Qualifying questions with "at the meta-level" means that the answer should be quite general in its implications.
You might ask me after I returned from Switzerland the other week, "What did you learn at the meta-level?"
A wrong answer is: "Zurich is a pretty city."
A possible answer is: "National pride is unaffected by the health of the economy." Or: "56 percent of the value of a trip is in the memories, not the actual travel."
Asking people what they learned from an experience is always illuminating. It tests how reflective they are (do they even ask themselves this question?), whether they are able to abstract general lessons from a specific experience (that is, answer at the meta-level), and whether they can separate out and discount the lessons rooted in unique circumstances (the lessons not generalizable).
(Hat tip Tyler Cowen, in an email, for this insight and the travel example above.)