Leaders' emotional cues may predict acts of terror or political aggression

Leaders often use rousing speeches to evoke powerful emotions, and those emotions may predict when a group will commit an act of violence or terrorism, according to new research published in the journal Behavioral Sciences of Terrorism and Political Aggression. Analysis of speeches delivered by government, activist and terrorist leaders found that leaders' expressions of anger, contempt and disgust spiked immediately before their group committed an act of violence.

"When leaders express a combination of anger, contempt and disgust in their speeches, it seems to be instrumental in inciting a group to act violently," said David Matsumoto, professor of psychology at San Francisco State University.

As part of a five-year project funded by the U.S. Department of Defense's Minerva Initiative, Matsumoto and colleagues studied the transcripts of speeches delivered by the leaders of ideologically motivated groups over the past 100 years. The analysis included such speeches as Osama bin Laden's remarks leading up to the bombings of embassies in Kenya and Tanzania.

The researchers analyzed the pattern of emotions conveyed when leaders spoke about their rival group and examined speeches given at three points in time before a specific act of aggression. They compared the results with the content of speeches delivered by leaders whose groups engaged in nonviolent acts of resistance such as rallies and protests.