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.