Peterr

I read the SF story you mentioned many years ago. From the style of the story, and my failing memory, it might be have been by Robert Scheckley.

IIRC the premise of the story was that the ETs were conducting an experiment in which the only really spontaneous jokes made by humans were of the instant "pun" kind, which nobody laughs at but only groan, and as for the jokes people laugh at, nobody knows who wrote them.

The finale of the story being that when the Human Race realised this fact it never laughed again (or something like that).