Peter Coleman, PhD, got his first taste of conflict resolution in the 1980s, as a mental health counselor in a psychiatric hospital. Back then, riots in mental hospitals weren't uncommon. "At this time there were a lot of violent offenders going into drug rehab or psychiatric hospitals," he says. Coleman turned out to be a natural peacemaker. When crises emerged, he could often defuse the situation by talking to the patients. "I just had an intuitive sense of how to do it," he says.

But the one-on-one work he and his colleagues were doing didn't seem to be enough. Coleman wanted to address the violence and drug addiction from a more societal level, "so that these kids don't get caught in these never-ending traps," he says. That desire led him to enroll in the doctoral program in social and organizational psychology at Columbia University.

Today, Coleman, a psychology professor at Columbia University, works with a multidisciplinary team to study the most difficult and intractable conflicts, such as the long-standing territorial dispute between India and Pakistan over the Kashmir region. These types of clashes represent about 5 percent of all conflicts, he says.

"We argue that they happen not just in the international domain, but they happen in families, they happen in communities, they happen all over the place," Coleman says.

Last year, he published "The Five Percent," a book that offers examples of intractable conflicts and the factors that helped facilitate their resolution. A key requirement seems to be some sort of major shock. For example, Coleman talks about a conflict between the anti-abortion and pro-choice communities in Boston. "They had gotten stuck in this very hostile vitriolic dynamic for years," he says. Then, in 1994, an anti-abortion advocate, John Salvi III, went to two women's health clinics in Brookline, Mass., and shot and killed two women. "That shooting kind of ruptured this dynamic," Coleman says. Three women leaders from the anti-abortion movement and three from the pro-choice movement began to meet in secret. Eventually, they came out publicly to argue that the vitriol had contributed to the violence, and the rhetoric changed.

Intractable conflicts don't seem to respond to traditional conflict resolution strategies, such as mediation. These tactics "not only seem not to have an impact, but they seem to make them worse," says Coleman. To understand how these conflicts can be resolved, Coleman and his colleagues employ tools from another field — complexity science. The researchers study conflict in the lab and the field, and they develop models that incorporate some of the most important parameters. Using complexity science to understand intractable conflicts enables Coleman and his colleagues to view them in a different way and find new strategies for interrupting the patterns of violence.