Since the modern inception of the Olympic Games in 1896, the international sports competition has not had two summer contests that look alike. Among a litany of oddities are the infamous 1904 St. Louis marathon, where under half of those starting were able to finish the race; the 1956 Blood in the Water water polo match between Hungary and the U.S.S.R. weeks after the Soviet invasion; and figure skating’s two appearances at the summer games, in 1908 and 1920. Not uncommonly, countries have boycotted or been barred from attending the Olympics, too. But in its 125-year history, fans have always remained in attendance—that is, until this year’s Tokyo Olympics.

As with so much else, COVID-19 changed everything. Japan’s prime minister spurred the decision to ban spectators, even family members, by issuing a state of emergency decree in Tokyo earlier this month in response to rising COVID-19 case numbers and the spread of the Delta variant. The previous plan was to fill competition venues at up to 50 percent capacity with local spectators.

From the perspective of sports psychologists, an Olympics without fans is a real-life science experiment that is helping researchers and clinicians to tease apart the true impact of a crowd of fans on its players—and on spectators at home. The strange circumstances under which the games are held may place unanticipated pressure on some athletes. On Tuesday, superstar gymnast Simone Biles dropped out of the women’s team event, telling teammates and reporters she wasn’t in the right "headspace" to compete. “It’s been really stressful this Olympic Games,” Biles told the Washington Post. “Just as a whole, not having an audience. There are a lot of different variables going into it.” Later, Biles also decided not to participate in the individual all-around event. 

Biles’ struggles are likely widespread among this year’s Olympic athletes. “On the court, on the fields, wherever their competition is, players have this uncertainty. They’re facing a situation they haven’t before,” says Louise Byrne, a sport and exercise psychology practitioner at Optimise Potential, a sports psychology consultancy in the U.K. Part of the ambiguity, she adds, was caused by the suddenness of the decision to disallow spectators, weeks before the games’ start.

The 2020 Summer Olympics—even the time-warped name underlines the bizarreness of the event—bears similarities and differences to other major sporting events that have had to devise creative solutions to staging competitions without spectators. The English Premier League and Spanish La Liga both supplemented game broadcasts with crowd noise from the soccer video game FIFA 20, mixed with game audio in real time. A Taiwanese baseball team and German soccer team began populating stands with cardboard cutouts of fans, and the trend caught on internationally, especially in U.S. baseball and basketball.

The pandemic has emphasized the importance of an onlooking crowd to the culture of sports. That explains why sports leagues’ compensation for the lack of live fans met with varying degrees of success, says Daniel Wann, a psychology professor at Murray State University in Kentucky, who studies sports psychology and fan behavior. “It’s not like the NBA has a committee designed to figure out how to invent fans if they aren’t there,” he says. “They were just making stuff up as they went along and doing as good a job as they could, but none of it seemed real to the casual or advanced fan.”

Cardboard cutouts of fans were intended to soften the disappointment of seeing empty stands, and even to console viewers watching at home. There’s a reason the camera angles of televised sports games often include a section of the stands, Wann says.

But the Olympics, by contrast, will not adopt any of these props. There will be no fake crowd noise or two-dimensional representations of fans for Teams USA or China. By one measure, disappointment is already palpable. Approximately 17 million Americans watched the opening ceremony, a fraction of previous Olympics’ viewership. Those who tuned in described it as “eerie” and “bleak.”

For one of the world’s top athletes, however, subverting one’s expectations does more than disappoint; it can also affect performance. Jamey Houle, the lead sports psychologist for Ohio State University Athletics and a former All-American gymnast, says competitive athletes are trained in visualization—imagining performing a certain action or motion, such as executing a roundoff back handspring in gymnastics. Without moving a muscle, players using visualization can solidify neural connections and activate their motor cortex, the region in the brain that controls movement.

To visualize most effectively, Houle says, athletes working with sports psychologists will try to simulate as closely as possible the conditions of actual gameplay. In preparation for the Tokyo Games, athletes may have practiced with fake crowd noises before the spectator ban was announced, he says. Empty stadiums may thus have a measurable impact on players’ performance.

This phenomenon is grounded in a psychological concept called social facilitation, referring to a change in a person’s performance that occurs when others are around compared to when a person is alone. Top-of-the-line athletes tend to perform better with a crowd than when alone, while lesser competitors falter. “If there's a lack of an audience, theoretically, you should see across-the-board maybe not quite as high a level of performance as you would have before,” Wann says. By that logic, fewer records may be set at this Olympics, and the spread among players—the difference between the highest and lowest outcomes—may be smaller.

Not having in-person fans impacts the home-field advantage, a statistically supported phenomenon, and one that would have benefited Japanese competitors this summer. Though there is mixed evidence concerning crowd noise’s effect on players’ concentration and ability, Wann says its absence is potentially more distracting than its presence. Houle says that when home football games at Ohio State took place last season without spectators, the stakes felt lower, and that seemed to have an impact on player performance. “The chatter I heard around that was that it felt like a high school football game,” he says.

The acoustics of a field, court or stadium without fans has unintended consequences, for players and viewers both. Without the roar of a crowd, in-game sounds travel further—grunts, predictably, but also talk among referees and, perhaps most embarrassingly, smack talk that was not meant to be heard. Wann says he often watches sports fans during a slow stretch of a game, and during the pandemic, took to watching reactions from the few fans allowed at games and the players themselves: “You'd see some of the people who are right down by the pitch, their eyes wide open during the time-outs. They're hearing things they might not have normally heard.”

This article has been updated on July 28.