Can’t get enough of behavioral economist Dan Ariely? That certainly seems to be a common condition at the Poptech conference in Camden, ME this week.

Ariely gave a mind-bending talk about the counter-intuitive notion that paying people more can actually make them perform more poorly — at almost the exact moment that Obama’s pay czar was unveiling plans to slash the bonuses of top banking and automotive executives by about 90 percent.

Here’s more from Ariely, on everything from the unforeseen consequences of the pay restrictions to the difficulty of measuring human happiness.

Video # 1: “We have a group of people who have been very successful at playing a lot of shenanigans on us.”

Video #2: “If you can be really funny for 10 minutes, I’ll give you $10,000.”

UPDATE: Watch a Reuters video interview with Ariely.

What do turn of the century lab rats, clutch NBA players like Michael Jordan, and Wall Street’s highest-paid executives have in common? Dan Ariely has some ideas.

“We study the irrationality of people and markets. 2008 was a very good year for us,” the behavioral economist noted wryly at the Poptech conference on Thursday.

As pay czar Kenneth Feinberg prepares his plan to slash bonuses at bailed-out banks and automakers, perhaps it’s time to question one of the central assumptions of the exec comp status quo: Does more compensation always make people more motivated and better at their jobs?

Ariely’s research suggests that past a certain level, it can have the exact opposite effect. “People have the tendency to villainize Wall Street,” Ariely said, “but the real enemy is human nature.”

Rewind the clock to 1909, when economists Robert Yerkes and John Dillingham Dodson put some rats in a maze. Parts of it were electrified. The question: Would higher levels of electricity (and hence pain, avoidance of which is a powerful incentive) make the rats learn the maze any faster?

The answer was yes, to a point. But past a certain level, the electricity became more of a stress than a motivator, and performance declined.