The facial structure of male baseball players helps to predict whether they’ll hit home runs on the field, according to new research.

The key to the study, published in the latest Biology Letters, is something known as facial width-to-height ratio (fWHR).

“Recent studies have begun to highlight how one’s facial width-to-height ratio is linked to a number of behaviors including deceptive behaviors, aggression, cooperation and financial performance in firms,” wrote co-authors Hikaru Tsujimura and Michael Banissy, of the University of London’s Department of Psychology.

“For example,” the study continues, “CEOs with a greater fWHR (that is, a wider face relative to height) have been shown to achieve superior financial performance for their firm.”

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For the baseball study, Tsujimura and Banissy collected images of Japanese professional baseball infield and outfield players in the Central League Pennant, which is one of the two Japanese professional baseball leagues. They used National Institutes of Health software to calculate the facial ratios. They also gathered performance statistics for each player from a Japanese baseball database.

The researchers were only interested in basic batting performance, so they focused on the relationship between fWHR and batting performance, including home runs, slugging percentage hits, runs-batted-in and on base percentages.

Players with wider faces relative to facial height consistently performed better than the others across two consecutive seasons.

The driver appears to be levels of testosterone, which other studies have shown can influence facial structure.

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“Some suggest that behavioral effects of testosterone may manifest as the motivation to achieve status or coarse physical strength,” the authors wrote. “It is feasible that these factors may mediate the relationship between batting performance and fWHR observed here.”

Still other studies have linked testosterone levels to finger length ratios. These studies compare the length of the index finger to the ring finger. For example, the lower the ratio is between the length of a man’s index finger and the length of his ring finger, the longer the man’s penis will be, according to one such study.

As for baseball prowess, there are clearly other factors besides testosterone levels that could affect the outcome.

A man exposed to less prenatal testosterone could achieve better results through greater determination and practice habits. Conversely, someone with the hormonally driven predisposition may not even pursue the sport. The individual’s build, weight, ethnicity, health status, age, income and life experiences could also be factors.

Image: Bloomimage/Corbis