I grew up in India. I remember elder folks in my family talking about how the "water" of a place made people different. And that if you moved to that place, slowly you'd become like them too. They attributed certain characteristics (aggressiveness, smartness, etc.) to the "water" of a place.
Now, of course, this had no scientific basis. But it would be interesting if what they thought was the "water", was actually the microbial composition of the traditional water sources there.
Curiously, they may be right - see "Lithium in drinking water and the incidences of crimes, suicides, and arrests related to drug addictions." https://www.ncbi.nlm.nih.gov/pubmed/1699579
The same can be said of lead. I'm fairly certain I've read of a study / theory that the drop in crime rates can be tracked back to removing lead from paint, gasoline, etc.
Full disclosure: I don't recall if this jumped the gap between correlation and cause.
I think that explanation is pretty widely accepted as being a cause of the past few decades' drop in crime rates (though not the only one). It's probably not possible to prove cause better than we have without obviously unethical experimental studies.
"There must be something in the water" and variations thereof is a common saying in the west, too. It's often heard as a response to learning that families of tall people or smart people come from the same town.
Let me play the devil's advocate for a just moment: water in the west is much more regulated. I doubt that some small difference in our water's mineral levels would change much in the brain. Something like chemicals or harsh or bacteria from heavily polluted water might be really different. Rivers downstream from pharmaceutical labs, heavy industrial area, etc. could mess up your body's balance.
> Let me play the devil's advocate for a just moment: water in the west is much more regulated. I doubt that some small difference in our water's mineral levels would change much in the brain.
Different water softness, different strains of bacteria. Back to step one.
If there were no regulations, the water in those cities would be the same to this day and wouldn't have made the headlines. A law is only as good as it is enforced. The Flint water crisis should be big enough of a wake up call to put the focus on the EPA and Safe Drinking Water Act (SDWA) and hopefully avoid similar issues in the future.
The situation is miles better than it was in the 1950s thanks to those regulations.
You probably mean- I haven't seen any research that tries to associate water impurities as parameters to human behavior as parameters.
Why do Indians always sound so defensive about their practices? As someone whose parents spent a decade in india- they attributes their happiness to the lifestyle they learnt in india. None of which had a clear basis in modern science.
"Why do Indians always sound so defensive about their practices?"
I feel like that's a broad overgeneralization, but regardless I'd wager a guess that it would have something to do with not wanting to sound like a charlatan or a fool. Even if it works for them, people can be awfully bristly about health and lifestyle practices when it comes from someone they don't know.
If a relative of yours moves to a far away town and comes back for visit and he acts very differently from how he used to, you might say to him: "oh that place's water has changed you".
I also just saw a video about 60 years fox breeding experiment in Russia to see how selection would change their behavior (they're now tame to human, not dog friendly but halfway).
Consider this to the relationship between climate/location/genes/culture.
I'm not sure what connection you're trying to make. Selective breeding is textbook "nature", and effects of things like the local composition of water is textbook "nurture".
Now, of course, this had no scientific basis. But it would be interesting if what they thought was the "water", was actually the microbial composition of the traditional water sources there.