My Plastic Brain Read online

  INTERVIEWS/CONVERSATIONS:

  Lila Chrysikou, interview and conversations during lab visit January 12–15, 2016.

  John Kounios, interview at Drexel University, January 12, 2016.

  Not all those who wander are lost.

  —J. R. R. Tolkien

  I’m wandering around Berlin in the rain, with only a soggy map to guide me. There's no doubt about it; I am definitely lost. It doesn’t matter how many times I mentally retrace my steps or turn the map upside down—I still have no idea whether to go left or right at this junction. The street sign in front of me is pointing completely the opposite way to what I was expecting, and it has put my sense of direction into a tailspin. Ironically, I’m on my way to meet a navigation researcher, who has brought me a gadget that she says could drastically improve my sense of direction in just six weeks. To meet her, all I need to do is work out which way to go….

  I have high hopes for this particular challenge. Every brain skill I have worked on so far has been underpinned by the question of whether it can be changed by working on a specific bit of circuitry. Thanks to psychologist Eleanor Maguire and more than a decade of her team's work with London's taxi drivers, though, navigation seems to be a done deal. Navigation ability can most definitely be improved with training, and this most definitely increases the size of the bit of the brain involved in the task. Over the past fourteen years, Maguire has shown time and again that spending a couple of years obsessively learning the layout of London streets increases the size of the hippocampus—a key brain area for spatial navigation (see the introduction). I will find out later that even this well-worn exemplar of neuroplasticity isn’t as straightforward as it might be, but for now, lost in Berlin, my hopes of changing my brain to be more taxi driver and less lost cause are high.

  The only question I had was about how to do this to my own brain. I could apply for a London taxi driver license and spend the next three years memorizing street maps, but let's be honest: I don’t have the time. And anyway, when I emailed Eleanor Maguire to see if she would be willing to check my skills out and help me improve them, London-cabbie-style, I got a very polite but pointed reply from her secretary saying that, sorry, but Professor Maguire is way too busy to have me in her lab anytime soon. “How about a phone call?” I asked. “It should take less than an hour.” Sorry, came the reply, the diary really is very full for the next year. It was all very polite, but the take-home message was clear: Not. Interested.

  Cue a frantic search for other researchers doing work in spatial navigation—and, in hindsight, I’m very glad I did, because before long I found something that sounded even more intriguing. A group of researchers in Germany is working on a very different approach to the problem of navigation—concentrating not on improving on what nature gave us but on adding an extra sense to test whether the human brain can assimilate it as one of its own. In this case, they are trying to add the ability to navigate using the earth's magnetic field. Pigeons can do it, migrating turtles can do it, and if these people have their way, it’ll be an optional extra for people, like me, wanting to improve their sense of direction by giving the brain a new bit of information that it can’t access naturally.

  Quite apart from the fact that this sounds incredibly cool, a bolt-on sense of direction sounds like something I could use. I spend a lot of time in the outdoors trying to wear out my young sheepdog so that he’ll go to sleep and let me get on with some work, but my sense of direction is so bad that I am too chicken to take him anywhere new on my own. On weekends, we go all over the place. My husband, Jon, has a freakishly good sense of direction, always knows where we left the car when we are out walking, and has an uncanny ability to take shortcuts to get back on the right path. I, on the other hand, take a few turns out of the car park, and it feels as if I’ve been blindfolded and spun around on the spot. Ask me to point back to the car and you might as well ask me to fly to it. So although I have the benefit of working at home and a good chunk of the English countryside to explore every day (and now, the need to reset my attentional focus and/or think creatively as the perfect excuse to get out in it), I don’t, because I am too scared of getting lost in the hills with no phone reception and having to consider eating the dog.

  Which is why, on a rainy September day in 2015, I am meeting Susan Wache, part of the team responsible for the feelSpace belt—a prototype navigational aid that constantly computes the direction of north and translates it into a vibration on the northward-facing part of the wearer's waist. I find her eventually, by applying my usual strategy in these situations: pick a direction, start walking, and hope for the best. When I finally got to the corner where we agreed to meet, I was so relieved that I hugged her like a long-lost friend. I think she was a bit surprised.

  The feelSpace is an expensive bit of kit, and it has taken months of badgering via email to persuade Wache's boss, Professor Peter König, of Osnabrück University, to let me take it home for the next six weeks. According to their studies so far, six weeks should be long enough for my brain to adapt, if indeed it is going to. I have Susan to thank for König's change of heart. She is, I soon discover, a card-carrying non-worrier and an optimist. When we meet, I have just finished the Oxford study, and we get chatting about everything I have been doing to change my negative mind-set. She tells me that she never thinks the worst and she never worries. “Why would I think I’m a terrible person?” she says, looking as if it's the craziest thing she's ever heard. “I’m not a terrible person!” Thanks to the force of her charm, enthusiasm, and willingness to trust a complete stranger with two thousand euros’ worth of technology, König finally agreed—so here I am for a crash course in how to use it.

  Susan runs me through the features of the belt over a couple of enormous ice-cream sundaes in a mall in central Berlin. Apparently, afternoon ice cream is very much a thing here—so it sort of counts as a cultural experience. It's not quite what we had planned, though. Having spent the morning trying to navigate the sights with only my brain and a cheap map from the tourist office, this afternoon I’m supposed to be continuing my tour but with an entirely new sense—the ability to feel the pull of magnetic north. Torrential rain, though, is not great for battery-powered bolt-on senses.

  So we order the least enormous-looking sundaes and settle down for a chat about the belt. She tells me that, in their previous experiments, after wearing the belt for six weeks, volunteers had a vastly improved sense of direction and had been able to rewrite their own internal maps, making everything align to magnetic north. Susan, a student in the lab at the time of the study, was one of the research subjects and, by the time we meet, has been wearing the belt on and off for about six months. She says the effects far exceeded her expectations—and even now she takes it with her whenever she can. “I was expecting to get a better map in my head from an aerial point of view, but that's not what happened at all. I got a better map, but it is like I am in the map. Like Google Street View, but everything is transparent,” Susan told me. It all sounds fantastically sci-fi.

  So we chat and eat, and eat and chat, and the sundaes never seem to get any smaller. Finally, when we are both utterly stuffed and feeling a bit sick, Susan whips the belt out of her rucksack and plonks it on the table. She tells me that they are working on a sleeker version for the consumer market—which should be launched fairly soon—but what I’m going to be trying is one of the research prototypes that they use in their studies. Immediately, I see why one of the volunteers had trouble getting it through US customs. It couldn’t look more like a bomb belt if it tried. It's a thick, black webbing affair, about three inches wide, with several bulges the size of cigarette packets around the hips, and two ends of a wire hanging down, topped off with an ominous-looking connector. To turn it on, you have to strap it around your waist, zip it together, and connect the ends of the wires—presumably with your best innocent face on.

  Some of the bulges are haptic motors, Susan explains, which create a similar kind of buzz to whe
n your phone is on vibrate. One of the bigger rectangular bulges is a GPS unit, which is wired into the haptic buzzers. The GPS constantly monitors the position of north, sending that information to the buzzers, so that the one pointing north vibrates. The other two large bulges on the belt are the batteries, she tells me, and hands over an industrial-looking charger that I’ll need to take with me.

  Maybe I have spent too much time on the paranoid streets of London, but as Susan stands up, attaches the belt, and, totally unselfconsciously, connects the two ends of the wires, I think that the people of Berlin are a bit too laid back for their own good. I glance around us nervously as the belt buzzes into life, but no one else bats an eyelid. Okay, so Susan is young, in her twenties, with bright ginger hair and an innocent face that matches her outdoorsy outfit, but if I saw a stranger doing this in a very public place, I’d run for the hills.

  Then it's my turn. I hold my clothes out of the way as Susan zips me into the belt and connects the wires. I’m less than relaxed and remark that I definitely wouldn’t do this in the middle of New York or London. She laughs. “This is Berlin, nobody cares.” Really? I’m sure I saw an armed policeman earlier…. Back at my friends Neil and Jess's apartment, where I am staying, and wondering if I’m just being weird, Jess (who is American) agrees with me. “You’d get Tased wearing that in New York,” she assures me. “At best…” I add darkly. I’ve already decided not to take it to Chicago with me next month when I go to a big neuroscience conference. As much as I’d love to try it out in another unfamiliar city, it's probably not worth the risk of being shot.

  Since we don’t have the option of exploring Berlin's historical sights this afternoon, Susan and I head instead to the Sony building—a massive covered square with a cinema on one side, where she tells me they hold the big movie premieres in Berlin. It's large enough to do the kind of navigation tasks that they do in lab studies to test people's sense of direction, and we can try them with and without the belt. These are a bit like those trust exercises you do on corporate bonding days. First, we turn the belt off, and I close my eyes and hold Susan's arm as she guides me around, taking lots of turns. After a minute or so, we stop and she asks me to point to the cinema. I do okay, pointing more or less in the direction where it is. There's a big fountain in the middle of the square, which makes enough noise to help me vaguely keep track of where I am, which probably counts as cheating.

  Then I turn the belt on, make a mental note of where on my body the belt is buzzing in relation to the direction of the cinema, and then close my eyes. Again, Susan walks me around in circles, making lots of turns and double backs, and then stops and asks me again to point to the cinema. This time it's so much easier. Before I was guessing, but this time I know I’m right. “It's over there,” I say confidently, and I’m right. It's almost too easy.

  With that we say our good-byes, and I take my new sense of direction back to Jess and Neil's apartment, which I am now very much aware is northeast of the Sony Center.

  The belt is big, heavy, and I feel incredibly self-conscious, but I quickly start to enjoy having a secret sense all to myself. That evening, though, when Neil and Jess show me around their neighborhood, me with belt attached, I discover that I am not the only one in the group with a mental compass. At one point, Neil gestures down a street and says, “We need to go this way.” “Aha!” I pipe up, feeling very pleased with myself. “You mean we need to go north?” “Yes,” he says, raising an eyebrow at me, as if that part was obvious. I had never considered that people might learn the position of north and use it to navigate in familiar environments. It's just not something I would naturally think of doing.

  The more I start talking to people about how they navigate, though, the more it becomes clear that what seemed to me like a freakish knowledge of where north is, held only by a few people I know, turns out to be a fairly common strategy. Unlike turtles, pigeons, and, according to a handful of studies, perhaps even cows and dogs, humans don’t, as far as we know, have an onboard compass, so knowledge of cardinal directions (the points of the compass) is only ever a learned skill.

  My husband, Jon, demonstrated how he uses this method when we stopped for a quick game of “guess which way is north” while we were out on a dog walk. “I know that the main road is over there, running that way, and that our house is south of it, and we came this way to get here, so north is over…there.” It made absolutely no sense to me at the time, but my hope is that with the help of the belt, I’ll be able to use this kind of thinking, too. Once I’ve learned the general lay of the land in relation to points of the compass, I should be able to mentally map everything in the environment in relation to that.

  I want to know more about human navigation skills, so I delve into the murky world of scientific literature and find something that I hadn’t been expecting: what I have isn’t, strictly speaking, a lack of navigation skills—I use one of two bona fide navigation strategies. Some people, like Jon and Neil, navigate by calculating the geometric layout of an area and linking them together to make a mental map. According to the research, this strategy is more commonly used by men and is useful if you need to keep a general gist of the landscape in mind.1 If you have a mental map in your head, it makes shortcuts much easier, as you can make an educated guess about which way is home. It also means that if you find out where north is, you can add that to your internal map, too.

  Others, like me—and, if research is to be believed, women in general—are much more likely to remember specific routes based on landmarks: follow this road until you reach the church, cross over and turn right at the next traffic lights—that kind of thing. The problem with this strategy is that it is harder to take a shortcut, because as soon as you are off a known route, you’re lost. It may explain why I have a reputation in my household for suddenly exclaiming, “Oh, we’re here!” when we reach a particular street corner. At which point Jon looks at me, confused, and says, “Err, yeah. Where did you think we were?”

  This “landmarks” strategy might actually work better in certain circumstances. In experiments, women tend to outperform men in navigating by landmarks and also generally have a better memory about what landmarks look like.2 And if you have enough landmarked routes banked, then making shortcuts between them is presumably less of a problem. Still, relying on landmarks with no mental overview of where you are and where you are going is far more likely to result in the kind of sense-of-direction failures that I have.

  As an aside, one theory for why these sex differences exist has something to do with the way that hormones act on the brain. Differences between the sexes don’t appear until puberty, and women get better at spatial navigation in the first week of the menstrual cycle, when estrogen is low.3 One idea is that women's brains evolved to specialize in skills that made them successful gatherers: remembering the detail of what good foraging areas look like and where they are in relation to each other. Men's brains are supposedly adapted to be better hunters. They’d need to travel farther, perhaps, keeping track of where they are in a wide, open landscape, and know how to make a beeline for home if a predator suddenly appeared, or how to save energy by dragging a woolly mammoth directly home rather than all around the caves.

  This theory is clearly untestable, and in this day and age, it actually doesn’t matter. The navigation skills I need have nothing to do with finding nuts and berries and everything to do with not getting lost in the countryside.

  One thing that does give me hope that I can improve on what I’ve got is that studies have shown that the best navigators are those who switch from landmark to mental-map strategies, depending on what works best in the circumstances—so, again, it's all about mental flexibility. In theory, then, if I can learn to mentally map my surroundings I’ll have a winning combination: a killer memory for landmarks, added on to a detailed cognitive map that is aligned to north. A landmark specialist with a sense of direction might turn out to be a very formidable navigator indeed.

  So far, thou
gh, I’m just guessing about my navigation strategy, and although studies have shown that people are generally pretty good at assessing their navigational ability (you can test your own using the Santa Barbara Sense of Direction Scale4), I’d like to know for sure. And anyway, I’m starting to get very curious about how well my brain's navigation system is working, and that would mean getting a look at my navigation circuits in action while having my brain scanned.

  Sadly, as well as Eleanor Maguire not being terribly interested in my hippocampus, her colleagues in the famous and eminent navigation group at University College London have told me that I’m too old to take part in their current brain-scanning study, and they are too busy and too lacking in funds to squeeze me in as a favor. So, while intriguing answers potentially lie a forty-five-minute train ride from my house, I find myself on another transatlantic flight: this time to the lab of Russell Epstein, an equally eminent navigation researcher at the University of Pennsylvania, in Philadelphia. When I cornered him at a neuroscience conference in Chicago, he very kindly agreed to scan my brain for clues and to test my navigation strategy. Once I know what my brain is doing and which bits are dominant, I can start to train it accordingly. At least that's the plan.

  I have just two days in the lab in Philadelphia, and Russell and his team have lined up a packed schedule of experiments, some of them in the brain scanner. Luckily, the jetlag is working in my favor, and I’m up at the crack of dawn and raring to go for my first appointment with Steve Marchette, a post-doctoral researcher in Epstein's research team, for the first of several experiments designed to test my abilities.

  Steve explains that there are two solutions to the problem of orienting yourself in space. One is to notice where objects are in relation to yourself—the chair is in front of me and to my right, for example. This is an “egocentric” strategy. The other way to do it is to take note of where things are in relation to each other and the space they are in—the table is about a foot away from the window, and the chair is at the side of the table that is closest to the door. This is called an “allocentric” strategy.