That said, humans do have abnormally large penises. I guess it has something to do with the fact that we are bipedal and walk upright. It seems absurdly unlikely to me that it has anything to do with preference--I mean, if we could have our way, we'd all have penises the size of our forearms (as opposed to the few of us here on that forum who have that very thing, that is...).
Maybe it's not preference but effectiveness.
Bear with me, please.
-A longer penis can deliver semen deeper into the vagina.
-The flared head, reaching past the initial tighter canal, can act to scoop out competitors sperm.
-Orgasm on the woman's part can help with conception as the cervix dips into the vaginal canal.
-Larger sizes do factor into the likelihood of female orgasm (I know it's not the only way but as we still debate the existence of the g-spot and plenty of men can't locate or figure out the clit I don't have much faith in Neanderthal cunnilingus and fingering being of much quality back in the day).
Conscious decision hasn't always played a role in adaptive evolution so there's no reason to assume it had a hand in this either.
yes, it's been suggested here before that big dicks have evolved more as an intimidation to other men than an enticement to other women.
I'm not sure that even makes sense unless the males recognized that size made a difference in procreation. I'm assuming they didn't use their dicks to club animals so what other significance could being larger have had?
I'd be curious to see the reasoning presented if you remember where this was posted.
As for keeping the size down that too would make sense as pain is a disincentive to repeat the experience and tends to hinder orgasm.
Anyone know if there's ever been a study on the evolution of the human vagina? Any studies comparing ours to gorillas?