This Job May Protect You From Alzheimer’s
know something like the back of your hand: to know a place or thing so well that you can remember every detail
Everton Thomas drove buses in East London. With four children to care for, his income wasn’t enough for the life he wanted. Then he learned that taxi drivers can earn more than 40,000 pounds a year. But first he had to pass the hardest taxi test in the world, called the Knowledge. Candidates must memorize the map of an entire city: 25,000 streets and 100,000 landmarks. Most need three to four years. Everton studied at least 35 hours a week while working a full-time job until he knew London like the back of his hand.
During the test, an examiner names two places in London. The candidate must recite the best route from memory, naming every road, without hesitation. Everton earned his license and became a taxi driver.
All that sacrifice may have bought Everton more than a higher income. In 2000, researchers discovered that London cabbies have a larger hippocampus. This brain region manages memory and navigation, and it grows with practice. A later study checked 9 million death certificates across 443 jobs. Taxi drivers had the lowest rate of Alzheimer’s deaths: about 1 in 100, against 1 in 60 overall. Bus drivers and pilots, who follow fixed routes, showed no advantage.
No one can prove that navigation protects the brain, but the hippocampus is one of the first places Alzheimer’s attacks. Everton spent years building a map of London inside his head for his family. He may also have been protecting his mind.
Sample sentences
I don’t need the recipe anymore. I know it like the back of my hand.
Ask him where anything is in the store. He knows those shelves like the back of his hand.
I thought I knew this neighborhood like the back of my hand, but yesterday I found a little park I had never seen.
