An anonymous reader shares a report from The Conversation, written by Hatim Sharif, a civil and environmental engineer who has "spent more than two decades staring at maps" and spatial data. Sharif finds one connection especially fascinating: the link between spatial reasoning and [1]why taxi drivers seem to have lower rates of Alzheimer's . From the report:

> Taxi and ambulance drivers are less likely than workers in almost any other job to die of Alzheimer's disease. That was the surprising result of [2]a 2024 study examining the death certificates of nearly 9 million people in the U.S. [...] Of the 9 million death certificates from January 2020 to December 2022 that researchers examined, taxi and ambulance drivers had the lowest risk of dying from Alzheimer's disease out of 443 occupations. After adjusting for age, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer's, compared with 1 in 60 people overall. This pattern did not extend to other driving jobs.

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> The researchers concluded that the key to reducing the risk of Alzheimer's was not driving itself but continuous real-time navigation: the constant work of locating yourself in space, tracking a destination and updating a mental map as conditions change. Drivers whose jobs relied on fixed or predetermined routes, like bus drivers and aircraft pilots, didn't seem to experience a similar advantage. Researchers believe the association between navigation-heavy work and lower Alzheimer's risk centers on the hippocampus, a part of the brain that governs memory and spatial navigation. It's one of the first brain regions that Alzheimer's damages: Problems with spatial navigation and orientation are among the earliest signs of the disease, sometimes surfacing before obvious memory loss.

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> In one landmark 2000 study, neuroscientists compared the brains of licensed London taxi drivers with those of people who did not drive cabs. Their findings provided the first evidence via structural imaging that regions of the adult brain [3]can measurably change under sustained navigational demand. To earn a license, London cabbies must memorize more than 25,000 streets within a 6-mile radius of Charing Cross, a challenge known as " [4]The Knowledge " that takes three to four years.

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> The researchers found that London taxi drivers had measurably more gray matter in the posterior hippocampus, a brain area tied to storing large-scale spatial maps. That volume [5]tracked with experience : The longer someone had driven, the larger that part of the brain. The change was built through practice, not inherited. While people who are good at navigation might gravitate to this kind of job, the job itself does have an impact on the brain. Together, these two studies make a coherent case: Work that intensively exercises the hippocampus may reshape it, and that reshaping may protect against one of the most feared diseases of aging.



[1] https://theconversation.com/taxi-drivers-rarely-die-of-alzheimers-how-complex-mental-maps-and-spatial-reasoning-protect-your-brain-286650

[2] https://doi.org/10.1136/bmj-2024-082194

[3] https://doi.org/10.1073/pnas.070039597

[4] https://tfl.gov.uk/info-for/taxis-and-private-hire/licensing/learn-the-knowledge-of-london

[5] https://doi.org/10.1073/pnas.070039597