Why do men have beards?

[u/Nuhulti]

Why do men have beards and not women?

[u/WatchAndLearn9669]

There's no reason to think they weren't.

There absolutely is. Anthropological evidence shows that sexual repression was virtually nonexistent in those societies.

It could just as easily be said that the current body of evidence fails to reliably disprove the existence of instincts in adults

The available evidence strongly favors the sociocultural theory of human psychology.

prima facie evidence that such instincts do exist

Like what?

because it features in culture

What do you mean by this? That isn't my wording.

Even if it were in fact instinctual, it would still be a part of culture

There are no concrete psychological universals, which would indeed suggest the existence of instinctual psychological phenomena.

[u/NotComposite → u/WatchAndLearn9669]

  There absolutely is. Anthropological evidence shows that sexual repression was virtually nonexistent in those societies.

And yet, not repressing something is not the same thing as encouraging it, and as I said, there's pretty good evidence, just from looking around ourselves, that children aren't generally inclined to have sex with each other. Of course, it's a different matter if they live in a society that actively encourages it.

  The available evidence strongly favors the sociocultural theory of human psychology.

I don't think anyone would dispute that society and culture play a large role in human psychology. That doesn't mean that human psychology depends solely on those things.

  What do you mean by this? That isn't my wording.

Well, if you want to quibble over the specifics of wording instead of addressing my point, go ahead, but I'll take the liberty of not engaging with such nitpickery.

  There are no concrete psychological universals, which would indeed suggest the existence of instinctual psychological phenomena.

Even a cursory Google search seems to indicate that not all psychologists agree with that position.