Global Impositioning Systems

Aporta notes, though, that gps is just one element of an “ecology of technologies” in Inuit life, stretching back to the rifle and the snowmobile, and encompassing even broader trends like the establishment of permanent settlements. “It’s also the first technology in the history of navigation that gives you an answer to a spatial question without you needing to be engaged at all,” he says. The net result is an increasing disconnection for young Inuit from the rhythms of their environment. And though the stakes are high in the harsh conditions of the Arctic, similar changes are taking place everywhere. “I like to ask my students questions about the Rideau River, which is right here,” he says, gesturing to a window overlooking the Carleton campus. “Where is the river flowing? How did people use it before? And people born in Ottawa have really struggled to give me environmental information about a feature they see on a daily basis.”

Across the hall from Véronique Bohbot’s tiny office on the ground floor of Douglas Hospital, on the south shore of the island of Montreal, a mock mri machine is set up, complete with a glass-panelled control room and an electric platform that slides the patient into a cylindrical imaging chamber at the touch of a button. Here, experimental subjects practise navigating through a virtual maze on a screen they can only see through a series of mirrors. They must learn to keep their heads perfectly immobile in order for Bohbot to be able to peer inside their brains once they’ve graduated to the “functional” mri machine off-site. fmri tracks the flow of blood to different parts of the brain, allowing near-real-time monitoring of which areas light up during different tasks. Iaria and Bohbot used the technology to confirm that spatial navigators use the hippocampus, while stimulus-response learners use another region of the brain called the caudate nucleus.

Another mri technique called “voxel-based morphometry” maps brains of different sizes onto a standard template, so the relative size of their subunits can be compared. In 2007, as a follow-up to the first study, Bohbot and her collaborators showed that the half of the population that prefer to use spatial strategies have bigger hippocampi, while the half that prefer stimulus-response navigation have bigger caudate nuclei — a predictable result, given the plasticity demonstrated by London taxi drivers. But that leaves an unresolved chicken-and-egg question: does using spatial strategies make your hippocampus bigger, or does having a bigger hippocampus make you more inclined to use spatial strategies?

To probe more deeply, Bohbot teamed with Jason Lerch, a researcher at the mouse imaging centre at Toronto’s Hospital for Sick Children. He trained a group of mice on a standard challenge called the Morris water maze, tweaking it so half the mice were forced to use spatial strategy and the other half stimulus-response. “Lo and behold, after only five days of training he scanned them on a seven-tesla mri and found grey matter differences in the hippocampus and caudate nucleus,” Bohbot says, “just like we did in humans.” Then they dissected the brains (a luxury they don’t have with human subjects) and found that the increased volume came from “dendritic arborization” — an increase in the number of connections to and from each neuron. “Instead of having a skimpy tree with one branch,” she says, “it’s going to have a dozen branches.”

Though the data can only be extrapolated so far, Lerch’s mouse studies suggest that human brains begin to reorganize very quickly in response to the way we use them. The implications of this concern Bohbot. She fears that overreliance on gps, which demands a hyper-pure form of stimulus-response behaviour, will result in our using the spatial capabilities of the hippocampus less, and that it will in turn get smaller. Other studies have tied atrophy of the hippocampus to increased risk of dementia. “We can only draw an inference,” Bohbot acknowledges. “But there’s a logical conclusion that people could increase their risk of atrophy if they stop paying attention to where they are and where they go.”

Of course, we do still navigate the local environments where we spend most of our time — our homes, our offices, our immediate neighbourhoods — without gps, so a change in brain structure is perhaps unlikely. And we also use the hippocampus to store autobiographical memories and to imagine the future. But Bohbot sees the decline in spatial thinking as part of a broader shift toward stimulus-response, reward-linked behaviour. The demand for instant gratification, for efficiency at all costs and productivity as the only measure of value — these sound like the laments of the nostalgist in the Age of the Caudate Nucleus. But here, they’re based on neuroscience. “Society is geared in many ways toward shrinking the hippocampus,” she says. “In the next twenty years, I think we’re going to see dementia occurring earlier and earlier.”

This was the point at which I started feeling guilty for giving my parents a gps system for Christmas last year. But of course gps has many positives. For patients suffering from disorders like Alison Kendall’s, satellite navigation has provided a crucial lifeline. Among the Inuit, gps is helping to map and preserve traditional routes, and the technology is actually spurring interest in navigational heritage among younger people. Cornell’s Gilly Leshed, too, saw benefits in her ethnographic study of gps users. Those with a poor sense of direction were able to explore more freely and were more likely to venture to new places, since directions home were always available at the press of a button. “Still, it doesn’t force them to be attuned to their environment,” she admits. “They’re freed, but they’re not challenged.” Leshed and others hope gps will eventually be designed so as to spur engagement with the landscape without sacrificing convenience — for instance by pointing to landmarks (“Turn left after the gas station”) rather than location-agnostic instructions (“Turn left in three blocks”).

When I was a kid, I had an old Mad magazine from the 1960s that bemoaned the advent of the electric scooter and predicted that by the end of the century North Americans would look like oversized bowling pins with tiny, vestigial legs, ripe for knocking over by lean Communist invaders. Rather than forgetting how to walk, however, 4.5 million Canadians now pay to join health clubs where they can spin their legs on treadmills and exercise bikes to make up the miles they no longer travel in their daily lives. Many others choose to forsake “efficiency” by biking to work or walking to the supermarket, because they’ve realized that letting technology do too much leaves their bodies worse off. We may soon take the same approach with our brains.

In her basement lab in Montreal, Bohbot gave me a foretaste of the spatial memory training program she and her students have been developing for the past four years. Donning the requisite 3-D glasses, I navigated around an eerily accurate virtual version of the Douglas Hospital campus, projected onto an enormous three-metre-wide screen that divided the otherwise uniformly black room in two. Bohbot’s group has created forty-six different virtual environments, each designed to force people to employ spatial memory rather than stimulus-response strategies. The proposed structure is an eight-week, sixteen-hour program featuring exercises that can run on a typical computer screen — though Bohbot isn’t sure how successful an at-home program would be. “It’s boring!” she admits. “And really, we have to be there administering it and telling people it’s supposed to be hard.”

For Kendall’s part, she was able, after six weeks of working with Iaria for an hour a week, to shorten the time she needed to form a cognitive map in a simple virtual environment from thirty-two minutes to five. Her success offered further evidence that her inability to form cognitive maps isn’t the result of hidden brain damage. She can do it; she’s just very bad at it. The precise combination of genetic and environmental factors responsible for this shortcoming remains unclear, but the results of her training are heartening. They suggest that, as with any cognitive task, we may differ in our natural endowments, but we can always improve.