With things like casava I wonder how the SA people got onto the effect in the first place, if it’s so weak and hard to disentangle. We have trouble doing that sort of thing now with meta-reviews and double blind studies!
The hard way: Generations of death. One family does things differently and starts a superstition about it. They do it and it works, but they don’t know why so they start a superstition. That becomes a myth.
This is also why Africa doesn’t just copy them. There is no respect for the myth and no understanding of the science, because the people who brought it over also disregarded the myth and assumed the plant was safe so didn’t do science until it was too late.
Does that work? The effect is weak, the pressure is competing with a lot more significant causes of death. And myths spread horizontally too. They’re not single family things, there can’t be enough variability and isolation to have a full Darwinian selection because it’s not like you have the tribes with the wrong belief being completely exterminated by that mistake.
That said, reading up on it it sounds like cassava can also cause acute poisoning, and that sounds like a much stronger feedback signal for people to notice.
Generations of data, fewer differences in environmental factors between members (diets, lifestyle, diseases, etc) to obscure the effect. For long-term effects like this, ‘modern science’ hasn’t really existed long enough to get much data in comparison to centuries of generational trial-and-error
Edit: also, long-term effects measured now have a bunch of confounders due to lifestyle change and rapid technological and medical development, while their conditions were basically stationary. Scientists would kill for that kind of data now!
With things like casava I wonder how the SA people got onto the effect in the first place, if it’s so weak and hard to disentangle. We have trouble doing that sort of thing now with meta-reviews and double blind studies!
The hard way: Generations of death. One family does things differently and starts a superstition about it. They do it and it works, but they don’t know why so they start a superstition. That becomes a myth.
This is also why Africa doesn’t just copy them. There is no respect for the myth and no understanding of the science, because the people who brought it over also disregarded the myth and assumed the plant was safe so didn’t do science until it was too late.
Read the book it is amazing.
Does that work? The effect is weak, the pressure is competing with a lot more significant causes of death. And myths spread horizontally too. They’re not single family things, there can’t be enough variability and isolation to have a full Darwinian selection because it’s not like you have the tribes with the wrong belief being completely exterminated by that mistake.
That said, reading up on it it sounds like cassava can also cause acute poisoning, and that sounds like a much stronger feedback signal for people to notice.
Once again, I will point to the source: Joseph Heinrich, the secret of our Success. Yes you are correct it is messy. It is debated.
Generations of data, fewer differences in environmental factors between members (diets, lifestyle, diseases, etc) to obscure the effect. For long-term effects like this, ‘modern science’ hasn’t really existed long enough to get much data in comparison to centuries of generational trial-and-error
Edit: also, long-term effects measured now have a bunch of confounders due to lifestyle change and rapid technological and medical development, while their conditions were basically stationary. Scientists would kill for that kind of data now!