I think, generally, most comics have to make a concerted effort to write and then study their jokes, like actors learning lines for a play. (Do comics have personal "joke books"? It seems to me like they would...)

I'm not sure. I was wondering if jokes access repressed material somehow so that that mechanism comes into play in some manner, but it seems like even the most innocuous jokes slip the mind (or at least, my mind.)
It seems like you would remember something that made you laugh.

You might be right that not everyone forgets jokes - but when I ask people "heard any good jokes lately?" , it seems most people can hardly remember any. I kind of extrapolated the results from my own small survey to the population at large.

...AND.... what makes things reeeeaaaallllllyyyy funny is the element of surprise in it... your brain is laxidasical... the joke is told, you follow the story line....

the element of *funny* is when the story line leads astray of the punchline.... so there is a paradigm shift...

we don't "remember" the elements leading up to noticing the paradigm shift unless we make a concerted effort at it... only the feeling of the shift itself...

AND jokes are of such a complete random nature, that even the topics around the jokes are seperate from the paradigm context wrapping them, so every day convesation isn't likely to stoke the reminince of, "oh yeah, fire hydrants, i know a recently told good joke about those!"

Hmmm, I wonder about this.

Maybe the brain is so busy with pattern making and pattern recognition, interpretting masses of input and trying to create sense out of near chaos, that a joke with an absurd ending is not kept by the brain because the information is absurd, i.e., is not consistent with established patterns or paradigms.

... as LITERALIZING memories tends to do.

So sorry for my negligence.