B (3:13)

All right. We are talking to Vikram Chibb, a biomedical engineer at Johns Hopkins University. You have studied people's brains to understand how they respond to rewards, like gold medals or whatever your own personal gold medal is. And you've also looked at what happens, what's going on, when people feel tired. And I wanted to ask you to tell us about that, like, what's actually happening in the brain when we are fatigued, right?

C (3:42)

So there are different types of fatigue that you could have, right? There's cognitive fatigue. Maybe you're doing. You're sitting at your desk and you're doing a lot of, you know, spreadsheets or something, right? Or writing. And then there's physical fatigue, which is, you know, running, you know, walking up a long flight of stairs, things like that. And what we found is that there are areas in your brain that are involved in sensing your internal state. And when those areas interact with motivational areas, that's kind of what gets you to feel fatigued. So you sense that your body can't produce any more output, any more effort, whether that's cognitive or mental, and that gets you to sort of shut down and feel tired.

B (4:26)

And does that fatigue, does it look different inside the brain when the stakes are higher or lower for somebody, when that reward is more on their minds?

C (4:39)

Yeah. So we haven't directly looked at higher or lower stakes. What we do know and what we're starting to see is that offering a little bit of reward can push you out of that fatigue state a little bit. So reward can sort of counteract the cost of effort that you have to do, right? So you can think of any action that you're doing is like a trade off between the effort costs that you're putting in and the reward you're getting out. So if I boost up that reward a little bit, right. It might motivate me more to overcome some of that feeling of fatigue and do the task that I'm set out to do, right?

B (5:20)

So, like, thinking of everybody at the Olympics right now, maybe an athlete might be totally exhausted, but if they know that if they push a little more, they could win gold, maybe they're more likely to actually be able to overcome that fatigue.

C (5:34)

Yeah, that's right. So like, you would think about like a speed skater, right? You see these people getting their Olympic records or gold medals, right? And, you know, they've for four years, they do their world, World cup events, you know, and they Do. Okay, right. Sometimes they. They. They break world records. But you see a lot of Olympic and world records broken in. In the Olympics.

D (5:55)

Right.

C (5:55)

And so what? One. One way to think about that. I mean, this is just speculative. Could. Could be that, like, okay, that added. That little added reward pushes them beyond their limit.

B (6:06)

That makes perfect sense, right? You have this offering of a reward, and you sort of do something superhuman. You can do better than you've ever done before. What about the flip side? What about when Olympians choke and they mess up on something that they've been able to do before? Just fine. Is that. Is that related to mental fatigue or is there something else going on?

C (6:26)

Well, we've sort of looked at that in terms of the heightened reward aspect of it as opposed to the fatigue aspect of it. So what we've done is we've kind of set up these, like, choking scenarios in the lab where we. Where we use incentive. And the incentive we've used is money. So we pay people, like, a lot of money. We tell them, okay, you're going to do a single trial, like, of a skilled motor task, essentially playing a video game. And on certain trials, we're going to give you $100 to do this trial. And what we find is that people do, as the incentives increase, 25, 50 people get better. And when you give them 100 bucks, they tend to choke under pressure. Their performance goes down. And we looked in the brain when that happened, and what we found was that there's this area deep in your brain that's responsible for reward processing called the ventral striatum.

B (7:20)

Ventral striatum.

C (7:21)

The ventral striatum. And so it activates when the rewards are high, and it actually tends to deactivate when you have potential losses. And what we found was that what would happen is when people were playing a task and really high incentives were on the line, they would begin, they would see that incentive. They'd be like, oh, wow, I have $100 to win. They would see that really high incentive, and they would view it as a loss. They would get worried about actually losing the really high incentive. And that worry about loss was related to how they choked under pressure. So the people that tended to worry more about that loss tended to choke under pressure more. They essentially reframed this positive thing, the hundred dollars, as, oh, my gosh, I could lose that $100.

D (8:06)

Right?

C (8:06)

So it's in their mind right now. What's interesting is the ventral striatum not only does reward processing, but it also does motor processes as well. So it Initiates motor action. And so what we think is that there was some crosstalk between those reward signals or those worry of loss signals and the motor signals, and that's what got people to do poorly when the stakes were high.

B (8:31)

Yeah. So if you're thinking that you might win the gold medal, that's great. And if you're thinking, oh, my God, if I mess up, I don't win the gold medal and I lose, then suddenly your, your brain can't work the same way.

C (8:46)

Yeah. So essentially it's. It's like a reframing. Right. So your brain is. Is reframing that incentive, and that reframing can get you to do poorly. Now, we've also found that if you train yourself to reframe the task in a different way and say to yourself, okay, I'm going to go into this trial and I'm not going to think about this individual trial. I'm going to think about the portfolio of all the trials I have to do. So like, for example, the portfolio of all the races I have to have to skate. If you do that, you don't focus on that loss as much, and you see less brain activity associated with this fear of losing. And you tend to do better under pressure. So cognitive reframing can sort of get you to overcome that choking behavior, or at least we've seen that in the lab.

B (9:34)

Yeah, yeah. You mentioned the ventral striatum. Are there other big parts of the brain that are at play when someone's under pressure or having performance anxiety going on that you look at?

C (9:44)

Yeah. So you can think of the reward areas. So ventral striatum, nucleus accumbens, prefrontal cortex. Those areas respond to reward. So the brain sort of activates when the rewards are very high. You can also think about the motor areas if we're thinking about Olympic sport. So motor cortex is an area that's responsible for coordinating your arm movements and your leg movements, or the cerebellum, that's another motor area. But you can also think about sort of cognitive areas because some of these events are very, you know, cognitively taxing. For example, like you see people doing curling. Right. You know, there's a lot of strategy and mental effort into say, like, how do I place this rock in the right place.

D (10:32)

Right.

C (10:32)

And so you can even think about working memory areas or prefrontal cortex. Again, that not only does reward, but does sort of higher order cognitive function.

B (10:40)

Yeah. And, you know, I'm watching them do it on tv. What is, what does attention from other people do to someone's experience of trying to do a difficult task, like having millions of people watch you on live TV as you're, you're taking your shot.

C (10:57)

Yeah. So, you know, that can be another incentive. Right. Social approval is, is an incentive. And so we've actually done studies in the lab where we've put people in the scanner, had them be watched while they're doing different tasks. And it's very similar to the reward scenario that I gave you before. Right. A couple people watching you can get you to boost your performance and actually like enhance performance a little bit. Right. But we've seen, you know, when crowds are really big, we haven't been able to do this in the lab because I don't know how to get thousands.

B (11:25)

Of people in the lab.

C (11:26)

But when, when there are a lot of people in the crowd. Right. That social incentive can be really high. And in the same way that the, the reward value, when it's really high for just monetary rewards, can get you to do poorly, that can happen in the social context as well. Right. And we see that, we see that time and again.

B (11:47)

So a little, a medium sized reward, a few people watching, really helpful, a lot. A giant reward, a ton of attention, like, can actually make it really difficult to do something. Olympians have to be able to compete with the most part pressure that I can imagine. So what can the rest of us learn from them in our maybe lower stakes personal gold medal events? How do we shift our focus, reframe our thinking so that we can do better under pressure?

C (12:23)

Yeah, I think using these cognitive approaches is helpful thinking about things in terms of the big picture as opposed to smaller, you know, bigger, smaller events that you get really myopic about and then worry about doing poorly on them. I think, you know, you, you have a big event happening, you have to give a big presentation at work, for example, and you, you worry about it for days and days and days. Whereas you could just think to yourself, like, oh, I'm gonna have, you know, a bunch of presentations over the year and like, it's okay if I don't do as well on this, I can sort of, I'll have other chances to do well. So I think reframing is something that we can do to get us to do well when the stakes are high for us.

B (13:01)

All right, awesome. Well, thank you so much for coming to chat about the Olympics and pressure and rewards with us. This is something I know I'm going to be thinking about as I watch the rest of the Games. And fingers crossed that those athletes can, can keep their mind on the big picture.

D (13:16)

All right, great.

C (13:17)

Thank you for having me.

B (13:21)

If you liked this episode, follow us. It really helps the show and means you never miss another episode. Also, check out our episodes on sled head, a condition affecting bobsleigh and skeleton athletes, and the physics powering the cool feats of other Olympic sports like ski mountaineering and the ski jump. This episode was produced by Rachel Carlson, edited by our showrunner Rebecca Ramirez, and fact checked by Tyler Jones. Kwesi Lee was the audio engineer. I'm Camila Domonosky. Thanks for listening to Short Wave from npr.

D (14:07)

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