Why do most people move to the left while walking?

Ever notice how you naturally gravitate in a certain direction when walking through a crowded mall or festival? Well, that’s not just in your head — you probably are! An interesting international study led by the University of Navarra, along with the Universidad Carlos III de Madrid (UC3M), found that humans have a slight but consistent tendency to move towards the left when walking.

This single discovery changes everything from airport design to stadium safety. The research, carried out in collaboration with researchers from Waseda University and the University of Tokyo (Japan), as well as Shanghai University (China), is published in Nature Communications.

Why we all lean left

For years, researchers assumed that crowds organised themselves through a simple formula: people interact, avoid bumping into each other, follow local customs, and adapt to their surroundings.

However, the new study revealed a missing piece of the puzzle."For decades, we thought that these collective patterns arose solely from the interaction between pedestrians. In our work, we have verified that a significant part of them does not emerge only when people gather, but is instead inherent to the individual," Iñaki Echeverría, a researcher in Physics and Applied Mathematics at the University of Navarra and first author of the paper, said in a statement.

When groups of people walk together, whether in enclosed rooms or wide-open spaces, they naturally move in a counterclockwise pattern. Though this is a small preference at an individual level, the effect is amplified when hundreds or thousands of people participate, creating collective patterns observable on a large scale."Not all group members exhibit this preference, but a large majority do tend to move counterclockwise.

This inclination ends up dictating the direction the group follows and gives rise to visible collective patterns," Echeverría explained.

It’s not culture, environment, or habit

The researchers noted that this counterclockwise tendency appears beyond cultural norms and environmental factors. To test traditional explanations, they conducted an extensive experimental campaign over several years in Spain and Japan. This helped them analyse whether the phenomenon depended on how pedestrians try to avoid colliding while walking, given that people in both countries typically move and dodge each other on opposite sides.

The study included groups of adults walking in controlled spaces, schoolchildren moving freely in an open yard, preschool children, and participants completing routes individually.The team also ruled out the possibility that there is a social norm making us prefer moving in a counterclockwise direction. They even surveyed people about social expectations."The results were clear: there was no notable social norm, and furthermore, if data analysis suggests anything, it is that the norm would be to walk in a clockwise direction — in complete contradiction with the experiment — meaning it cannot explain the observations," Anxo Sánchez, from the Mathematics Department at UC3M, stated.The researchers found that this tendency persisted even when other factors traditionally considered responsible were removed. This pattern was seen even in young children who hadn’t yet learned walking rules, in open spaces with no barriers, and in countries with different traffic patterns."We wanted to find out if the phenomenon depended on cultural norms, interaction with the environment, or pedestrian avoidance strategies.

The results indicate that none of these factors, on their own, fully explains what we observed," Iker Zuriguel, Professor of Applied Physics at the University of Navarra and one of the main authors of the study, pointed out.

Designing better public spaces

The findings provide new knowledge about human behaviour, and these insights can be applied in fields such as urban mobility and the management of large crowds. This information is crucial in environments with a high concentration of people, such as airports, train stations, shopping centres, or sports venues, where models are increasingly used to optimise routes and reduce congestion."Better understanding the factors that influence the way we move allows for the development of more precise models of how people circulate in shared spaces. This information could be useful for designing more efficient infrastructure and creating environments that better adapt to how we move in our daily lives," Zuriguel added."The results suggest that individual predispositions also play a relevant role in the emergence of collective movements. Furthermore, the study opens up new questions about the biological origin of these tendencies, as similar phenomena are observed in other animal species, from schools of fish to insect colonies," Echeverría concluded.