It's the province of riot cops, marching bands, and Hitler youth, not to mention a few millenia of militaries. And its effects—perhaps not so surprisingly—extend far beyond organization or pomp and circumstance. According to a new study from the University of California Los Angeles (UCLA), marching in unison could actually shape men's estimations of their own and others' physical prowess.

"We have found that when men are walking in step with other men, they think that a potential foe is smaller and less physically formidable and less intimidating than when they're just walking in no particularly coordinated manner with other men," said anthropology professor and lead study author Daniel Fessler. "That calculation appears to make men who march with other men feel less vulnerable and more powerful and their potential foe more easily vanquished."

"Simply walking in sync may make men more likely to think, 'Yeah, we could take that guy!'" Fessler said.

For their experiment, Fessler and co-author Colin Holbrook—whose findings are published online in the journal Biology Letters—recruited 96 undergraduate men at UCLA. Half were instructed to walk in lockstep with a partner, while another half were asked to walk alongside a partner but without moving uniformly. Afterward, the students took several tests, "most of them to disguise the real purpose of the study" and one that involved looking at a photo of a man with an angry expression. Participants were asked to estimate the angry man's height and pick his build from a roster of six silhouettes of various heights and muscularity.

Young men who had walked in unison with their partners wound up judging the man as significantly shorter and smaller than those who had walked normally. On average, they guessed him to be about an inch shorter than the other group of participants did. The researchers note that while the difference in perception was relatively small, the association was consistent enough that there's only a 0.01 chance of it being a fluke.

Fessler and Holbrook suggest that humans evolved, quite logically, to view moving in unison as a sign of group strength. "The ability to move in unison indicates that one is part of an effective fighting alliance," said Fessler. "That's no accident. In order for individuals to be synchronized, they have to be motivated to coordinate their behavior—they have to be paying attention to what one another are doing, and they have to be skilled and competent. A deep part of our brain registers this connection."