I have only a vague idea if people still do it very often in real life. I'd say yes, but it's no first-hand experience (and refers to Germany not the US). I've never been into the dating-business as an adult, I was seventeen when my hubby and I met.
Which brings me to the next question: yup, we did have sex on the first night, we had sex some weeks before we were officially a couple. And for the last 23 years we've lived happily ever after and I think we have a very good and loving relationship.
Way to go, Bud! I certainly didn't mean to imply this never happens. As I said, I have a couple of friends with similar experiences. Well, in one case, they divorced about a year later, but that had less to do with having sex too soon than getting married too soon.
I have to admit that it adds the stereotype of "the prude Americans".
That's us!
Agreed this makes evolutionary sense. But it makes also evolutionary sense to stick with the female you had sex with and help her raise the joined offspring. The chances for the offspring to live to adulthood (and reproduce themselves) are much better if two adults care for the progeny. The less offspring a species produces in general, the more important it is to care for them. And humans and other higher mammals do not produce as much offspring as, say insects.
This makes sense from a species-wide perspective. But evolutionary psychology focuses more on how individual genes get passed along, through behavior that increases the likelihood of having surviving offspring with one's own genes. A man who raises a child not related genetically will not pass along his genes, so the behavior of wanting to raise someone else's kids (and, by extension, to stick with a woman who seems like she'd be likely to HAVE someone else's kids) does not get passed on as frequently.
Evolutionary it can also make much sense for females to be promiscuous, and therefore let several males believe they are or at least could be the father of their offspring. Female lions and chimpanzees do this for example.
Yes, this could be a successful strategy. But apparently it's not the one that developed for humans, or we wouldn't have the word "slut." Or at least, we'd have a male equivalent. Human women who sleep around are often judged negatively, in most if not all societies -- from being called sluts to being stoned to death, even for the "crime" of being raped.
Evolutionary psychology often means working backwards, from observing the behavior to determining the logical Darwinian reason. Though that leads to the frequent criticism that evolutionary psychology is just about making up explanations for whatever you want. I don't agree with this, but I can see the point.
And it's tricky.
Yup.