Yes I don't see much correlation between **** mother and **** father creating **** child, it does seem pretty random... I thought that maybe there could be some genetic factor though, that could skip generations, even multiple generations. e.g. INFJ woman has INFJ great-great grandchild (this could be a nurture reason though and also not heredity). Yes it would be interesting to see types in isolated communities and what personality traits are seen as desirable/essential in their communities to survive.
I think it's more likely to be something along the lines of multiple genes acting in concert that produce the difference. Mom had the fire, dad had the water, but we couldn't steam the veggies 'til they were both in the same place.
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referencing some other comments:
A mutation would suggest that an N parent and especially two N parents would have a significantly higher statistical chance of passing on their mutation to their children - producing more N children than S children both in general and when compared to two S parents. The statistics haven't borne this out, however, which is why the conclusion so far has been that it's not heritable.
Evolution also doesn't work with a "purpose," or kill people off because they're less "valuable", sometimes if Society finds you so disgusting and invaluable that it shuns you to the extent that you can't survive or never procreate... that's something, but that's not very common. Evolution doesn't know that you're a leader or a grunt. It's not a conscious process. Your genes get passed on if you survive and procreate, that's it. If anything, a leader in an environment where selection pressures are high are going to have a greater chance of passing on a great deal of their genes. Leaders of groups that live in such environments often have the best food and living conditions, have greater amounts of protection, and access to more partners for mating purposes. In environments that don't have high selection pressures, whether or not someone is a leader is a bit of a moot point.
Looking at spiritual and philosophical master works... a lot of them seem to have been written by or influenced by people who were N's of varying sorts. N's existed through-out most parts of written history so far as we can tell. So it's not some new-fangled evolutionary advancement. Plenty of S's adopt the spiritual writings and beliefs of N leaders, but idealizing those thinking styles obviously has not turned them or most of their children into Ns... so influence very likely has little to do with it.
You have blueprint for your entire body, cells replicating and usually falling right into place (so long as that blue print does not have a smudge in it somewhere, causing a defect)... how could every single part of your body be mapped out in your DNA and work like a well oiled machine once built so long as it's care for... but not your brain? Referencing those Twin studies again - these have shown pairs identical twins, raised in entirely different families, never having met one another, but sharing most of their tastes in food, music, mates - even often sharing complex behavioral habits. Because what they shared was not nurture, not their environment, but their complete genetic make-up, this suggests a very high genetic predisposition component to personality. That's not the same as saying "heritable", as I mentioned before, when you're mixing two sets of genes to make a child the resulting mix is going to be different every time (except in the obvious case of identical twins lol). Twins who are raised together, may purposefully decide to differentiate depending on how they're treated. Sometimes there's an outside competing influence causing them to move away from what comes naturally. It would actually be interesting to see sets of identical twins raised together in an environment that caused them to compete for individuality in this way, but who move apart and don't spend much time together any more. I wonder if after many years, what comes naturally will re-emerge as their typical behaviors.
