The hooking-up phenomena has been traced back to the 1960s and the 1970s, when male and female students were thrown together in apartment-style dormitories, and there was a revolt against strict rules on having a member of the opposite sex in your dorm, lights out and curfews.
But consider this:
BEN: Well how did it happen?
MRS. ROBINSON: How do you think.
BEN: I mean did he take you up to his room with him? Did you go to a hotel?
MRS. ROBINSON: Benjamin, what does it possibly matter?
BEN: I’m curious.
MRS. ROBINSON: We’d go to his car.
BEN: Oh no. In the car you did it?
MRS. ROBINSON: I don’t think we were the first.
Hmmm. This seems to predate the NPR estimate of when hooking up began. And hey, maybe there are even earlier examples of casual sex sometime in human history…
UPDATE: In case you’re curious, it was a Ford.