On a rush hour zebra crossing, meander through the oncoming crowd, eyes wandering over the faces in front of you. This path finding might feel like something you are doing on your own. However, scientists studying the movements of crowds have found that a simple journey through a crowd is much more like a dance we perform with our fellow human beings.
And so it might not be too surprising to learn that a person staring at a phone and getting lost walking in a private world is really playing around with the vibe, according to a study published Wednesday in Science Advances magazine.
People use a variety of visual cues to predict where other members of a crowd will go next, said Hisashi Murakami, professor at the Kyoto Institute of Technology and author of the new paper. Curious about what would happen if attention to these details were disrupted, he and his colleagues filmed two groups of students walking about a 30-foot walkway in a series of outdoor experiments on the Tokyo University campus.
The groups approached each other at a normal pace. When the groups met, the students intuitively performed a maneuver familiar to those studying crowds: they formed lanes. When one person at the head of a group found a way through the oncoming group, others fell behind that person, forming multiple bands of walkers as they passed each other. It was effortless and almost instantaneous.
The researchers then asked three of the students to do a task on their phones while they walked – simple single-digit addition, not too strenuous, but enough to keep their eyes looking down instead of forward.
When these students were placed in the back of their group, the distraction did not affect how the groups moved past each other. But when the distracted hikers were at the head of the pack, the pace of the entire group slowed dramatically. It also took longer for clear lanes to form.
Distracted people didn’t move smoothly either. They took great sideways steps or avoided others in ways the researchers rarely saw when there were no distractions. The inattentive pedestrians in the experiment also induced this behavior in others; The people who weren’t looking at their phones moved more jerkily than they did when there weren’t any phone catchers. It seemed that some people who did not pay their full attention to navigation might change the behavior of the whole crowd of 50+ people.
Looking at your own phone could have this effect, as it deprives others of the information contained in our gaze, the researchers suggest. Where we look while moving sends details of where we want to go next. Without this, it is more difficult for passers-by to gracefully avoid us. And if we just avoid other people while moving with our eyes averted, instead of moving on purpose, we become even more unpredictable.
As more people use smartphones and other devices that contribute to distracted walking, architects and city planners who deal with the movement of crowds may need to take this changed behavior into account, the researchers say.
Dr. Murakami plans to next track people’s eye movements as they walk past each other. He hopes these studies will show how our gazes help us navigate the crowd – the messages we convey about our next steps when we perform this daily ritual, all without knowing it.