NAVIGATION
If cabbies' uncanny recall of locations and routes seems superhuman, it's for good reason: They have more gray matter devoted to navigation than the average person.
Eleanor Maguire, Ph.D., a neurologist at University College London, used magnetic resonance imaging (MRI) scans to compare the gray matter density in the brains of 16 taxi drivers with that of 16 inexperienced motorists. Surprisingly, the amount of time subjects spent navigating the roads was correlated with the size of their hippocampus, a brain structure devoted to memory, suggesting that the longer cabbies cruise the streets, the larger that brain area grows. "There is a lot of evidence that the hippocampus can increase in size in some species depending on the spatial demands put upon them," says Maguire, "like finding food and mates," or the fastest way to the airport.
