SuperFreakonomics Author: "Your Job is to Attack Us."

"How many of you wash your hands?"

Stephen Dubner, co-author of Freakonomics and the new SuperFreakonomics, was prodding the Monday night audience at the Washington Post Conference Center in Washington, DC. A forest of hands sprung from the seats. "Maybe I should rephrase," said co-author Steven Levitt, an economist. "How many people don't wash their hands." Two young men raised their arms in mock pride. Audience members alternatively chuckled and grimaced, but Levitt turned the joke on them.

"We know that a whole bunch of you are lying," he said. Studies show as little as 9 percent of men really, truly wash their hands. The audience laughed again, this time with a hint of discomfort (nine percent?). And in a moment, we had a microcosm of the night's three lessons: People lie. Conventional wisdom is asking for it. We should all laugh more about economics.

Freakonomics, a sociological tapestry of anecdotes strung on a simple axiomatic thread - incentives matter -- was a runaway success. So Stephen and Steven doubled down on the formula. The book launch event for SuperFreakonomics, hosted by Hooks Books, was predictably a lot like the original material, chock full of colorful characters and stories that are supposed to seem out of place for a book that rhymes with economics: Prostitutes, monkey sex, various flavors of debauchery.

One anecdotal gem was an altruism study where participants got $10 and chose to give all, some or none of it to a stranger. The average donation was about $3. That sounds decently generous, perhaps even altruistic. But when researchers added the option to take money from the stranger, participants gave less. A majority even stole. If we have an altruistic bone in our body, the study suggested, it's not very strong.

Levitt and Dubner have drawn controversy for the book's chapter on global warming. The night's first and only global warming question - from a young man at the Union of Concern Scientists about carbon dioxide emissions - sent Dubner off on a long retort that crescendoed from a sound discussion of carbon dioxide basics to a defensive rejection of the idea that he should even pretend to answer the question.

"If [global warming] is a big enough problem to worry about, which we think it is, and if the goal is how to cool the earth in time, what do you do?" Dubner began. "We realized the most common idea ... carbon mitigation ... is probably too little, too late and too optimistic."

Small improvements like driving a Prius are easily off-set, he added. "If you drive to the store and buy a hamburger, you cancel it out" because of the ecological cost of producing meat. The solution to our climate change crisis is more likely in the field of geoengineeing than the currently discussed methods of carbon reduction.

But that's where Dubner took a turn, claiming he felt "attacked on crazy, made up, ideological ... falsified grounds." He added, "it's hard for us to know who to take seriously ... Your job is to attack us. I want to have a meaningful dialogue. Your tactics do not suggest that you are of a like mind. Our publicist loves it." As Dubner went on, his defensiveness turned crass. To smatterings of laughter, he added, "Maybe we just deeply misunderstand Washington." When the young man tried to request time to speak to Dubner privately after the event, the audience groaned. Global warming debates were boring now.

The rest of the audience's questions were lighter fare: What makes conventional wisdom conventional? Is the Chicago School of economics wrong? Each question sounded like the headline of a Freakonomics blog post, and Stephen and Steven responded with trademark sparkling anecdotes told with a economical dispassion that somehow made them funnier.

After the event was over, I went to the men's room. When I walked in, a man was washing his hands. On my way out, another man came out from a stall. He also washed his hands. So did I. Three for three. Incentives matter. Reminders help, too.