This Study takes genetically identical fish and puts them in indentical environments and demonstrates that they show a lot of individuality:
we find that (i) substantial individual variation in behaviour emerges among genetically identical individuals isolated directly after birth into highly standardized environments and (ii) increasing levels of social experience during ontogeny do not affect levels of individual behavioural variation. In contrast to the current research paradigm, which focuses on genes and/or environmental drivers, our findings suggest that individuality might be an inevitable and potentially unpredictable outcome of development.
This, of course, is a fish study, but if even fish have such individuality, I think it is a good bet that the same can be said for humans.
I've thought often about this thing we might call "individuation." I notice that my brother and I, both of us being quite disagreeable, tend to do like different things.
ReplyDeleteI like eating a lot, he likes eating small portions. I like going out to eat for food that is pretty good but don't care to splurge for the diminishing returns of gourmet food, he finds all foods beneath gourmet to be a general waste of time.
I like gyms and running, he likes home workouts. I like the outdoors, and any related hobby, he hates the outdoors. Just about any trait you name, if I take a certain stand, he goes the other way.
You could say that this is some freak accident of massively divergent genes.....but we aren't that different in other polygenic traits, such as height.
And that neglects the real-life observation of two brothers who have no biases for or against a random hobby or thing, who end up diverging....for apparently no reason.
I often wonder if these multiple adopted child families have the same issue with their adopted children. With the kids being adopted, they might have the same sort of negative, disagreeable temper that my brother has. And that disagreeableness might drive them to do the opposite of their adopted siblings. Their temper driving anti-correlation of traits. And this anti-correlation effect might counterbalance the other correlation effects that shared familial environment might create (for them, or even for other more normal families).