Think about some of the consequences of comparisons. And here I want to focus on the way comparisons can actually lead to very good outcomes. And I want to focus on the link between comparisons and motivation. So here's one other thing that can be very good and constructive about comparisons. And I'll start off with a story about a Duke-Michigan game. Duke was down by one point at halftime. You can imagine what happened in that locker room. You can think about the motivational speech the coach might have given them. Duke came out roaring in the second half, they exploded, and what had been a really intense close game became a blowout. It turns out it wasn't unique to this Duke-Michigan game. It turns out that if we looked at 18,000 NBA games, which Jonah Berger and Devin Pope did. They analyzed over 18,000 games, and they found a discontinuity where teams down by one point at the half were actually more likely to win. That is, in general, if one team's winning by a lot they're likely to win the game. So if you're ahead at the halftime, it generally helps predict who wins at the end of the game, except for if you're down by just a very little bit. Because when you're down by a very little bit, you're motivated by that comparison. And that motivates you, it increases effort. And people down by one at the halftime are actually more likely to win. Now, here we find that it's not just in sports. We can see this on the global stage, we think about the space race. Now if we were to go back in the space race we were to go back to 1950s. And in July, 1955, Eisenhower came out and said the United States will launch a science satellite to orbit Earth. That was his goal. He came out with that goal, and then was surprised when the US wasn't the first to launch a satellite, but the Russians were. We're in a space race with the Russians, and Russians launched Sputnik. And that Sputnik crisis has actually carried forward for decades, and we still invoke Sputnik to think about how we're falling behind and need to catch up. So here the US felt like they were behind and needed to catch up, and it motivated an incredible government action. So we had the National Defense Education Act. It led to scholarships, NARPA, NASA. We invested an incredible amount of money. The NASA budget alone took off. You see this budget growing incredibly, where at the time it was $6 billion. Today that would be $32 billion. So in 1960s we were spending a huge fraction of the national budget just on the space budget. If I were to ask what's the right amount to spend, it's hard to tell, but we knew that we were falling behind. And in that comparison, by comparison we were down relative to the Russians. They had launched Sputnik to orbit Earth before we did. And that motivated us because of that comparison. And it challenged us and motivates to accomplish great things. So we can think about if we were to recast this one small step for man, but it turns out to be one giant leap, not just for mankind but for America over the Soviets. Now social comparisons matter in a lot of cases, but no more so than in rivals. Rivals are special comparisons. Rivals are people with whom we have an extra psychological rivalry. We get a benefit from beating a rival in a way we don't with anybody else. And in fact, Gavin Kilduff has studied rivals in running races. Analyzed lots and lots of rivalries, and found that runners run faster when they have a rival in that race. So if you're racing against a close rival, you're likely to get a better time. It's not just runners. We find this in many different contexts. And here, for those of you that are big basketball fans, you'll remember the Larry Bird, Magic Johnson rivalry. And here, Larry Bird said the first thing I would do every morning was look at the box scores to see what Magic did. I didn't care about anything else. This is intense focus, intense focus on a rival. So here we can see and think about motivation. And I already alluded to the Tarheels and Blue Devils before. These are rivals that are in close proximity to each other. Both of them have won national championships, and to win a national championship you need a lot of things. You need good coaching, you need great players, you also need a lot of motivation. And what you see is here in 92, Duke wins, 93 UNC wins. Now that'd be remarkable if it happened once, but then you see the reverse happening in 2009, UNC wins and then Duke wins the following year. So here we can see rivals motivated, highly motivated by each other. Now it happens in all kinds of relationships, if you look at sisters, a study of sisters where one's in the labor force and one stays at home. One of the things that drives whether or not one of these women works outside the home is how much their husbands make. And we find that if the husband earns less than the sister's husband that household income seems like it's not enough. And that woman is motivated to work outside the home. Interestingly, it's not that absolute amount of money that matters. It's the relative amount that really matters. So here's the broad idea, that is comparisons can motivate us and in many cases it can be very constructive motivation. But when you think about it in check, that is, not all that motivation is good, and we'll think about some of that next.