The 2012 edition of Social Psychology Matters opens with a chapter titled "Crowds." The introduction begins by telling the story of Dylan Yount and the "crowd of onlookers gathered at the foot of his building" who watched him jump of a third-story ledge.
As we wrote in our recent feature "Public Influence," some in the crowd shouted "Jump!"
Upon hearing the details of Yount's suicide, the natural question was: How could people yell that? The chapter, written by social psychologists John Dixon and Kesi Mabendran, seeks to explain just that.
It has something to do with the concept of "deindividuation." Coined in 1952 by a team of social scientists led by Leon Festinger, deindividuation is "a process of immersion within a group such that members cease to view themselves as separate and distinct individuals."
The theory is not a be-all-end-all. As the authors explain, critics of deindividuation "point out that crowd behavior is often more and not less socially regulated than individual behavior."
However, deindividuation does make some sense of otherwise inexplicable actions. The theory helps explain how people in the crowd below Yount's building -- many of who were probably normal, upstanding citizens -- could act so cruel in that moment.
"Certain contextual factors -- notably the sense of being part of a large group gathered under a building, emotional tension at the prospect of watching someone jump to their death, and the focus on a dramatic external event -- would have created a situation in which individuals' self-awareness was reduced," Dixon and Mabendran write. "As a result, their sense of themselves as discrete morally culpable individuals would also have been reduced."
This could also explain why more people didn't yell "Don't jump!" Moral culpability was diffused among the hundreds in the crowd: hopefully somebody else will say something, but if nobody does, well, at least you're not the only one.
According to deindividuation, people in crowds are more susceptible to acting like fools when others around them are acting like fools. Actions -- laughter, anger, or whatever else -- can be contagious.
"For this reason, on 16 February 2010, underneath the building on Powell Street, when one person shouted jump, others followed suit," the textbook states. "And when one person laughed or pulled out a mobile phone to take photographs of Mr. Yount's distress, others did so too."