Scientists accidentally discover an inherent human tendency for counterclockwise movement

When humans walk freely in open or enclosed spaces, they naturally tend to veer in a counterclockwise direction. This individual bias provides evidence that intrinsic personal tendencies shape how large crowds spontaneously organize themselves. These findings, published in the journal Nature Communications, suggest new ways to understand human movement.

In the study of pedestrian dynamics, scientists observe how large groups of people move together in shared spaces. In crowded areas, people often spontaneously form opposing lanes or alternate like a zipper when passing through a narrow doorway. These patterns are known as emergent behaviors. An emergent behavior occurs when simple actions taken by individuals combine to create a complex, coordinated group pattern without any central leader.

In the past, experts thought these collective crowd patterns arose mainly from social interactions and environmental boundaries. For example, people stepping to the right to avoid a collision might eventually cause an entire group to rotate in a specific direction near a wall. Other theories suggested that learned social habits, such as driving on a particular side of the road, dictate how crowds navigate.

To test these assumptions, an international research team designed experiments to determine if the counterclockwise rotation seen in crowds is a social phenomenon or a built-in individual bias. The research team was led by Iñaki Echeverría Huarte, a researcher in the Department of Physics and Applied Mathematics at the Faculty of Sciences at the University of Navarra in Pamplona, Spain. The project included researchers from Waseda University, the University of Tokyo, Shanghai University for Science and Technology, and Universidad Carlos III de Madrid.

Echeverría Huarte noted that the project was a collaborative effort that grew out of years of patient experiments. In fact, the initial discovery happened entirely by chance. “It was entirely serendipitous,” he told PsyPost. “During the COVID-19 pandemic we were running experiments on social distancing, trying to understand how many people could safely share a room, and while analyzing that footage we noticed by chance that people kept walking counterclockwise.”

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That unexpected observation became the starting point for everything that followed. To formally study the behavior, the authors conducted their first experiment at the University of Navarra. They recruited 50 adult participants and placed them in a confined circular area with a radius of 5 meters. The participants were instructed to walk randomly for several intervals of about 40 seconds. A camera mounted 10 meters above the area recorded their exact paths at 15 frames per second.

Before the walking trials, the researchers tested whether each person preferred turning to the left or right when facing a wall. They then mixed these individuals into different group sizes and combinations. To track the rotation, the scientists calculated a mathematical score for the collective motion, measuring whether the group favored one direction.

The results showed a persistent counterclockwise rotation across all groups. This happened regardless of the overall group density or the ratio of people who preferred turning right. “If you ask a group of people to walk around freely, with no rules or instructions, they will very likely end up going counterclockwise,” Echeverría Huarte said. He called this a small, playful fact about human behavior that most people have never noticed.

To see if the walls caused this rotation, the authors moved their next experiment to an open space. They observed 107 teenagers, aged 13 to 14 years old, walking freely in a 50 by 60 meter schoolyard. Drones recorded the students from 40 meters above the ground, capturing video at 30 frames per second. The researchers used a custom computer program to track the walking speeds and positions of every student.

Even without physical boundaries to guide their movement, the teenagers consistently rotated in a collective counterclockwise direction. The mathematical distribution of their walking paths matched the results from the enclosed arena. This suggests that interactions with walls or fences are not the primary cause of the rotational bias.

Next, the researchers traveled to Japan to test the collision avoidance theory. In Spain, pedestrians typically step to the right to avoid bumping into someone approaching them. In Japan, pedestrians generally step to the left, which the researchers confirmed through a preliminary picture survey. If stepping aside caused the group rotation, the Japanese participants should have rotated clockwise.

The team recruited 39 adults to walk randomly in a circular enclosure with a radius of 4 meters. The participants wore colored hats to help the tracking software map their exact coordinates. Surprisingly, the Japanese groups also exhibited a consistent counterclockwise rotation. This finding refutes the idea that local collision avoidance maneuvers drive the group movement pattern.

Echeverría Huarte noted that the results repeatedly surprised the research team. “The biggest surprise came in Japan, where road traffic and spontaneous pedestrian lanes go the opposite way to Spain, so we were convinced the rotation would flip there,” Echeverría Huarte said. “When my colleague Claudio Feliciani sent me his first video from Tokyo, my reaction was immediate: ‘No way, this is counterclockwise again.’ Its robustness across cultures is what makes it striking.”

The team also wanted to explore whether learned adult rules influence this behavior. They analyzed pre-existing video data of preschool children running freely during a musical activity in a Japanese nursery school. Since young children under the age of six have not yet fully absorbed adult societal rules, their behavior offers a look at more instinctive movement.

The tracking data showed that the children displayed a highly stable and pronounced counterclockwise motion. In fact, the children moved in a cohesive vortex pattern, completely aligning with one another. This suggests that the counterclockwise walking bias is present long before humans learn complex social rules regarding traffic or pedestrian flow.

To ensure no unspoken social expectations were at play in adults, the scientists surveyed 168 university students in Spain. They showed the students a picture of a circular arena and asked which way they would personally walk. The researchers also asked the students which way they expected others to walk, measuring what behavioral experts call empirical and normative expectations.

The survey results showed no consensus on a counterclockwise social norm. In fact, nearly forty percent of the respondents expected people to walk in a clockwise direction, which directly contradicted the physical experiments. Because the actual physical movements did not match the expectations, the researchers concluded that a conscious social rule is not responsible for the behavior.

Finally, the researchers sought to isolate the behavior completely by testing 209 adults walking alone. Each person walked freely for 60 seconds inside an empty hexagonal enclosure while a camera tracked their individual path. The researchers assessed each participant through physical tests to find their dominant hand, dominant foot, and dominant eye. To test visual influences, they also asked 49 of these participants to walk while wearing a patch over their right eye.

Even when walking entirely alone, the participants showed a strong mathematical preference for counterclockwise movement. The scientists found no statistical differences based on a person’s dominant hand, dominant foot, or dominant eye. Wearing an eye patch also did not change the walking bias. These single-person trials provide evidence that the counterclockwise preference is an inherent individual trait rather than a byproduct of crowd dynamics.

“The deeper one is scientific: for physicists, this reframes how we think about complex systems,” Echeverría Huarte said. “We usually assume that the patterns we see in a crowd emerge from the interactions between its members, but here the collective rotation does not come from the group at all, it comes from a bias each person already carries individually. It shows that some collective patterns may have hidden individual origins we had overlooked.”

As with all research, there are limitations to consider. The sample sizes for individuals with specific traits, such as being left-footed or left-handed, were relatively small. Because of this, minor biological influences on walking direction cannot be completely ruled out by the current data. Additionally, the participants were all healthy children, teenagers, and young adults.

“We can say with confidence that the bias is individual and very robust, but we cannot yet explain its origin,” Echeverría Huarte said. “Our best interpretation points to subtle body asymmetries at the level of the sensorimotor system, though this is not settled.” The sensorimotor system refers to the parts of the brain, nerves, and muscles that work together to process sensory information and control movement. Echeverría Huarte also noted that he would caution against overselling practical applications, which at this stage remain modest.

One should avoid assuming that this counterclockwise bias will dictate behavior in every real-world scenario. In highly structured environments, explicit goals or dense crowding might override this subtle natural tendency. People navigating a crowded train station with visible signage and static obstacles may not exhibit the same looping behavior seen in these empty testing arenas.

“The biggest open question is the origin: why this individual bias exists in the first place,” Echeverría Huarte said. “We are now running virtual reality experiments precisely to isolate locomotion from other cognitive factors and test whether the asymmetry sits in how we sense, integrate or execute movement. Finding the root cause is the next big step.”

As the team continues to investigate the biological roots of human walking patterns, they reflect on the unexpected nature of their initial discovery. “Sometimes the most interesting findings are the ones you were not looking for,” Echeverría Huarte said.

The study, “Individual locomotor bias drives counterclockwise motion in pedestrian crowds,” was authored by Iñaki Echeverría-Huarte, Claudio Feliciani, Zhigang Shi, Katsuhiro Nishinari, Angel Sánchez, Angel Garcimartín, and Iker Zuriguel.