four years,” said neuroscientist Dr Hugo Spiers, head of the Spatial Cognition Group at University College London, who is an author of the study. The results showed that the retired taxi drivers performed worse on navigation tests than those still behind the wheel. “We were able to show that their abilities did drop away if they weren’t using their knowledge on that particular test.” Spiers also believes there is a danger in relying on technologies like GPS but he is quick to point out that the biggest risk lies in users being unwittingly led into perilous situations. Among the fatalities blamed on satnavs (satellite navigation devices) was the death of a driver who, in 2010, plunged into a reservoir in Spain. “There is a genuine potential for risk in relying on a satnav,” said Spiers. “But the actual health risk of not using your brain effectively is not known.” The way in which navigational technology is used could also affect its impact on our own abilities, says Spiers. While audio instructions to drivers remove the need to think about navigation, he says, the use of smartphone apps as digital maps is very different. “In the old days, you had to print out or take an A to Z map in your pocket – what we are doing now is just using computer- aided information and you are having to think really quite hard about where you are going and interact with this