Contingency Planning

Researcher Says 95 Percent Of People Are Sheep Following Flock In Disaster Scenarios

March 4, 2008

Have you ever arrived somewhere and wondered how you got there? Scientists at the University of Leeds in the United Kingdom believe they may have found the answer, with research that shows that humans flock like sheep and birds, subconsciously following a minority of individuals.

Results from a study at the University of Leeds show that it takes a minority of just five percent to influence a crowd’s direction -- and that the other 95 percent follow without realizing it.

The findings could have major implications for directing the flow of large crowds, in particular in disaster scenarios, where verbal communication may be difficult.

“There are many situations where this information could be used to good effect,” said professor Jens Krause of the university’s Faculty of Biological Sciences. “At one extreme, it could be used to inform emergency planning strategies and at the other, it could be useful in organizing pedestrian flow in busy areas.”

Professor Krause, with Ph.D. student John Dyer, conducted a series of experiments where groups of people were asked to walk randomly around a large hall. Within the group, a select few received more detailed information about where to walk. Participants were not allowed to communicate with one another but had to stay within arms length of another person.

The findings show that in all cases, the ‘informed individuals’ were followed by others in the crowd, forming a self-organizing, snake-like structure.

“We’ve all been in situations where we get swept along by the crowd,” Krause said. “But what’s interesting about this research is that our participants ended up making a consensus decision despite the fact that they weren’t allowed to talk or gesture to one another. In most cases the participants didn’t realize they were being led by others.”

Other experiments in the study used groups of different sizes, with different ratios of ‘informed individuals’. The research findings show that as the number of people in a crowd increases, the number of informed individuals decreases. In large crowds of 200 or more, five percent of the group is enough to influence the direction in which it travels. The research also looked at different scenarios for the location of the ‘informed individuals’ to determine whether where they were located had a bearing on the time it took for the crowd to follow.

“We initially started looking at consensus decision making in humans because we were interested in animal migration, particularly birds, where it can be difficult to identify the leaders of a flock,” Krause said. “But it just goes to show that there are strong parallels between animal grouping behavior and human crowds.”