The finding arrived by accident. Researchers studying social distancing during the pandemic were reviewing footage of how many people could safely share a room, and noticed that the crowds in the video kept drifting counterclockwise.
They then spent several years trying to make the effect go away, and could not.
The work, published in Nature Communications by teams from Waseda University, the University of Tokyo, Shanghai University for Science and Technology, Universidad Carlos III de Madrid and the University of Navarra, ran experiments in enclosed arenas, in open spaces with no walls, on playgrounds with schoolchildren, with preschool children, and with 209 adults walking entirely alone inside a hexagonal boundary made of chairs and tables. The leftward preference showed up in all of them.
It did not depend on dominant hand or foot. It did not depend on sex. It appeared in both Spain and Japan, countries whose pedestrians pass each other on opposite sides. It survived patching one eye. It was present in young children who had not yet absorbed any social rules about walking. Younger participants showed a stronger bias, though nobody over their mid-thirties was included.
Claudio Feliciani, who worked on the study at the University of Tokyo, described the result as completely unexpected, on the reasonable grounds that people wandering at random ought to turn as their needs suit them. The team’s current suspicion is that it reflects some asymmetry at the biomechanical level. They do not know.
Here is why a small, slightly comic fact about human locomotion is worth a cafe owner’s attention.
The researchers were able to reconstruct the way large crowds organise themselves mathematically, using only data from individuals walking alone. The collective pattern was not produced by people reacting to each other. It was already present in each person before anyone else entered the room.
Most explanations of customer behaviour in a retail space assume interaction. People queue here because the queue formed here. People cluster at that end because that end is busy. The study suggests that a meaningful part of the pattern is upstream of all of that, built into the bodies walking through the door, and that it will show up identically on a quiet Tuesday with four customers as on a Saturday with forty.
The practical reading is to stop treating your floor plan as neutral. If people entering a space tend to drift left, then the left-hand wall is your most valuable surface and the right-hand corner is where things go to be ignored. The till placed to the right of the entrance is fighting the room. The display positioned at the counterclockwise end of the drift is being seen by almost everybody without anybody having decided to look at it.
The researchers point out that airports, museums, train stations, shopping centres and stadium forecourts may all be affected, particularly when crowds form, and that understanding it could improve evacuation planning and venue design.
It is also just a lovely fact. Several hundred people were asked to walk around a room on their own, and almost all of them turned the same way without noticing.
The room was empty. The pattern was already there.
