That monologue running inside your head—you know, the one that can unfurl at a rate exceeding several thousand words per minute—has been having a moment of late. It’s the topic of numerous sports-psychology studies and the star of the 2021 bestseller Chatter, by University of Michigan psychologist Ethan Kross. Taking control of one’s inner voice has transitioned from pat self-help bromide to battle-tested, evidence-based performance hack.
That’s what we’ve been led to believe, anyway. In practice, once you get past the basic claim that the words inside your head matter, evidence that they can be turned to your advantage gets pretty thin on the ground. What exactly should you say to yourself? How often? And in what circumstances? These are the sorts of practical questions researchers are aiming to tackle. One study found that switching self-talk from first-person (“I can do this”) to second (“You can do this”) improved cyclists’ 10K times by 2.2 percent, presumably because the shift entailed a greater sense of distance from what might otherwise seem like an overwhelming challenge.
What sports psychologists call motivational self-talk may sound suspiciously like what the self-help progenitor Norman Vincent Peale called the power of positive thinking—the idea that “what you believe, you can achieve.” But the updated version does have some empirical heft behind it. Numerous studies over the years have shown that, during endurance exercise, it’s your perception of how hard you’re working that determines whether you speed up or slow down. Subtle external cues, like shouts of encouragement from spectators (as University of Pittsburgh scientists showed in a 2004 study), can make physical effort feel less strenuous, even though heart rate, lactate levels, and muscle fatigue remain unchanged. So, too, it turns out, can internal cues, such as telling yourself “You can do this” instead of “Screw this, I’m cooked.”
In a 2014 study, for example, a research team led by Samuele Marcora, then at Bangor University in Wales, recruited 24 volunteers and taught half of them to use positive self-talk during exercise. The process was simple: after performing a cycling test to exhaustion, the subjects wrote down thoughts that had occurred to them while pedaling, identified the positive ones, then used those during at least three subsequent workouts. Two weeks later, they repeated the cycling test. Sure enough, the self-talk group lasted 18 percent longer, while the control group experienced no change. The reason, the research team determined, was that although subjects were performing at the same level, those who altered their self-talk rated the effort easier during the second test.
Once you get past the basic claim that the words inside your head matter, evidence that they can be turned to your advantage gets pretty thin on the ground.
This experiment and others like it leave an unanswered question, though: Does negative self-talk slow you down, or does positive self-talk speed you up? Earlier this year, in a study published in the journal Psychophysiology, researchers led by Fabien Basset of Memorial University of Newfoundland added some relevant data to the debate. They recruited 29 volunteers and gave them self-talk training. A third of them were then assigned to run on a treadmill for an hour at a moderate (but not all-out) pace while using their positive self-talk training. A second group did the same run, but were assigned negative self-talk, statements like “My energy feels low” and “I want to quit.” The third group, meanwhile, completed the run while listening to an audio documentary called Stephen Hawking: Master of the Universe, designed to distract them and push both positive and negative self-talk from their minds.
Surprisingly, no difference was noted between the groups assigned positive self-talk and those who listened to Hawking’s musings on physics, suggesting that distraction is just as good as cheerleading. Negative self-talk, on the other hand, made the effort feel significantly harder. Runners in this group had a faster breathing rate, along with higher levels of the stress hormone cortisol in their saliva, indicating that doomsaying can trigger anxiety and stress, thus contributing to a physiologically self-fulfilling prophecy.
This is an important finding, because negative thinking is the default option for many endurance athletes. A Danish study published last year in the journal Consciousness and Cognition looked at the internal monologues of 165 runners. Compared with badminton players, they were more likely to report themes such as “I can’t keep going” and “I’m not going to make it.” The only response that was even more common among runners than those gloomy self-assessments was “What will I do later today?”—a means of distraction similar to the Hawking documentary.
There’s an important caveat regarding Basset’s findings, however. The pace for the one-hour run was 70 percent of subjects’ VO2 max, which is a moderate effort. In an all-out race, you’d expect a much greater flood of intrusive negativity driven by mounting physiological distress. And you would probably have a lot more trouble staying focused on Hawking’s ideas. Modes of distraction like podcasts and music might be great when you are cruising along on an easy training run, but if you are trying to push your limits, then you have to grapple more directly with task-specific feelings and emotions. At mile 20 of a marathon, there’s no room for neutrality: it’s a mental battle between the agony you are enduring now and the ecstasy that awaits you down the road—if you can manage to hang on that long.
With that in mind, I would be cautious about overgeneralizing based on Basset’s results. There are clearly some situations where avoiding negative self-talk—for instance, by distracting yourself—is helpful. There are likely other situations, including grueling races, where having a well-practiced arsenal of encouraging phrases at your disposal might be an asset. And as I learned a few years ago from Phil Wallace, a self-talk researcher at Canada’s Brock University, there may even be some scenarios that don’t fit neatly into either category.
Back in 2017, Wallace was the lead author of one of the studies that helped establish motivational self-talk as a science-based intervention. He showed that cyclists could be trained to alter their self-talk in light of how hot they felt while riding in 95-degree heat, and consequently to ride faster. He also uses self-talk when coaching athletes in the real world. Most of them find the approach useful, he told me, but there was one mountain biker who simply could not get rid of the negative thoughts that flooded his mind whenever another rider was on his back wheel. “I can’t maintain this pace,” he would tell himself. “This guy is going to blow past me.”
Fortunately, the mountain biker came up with his own solution. If negative self-talk was harmful, he decided, he would weaponize it. Whenever he was locked in tight competition, he’d tap into that stream of negative thoughts—and shout them at the other rider. “At the end of the day, these interventions are tools,” Wallace says. “Some people use a tool like a screwdriver to screw something in, and some people use the back end to hammer in a nail.”