The “look elsewhere” effect and false positives

In the NYT, George Johnson suggests that the frequency of new discoveries is declining and while false positives increase: “The phenomenon is called the ‘look elsewhere effect.’ Suppose you have it in your head that extraterrestrials are beaming, in binary code, some particular signal — the opening notes of Beethoven’s Fifth Symphony. You aim your radio telescope at a point in the sky and find nothing. So you look elsewhere, trying one spot after another until finally you hear the triumphant sound. Was it broadcast deliberately or was it a random signal — space monkeys banging on xylophones?”