Despite the grim outlook of the national economy chuckles were aplenty at the "Freakonomics" presentation Tuesday evening. The co-authors of the best-selling book, Steven D. Levitt and Stephen J. Dubner, gave the 17th presentation for the John T. Vucurevich Foundation to a crowd of about 1,500 people.

Carson Aasen, 67, of Rapid City attended the event with his daughter. Aasen said he liked the concept the authors take in explaining economics to the general public.

"They give common-sense answers to the economy and economics," Aasen said. "I think it has more merit now than ever before."

Rapid City couple Steve and Kristin Conzet, both 38, are fans of the popular book. Steve has loaned the book on four occasions to co-workers, and Kristin said she has recommended it to numerous others.

"To me, it brings up interesting points," said Steve. "I like one part of the book where it talks about what sumo wrestlers and teachers have in common. It comes down to the incentive for reward. On certain levels, people will do things to meet them."

That's something the second "Freakonomics" discusses, Levitt said, in previewing his study of prostitution in Chicago. He related the story of a former military computer programmer who earned $80,000 a year and switched careers that earned her $300,000 a year. But she was indifferent. His suggestion? Raise her hourly rate from $300 to $400. If you're not happy, you're not charging enough, advised the economics professor at the University of Chicago.

Beyond their personal situation, many people generally want to fix the world. But Dubner, a journalist for the New York Times and New Yorker magazine, said we need to know how the world really works first.

He asked the audience how many don't wash their hands after using a public restroom. No one raised their hands.

Dubner said he was certain some people were lying because he did a study at the sink of a men's public bathroom. He found 30 percent didn't wash after doing their duty.