In J.M. Barrie’s “Peter Pan,” Tinkerbell, the little blond fairy you might picture from the 1953 Disney adaptation, can only live if others believe in her existence. In the play, she’s revived from near death by the audience’s applause. To my knowledge, no production has ever denied her that ovation. Luckily for her, it’s in the script — she survives to the final curtain whether the audience truly believes or not.
A variation of this “Tinkerbell effect,” the idea that be...