3 ms·

Brilliant comment—-The effect could easily be an ascertainment bias that is downstream of winnowing 55-70 year-old drivers who cannot hack route selection effec

Brilliant comment—-The effect could easily be an ascertainment bias that is downstream of winnowing 55-70 year-old drivers who cannot hack route selection effectively anymore. They drop out and take on other jobs.

noduerme 2y ago
I'm not so sure. The study didn't stipulate that taxi driving was the patient's last occupation, nor how long they did the job for. Also, with Alzheimers, aren't older memories the last to go? A driver would probably be more likely to have trouble finding their keys before they forgot the streets they'd been driving for 30+ years. At that point, it would be hard to train for another job. Additionally, I've never heard of a cab driver losing their license for getting confused en route. Taking the wrong way on purpose can lead to some disciplinary action, but even that is rarely if ever pursued.
- robwwilliams 2y ago
  I am not sure either. The authors (more correctly, the author of the review of the the parent paper) imply that the constant challenges to adapt to complex spatial navigational tasks is the most likely explanation. Familiarity with routes is not the key variable (no bus driver benefit). It is active navigational adjustment or perhaps just ascertainment. Controlling for ascertainment bias would be possible but hard because you would face secular confounds (e,g., impact of COVID-19 on taxi drivers vs other professions). By the way, the original l”London taxi drivers have larger hippocampii paper” was NOT replicated. So sad since this is such a fun story.
  - noduerme 2y ago
    From a programmer's and former taxi driver's perspectice, finding a fuzzy path through something chaotic and shifting like a city optimizes for very different logic than finding a path through a maze or a jam of vehicles. It's reducing from a big picture versus trying to iterate solutions from a small picture. And I can't tell you how many times I get in a lyft these days and know better than the GPS how to get around a traffic snarl, because pathfinding generally doesn't consider what might happen to traffic 30 minutes from now given the current conditions (if everyone is headed northeast to a concert, for example).
- robwwilliams 2y ago
  Here is there selection criterion and justification: “occupations involving extensive day-to-day navigation, with often unpredictable, real time navigational demands.” All subjects died between Jan 1 2020 (COVID) to Dec 31, 2022. There was no data on duration between active employment in listed employment categories and age of death. This is a problem given the fact that Uber and Lyft have radically changed the taxi industry in 101 ways that will interact with age of drivers. Not true of ambulance drivers. Mean age of death of target groups: 64 (ambulance) to 68 years (taxi) and mostly men. Both values are awfully (sadly) low. I want to understand the poor expectancy of ambulance drivers. Is it stress? And here is summary of their analysis: >For each occupation, we first calculated the percentage of deaths due to Alzheimer’s disease and the mean age at death in years (ie, average life expectancy). We plotted the association between these two variables, with each observation reflecting a single occupation. The purpose of this analysis was to illustrate the need to account for the person’s age at death since the risk of Alzheimer’s disease rises with age and therefore Alzheimer’s mortality would naturally be lower in occupations with a lower life expectancy. And here is their discussion on ascertainment bias (great job): >Firstly and perhaps most importantly, selection bias is possible because individuals who are at higher risk of developing Alzheimer’s disease may be less likely to enter or remain in memory intensive driving occupations such as taxi and ambulance driving. This could mean that the lower Alzheimer’s disease mortality observed in these occupations is not due to the protective effect of the job itself but rather because those prone to the disease may have self-selected out of such roles. However, Alzheimer’s disease symptoms typically develop after patients’ working years, with only 5-10% of cases occurring in people younger than 65 years (early onset).1114 While subtle symptoms could develop earlier, they would still most likely be after a person had worked long enough to deem the occupation to be a so-called usual occupation, suggesting against substantial attrition from navigational jobs due to development of Alzheimer’s disease.
  - noduerme 2y ago
    >> The purpose of this analysis was to illustrate the need to account for the person’s age at death since the risk of Alzheimer’s disease rises with age and therefore Alzheimer’s mortality would naturally be lower in occupations with a lower life expectancy. Just a nit: This sort of analysis seems lazy, because while it's true that without advanced age one's likelihood of dying from Alzheimers is lower, it's also true that without Alzheimers one's likelihood of dying at advanced age is lower. The dataset used for the non-Alzheimers death rate should be adjusted for what the death rate would be if Alzheimers didn't exist, not the death rate from all other age-related causes in a world where it does exist.

noduerme 2y ago

I'm not so sure. The study didn't stipulate that taxi driving was the patient's last occupation, nor how long they did the job for. Also, with Alzheimers, aren't older memories the last to go? A driver would probably be more likely to have trouble finding their keys before they forgot the streets they'd been driving for 30+ years. At that point, it would be hard to train for another job. Additionally, I've never heard of a cab driver losing their license for getting confused en route. Taking the wrong way on purpose can lead to some disciplinary action, but even that is rarely if ever pursued.

robwwilliams 2y ago
I am not sure either. The authors (more correctly, the author of the review of the the parent paper) imply that the constant challenges to adapt to complex spatial navigational tasks is the most likely explanation. Familiarity with routes is not the key variable (no bus driver benefit). It is active navigational adjustment or perhaps just ascertainment. Controlling for ascertainment bias would be possible but hard because you would face secular confounds (e,g., impact of COVID-19 on taxi drivers vs other professions). By the way, the original l”London taxi drivers have larger hippocampii paper” was NOT replicated. So sad since this is such a fun story.
- noduerme 2y ago
  From a programmer's and former taxi driver's perspectice, finding a fuzzy path through something chaotic and shifting like a city optimizes for very different logic than finding a path through a maze or a jam of vehicles. It's reducing from a big picture versus trying to iterate solutions from a small picture. And I can't tell you how many times I get in a lyft these days and know better than the GPS how to get around a traffic snarl, because pathfinding generally doesn't consider what might happen to traffic 30 minutes from now given the current conditions (if everyone is headed northeast to a concert, for example).
robwwilliams 2y ago
Here is there selection criterion and justification: “occupations involving extensive day-to-day navigation, with often unpredictable, real time navigational demands.” All subjects died between Jan 1 2020 (COVID) to Dec 31, 2022. There was no data on duration between active employment in listed employment categories and age of death. This is a problem given the fact that Uber and Lyft have radically changed the taxi industry in 101 ways that will interact with age of drivers. Not true of ambulance drivers. Mean age of death of target groups: 64 (ambulance) to 68 years (taxi) and mostly men. Both values are awfully (sadly) low. I want to understand the poor expectancy of ambulance drivers. Is it stress? And here is summary of their analysis: >For each occupation, we first calculated the percentage of deaths due to Alzheimer’s disease and the mean age at death in years (ie, average life expectancy). We plotted the association between these two variables, with each observation reflecting a single occupation. The purpose of this analysis was to illustrate the need to account for the person’s age at death since the risk of Alzheimer’s disease rises with age and therefore Alzheimer’s mortality would naturally be lower in occupations with a lower life expectancy. And here is their discussion on ascertainment bias (great job): >Firstly and perhaps most importantly, selection bias is possible because individuals who are at higher risk of developing Alzheimer’s disease may be less likely to enter or remain in memory intensive driving occupations such as taxi and ambulance driving. This could mean that the lower Alzheimer’s disease mortality observed in these occupations is not due to the protective effect of the job itself but rather because those prone to the disease may have self-selected out of such roles. However, Alzheimer’s disease symptoms typically develop after patients’ working years, with only 5-10% of cases occurring in people younger than 65 years (early onset).1114 While subtle symptoms could develop earlier, they would still most likely be after a person had worked long enough to deem the occupation to be a so-called usual occupation, suggesting against substantial attrition from navigational jobs due to development of Alzheimer’s disease.
- noduerme 2y ago
  >> The purpose of this analysis was to illustrate the need to account for the person’s age at death since the risk of Alzheimer’s disease rises with age and therefore Alzheimer’s mortality would naturally be lower in occupations with a lower life expectancy. Just a nit: This sort of analysis seems lazy, because while it's true that without advanced age one's likelihood of dying from Alzheimers is lower, it's also true that without Alzheimers one's likelihood of dying at advanced age is lower. The dataset used for the non-Alzheimers death rate should be adjusted for what the death rate would be if Alzheimers didn't exist, not the death rate from all other age-related causes in a world where it does exist.