IRA FLATOW: The NFL season is in full swing, and if you’ve been watching football for a long time, you may have noticed some changes. The uniforms and the helmets have changed a lot, but did you notice that the numbers are different too? Really. Here’s the story.

For most of the NFL’s history, wide receivers could only pick Jersey numbers between 80 and 89, but in 2004 the league loosened this policy, allowing players to also pick numbers between 10 and 19, which it turns out many preferred, saying that the 1 looked slimmer than the 8 and made them feel thinner and faster.

So as of 2019, 80% of wide receivers make the switch, but is there an actual association between the smaller numbers and the perception of body size?

When Ladan Shams, professor of psychology and neuroscience at UCLA, heard about this, she ran a study to confirm the superstition, and touchdown. Turns out those wide receivers were on to something. Dr. Shams, welcome to Science Friday.

LADAN SHAMS: Thanks for having me.

IRA FLATOW: Nice to have you. Why did you want to do this study? How did you come up with this idea?

LADAN SHAMS: Well, it was inspired by an interview with an ESPN reporter who had done a survey and had discovered this preference by the athletes. I wondered if there is a perceptual basis to this preference, and because no one had looked into this, the association between numbers and perceptual size, we decided to test this ourselves.

IRA FLATOW: All right. Tell me how you went about testing it.

LADAN SHAMS: We presented pictures of football players, computerized images, and we created a large variety of sizes and colors of jerseys and skin tones with a variety of different numbers, but the numbers varied from 80 to 89 and from 10 to 19. We made sure that each of these players was presented twice, once with a low jersey number and once with the high jersey number.

So we asked them to rate the slenderness or huskiness of each player. Then we went back and looked at how these ratings compared for the same player, and we noticed that the athletes with high jersey numbers were rated as more husky or less slender than the athletes with low jersey numbers.

But we didn’t fully trust these results, because online experiments– there are a lot of factors that we cannot control. So we decided to repeat this in the lab when the university reopened and controlled for other factors, and we got the same results.

IRA FLATOW: What was your reaction that this perception was actually confirmed in the data?

LADAN SHAMS: It was really surprising even though we had a hunch that there may be something going on in terms of association between size and number. But this was still surprising because it is a connection between something which is really high level of processing in the brain– the understanding of numbers.

And numbers are concepts that we learn and we have to acquire knowledge about to appreciate that 80 is larger than 18, or so on. And the task involved a fraction of a second of looking at these pictures. Yet the knowledge and concept of numbers influence the perception of size. So this was very surprising for us.

IRA FLATOW: So– it wasn’t that the 1 is skinnier and makes you feel like you’re skinnier, and the 8 is bigger and huskier. It was that the number was higher so you felt it made you feel huskier?

LADAN SHAMS: Yes. Exactly. It’s not the visual size of the number, but it’s the understanding the concept of the number that is influencing the perception of size.

IRA FLATOW: So you can’t say that wide receivers with lower numbers actually make more completions or are more agile than those with higher numbers?

LADAN SHAMS: That’s right.

IRA FLATOW: Yeah. What are some of the ways to think about how this research can be applied to our daily lives outside of football? Is there a way that can happen?

LADAN SHAMS: Well, the brain is in the business of making educated guesses– the shape of objects, the color, the size, the speed. All of these things have to be estimated non-stop, every moment of our waking hours, for us to be able to function. The exposure to these associations help us make better educated guesses– estimate things more accurately and more precisely on a daily basis.

This is an implicit bias. It’s a demonstration of how unaware we are of all the things that get stored and noticed by our brains even when we’re not paying attention. Really, the only effective way to get rid of implicit bias is to change those underlying statistical patterns and regularities.

So if we want people to be less biased towards a certain group, we just have to make sure that those groups and individuals have a better representation, and that would lead, in turn, to learning of those associations or unlearning of the past associations.

IRA FLATOW: Well, I want to thank you for taking time to be with us today, Dr. Shams. I don’t think I’ll ever look at a wide receiver the same way.

LADAN SHAMS: It was my pleasure.

IRA FLATOW: Dr. Ladan Shams is professor of psychology, bioengineering, and neuroscience at UCLA.

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