What we did was to look at a set of current London taxi drivers and a set of London taxi drivers that had been retired for about four years, said neuroscientist Dr Hugo Spiers, head of the Spatial Cognition Group at University College London, who is an author of the study.

We studied a group of current London taxi drivers and a group of retired London taxi drivers, said Dr Hugo Spiers of University College London, who is an author of the study.
