main thing was that I thought about what was I most passionate about and what was I most excited about in life going forward. And when I thought about, you know, what are these one or two or three things, when football all of a sudden was not one of these top two or three things, and football is actually, you know, actively hindering me from doing some of these things, well, then it became a real conversation. Was your fiancé eager and ready for you to not only open this dialogue, but to make the decision that you did? Yes, quite, quite ready. Yeah. And what about your mom? Yes, she has been ready.

What about your dad? Not in favor. Yes. So what I did was I called John. John Harbaugh, the coach? Yes. Head coach? Okay. Head coach. I thanked him and the Ravens because, quite frankly, I thoroughly loved my time in the NFL. I loved my time with the Ravens. And he expressed sentiments that he has the utmost respect for me, and I, we had a very positive conversation. He even called me recently to, you know, check in on me and see how things are going at MIT.

Were you concerned at all that your retiring would signal to the world that, holy cow, this is very startling and a very strong indictment. Yes. And this was actually a serious, serious concern of mine because yes, I am retiring. I did retire. But at the same time, I love the NFL. I love football. And I wouldn't trade my experiences for the world. And I do believe football is a great game. And I didn't want to be, for lack of a better word, I didn't want to be perhaps just fodder for certain, you know, anti-football establishments. Do you think football survives long term? Yes. Yes, of course. I take no pleasure at all in the suggestion that I might have helped kill off football. That, again, is Alan Schwartz, who's reporting in The New York Times, highlighted the connection between football and brain damage.

I hope that football stays around, and I'm very confident that it will. Because why? Because two things. One, NFL owners are not in the business of having their $2 billion assets disappear. And the game will adapt. I'm not sure exactly how all this is going to play out, but the game, it's a great game. It's just played more recklessly than I think the market will allow. Because this affects a game we love, a game that defines communities, a game that is really the lifeblood for many colleges, there's a lot of resistance to really addressing this problem in the way it should be addressed.

That's Anne McKee. I just want people to be aware of this disease, and I want individuals who decide to play football or to continue to play football to be aware of it so that they can make as many individual changes to keep their head out of the game, to limit the amount of head impacts they experience, and make as an informed decision as they can regarding their own future. And what is the NFL doing? The league sent us a statement that read, in part, the NFL has made real strides to do everything it can to better protect players and make the game safer. And it pointed to 47 rule changes since 2002. These include requiring more medical personnel to help diagnose head injuries, more careful treatment of players suspected of sustaining a concussion, and the prohibition of certain plays and procedures that have been deemed too risky. I think the responsible thing is to make some real changes in the game,

limiting the amount of head contact, limiting practice, raising the age that children start to play football, maybe limiting a playing career, and really addressing with some strong research support how to identify this disease in people while they're still living and come up with treatments for it. All that said, Anne McKee says it's hard to know exactly what to do since the science on brain injury is still young,

and since there are some surprising wrinkles, like the correlation or lack thereof between concussions and CTE well repeatedly in our studies we've looked at concussion and number of concussions and in none of the studies have concussions correlated with the development of CTE we've had individuals with no reported concussions who have CTE and We've had individuals with no reported concussions who have CTE, and we've had individuals with a number, high numbers of concussions who don't have CTE. But the one thing that seems to be holding up, it's years of exposure to the sport and the length

of playing career. And by that, the number of sub-concussive hits, that is the same impacts that lead to concussions in some people and symptoms, don't rise to the level of symptoms in others. And it's really the duration of the career, the cumulative number of what we call sub-concussive hits that seems to correlate best with the presence and severity of CTE. There's one more point about the brain, obvious maybe, but often overlooked. The brain is just this marvel, and it really controls our personality, our thoughts, our experiences, our emotion, even our reflexes and our athleticism. that's what the risk is here. It's not like an arm or a knee. You'll still be the same person, even if you have difficulty moving or pain when you move. But the brain is actually your identity.

Especially if you're the kind of person getting your Ph.D. in math at MIT. I'm interested in Voronoi diagrams, centroidal voronoi tessellations, but also interested in other things. My advisor is this guy, Michelle Gomez, and he specializes in combinatorial optimization. And so I've been working on a lot of combinatorial optimization lately, and this is what I've been learning a lot about. So I do have diverse interests. I do want to hear what you think about the extent of any brain damage you may have done by playing all the football you've played. That's a good question. How much brain damage do I have?

Hmm. I don't know. And it's extremely hard to know. And while there are encouraging signs for me at the moment because I don't have any problems currently, again, I don't know. And I don't know how much of an effect having played football will have on, you know, my experiences later in life. To know with certainty is a very hard thing in this area, I believe. John Urschel always knew that playing football involved risks, as does just about anything in life. But when risk tipped into uncertainty, well, that seems to have been his tipping point. I mean, from my own perspective,

I think it's wise because I think that doing mathematics could provide a lifetime of pleasure and success, whereas being a very successful football player can provide you with five to ten, maybe fifteen years of success. That, again, is Andrew Lowe, who teaches finance at MIT. Maybe he and Urschel can be friends. If you don't know what the odds are, you really have to just say, it's probably not something that I'm comfortable doing. I think he's making a very human decision. Because we don't know what the odds are, the potential loss, both for him and for the community, it could be incredible. I mean, imagine if Albert Einstein ended up being a linebacker for his football team, and we never

would have gotten the theory of relativity because he got tackled during a particularly nasty game. So if you don't know what you're giving up, if you don't know what the odds are, it's actually very easy to say, you know what? I don't think I want to play. Coming up next time on Freakonomics Radio, we're talking about talking. I find it fascinating that there's 7,000 different ways to do what we're doing right now. We talk about how talking began. There are many, many theories as to why people started using language. And some of them are ones where you want it to be true because it's cool.

And if we could start over, what would that look like? The truth is that if we could start again, I don't think anybody would wish that the situation was the way it came out. We return to our Earth 2.0 series with a look at our modern day Tower of Babel. That's next time on Freakonomics Radio. Freakonomics Radio is produced by WNYC Studios and Dubner Productions. This episode was produced by Stephanie Tam with help from Eliza Lambert. Please don't take our fair treatment of John Urschel and the Baltimore Ravens as any sort of endorsement of the Ravens. Freakonomics Radio is firmly a fan of the Pittsburgh Steelers.

Our staff also includes Allison Hockenberry, Merritt Jacob, Greg Wazowski, Emma Morgenstern, Harry Huggins, and Brian Gutierrez. We had help this week from Sam Baer. The music you hear throughout our episodes was composed by Luis Guerra. Special thanks to Andy Lancet, New York Public Radio's director of archives. You can subscribe to Freakonomics Radio on Apple Podcasts, Stitcher, or wherever you get your podcasts. You can also find our entire archive on Freakonomics.com. You can stream or download every episode we've ever made. You can read the transcripts, and we list links to all the underlying research. We can also be found on Twitter, Facebook, or if you want to send us an email, we are at radio at Freakonomics.com.

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