Wayfinding

by M. R. O'Connor

  Genetic predisposition might potentially limit atrophy, but does exercising spatial cognition prevent deterioration? Bohbot thinks that early interventions focused on spatial memory might actually decrease conversion rates to Alzheimer’s, and that good spatial memory could protect individuals from the disease. Aging people who practice using their spatial memory have a more active hippocampus, a larger hippocampus, and better cognitive health. She has already found that participants who use spatial strategies show reduced risks of dementia when tested on the Montreal Cognitive Assessment, a test used to detect mild forms of cognitive impairment. Her work is now focused on finding ways to teach people how to improve spatial memory and their cognitive health. Among her recommendations are regular exercise, a Mediterranean diet full of omega-3 oils, meditation and deep breathing, as well as plenty of sleep. Most important, she advises actively building cognitive maps. Take new streets and shortcuts to get places; regularly draw a bird’s-eye view of your environment with landmarks; incorporate new behaviors and routes into your daily life. The benefits of hippocampal health appear to be far-reaching. “There’s some studies that show people who have a larger hippocampus have more sense of control over their lives,” she told me. “What would that mean? One interpretation is that if you have better episodic memory, you can better remember what happened. And if you can better remember what happened, you can remember mistakes to avoid and good actions to repeat in order to obtain a desired outcome, and have a better sense of control. That itself is less stressful and you can better cope with things that happen in your life. Control is a mechanism to deal with adversity.”

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  In the fall of 2017, Bohbot and ten other researchers published a report called “Global Determinants of Navigation Ability,” in which they looked at the performance of 2.5 million people globally on a virtual spatial navigation task and then broke the data down to understand whether there were similar profiles in cognitive abilities between countries. One of the authors and architects of the study was Hugo Spiers, the neuroscientist at University College London who a decade earlier had studied the brains of London’s taxi drivers, revealing that they possessed more gray matter in their hippocampi than bus drivers. At the annual conference of the Charles River Association for Memory at Boston University, Spiers presented the results of their findings from this latest study to an audience that included several eminent memory researchers, including Howard Eichenbaum. The data in Bohbot and Spiers’s study was generated using a video game called Sea Hero Quest. The game, which can be downloaded on any smartphone or tablet, is a spatial orienteering task in disguise. The goal is to navigate a boat in search of sea creatures in order to photograph them, and there are two ways to do this: players can travel along a twisting and turning waterway and then shoot a flare in the direction of the position where they started, or they can memorize a map beforehand that gives them a series of checkpoints they need to find their way to. The former is an example of dead reckoning (or path integration), while the latter is what the researchers define as wayfinding. Spiers reported that the game had been played three million times by people age eighteen to ninety-nine in 193 countries, from India to America, Brazil to Australia. The results were fascinating.

  The data shows that spatial navigation ability starts declining in early adulthood, around nineteen years of age, and steadily slips in old age. People from rural areas were significantly better at the game. When it came to countries themselves, Australians, South Africans, and North Americans showed generally good spatial orientation skills, but the real outliers were Nordic countries. Players from Finland, Sweden, Norway, and Denmark, as well as Australia and New Zealand, showed the most accurate dead reckoning skills. What explains this? Spiers displayed a scatter diagram that showed a causation between GDP per capita and navigational ability. This might have something to do with factors such as healthcare, education, and wealth. But the truly indicative factor is not whether a county has a high GDP, but whether it participates in the competitive sport of orienteering, in which people use a map and compass to race each other to various checkpoints outdoors. It so happens that orienteering is hugely popular in Nordic countries. Spiers pointed out that the number of world championship medals won by Nordic countries between 1966 and 2016 is strongly correlative for how good players are at Sea Hero Quest.

  Someone in the audience raised the possibility that the study data is skewed because only people who are confident at engaging with a virtual reality interface would voluntarily do the task. What I wondered was whether access to the internet or a computer had also confined the data. What if even the best in-game navigators of those three million people who have played the game were some of the poorest navigators on the spectrum of what is humanly possible? While players from northern European countries generally scored high on Sea Hero Quest, other studies hint that dead reckoning skills in these countries might be nothing special. For instance, the American linguist Eric Pederson has tested men and women belonging to wild mushroom–hunting clubs in the Netherlands on their dead reckoning skills by asking them to point back to their car after walking several miles in the woods. Despite their practice at foraging in the outdoors, their accuracy was terrible in comparison to studies conducted among indigenous communities in Australia or Mexico. “From a dead-reckoning point of view,” linguist Stephen Levinson has written, “these estimates show that these participants have constructed no clear representation of their current location in the mental map of their immediate environment or integrated that local map into the larger world they know.” Rather than navigate their way back, the main strategy of the Dutch mushroom pickers was to pilot in one direction and retrace their steps.

  Sea Hero Quest wasn’t really created to further science’s understanding of how navigational strategies vary across nations or cultures. It was made in order to amass data that will help create a diagnostic tool for Alzheimer’s. Spatial ability and memory function are so closely correlated in the human brain that by creating a global benchmark for spatial navigation—what normal is—Spiers and his colleagues hope to be able to make accurate predictions about what a person’s spatial navigation performance should be based on their age, gender, and nationality. Doctors typically use language tests to diagnose early-onset dementia or Alzheimer’s, but testing a person’s spatial cognition performance against these indices could possibly predict even earlier signs of cognitive ailments.

  I met Spiers at his office at University College London to talk about the hippocampus and its role in memory. “There are a lot of researchers working on spatial navigation and tasks in rats and mice, thousands of them. They aren’t interested in space, they use space to get to memory,” he reflected. “I came into the field through memory but then space seemed to become more rich. I’ve always loved maps and how we actually find our way. It’s got this fascinating philosophical element as well. What is space? What is a place?” It struck me that Sea Hero Quest cleverly masks a medical test as a video game, but its brilliance is in how it exploits the relationship between space and memory, using one to get to the other.

  So why, I asked him, did he think navigation is closely tied to episodic memory in the brain? “O’Keefe and Nadel argued that space is something that you can pin things on because it’s stable,” he posited. “So it’s one system, they are totally tied. Space is like a scaffold for adding your memories onto a map.”

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  Spiers told me he is often asked whether satellite navigation devices are rotting our brains. His response is that it’s important to appreciate the different ways we can utilize these technologies. Using Google Maps on one’s phone to figure out a route to get somewhere is not dissimilar from using a print map; following turn-by-turn directions to get somewhere is an entirely different matter. In the spring of 2017, Nature Communications published the result of a study Spiers coauthored that tested twenty-four people using GPS to navigate London’s Soho neighborhood. It clearly showed that using a GPS na
vigation system to get to one’s destination essentially switches off distinct parts of the brain, including the hippocampus. “Our results fit with models in which the hippocampus simulates journeys on future possible paths while the prefrontal cortex helps us to plan which ones will get us to our destination,” Spiers told a reporter. “When we have technology telling us which way to go, however, these parts of the brain simply don’t respond to the street network. In that sense our brain has switched off its interest in the streets around us.”

  Véronique Bohbot does not use GPS. While she was careful to point out that no one has yet designed a study to test whether GPS use causes hippocampal atrophy, there is plenty of evidence that following turn-by-turn directions means we are simply not using a spatial strategy to wayfind. In fact, using a GPS is very much like using the response strategy that exercises the caudate nucleus at a cost to the hippocampus. And because of the remarkable plasticity of the brain, not activating and exercising the hippocampus leads to decreased gray matter. Scientists do know that turn-by-turn directions activate the caudate nucleus, and its response strategy bypasses the creation of cognitive maps. “With GPS you might have even less of a reason to pull out that map than we already do,” Bohbot said. Lynn Nadel, her doctorate advisor who first connected hippocampal development to infant amnesia, has scoured the data in Bohbot’s studies and agrees that the risk of letting our hippocampus atrophy is considerable. “There is a use-it-or-lose-it thing about the brain,” said Nadel. “We know on the flip side about taxi driver studies, you can increase the capacity of the system by using it a lot. My gut instinct is yes, if people stop using their brains and totally devote themselves to their handheld devices to find their way around the world, that could have a negative effect on getting around and spillover effects on other things like memory.”

  Market research shows that the number of turn-by-turn navigation application users reached four hundred million in 2017, a fourfold increase since 2011. Even so, there have been just a handful of studies looking at the impact of using GPS. One of the first was in 2005 when researchers at the University of Nottingham tested twelve drivers who had used either GPS or a traditional paper map, and then measured their landmark, route, and survey knowledge afterward by requiring them to draw detailed maps of their route. The drivers who used GPS remembered fewer scenes, were less accurate, and drew simpler maps with minimal landmarks. The crucial difference between the two methods, the researchers argued, was decision-making—GPS users were not engaged in making decisions.

  A couple of years later, researchers at Carleton University conducted a study of 103 individuals and found that using GPS had a number of nefarious consequences for drivers in regard to attention and engagement. Using it replaced direct perception and eliminated the need to gather, integrate, comprehend, and process information from the environment. It also rid drivers of the need for wayfinding, decision-making, and problem-solving. In 2008, Cornell University researchers argued that using GPS reduced a driver’s process of interpreting the spaces around them—the process of turning space into place, in other words—while immersing them in a virtual environment, the perspective of the GPS screen. The driver quite literally relies on the virtual representation of the road rather than their unmediated perception of the physical road. Even using GPS while walking seems to change how we move through space: Toru Ishikawa and a team of researchers reported in 2008 that people using GPS while walking did so more slowly, made greater direction errors, and found wayfinding tasks more difficult than those who used paper maps or relied on direct experience.

  One academic currently designing a study of how GPS affects the way humans engage with the task of wayfinding is Harry Heft, the professor of environmental psychology at Denison University who studied with James Gibson. “The GPS diffuses that whole way of engaging the world,” he told me, “because you don’t even really have to look at the world very much.” GPS has in a way exacerbated changes that were already underway once highways became a predominant medium for travel, he continued. “The highway system is so disconnected from the terrain and the topology. I think what GPS does is lead you even further away from that.”

  The vigor of memory is likely one of the first victims of failing to exercise the hippocampus, but it’s not the last. We use the neural circuit not only to reconstruct the where and when of the past but also to build images of the future; it is the locus of our imagination. For instance, when asked what he was going to do the next day, the patient H.M. could only manage to say, “Whatever is beneficial.” In the 1980s, the psychologist and neuroscientist Endel Tulving also found that his amnesiac patients experienced difficulty imagining the future. Later, in 2007, a series of neuroimaging studies confirmed that the ability to both remember and imagine uses a common brain network that includes the hippocampus. Eleanor Maguire of University College London has proposed that perhaps the hippocampus is not solely responsible for episodic memory, future thinking, and spatial navigation but is necessary for constructing scenes that are crucial to these exercises. Scene-construction theory, as she points out, offers a unified account of why the absence of the hippocampus in individuals destroys so many seemingly disparate functions.

  We engage in fascinating gymnastics when we simulate the future—recombining information from our semantic and episodic memory and shaping it into new mental representations of hypothetical events. Our brains are like prediction machines, generating episodes that might occur in the near or distant future and using them to plan, problem-solve, and achieve goals. In this way the human imagination is like a beacon that orients us, helping us to make decisions about where we want to go and how we might get there, as well as self-regulating our behaviors and emotions in the service of a destination or a destiny. Indeed the ability to imagine is a pillar of our autonoetic consciousness, the emergence of which likely set us on our current evolutionary path by extending our identities beyond the present moment into the past and future.

  In 2011, researchers Benjamin Baird and Jonathan Schooler showed that we often engage in autobiographical planning and thinking about the future during mind-wandering episodes, those periods when we allow ourselves to fluidly travel between the past and the future. They proposed that mind-wandering enables cognitive operations that are “likely to be useful to the individual as they navigate through their daily life.” Tulving described autonoetic consciousness as mental time travel. In the book Predictions in the Brain, edited by Moshe Bar, a team of psychologists from Australia and New Zealand point out that our capacity for mental time travel and grammatical language likely coevolved to allow us to share episodic information with one another. This probably occurred during the Pleistocene, a period in which they speculate climate changes necessitated greater social cohesion and future planning, and the prolongation of development from infancy to adulthood—that is, when childhood originated.

  In light of the hippocampus’s role in future imagining, what are the consequences of decreasing its activity? Could it be that the more we willingly outsource our brain’s attention and abilities to a GPS device, the less detailed and more hazy our imagination of the future becomes? Could our societal visions of a collective good, and the steps required to make it so, dissolve into blank spaces too, disorienting us in a far deeper sense than merely losing our way? Navigation, it turns out, may not be something that we excise from our cognition without existential impacts, influencing our ideas about who we are and our destiny.

  There are smart people who argue that technologies that offload the cognitive burden borne by individuals are good. In his book The Future of the Mind, the physicist Michio Kaku describes a future in which we’ll be able to implant memories in our brain, short-circuiting the time it takes to learn new skills and acquire knowledge. For those concerned that such implants would lead to significantly diminished cognitive abilities, that without the necessity of developing important neural architecture for learning and retaining memories and information we might be less int
elligent humans, Kaku reassures us that eventually better designed, artificial brains will fix the problem. Kaku even discusses the possibility of implanting artificial hippocampi. Indeed, Theodore Berger, a biomedical engineer at the University of Southern California, has developed a hippocampal implant—a silicon chip that electrically stimulates neurons, and tested it on rats and rhesus monkeys with the aim of improving long-term memory in individuals with Alzheimer’s or brain damage. A company called Kernel is reportedly already using it in human trials. In Singapore, scientists have created artificial grid and place cells in software that they claim a robot used to explore an office space. Google has created an artificial intelligence program that can use memory and reasoning to navigate London’s underground tube system. But reading about these technological experiments, I found myself revolting against the implicit vision of a technoscientific utopia in which humans can download memories into artificial brains like robots, while robots develop neural networks that think like us. What value will individual experience, practice, and skill have in that future? What pleasure would there be in learning, in childhood, in open-ended exploration, of accidental discovery, of autonomously finding our way? What good could possibly come from outsourcing cognitive processes that were an essential aspect of making humans human? But maybe that future is already upon us.