Researchers say the hippocampus may explain the occupational pattern
A 2024 study examining nearly 9 million U.S. death certificates found that taxi and ambulance drivers had the lowest risk of dying from Alzheimer’s disease among 443 occupations. The records covered January 2020 through December 2022.
After researchers adjusted 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.
The pattern did not extend to every driving occupation. Bus drivers and aircraft pilots, whose work relied on fixed or predetermined routes, did not appear to have the same advantage. The researchers concluded that continuous, real-time navigation — locating oneself, tracking a destination and updating a mental map as conditions change — may matter more than driving itself.
Researchers believe the association may center on the hippocampus, a brain region involved in memory and spatial navigation. Alzheimer’s damages the hippocampus early, and problems with spatial navigation and orientation can appear before obvious memory loss.
A 2000 study comparing licensed London taxi drivers with people who did not drive cabs provided early structural-imaging evidence that regions of the adult brain can change under sustained navigational demand. To earn a license, London taxi drivers must memorize more than 25,000 streets within a 6-mile radius of Charing Cross. The training, known as “The Knowledge,” takes three to four years.
That study found that London taxi drivers had more gray matter in the posterior hippocampus, a region tied to storing large-scale spatial maps. The volume tracked with experience: The longer a driver had worked, the larger that part of the brain appeared to be. The findings indicated that the change was built through practice, rather than inherited.
The research raises a question for people whose spatial work happens through a computer. Cartographers, urban planners and geospatial analysts may use geographic information systems to layer population data over flood-exposure maps, examine road geometry or map land cover from satellite imagery. That work requires them to hold multiple data layers, coordinate systems and scales in mind.
A taxi driver navigates from street level, while a GIS researcher may picture space from above — a form of reasoning cognitive scientists call allocentric. The source report said the perspectives overlap in the brain because the hippocampus can build maps from outside viewpoints as well as from a navigator’s own position.
Other research points in the same direction but does not establish that computer-based spatial reasoning protects against Alzheimer’s. In 2023, researchers used a machine-learning model and data from more than 22,500 people to predict which ZIP codes had higher Alzheimer’s rates with 84% accuracy based on environmental complexity.
People living in environments with dense street networks, many intersections, diverse points of interest, landmarks and multiple route options were less likely to develop Alzheimer’s, according to that research. A follow-up study linked geospatial complexity in a person’s surroundings to greater volume in brain regions involved in spatial navigation.
Those studies examined where people live, not the work they perform. Whether spatial reasoning through a screen engages the same circuitry as navigating a real city remains untested.
The findings fit within broader research linking mentally complex occupations with delayed cognitive decline and lower dementia risk, even after accounting for education. Research on cognitive reserve describes the brain’s capacity to continue functioning despite disease and may help explain why people with similar disease burdens can show different levels of cognitive impairment.
Spatial reasoning can be trained through GIS and remote-sensing instruction offered in geography, engineering, public health and environmental science programs worldwide, according to the source report.
Hatim Sharif, a professor of civil and environmental engineering at The University of Texas at San Antonio, wrote the source article.