NFL scores: Your team is probably less invincible than you imagine

As the NFL season opens, a British study shows NFL sports fans are overly optimistic about their teams. And scientists have found a better way to measure the cognitive trick of 'optimism bias.'

It may not be surprising to some, but a small British study on optimism bias published Wednesday in the journal PLOS ONE suggests that National Football League (NFL) fans are overly optimistic about the winning prospects of their favorite teams. They’re also overly pessimistic about the chances of triumph among their favorite teams’s rivals.

Study authors say this not only is key information for sports fans, but can also promote better understanding of the ubiquitous cognitive trick of “optimism bias,” the belief that one is more likely to experience a positive outcome over one’s peers, and vice versa with a negative outcome.

“Optimism bias is a well-documented phenomenon, but is difficult to measure in the real-world as there are so many factors to consider," said University of Oxford neuroscientist and study co-author Olivia Guest in a press release.

“Using the zero-sum closed system of the NFL, we have been able to conclusively demonstrate optimism bias since people's collective expectations exceed the total number of wins possible," Guest adds.

In an April survey of 1,116 NFL fans in the US who were asked to predict how many of the 16 games this season their most and least favorite teams would win, researchers from University College London and University of Oxford found that on average fans predicted 9.59 wins, though the largest possible number of wins can only be eight given the number of games where only one of two teams can win.

Among those deemed most knowledgeable about football – 86 percent of participants – based on a survey question about the penalty for offsides, the prediction was even higher at 10.3 wins predicted out of 16 games. Both groups predicted that teams they disliked would win 6.1 games.

“Fans and experts alike can get focused on improvements or changes for the team that they follow and don't realize that it's an arms race with other teams who are also improving,” explained the study’s senior author Brad C. Love, a psychology professor at University College London.

This applies to other areas of life, as optimism bias is not unique to sports fans. It was first recognized in 1980 by Rutgers University social sciences professor Neil D. Weinstein. He found that most college students believed their chances of experiencing 42 life events like divorce and alcoholism were lower than that of other students, and that their chances of owning a home and living past 80 were higher.

“People are unrealistically optimistic because they focus on factors that improve their own chances of achieving desirable outcomes and fail to realize that others may have just as many factors in their favor,” the study said.

This might be a good thing – unless there's betting involved – given that social scientists have found that optimism is associated with health, and pessimism with depression. But optimism bias can also be dangerous to health and well-being. People not expecting a negative outcome may fail to take steps to prevent it. And it may also make some less likely to resist risk-related behavior like smoking.

Researchers are continually trying to better understand this mental trick and sports, in some ways, is an ideal arena for the study.

“NFL is the perfect system to study optimism bias because it's zero sum – one team winning means another team losing," said Prof. Love in the news release.

So in a zero-sum scenario, according to the study, optimism bias is more conclusive because people’s predictions are collectively inconsistent.

What is also conclusive, the study shows, is that the New England Patriots were both the most liked (among 7.7 percent of respondents) and most disliked (17.3 percent) team. And that both fans and rivals predicted the Patriots will do well in 2015, with fans expecting only one more win in the 2015 season than “Patriots-haters,” according to the study.