Your walk carries information about how much of a threat you might pose. Wirestock Creators/ShutterstockHumans have been fighting each other since the earliest stages of our species’ history. Scientists believe that these fights changed how we evolved, particularly men. This is known as intrasexual selection, where competition between members of the same sex shape how they evolve. My new research raises the possibility we may have evolved to detect clues about whether a man is dangerous from the way he walks. As it was men who were more likely to engage in physical fights in our early history, it would be beneficial for them evolve to win and survive a fight. Men are still more likely to be the perpetrator of violent crimes, and men account for a higher proportion of victims of violence when the perpetrator is a stranger. Read more: How much do we actually know about the psychology of violence? Men on average not only have 80% more arm muscle mass and 50% more lower body muscle mass than women but also tougher skulls to help them survive their fights.You may win a fight, but if you win with a broken jaw, it will not feel like much of a victory when you try and eat. So evolving the ability to tell if someone can hurt us would have allowed our ancestors to ready themselves for a fight or try and avoid the confrontation if the risk seemed too high. And it seems that we are good at this, according to research over the last two decades. In a 2009 study participants from several countries including Bolivia, Argentina and the US were asked to look at photographs of men’s faces and bodies. They could tell when a man was strong, even from just looking at the face pictures. When they looked at photographs of women, the participants could still assess strength, but less accurately compared to the photographs of men. Voices hold important information about other people’s strength too. A 2010 study had participants listen to voice recordings of native speakers in English, Spanish, Romanian and indigenous Bolivian language Tsimane. Participants could accurately estimate the speakers’ upper body strength, although they were less accurate when it came to female speakers than men. If you find someone’s walk intimidating, it’s not just you. LBeddoe/Shutterstock But when a fight is coming our way, it is unlikely that we would only see the person’s face, or just hear their voice. Research, helped by modern day motion capture techniques, has started to show humans can detect a potential threat from body language. These techniques can produce a computer-generated representation of someone that hides certain physical features. It can make a tall person and short person look the same height or make a person with a lot of muscle look like someone who has very little. Researchers using these techniques in a 2016 study found that participants could still detect when someone is strong, even though they couldn’t tell what the person looked like. This suggests that there may be something in the way we move that shows to someone else that we can harm them. One of the videos made with motion capture techniques for the author’s study. For our new research, my colleagues and I used similar motion capture techniques to represent how 57 different men walked without showing their size. We then asked 137 participants to watch three-second (on average) representations of the models walking.On average the participants rated the men who were physically bigger (a combination of BMI, bicep, shoulder, chest, and waist circumferences) as higher in physical dominance, even though they couldn’t see how big they were. Higher physical dominance means they are more likely to win a fight. What we may have found are specific movements that could indicate someone’s size and so their potential ability to cause physical harm. Men who were perceived as being more likely to win a fight had more of a swagger to them, where their shoulders moved more in a swaying motion. This is almost the stereotypical walk of the western movie hero. The exact nature of this link isn’t clear. Might we simply have evolved to spot bigger men, who tend to walk with a confident swagger? Or are we alert to signals that these men might want to do us harm?Previous research has suggested men may, consciously or subconsciously, try to give off intimidating signals through their walk.A 2003 study by cognitive psychologist Nikolaus Troje of people’s perception of other people’s gait used this style of walking as a caricature of male walking style. He pointed out that male animals often try to occupy as much space as possible to appear bigger than he is. “Like in pigeons where the male puffs up his feathers or like in lions where the male evolves its mane, we find in our species sex-specific differences in the way to move which eventually result in men to appear bigger and heavier.” It’s also worth noting we found other factors could affect people’s perception. Women participants were more likely to rate the men in the videos as high in physical dominance than the male participants. And older people rated the men’s movements as higher in physical dominance compared to younger participants. However, our natural movement, our walk, is surprisingly hard to change. So being able to read the signs of danger in someone walking towards us would be a very valuable skill to evolve.Connor Leslie does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.