SOLVED. sci-fi short story about aliens implanting rhyming songs/games in our heads as an experiment [s]

[Cumbling Michael]

Possibly Asimov's "Jokester"? It was included in Earth Is Room Enough, and Robot Dreams

[Cumbling Michael]

No? Odd, that. The closing paragraphs of "Jokester" not only parallel the plot you described, but in almost exactly the same words. See here "(view spoiler)[ ""Multivac says," said Whistler, "that the only purpose that fits all the data is that the jokes are intended to study human psychology. We study rat psychology by making the rats solve mazes. The rats don't know why and wouldn't even if they were aware of what was going on, which they're not. These outer intelligences study man's psychology by noting individual reactions to carefully selected anecdotes. Each man reacts differently ... Presumably, these outer intelligences are to us as we are to rats." He shuddered.(...) All right. Take it. Multivac states that, once even a single human discovers the truth of this method of psychological analysis of the human mind, it will become useless as an objective technique to those extraterrestrial powers now using it."
"You mean there won't be any more jokes handed out to humanity?" asked Trask faintly. "Or what do you mean?"
"No more jokes," said Whistler. "Now! Multivac says now! The experiment is ended now! A new technique will have to be introduced."
They stared at each other. The minutes passed.
Meyerhof said slowly, "Multivac is right."
Whistler said haggardly, "I know."
Even Trask said in a whisper, "Yes. It must be."
It was Meyerhof who put his finger on the proof of it, Meyerhof the accomplished jokester. He said, "It's over, you know, all over. I've been trying for five minutes now and I can't think of one single joke, not one! And if I read one in a book, I wouldn't laugh. I know."
"The gift of humour is gone," said Trask drearily. "No man will ever laugh again."
And they remained there, staring, feeling the world shrink down to the dimensions of an experimental rat cage - with the maze removed and something, something about to be put in its place. (hide spoiler)]. If this is not the story, then someone has ripped off the Asimov tale lock, stock, and barrel.