We’ve all come to rely on smartphones and in-car GPS systems to find our way in the world. But when we follow their directions, the parts of our brain usually used for navigation appear to sit idle.
A series of experiments performed by researchers at University College London had volunteers navigate simulations of the area known as Soho in the U.K.'s capital, while fMRI scans captured their brain activity. Sometimes they had to find their own routes, other times they were fed turn-by-turn directions similar to those given by a car’s GPS or a smartphone.
The results show that when navigating the old-fashioned way, spikes of neuronal activity in their hippocampus, a brain region linked to navigation, and the prefrontal cortex, associated with planning, occur as people enter new streets. The spikes are more pronounced when there are more possible choices to make on an upcoming stretch of road. That activity isn't observed when people are receiving turn-by-turn directions.
“When we have technology telling us which way to go ... these parts of the brain simply don’t respond to the street network,” explained Hugo Spiers, who led the research, to the Guardian. “In that sense our brain has switched off its interest in the streets around us.”
Interestingly, the study also shows that, when it’s active, the hippocampus also appears to keep track of the progress made during a journey. So it’s perhaps not surprising that when navigation systems do betray us—a problem that is, mercifully, becoming increasingly rare—we’re left at rather a loss over how to rectify the situation.
As for how it’s affecting the human ability to navigate more generally? Well, this is a single study, so it’s unreasonable to draw sweeping conclusions. But Spiers does warn Scientific American that “if you think about the brain as a muscle, then certain activities, like learning maps of London’s streets, are like body building … and all we can really say from our new findings is that you’re not working out these particular bits of the brain when you’re relying on [turn-by-turn directions].”