As a child in Chicago, Stephanie de Silva, 23, felt the city helped her get to the places she wanted to go. Streets had directional names, such as “West” or “North”, and often intersected at right angles. When in doubt, she always managed to place herself in relation to Lake Michigan.
But when she moved to London, where she now studies cognitive science, Stephanie suddenly found that without using a map on her smartphone, she couldn’t find her way to a restaurant two blocks from her home. Many of the streets were crooked. Sometimes they seemed to lead nowhere.
“I don’t think cardinal directions exist here,” she commented. “I’ve been living here for six months and I don’t know which direction I’m facing.”
Scientists at the laboratory where Stephanie studies, at University College London, along with colleagues from the UK and France, have found an explanation: people who spend their childhood in predictable cities, which follow a checkered urban layout, such as Chicago or New York, seem to have difficulty to orient themselves with the same ease as those who grew up in more rural areas or cities with a more complex layout.
Published in the journal Nature last Wednesday, these findings suggest that where people lived in childhood influences not only their health and well-being, but also their ability to orient themselves later in life. Like language, navigation is a skill that appears to be more malleable at a stage in life when people’s brains are still developing, the researchers concluded.
The study authors hope their discovery will eventually lead to the creation of navigation-based tests to help diagnose Alzheimer’s disease. According to them, getting lost is something that sometimes occurs earlier in the course of the illness than memory problems.
The researchers created virtual navigation tests to measure cognitive decline, but they can only interpret the results when they know what other factors influence people’s ability to find their way.
The study suggested that one of the forces shaping people’s ability to navigate is the kind of places they lived in as children.
“The environment matters,” explained Hugo Spiers, professor of cognitive neuroscience at University College London and one of the study’s lead authors. “The environment to which we are exposed has a secondary effect on cognition, which manifests itself until we reach our 70s.”
It took a series of unlikely events — involving a cell phone company, a controversial YouTuber and a custom-built video game — to generate the large dataset that underpins the study.
In 2015, Michael Hornberger, who studies dementia at the University of East Anglia in England, heard about a company interested in investing in dementia research.
Having just attended a workshop on the use of games in science, he proposed a video game that would help him find out how people of different ages, genders, and geographic locations would perform in navigational tasks. Hornberger imagined that such a game would create benchmarks for evaluating patients who might be in the early stages of Alzheimer’s disease.
To his surprise, the interested company funded his idea. It was Deutsche Telekom, which owns a major stake in T-Mobile. Known as Sea Hero Quest, the smartphone game involved driving a vessel to look for sea creatures. To attract gamers, the company launched an advertising campaign that included a video of PewDiePie, YouTube’s biggest star at the time, who would later be sanctioned by the platform for using anti-Semitic language.
Scientists expected the game to attract 100,000 people in western Europe. Participants would test their navigation skills and at the same time provide basic demographic information, such as whether they had spent their childhood in cities or in the countryside.
Instead, more than 4.3 million people participated, generating a global database of people’s ability to orient themselves in space. “We had underestimated the world of gamers,” commented Hornberger. “What happened exceeded all our expectations.”
Despite its simplicity, the game has been shown to predict people’s ability to orient themselves in real places, including London and Paris. In recent years, the research team has used the resulting data to prove that age slowly erodes people’s navigational skills and that gender inequality is an indicator of whether men will perform slightly better than women.
The most recent study focused on an issue that its authors described as more difficult: do cities, however gridded, have the effect of improving people’s navigation skills by offering them multiple options for getting around? ? Or do people coming from more rural areas, where distances between places are great and trails tortuous, develop superior navigational skills?
To find out the answer, the researchers studied game data from 400,000 gamers from 38 countries. The effect was clear: People who reported growing up outside cities showed better navigation skills than those who grew up in cities, even when the scientists included age, gender, and education level in the calculations.
The only situation where people who grew up in more predictable cities did better was at simpler levels of the video game.
Players of different nationalities performed differently. Urban dwellers in some countries, such as Spain, almost matched rural dwellers in terms of their navigational skills. In other countries, like the United States, people raised in cities were at a huge disadvantage.
One explanation, the researchers suggested, is that in countries whose largest cities are irregular and complex patchwork quilts, such as Spain, the chaotic layout of streets has sharpened people’s navigational skills. In countries known for their more predictable urban layouts, such as the US, people coming from outside cities had a greater advantage.
“Whoever grew up in a city like Chicago, Buenos Aires or Montreal — cities with a very checkered layout — doesn’t train their navigation skills as much as someone who grew up in a more complex city, like London or Paris, where the streets are much more crooked and uneven” , said Antoine Coutrot, a scientist at the French National Center for Scientific Research and another lead author of the study.
To address objections that people outside cities were only succeeding because the video game is set in nature, the study authors wrote that their findings were replicated with a smaller group of participants invited to play a different game, City Hero Quest, with the same goals, but with a car instead of a boat.
The study speculated that the more complex environments may help the formation of new neurons in the hippocampus, a brain structure important for memory. But the authors highlighted that people can still hone their navigation skills later in life.
Some authors have also noted that the layout of the streets is not the only factor that makes navigation in a city difficult or easier. Visible landmarks can be important, but are more difficult to quantify for research purposes than a road network.
To assuage privacy concerns and prevent science from getting in the way of the game, the marine game avoided asking specific questions about where players were, their profession, or their usual modes of transportation.
As a result, researchers no longer have access to some potentially relevant information about the creation of participants. Even so, some commentators viewed the project with skepticism for privacy reasons. Among the unknowns were how GPS changed people’s navigation experiences, although Spiers noted that younger participants produced similar results to older people.
Translation by Clara Allain
