Mr. Lehman could predict the prices of foreign-exchange futures more accurately than he could call a coin flip. But, being a rat, he needed the right bonus package to do so: a food pellet for when he was right, and a small shock when he was wrong. (Also, being a rat, he was not very good at flipping coins.)
Mr. Lehman was part of “Rat Traders,” a project overseen by the Austrian conceptual artist Michael Marcovici, whose work often comments on business and the economy. For the project, Marcovici trained dozens of rats to detect patterns in the foreign-exchange futures market. To do this, he converted price fluctuations into a series of notes played on a piano—if a price went up, the next note was higher—and then left it up to the rat to predict the tone of the note that followed. With some prodding, the rats began forecasting price changes, and Marcovici says that they were outperforming human traders after a few months of training—a claim, though, that’d require testing more thorough than what was done here.