Is GPS All in Our Head? IT'S a question that probably every driver with a Garmin navigation device on her dashboard has asked herself at least once: What did we ever do before GPS? How did people find their way around, especially in places they'd never been before? Like most questions asked in our tech-dependent era, these underestimate the power of the human mind. It is surprisingly good at developing "mental maps" of an area, a skill new research shows can grow stronger with use. The question is, with disuse - say, by relying on a GPS device - can we lose the skill too? The notion of a mental map isn't new. In the 1940s, the psychologist Edward C. Tolman used rats in mazes to demonstrate that "learning consists not in stimulus-response connections but in the building up in the nervous system of sets which function like cognitive maps." This concept is widely accepted today. When exploring a new territory, we perceive landmarks along a route. By remembering their position and the spatial relations between the streets, locations and landmarks we pass, we are able to develop survey knowledge (stored in the mind like a mental map), which enables us to indicate directions, find shortcuts or detours - in short, to react and navigate comfortably. It's not all in our heads, though: physical maps help us build cognitive maps. By depicting the spatial relations in a big context, they provide a useful reference to integrate navigational experience. In one experiment, I had 26 residents of Tübingen, Germany, navigate a three-dimensional model of their hometown by wearing head-mounted displays. My team and I asked them to point to well-known locations around town not visible from their current perceived position. Varying their viewing direction - facing north, facing east - we then assessed their pointing error. All participants performed best when facing one particular direction, north, and the pointing error increased with increasing deviation from north. In other words, by using knowledge gained from navigation to link their perceived position to the corresponding position on a city map, participants could easily retrieve the locations from their memory of city maps - which, after all, are typically oriented north. If maps help us, what is the problem with GPS? A lot: new research shows that the more we rely on technology to find our way, the less we build up our cognitive maps. Unlike a city map, a GPS device normally provides bare-bones route information, without the spatial context of the whole area. We see the way from A to Z, but we don't see the landmarks along the way. Developing a cognitive map from this reduced information is a bit like trying to get an entire musical piece from a few notes. Our brains act economically: they try to decrease the amount of information to be stored (e.g., by relating new thoughts to already known content) and avoid storing unnecessary information. That may be the unconscious appeal of a GPS, but it means we're not pushing our brains to work harder. And a GPS device may even contradict your mental map by telling you to go left (e.g., for a faster highway) while your target is actually to the right. All of this leads us to use our mental maps even less. But shouldn't we just accept that GPS is a good substitute for old-fashioned maps? Navigational devices can be time-savers, but they can easily become crutches. Break your GPS, and you may find yourself lost. And there is more: The psychologist Eleanor A. Maguire and her colleagues at University College London found that spatial experience actually changes brain structures. As taxi drivers learned the spatial layout of London, the gray matter in their hippocampal areas - that is, the areas of the brain integrating spatial memories - increased. But if the taxi drivers" internal GPS grew stronger with use, it stands to reason that the process is reversible after disuse. You may degrade your spatial abilities when not training them, as with someone who learned a musical instrument and stopped playing. Navigating, keeping track of one's position and building up a mental map by experience is a very challenging process for our brains, involving memory (remembering landmarks, for instance) as well as complex cognitive processes (like calculating distances, rotating angles, approximating spatial relations). Stop doing these things, and it'll be harder to pick them back up later. How to avoid losing our mental maps? The answer, as always, is practice. Next time you're in a new place, forget the GPS device. Study a map to get your bearings, then try to focus on your memory of it to find your way around. City maps do not tell you each step, but they provide a wealth of abstract survey knowledge. Fill in these memories with your own navigational experience, and give your brain the chance to live up to its abilities. Julia Frankenstein is a psychologist at the Center for Cognitive Science at the University of Freiburg.