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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. Location is very

> In one landmark 2000 study, neuroscientists compared the brains of licensed London taxi drivers with those of people who did not drive cabs. Location is very important here. London cabbies have to pass The Knowledge which is an extremely difficult memory exam that only people with particular kind of brain can do.

artisinal 2mo ago
Indeed. Elsewhere in the world taxi drivers just follow the GPS.
- SoftTalker 2mo ago
  We had taxis long before GPS. When I was in my early 20s I had a job delivering pizza. I very quickly learned the delivery area, I knew pretty much every street and alleyway and shortcut to get from one place to another. Much smaller than London but I think the human brain is very good at remembering routes and where things are in an area, as this would have been an evolutionary advantage (go out hunting and be able to find your way back). No GPS, didn't even carry a map with me. We had a large map on the wall at the store, and if I had to deliver to a street I didn't recognize I'd find it on the map, see where it was relative to the streets I did know, and then I never had any problem finding places.
  - pryelluw 2mo ago
    Same. First thing they had me buy was a map book with all the local neighborhoods. The map on the wall helped get shortcuts from others. This is where I learned the difference between the different kinds of shortcuts. Some saved time, others distance, and some even potholes. It was a fun time.
    - deleted 2mo ago
      [deleted]
  - OptionOfT 2mo ago
    My 2019 car had the cardinal directions in the mirror (N, NE, E, ES, S etc). My 2025 does not anymore. I hate it. I think it helps to get that baseline of orientation, and then you look at the street numbers, and it all starts to come together.
    - clickety_clack 2mo ago
      Pretty much my only issue with CarPlay is that I can’t seem to set the map so that north is up. It turns everything into “third right ahead” instead of “this is just 2 blocks east of that coffee shop I was at last week”.
      - kccqzy 2mo ago
        CarPlay is merely the technology of having your phone take over a screen in the vehicle. It’s not a mapping map. Plenty of mapping apps support north up. But in any case, I found that if you want to remember routes, it is far better to study the route before you begin driving, and then not rely on CarPlay altogether. This gives you much higher awareness of street names and directions.
    - deleted 2mo ago
      [deleted]
    - toast0 2mo ago
      Suction cup compasses are ~ $10 on amazon if it bothers you. Won't be in the mirror though.
      - OptionOfT 2mo ago
        I think I should be able to add it to the iDrive. How much did BMW save by removing it from the mirror? $0.05 / mirror?
      - cenamus 2mo ago
        You'd also need to mount them facing up, pretty inconvenient when driving
  - al_borland 2mo ago
    I suspect GPS has made this much worse. I shining example was an Uber I got in Chicago, where GPS doesn't work well due to all the buildings. The guy drove around the same block 3 times, blindly following the GPS. It was infuriating.
    - SoftTalker 2mo ago
      And Chicago is one of the easier cities to navigate, as it's almost entirely a grid.
      - walthamstow 2mo ago
        Yeah I don't think grids are comparable to old world cities like London
  - jerlam 2mo ago
    There weren't a lot of taxis outside of major cities. I think widespread GPS allows ridesharing apps like Uber and Lyft to exist in suburbs and other places where taxis weren't a thing before, because it dramatically lowers the bar.
    - stymaar 2mo ago
      > There weren't a lot of taxis outside of major cities What? In my country at least (France), taxis have been a thing even in the countryside for as long as cars existed (or rather, as long as the telephone has). And I'd be very surprised if that wasn't also the case in most of Western Europe. In fact it's a much easier job when it comes to routing and knowing your passengers' destinations than doing it in a metropolis.
      - keiferski 2mo ago
        In America, ordering a taxi before rideshare apps was unreliable at best, if you were outside of central parts of major cities. More than one time I got stuck somewhere and had to walk 4 hours home.
        disgruntledphd2 2mo ago
        > In America, ordering a taxi before rideshare apps was unreliable at best, if you were outside of central parts of major cities. This was not the case everywhere. For instance, Ireland deregulated taxis in 2002, and service improved massively after that. It's funny how many amazing tech developments are really just a reaction to the peculiar pathologies of American/SF culture.
      - orcasushi 2mo ago
        I guess countryside France is still only 2 hours from Paris or Marseille, while countryside USA is maybe 8 hours or more from a metropolitan area. Not to mention that the population in this usa countryside is already way lower then any population density in the whole of France. Operating a taxi corp there would simply be not viable on a financial term.
- nottorp 2mo ago
  Maybe when they're new. In time they tend to learn the shortcuts that the apps don't show and ignore navigation here and there.
deleted 2mo ago
[deleted]
graemep 2mo ago
The first study referenced is in the US, and across 443 occupations.
genxy 2mo ago
People who would pass The Knowledge test might already develop dementia at a much lower rate.
- inglor_cz 2mo ago
  Plausible, but then you'd expect to find the same effect in other people who passed similarly demanding tests once. For example in people who studied something geometry-heavy. Also, The Knowledge Test is, IIRC, passed only once and then you do not have to retake it for the rest of your career. If a test passed in your 20s or 30s predicted accurately a much lower incidence of Alzheimer's in your 60s, that would be a remarkably strong early signal. Not impossible, but worth extra scrutiny. For the vast majority of old age conditions, we cannot predict them so long in advance.
  - PaulRobinson 2mo ago
    The Test is repeated every day you get in the cab. If you get into a black cab in London and ask to be taken to any location, anywhere within 6 miles of Charing Cross, that driver will know immediately the right route to take without satnav. To get to that point they need to know 25,000 streets and many, many landmarks - statues, museums, galleries, restaurants, hotels, and so on. I used to regularly drink with a cabbie in London, and he said that every time somebody got in the back his heart rate would rise, as he'd realise he's "on" and about to have to work out where to head from scratch. Within 30 seconds he'd have every step of the way worked out, down to which lanes at which intersections, no matter where in London he was or where he was going. That's the thing that's likely going to reduce Alzheimer's.
    - genxy 2mo ago
      One of the things that seems effective in reducing Alzheimers is a "flushing action" inside of the brain (Glymphatic system). I wonder if this spatial reasoning maps into a spatial activation in the brain. It would be interesting to put London cabbies in an fMRI machine and have them plan routes. It would also be interesting to look at sleep traces of cabbies. https://en.wikipedia.org/wiki/Glymphatic_system https://en.wikipedia.org/wiki/Glymphatic_system
BrandoElFollito 2mo ago
There is (or at least - was) a similar test for Paris taxi drivers. They needed among others to explain turn by turn the drive between two places indicated by the examiner. Today this knowledge is arguably less useful.
cromka 2mo ago
> that only people with particular kind of brain can do. That's yours speculation, isn't it?Because if so, it would corroborate the same conclusion, i.e. if you exercise your memory regularly, you are less likely to develop Alzheimer's.
neuralkoi 2mo ago
They have to memorize 25,000 streets. The test is no joke. [0] [0] https://www.youtube.com/watch?v=ur61kzXjvN8 https://www.youtube.com/watch?v=ur61kzXjvN8
- hahahaa 2mo ago
  Would they typically also relearn this at intervals. If you take 5000 rides a year, maybe 2000 streets that is 23000 you didn't get to remember though experience.
  - phist_mcgee 2mo ago
    They also have to remember where roadwork is/was and what kind of traffic is best/worst at a given time. There's a fantastic Tom Scott video on it https://www.youtube.com/watch?v=ZmWREtcDVBE https://www.youtube.com/watch?v=ZmWREtcDVBE
- nojvek 2mo ago
  Test may be no joke. But the test is also a joke in the world of GPS and Uber. I am glad Uber plowed through various stupid regulations constraining supply to bring a service with drastically more supply.
  - KaiserPro 2mo ago
    > I am glad Uber plowed through various stupid regulations What like safety checks? London had a huge minicab system, which is very much not knowledge based. Addison lee also had internet booking of cabs way before uber, but with the advantage that cars were roadworthy and the drivers were safety vetted. TFL came down hard on uber 1 for safety and 2 for clogging up the fucking roads and making busses slow. (see https://bsky.app/profile/garius.bsky.social https://bsky.app/profile/garius.bsky.social for more info)
    - creaturemachine 2mo ago
      It's very comforting when your cabbie knows exactly where you want to go with one prompt, versus being with some uber droid who can't look past their phone.
jredwards 2mo ago
Correlation and causation and all that. A number of the women in my wife's family have been diagnosed with Alzheimers. All of the women I know in her family also hate driving, because they find it very stressful. It's plausible that people prone to Alzheimers are less likely to be comfortable driving.
- bell-cot 2mo ago
  Best wishes for your wife's and your continued health.

artisinal 2mo ago

Indeed. Elsewhere in the world taxi drivers just follow the GPS.

SoftTalker 2mo ago
We had taxis long before GPS. When I was in my early 20s I had a job delivering pizza. I very quickly learned the delivery area, I knew pretty much every street and alleyway and shortcut to get from one place to another. Much smaller than London but I think the human brain is very good at remembering routes and where things are in an area, as this would have been an evolutionary advantage (go out hunting and be able to find your way back). No GPS, didn't even carry a map with me. We had a large map on the wall at the store, and if I had to deliver to a street I didn't recognize I'd find it on the map, see where it was relative to the streets I did know, and then I never had any problem finding places.
- pryelluw 2mo ago
  Same. First thing they had me buy was a map book with all the local neighborhoods. The map on the wall helped get shortcuts from others. This is where I learned the difference between the different kinds of shortcuts. Some saved time, others distance, and some even potholes. It was a fun time.
  - deleted 2mo ago
    [deleted]
- OptionOfT 2mo ago
  My 2019 car had the cardinal directions in the mirror (N, NE, E, ES, S etc). My 2025 does not anymore. I hate it. I think it helps to get that baseline of orientation, and then you look at the street numbers, and it all starts to come together.
  - clickety_clack 2mo ago
    Pretty much my only issue with CarPlay is that I can’t seem to set the map so that north is up. It turns everything into “third right ahead” instead of “this is just 2 blocks east of that coffee shop I was at last week”.
    - kccqzy 2mo ago
      CarPlay is merely the technology of having your phone take over a screen in the vehicle. It’s not a mapping map. Plenty of mapping apps support north up. But in any case, I found that if you want to remember routes, it is far better to study the route before you begin driving, and then not rely on CarPlay altogether. This gives you much higher awareness of street names and directions.
  - deleted 2mo ago
    [deleted]
  - toast0 2mo ago
    Suction cup compasses are ~ $10 on amazon if it bothers you. Won't be in the mirror though.
    - OptionOfT 2mo ago
      I think I should be able to add it to the iDrive. How much did BMW save by removing it from the mirror? $0.05 / mirror?
    - cenamus 2mo ago
      You'd also need to mount them facing up, pretty inconvenient when driving
- al_borland 2mo ago
  I suspect GPS has made this much worse. I shining example was an Uber I got in Chicago, where GPS doesn't work well due to all the buildings. The guy drove around the same block 3 times, blindly following the GPS. It was infuriating.
  - SoftTalker 2mo ago
    And Chicago is one of the easier cities to navigate, as it's almost entirely a grid.
    - walthamstow 2mo ago
      Yeah I don't think grids are comparable to old world cities like London
- jerlam 2mo ago
  There weren't a lot of taxis outside of major cities. I think widespread GPS allows ridesharing apps like Uber and Lyft to exist in suburbs and other places where taxis weren't a thing before, because it dramatically lowers the bar.
  - stymaar 2mo ago
    > There weren't a lot of taxis outside of major cities What? In my country at least (France), taxis have been a thing even in the countryside for as long as cars existed (or rather, as long as the telephone has). And I'd be very surprised if that wasn't also the case in most of Western Europe. In fact it's a much easier job when it comes to routing and knowing your passengers' destinations than doing it in a metropolis.
    - keiferski 2mo ago
      In America, ordering a taxi before rideshare apps was unreliable at best, if you were outside of central parts of major cities. More than one time I got stuck somewhere and had to walk 4 hours home.
      - disgruntledphd2 2mo ago
        > In America, ordering a taxi before rideshare apps was unreliable at best, if you were outside of central parts of major cities. This was not the case everywhere. For instance, Ireland deregulated taxis in 2002, and service improved massively after that. It's funny how many amazing tech developments are really just a reaction to the peculiar pathologies of American/SF culture.
    - orcasushi 2mo ago
      I guess countryside France is still only 2 hours from Paris or Marseille, while countryside USA is maybe 8 hours or more from a metropolitan area. Not to mention that the population in this usa countryside is already way lower then any population density in the whole of France. Operating a taxi corp there would simply be not viable on a financial term.
nottorp 2mo ago
Maybe when they're new. In time they tend to learn the shortcuts that the apps don't show and ignore navigation here and there.

deleted 2mo ago

[deleted]

graemep 2mo ago

The first study referenced is in the US, and across 443 occupations.

genxy 2mo ago

People who would pass The Knowledge test might already develop dementia at a much lower rate.

inglor_cz 2mo ago
Plausible, but then you'd expect to find the same effect in other people who passed similarly demanding tests once. For example in people who studied something geometry-heavy. Also, The Knowledge Test is, IIRC, passed only once and then you do not have to retake it for the rest of your career. If a test passed in your 20s or 30s predicted accurately a much lower incidence of Alzheimer's in your 60s, that would be a remarkably strong early signal. Not impossible, but worth extra scrutiny. For the vast majority of old age conditions, we cannot predict them so long in advance.
- PaulRobinson 2mo ago
  The Test is repeated every day you get in the cab. If you get into a black cab in London and ask to be taken to any location, anywhere within 6 miles of Charing Cross, that driver will know immediately the right route to take without satnav. To get to that point they need to know 25,000 streets and many, many landmarks - statues, museums, galleries, restaurants, hotels, and so on. I used to regularly drink with a cabbie in London, and he said that every time somebody got in the back his heart rate would rise, as he'd realise he's "on" and about to have to work out where to head from scratch. Within 30 seconds he'd have every step of the way worked out, down to which lanes at which intersections, no matter where in London he was or where he was going. That's the thing that's likely going to reduce Alzheimer's.
  - genxy 2mo ago
    One of the things that seems effective in reducing Alzheimers is a "flushing action" inside of the brain (Glymphatic system). I wonder if this spatial reasoning maps into a spatial activation in the brain. It would be interesting to put London cabbies in an fMRI machine and have them plan routes. It would also be interesting to look at sleep traces of cabbies. https://en.wikipedia.org/wiki/Glymphatic_system https://en.wikipedia.org/wiki/Glymphatic_system

BrandoElFollito 2mo ago

There is (or at least - was) a similar test for Paris taxi drivers. They needed among others to explain turn by turn the drive between two places indicated by the examiner. Today this knowledge is arguably less useful.

cromka 2mo ago

> that only people with particular kind of brain can do. That's yours speculation, isn't it?Because if so, it would corroborate the same conclusion, i.e. if you exercise your memory regularly, you are less likely to develop Alzheimer's.

neuralkoi 2mo ago

They have to memorize 25,000 streets. The test is no joke. [0] [0] https://www.youtube.com/watch?v=ur61kzXjvN8 https://www.youtube.com/watch?v=ur61kzXjvN8

hahahaa 2mo ago
Would they typically also relearn this at intervals. If you take 5000 rides a year, maybe 2000 streets that is 23000 you didn't get to remember though experience.
- phist_mcgee 2mo ago
  They also have to remember where roadwork is/was and what kind of traffic is best/worst at a given time. There's a fantastic Tom Scott video on it https://www.youtube.com/watch?v=ZmWREtcDVBE https://www.youtube.com/watch?v=ZmWREtcDVBE
nojvek 2mo ago
Test may be no joke. But the test is also a joke in the world of GPS and Uber. I am glad Uber plowed through various stupid regulations constraining supply to bring a service with drastically more supply.
- KaiserPro 2mo ago
  > I am glad Uber plowed through various stupid regulations What like safety checks? London had a huge minicab system, which is very much not knowledge based. Addison lee also had internet booking of cabs way before uber, but with the advantage that cars were roadworthy and the drivers were safety vetted. TFL came down hard on uber 1 for safety and 2 for clogging up the fucking roads and making busses slow. (see https://bsky.app/profile/garius.bsky.social https://bsky.app/profile/garius.bsky.social for more info)
  - creaturemachine 2mo ago
    It's very comforting when your cabbie knows exactly where you want to go with one prompt, versus being with some uber droid who can't look past their phone.

jredwards 2mo ago

Correlation and causation and all that. A number of the women in my wife's family have been diagnosed with Alzheimers. All of the women I know in her family also hate driving, because they find it very stressful. It's plausible that people prone to Alzheimers are less likely to be comfortable driving.

bell-cot 2mo ago
Best wishes for your wife's and your continued health.