Based on experiments conducted by himself and others around his work, Banksy, the famous street artist, could write an economics dissertation on the monetary value of art. In a way, that unwritten paper could be his crowning achievement.

The self-shredding stencil of a girl letting go of a heart-shaped red balloon, which made headlines over the weekend, was only Banksy's latest contribution to the empirical study of the value of art.

With his latest stunt — the shredder embedded in the frame was turned on remotely after the hammer fell on a $1.4 million sale — the spray-painting star tested the nature of demand at the high end of the market.