What Doesn't Kill Us

by Scott Carney

A recent study of cab drivers in London offers a glimpse into how wayfaring corresponds to specific brain structures. In order to get their taxi permit London cab drivers have to memorize the convoluted rat’s nest of English streets and be able to navigate the entire metropolis without maps. Researchers hooked up cabbies to MRI machines and discovered that the longer they drove cabs, the larger the volume of their hippocampi increased. The finding proved that thinking spatially can drastically change the brain. However, and perhaps more interesting, is that once the drivers retired, their brain structures returned to ordinary sizes. It’s strange to think about how quickly a human sense can disappear when it falls into disuse. Even when it is the most defining characteristic of a person, simply not exercising the neural muscle over a short time can make someone entirely dependent on external resources. While digital maps are a fairly recent phenomenon, there are other much more fundamental biological abilities that have simply vanished from our everyday use altogether. They lie there dormant and unused until the right stimulus wakes them up.