I’m of the opinion that human behavior is influenced a lot more by heredity than society is really willing to admit. (Especially not American society, but in some senses America is the country for people who are weird by the standards of their own ancestral nations, so it makes a lot of sense for that to be the case.)
I came to this conclusion gradually, by piecing together several smaller observations over the course of growing up.
The first observation was that scientists are not exactly trustworthy paragons of objective truthfulness when they start assigning species names to various animals. In biology class, I got the impression that figuring out which animals were one species and which animals were another species was something fairly clear-cut and objective; cats and dogs, horses and donkeys, that sort of thing. Finding out that “speciation” is basically just an arbitrary system of labels that scientists argue with each other about was the first clue. But the element of speciation that made me think that behavior is influenced by genetics is that behavior can be the metric by which scientists divide species. If one population has a different courtship behavior than another population, such that the two don’t interbreed where their ranges overlap, they’re different species. Even if they look basically identical, as in the case of eastern and western meadowlarks.
The next observation is that people have different personality types, and while people’s personalities do vary widely within single families, nobody chooses their own native temperament. I did not choose to be INTJ, and most of my social life has been a process of figuring out how all these weird other people (you know, all those normal people) behave so that I can fit in – if I want to. Because humanity has reason and agency, I’m not locked into asocial bookworm behavior, and I can mimic extroversion – but it’s draining. I’m still an introvert even when I deliberately alter my “natural” behavior. And when you “scale up” to national stereotypes, you end up seeing “national temperament” cropping up a lot. No doubt national culture plays a part in the expression of temperament, but exuberant personalities are not likely to perfectly adapt to the stifling of stoicism and vice versa – even with cultural expectations influencing appropriate behavior.
When dealing with animal species, however, it’s very plain that temperament IS hereditary. When choosing a pet, people will research the breed’s behavioral traits to narrow down their options. The Russian fox experiment has proven that you can, in fact, breed for domesticity – and you can breed for the opposite, too. There are always outliers, since temperament is a continuum, not binary, but you can generally expect a certain kind of behavior out of certain breeds and not others.
Now of course I don’t think that this observation – that behavior is influenced by heredity – is in any way incompatible with “free will” or moral agency. Free will, in scare-quotes there, probably tips you off that I’m going to explain this. Since I’m a part of Team Calvin, I suppose somebody will say that I’m a determinist and don’t believe in free will anyhow, but that’s not actually the case. If I were a determinist, I wouldn’t believe that human beings have moral agency, but of course everyone believes that human beings have moral agency: that’s why we have courts of law.
There are a great many influences on human behavior that come from external sources. We don’t flap our wings and fly south for the winter because we don’t have wings; we had to invent airplanes for that, and then some people did start flying south for the winter. Our free will is constrained by what is possible for us to do; and we choose what we want to do out of all the options that we perceive. Sometimes those actions are a response to biological reality: get hungry, eat food. But if you’re on a diet, you might get hungry and choose not to eat food, or to eat a different food than the kind you actually want.
Human “free will” is obviously not radically free of the constraints imposed upon it by physical reality. If you decide to stop eating and gain all your nutrients by soaking up sunlight, well, you can stop eating, but sunlight isn’t going to sustain you just because you willed it. Humanity can want things that don’t exist. Sometimes, that turns out in our favor, like inventing airplanes for flying; and sometimes it turns out not in our favor, like inventing the TSA for “security.”
But despite humanity’s moral agency and creativity, behavior does not stand alone and solitary in the world of Platonic ideals, being influenced by nothing. I think this is something women understand quite well, given that our own emotional states are often influenced quite strongly by the physical reality of hormones. While agency means everyone does choose how to behave in response to things like raging hormones, the fact that the virtue of self-control must be practiced habitually means that yes, behavior certainly IS quite strongly influenced by physical biology. And physical biology is hereditary, therefore… behavior has a hereditary component.
Civilizing children by raising them properly is an exercise in teaching them to modify their behavior – behavior that is driven by innate desires – with virtues like self-restraint, patience, and reason. Everyone has a slightly different process to adapt their own “instincts” to acceptable behavior, because some people have different inherent preferences. Introverts have to work hard to be social, but that comes easily to extroverts; berserker personalities have to work harder to keep their cool than stoic personalities. And as genetic science progresses, we find that there is a genetic basis to personality traits – precisely as one would expect from looking at the world around us.
That doesn’t mean that human behavior is deterministic – only that people’s coping mechanisms have to be different in order to deal with their innate differences. One size does not fit all.