FRANKNOTE

MONTREAL: 'Listen to this," Daniel Levitin said. "What is it?" He hit a button on his computer keyboard and out came a half-second clip of music. It was just two notes blasted on a raspy electric guitar, but I could immediately identify it: the opening lick to the Rolling Stones' "Brown Sugar."

Then he played another, even shorter snippet: a single chord struck once on piano. Again I could instantly figure out what it was: the first note in Elton John's "Benny and the Jets."

Levitin beamed. "You hear only one note, and you already know who it is," he said. "So what I want to know is: how we do this? Why are we so good at recognizing music?"