Lower numbers on sports jerseys make players look slimmer: study

By Stephen Beech via SWNS

Sports players who wear low numbers on their shirt really do look thinner, according to new research.

A scientific study of American footballers has stood up the long-held theory.

An ESPN report in 2019 looked at the reasons so many NFL wide receivers prefer to wear shirt numbers between 10 and 19.

The story found that many of the players simply believed the lower numbers made them look faster and slimmer than the higher numbers traditionally assigned to their position.

Professor Ladan Shams, of University of California, Los Angeles, (UCLA) offered a psychological explanation for the phenomenon at the time, but emphasised that there was no scientific research on the topic.

But a new UCLA study, led by Shams and published in the journal PLOS One, reveals that the wide receivers really were onto something.

Participants in two experiments consistently said that images of players in shirts numbered from 10 to 19 looked thinner than those in jerseys numbered from 80 to 89, even when the body sizes were the same.

Shams, the study's senior author, says the findings suggest that previously learned statistical associations between numbers and sizes influence the perception of body size.

She said: “How we perceive the world is highly influenced by our prior knowledge.

“In our daily lives, numbers written on objects - on a bag of sugar in the supermarket or weights in the gym - usually represent the magnitude of the objects.

"The higher the number, the bigger or more massive the object generally is.

“Previous research has established that our brains are very good at detecting and storing statistical associations and regularities, unbeknownst to us, and those associations can shape future perception.”

An old NFL rule required wide receivers to wear shirt numbers between 80 and 89, but that was changed in 2004, allowing them to wear lower numbers if they preferred.

By 2019, when ESPN published its story, nearly 80 per cent of wide receivers wore a shirt number between 10 and 19.

When Shams, a specialist in the science of perception, saw her other work ground to a halt during the Covid pandemic, she returned to shirt numbers.

With her research group, she devised an online study to test her suppositions about the popularity of lower numbers.

Participants were shown computer-generated images of players in identical poses - but with different body sizes, skin and jersey colors - and were asked to judge their slenderness.

They saw each player twice - once each in jerseys with high and low numbers.

In general, the players in shirts numbered 10 to 19 were perceived as thinner than players in numbers 80 to 89, regardless of their body size and their skin or jersey color.

When Covid restrictions eased, the UCLA team repeated the experiment in person.

They addressed concerns that because the numeral 8 is wider than 1, simply the amount of shirt space occupied by numbers from 80 to 89 could make players look bigger.

So they chose number combinations that used the same numerals, but varied only in which digit came first: 17 and 71, 18 and 81, 19 and 91.

In the second experiment, participants still perceived the players with higher numbers to be bigger than players with lower numbers, although the effect was lower than in the first experiment.

Shams says the results "strongly support" the hypothesis that when processing perception of body size, the brain leans on learned associations between numbers and objects’ size attributes.

She said the finding is consistent with previous research showing that statistical learning is a fundamental and universal learning mechanism.

Shams says those learned associations generally help the brain interpret sensory input - such as the pattern of light receptor responses in the eye - because sensory input can be noisy, unreliable and ambiguous.

She said the ability to perceive the world faster and more correctly is critical for survival.

Shams explained that while how viewers perceive football players’ body size has little effect on their performance, such perceptual and cognitive biases can be more harmful in other areas of life: for example, when they influence judgment, decisions and behavior toward people or social groups, a phenomenon often referred to as implicit bias.