Boys and girls live in totally separate worlds today. I can't think of any counter-examples to that big picture, except for the fact that girls are much more likely to have a gay friend these days. So I'm restricting this to boy-girl interactions or relationships where both are straight. I'll list some I've posted on before, and others that occur to me off the top of my head. But I wasn't a teenager in the '80s or before, so there may be lesser known boy-girl practices that are now dead and that I'd have no clue to look at. What else comes to mind?
- Boys and girls don't hang out in public in groups of friends. It's either a group of guys or group of girls (perhaps with some gays). I don't even notice cars that carry a mix of young guys and girls. That must reflect a lower level of mixed-sex social circles than before. So I'd guess that they don't even hang out at each other's houses or share the same cafeteria table spaces like they used to.
- At house parties or in dance clubs and bars, girls don't leave their friends alone. If they get the sense that one of their friends wants to slip away and pair up with a boy, whether for something light or heavy, they become cock blocks -- a phrase that did not exist before because there was rarely such a thing. They steal the friend back, or sometimes just walk off as a group, knowing that the girl (being a girl) cannot take being stranded by her clique and will fall in line behind them. In mixed-sex times, they would've left her alone, and if not, she would've told them to mind their own business, get a life of their own, etc.
- In the same settings as above, girls form tight circles meant to keep the world out, rather than having a more open formation like when they used to be boy-crazy. Watch a school dance or night club scene from any '80s teen movie, and notice how absent this is. Today even if there are only two girls, they face each other at close distance, closing out the rest of the world. I recall this closed formation only during 6th grade dances. It's as though teenage and 20-something girls today haven't socially matured beyond the level of middle schoolers when it comes to interacting with boys -- and therefore, boys haven't matured either for want of contact with girls.
What is a more open formation? Standing side by side, making a semi-circle, etc., showing your openness to being approached. The closed formation holds even in totally safe settings, and times are incredibly safer now anyway, so this is not simply a shift to deal with a greater level of danger at parties or clubs.
- There's all that terrible "girls gotta stick together" music that blew up with the Spice Girls in the '90s, although you could probably find some less popular examples from the early-mid '90s (like Queen Latifah's "U.N.I.T.Y"). The girl groups from the '60s through the '80s didn't sing about that at all -- they were boy-crazy and fought against other girls over their dream boys, which was reflected in myriad "choose me over her" song lyrics. In the '90s and 2000s, girl singers were either of the "girls united" camp or the "it's all about how hot I am" camp. Barf me out.
- On the guy side, how many songs are there about awkwardly falling for a close chick friend of yours? That can only happen when boys and girls socialize a fair amount inside and outside of school. I don't mean the girl who you're barely acquainted with, or who you only spy from afar after 2nd period as she's going down the stairwell that you're walking up. These songs are hard to pin down in any time because usually the guy who's fallen for a close friend appropriates a song that is probably about an actual boyfriend / girlfriend relationship, like "Bizarre Love Triangle."
Still, my impression is that these used to be common enough, at least from 1969's "Na Na Hey Hey Kiss Him Goodbye" up through 1986's "Amanda," plus a lot of less popular stuff in the '80s by college rock bands like The Smiths ("There Is A Light That Never Goes Out"). I'm probably missing another big one from the late '80s and early '90s... Mr. Big's "To Be With You"? LOL, someone please give us a better example than that.
In any case, I don't remember hearing this type of song during the mid-'90s and after. Plenty of unrequited love songs by alternative / emo geeks, whether about girls in general not paying them attention or about a specific girl to whom he's invisible (possibly a current girlfriend), but again I mean someone who the guy has hung out with long enough for her to be in his circle of friends. And they have to have been big popular songs to count here, not a band that's unrepresentative of the zeitgeist.
What else is there that shows how separate boys and girls live today?