I most have read it on the online site of either Asimov's or Analog's annual docket of Nebula and Hugo award candidates, when they make the stories freely available. It was at the same time as "Fossil Game", a Tom Purdom short story that appeared in Year's Best SF 5 (2000) the next year, or so I believe. So this would have been the 1999 docket. A techno zen buddhist is sent to roam the various stellar destinations uncovered by man, equipped with a brain implant that records emotions. He goes to a world where the ground- and space-based ruins of an advanced dead alien species can still be found. The conclusions of the story are that these aliens naturally evolved to eventually have their entire cognitive functions become automatic (i.e. counting 4 coins on a table is an automatic function for a human, but counting...let's say, 11 coins is not; one needs to count them one by one), and their civilization fell due to it. Doing physics and math and a hundred other higher brain activities became instinctive, but ultimately useless as their instincts took over completely, and in instinctive situations doing high physics - maintaining space travel, fusion-based energy sources, telecommunications, etc - are ultimately irrelevant to survival. Ringer, anyone?