“If you simply ask someone to start walking, whether strolling through a museum, a supermarket or an empty room, it is surprisingly likely that the person will end up going counterclockwise,” said Dr Iñaki Echeverría Huarte, from the University of Navarra, in Spain.
As with many important discoveries in science, the revelation originates from luck. During the pandemic, researchers carried out experiments to see how many people were able to share a space while maintaining a safe distance. When reviewing the videos, they noticed that the crowds walked predominantly in a counterclockwise direction.
The surprise began a complete research project. Scientists carried out a series of experiments in which individual pedestrians or small groups walked through enclosed spaces. Repeatedly, researchers have observed the tendency to walk counterclockwise.
Suspecting that cultural norms could influence the result, the team teamed up with Dr. Claudio Feliciani, from the University of Tokyo. He obtained the same results in Japan. The finding remained even when considering whether people were right-handed, used the right foot or the right eye as dominant, and appeared in both men and women. The only difference identified was a more pronounced bias in children.
“Each of us carries a small personal bias to turn slightly to one side, and when many people share a space, these small deviations add up to a net counterclockwise rotation,” said Echeverría Huarte. Details were published in the journal Nature Communications.
Scientists are still unsure of the source of the bias, but they have conducted additional virtual reality and other experiments in which people simulate having a broken leg, hoping to advance understanding. Team jokers joked that the opposite trend could appear in Australia and that the Coriolis effect, in which the Earth’s rotation deflects the direction of the wind, would be involved.
“We don’t know why this happens, but we believe that, by understanding the reasons, we could better understand how we perceive the world,” said Feliciani. “This could help make other discoveries that are perhaps more important than this one.”
Humans are not the only species to display such a preference. Researchers in Bristol have shown that fire ants have a bias to turn left when exploring unfamiliar nests.
The suspicion falls on biomechanics. “None of us are perfectly symmetrical, and the way each person’s brain gathers sensory information and coordinates it with muscles seems to gently tilt it to one side,” said Echeverría Huarte. “I must be honest, though,” he added. “We have tested several ideas and the bias continues to show up stubbornly, so the exact mechanism is still an open question.”
Understanding bias can make simulations of crowds and evacuations more realistic and help design the spaces we move through every day, from museums to supermarkets to train stations, said Echeverría Huarte.
At the first modern Olympic Games in 1896, athletes ran clockwise around the track, but this was changed in 1913 because most competitors considered this an “unnatural direction to run”, said Professor Gareth Irwin, head of sports and exercise biomechanics at Cardiff Metropolitan University.
Running counterclockwise is now written into the Laws of Athletics. “It is reasonable to assume that this arose due to the right-leg dominance of the population,” he said. “Running around the curve counterclockwise applies more internal force to the right side of the body.”
But it may be less about biomechanics and more about the social dominance of people with a right-leg preference, he added. “The idea of right-sided dominance transcends sport and athletics, and can be seen in other areas, such as supermarket design, influencing the direction in which companies intend for people to walk and move around the store,” he said.
