Before the first performance [of the exuberant final movement of Brahms’ First Symphony], the conductor told his musicians to "Think about the finest performance of this piece that you can remember. Play it that way." Before the second performance, he gave a quite different instruction: "Play this piece in the finest manner you can, offering subtle new nuances to your performance."

Members of a local community chorus — musically sophisticated men and women who are not professional performers — were asked if they heard a difference after listening to recordings of both.

"Overwhelmingly, they said yes," Russell reported. "The next question was: Which do you prefer? Overwhelmingly, they preferred the mindful one."

The musicians reported they, too, found the second performance a more enjoyable experience. When asked for specifics, players and listeners offered similar descriptions: "There was more energy." "The dynamic range was wider." "The louds and softs were more pronounced."

In other words, attempting to recreate an "ideal" performance proved somewhat stultifying, while staying on the lookout for new nuances was clearly liberating.

“We have data with dolphins," she said. "We had trainers who were mindful or mindless. In the water, they were instructed either to think familiar thoughts, such as 'Think about all that you know to be true about dolphins,' or to think novel thoughts, such as 'How is the dolphin you're interacting with different from the other dolphins there? How is it different today than it was the last time you interacted with it?'

"When the trainer is mindful, the dolphin swims to him or her faster and stays longer," she said. Whether you're a marine mammal or a Beethoven buff, "You can tell when the light's on but nobody's home. And you can feel it in art."