Model behavior

By Catherine Behan
News Office

How is it that very few Americans recycled in the 1970s, but by the 1990s recycling bins were flying off store shelves? And how can laws encourage society to make such desirable changes?

Randal Picker, Professor in the Law School, has developed a new tool to map the changes in society's norms -- the unwritten "rules" of society. In a detailed computer program that illustrates a fictional society, Picker uses game theory to show how people watch their neighbors choose the "best" or most lucrative option.

"It's an artificial society where we can test ideas and control for certain factors. I can play 'what-if' in my computer communities," Picker said. "The question is, how do we get everyone to choose the best option?

"This program gives us a way of gaining an understanding that we didn't have before about how social norms develop and change. I hope we can ultimately use the results to give us insight into making better laws."

Picker described his work in the Law School's annual Katz lecture on Nov. 13. David Strauss, the Harry N. Wyatt Professor in the Law School, introduced Picker's lecture, calling his work groundbreaking.

"Randy is addressing one of the oldest puzzles in the study of society, a puzzle that in a way sets the stage for any study of law," Strauss said. "The puzzle is: when do people voluntarily choose to act in cooperative and socially beneficial ways, without any legal compulsion? Enormous quantities of ink have been spilled on this question over the years. Randy's work brings to bear on this issue a creative and highly rigorous analytical approach that may just be a genuine breakthrough in the study of this age-old problem."

Picker, an economist as well as a lawyer, is part of the University's long tradition of using economics to understand and explain social questions. "Economists are often thought to believe that the social context in which we do things is irrelevant," Picker said. "That may be foolish. This just gives us another set of constraints that we need to take into account to understand how people make decisions."

Picker's work, published this month in the University of Chicago Law Review, demonstrates how and why our society has dramatic shifts in norms. Such norms can change quickly -- sometimes prompted by laws. In the 1960s, for example, seat belts hung limp at car doors. When laws were passed requiring people to wear seat belts, it became "right" to wear them. Not wearing seat belts now carries not only a legal penalty, but a social cost -- the implication that one is not playing by the rules.

Picker's computer model -- a complex series of computer movies -- shows the metamorphosis of such norms. As members of the "society" of a three-dimensional grid watch their neighbors and change to the new, "good" norm, the model illustrates how quickly and effectively those norms can change.

The model may be able to explain, for example, the huge increase in consumer bankruptcies, Picker said. As more and more people filed for bankruptcy, the stigma attached eased. Within a decade, the social cost of filing for bankruptcy has decreased substantially.

Picker says he now needs to refine the computer models to include factors such as the cost of the transactions. In his computer-model societies, people don't lose anything by changing their minds, but in the real world they often do.

Picker's computer models can be found on his home page at www.law.uchicago.edu/Picker/AWorkingPapers/norms.html.