That’s part of “nurture.”
Unless were talking about gender expression and sexuality, and then the right believes it’s nurture. It’s as if people pick the one they think bolsters their argument with no regard for any actual evidence.
We’re going to be largely stuck with anecdotal evidence, until someone gets ethical approval to separate numbers of identical twins at birth, adopt them out to different parents then stick an always-on camera on each.
Minute differences seem to have huge effects; I mean, a friend of mine has a pair of identical twins, who she’s largely brought up as a single Mother. One twin’s extroverted, loved science at school and is trans male, the other is extremely shy, artistic and slightly tends towards the girly*. They’re really close, do as much as possible together and one’s done all the talking for both whenever possible since they were still toddlers. They’re both smart, but in terms of personality they’re utterly different, how on earth would you even start dividing up causes?
*Said friend had mentioned her 3 kids, but neglected to mention that two were identical twins. First time I went round her house, when they were 8, a little kid saw me come in, froze, squeaked in evident fright and ran away upstairs; 30 seconds later what appeared to be the same kid suddenly appeared next to me and spent the next 10 minutes trying to show me all their coolest possessions. I thought she had one really really weird child until the other came down for food some hours later.
It’s my considered opinion that parents cannot change their children’s personalities but they sure can make them unhappy to have the personalities they were born with. And vice versa of course.
Children who were born with personalities that their parents understand and appreciate are very lucky.
Fake question - nobody likes black licorice.
There is no “identical DNA”.
Based on recent research using single cell sequencing techniques, there is variation in the DNA of neurons in the brains of humans.
https://www.cell.com/cell-reports/fulltext/S2211-1247(14)00627-5
Are you sure? Really, really sure?
Until very recently, we thought that people who hated cilantro, or those to whom cucumber and melons (the ones rugby balls are shaped as) taste identical and absolutely horrible, were just picky. Turns out both are a matter of genetics.
Then why do they make it?
I love black licorice.
What exactly do you think we haven’t figured out? The answer is both environment and genetics, all the time, 100%.
Yes, that is more complicated than “he was born that way” or “that’s how he was raised”, but just because people don’t like complicated answers doesn’t mean we don’t know the answer.
I have twin sons (fraternal, not identical) whose personalities, handedness, skill sets, temperaments, etc. are different. So nature, right? But they also have a lot of things in common, especially food preferences and entertainment choices, so that’s nurture, right? But they’ve always been drawn to entirely different kinds of women - height, body type, interests, personalities, and so on. So that’s, ehh, you figure it out.
The answer is obviously both. But people like to pretend with the fervor of a flat Earther that it’s one or the other when it suits their political indoctrination or motives.
Which people are these?
Again, sure it is both. My OP, should anyone chose to read it, was about to what influence Nature or Nurture play on particular traits in a person. Again, we all agree eye color is nature, we all agree something like pop culture knowledge in a young child is likely nurture.
And I like black licorice, my father ate it often when I was little. I have no doubt if I had tried it the first time at age 20 I would hate it. Consider all the bizarre things people eat in other other cultures regularly. Is it likely you would eat live grubs as a street snack if you hadn’t had them early and often?
Here is a paper that discusses on the best twin studies, and it found there was not a single personality trait in which fraternal twins reared together were more alike than identicals reared apart.
Here is a good article about twin and adoption studies.
There is another complicating factor that has only been touched upon, but the external factors on gene expression (epigenetics) which can be influenced heritable or environmental factors. In other words, you could have identical siblings who carry the same genome but with different expression resulting in differences in development and phenotypical expression, which means that there is a cofounding influence on both “nature” and “nurture” that could both affect any particular factor to be measured. There are certain aspects of gene expression which are pretty deterministic, such as the basic body planform, skin color, hair type, et cetera, but the expression of many complex factors including behavior, emotional resilience, general intelligence, et cetera may be heavily influenced by both the the expression of the genome and ostensibly non-epigenetic environmental factors such as nutrition, modeling of behavior, availability of educational resources and influences, et cetra (although there is increasingly strong evidence that emotional conditioning and nutrition can have significant epigenetic effects, both directly on an organism and conveyed by inheritance from parents).
So, on top of the difficulty for controlling or correcting for environmental factors (which is essentially impossible to do at a detailed level on a study with sufficient population necessary to develop statistical significance to any measurement so these are often reduced to general demographic factors), the cofounding variables that could influence behavior via the effects on gene expression make the question essentially meaningless as a binary response. The question is better frame as, “What environmental influences affect gene expression and resulting behavior or phenotypical development?” which is a far more complicated and nuanced question to ask, and does not lend itself to assigning simple percentages, but at least can potentially have a rigorous result rather than handwaving or trying to game an increase in statistical confidence by removing most of the potentially contributory variables.
Stranger
To be even simpler:
If everything is Nurture, social programs can have a 100% success rate, nobody is inherently too stupid or evil to prosper in the right environment, and there are no parts of society which cannot be changed.
If everything is Nature, then current hierarchies are immutable, current social and gender roles are immutable, and simply abandoning the inconvenient to poor outcomes or worse is justifiable on the grounds of Social Darwinism.
In point of fact, it seems to be the case that most people are pretty moral at least towards what they see as “their group” and will respect basic norms such as fairness without needing much or any explicit instruction. A simple piece of evidence in favor of this is that even monkeys reject blatant forms of unequal pay and, to the best of my knowledge, there’s never been a Monkey Marx or a singly Monkey Wobbley. It’s as innate as anything in primates is. A stronger case in favor is the simple existence of cities: If even 1% of people were simply completely amoral and committed violent crime at random, a city the size of New York City would never be able to stand it. It would collapse in a wave of pure anarchy.
I resolved this issue for all time in 1984, during a session of Dungeons & [del]Drugs[/del] Dragons. A Paladin in my game used his detect evil ability on a Red Dragon’s egg. The egg did, in fact, detect as evil…
And when you add in the variation of neuronal dna due to copying, the problem of isolating variables becomes even more difficult.