Follow the Leader – Insight into Human Decision Making

Psychiatry_Psychology2.jpgScientists at Leeds University, England believe that they have found the answer to how a lot of our unconscious actions are generated — by simply following our herd of brethren!

A new study demonstrates that it only takes about 5% of people to have a decisive influence on the direction that a crowd of people would take, and the rest simply follow. Prof. Jens Krause a behavioral ecologist, with PhD student John Dyer, designed a series of experiments at Leeds where groups of people were asked to walk around randomly in a large hall. Within the group, a selected few participants received more detailed instructions about how and where to walk. Participants were not allowed to communicate with any another person but had to stay within an arms length of each other.

The study showed these “snake-like patterns” people unconsciously adopted, as they began following others without being unaware that they were doing so. In a way, they had adopted a consensus decision, but being totally unaware of it. The study used different crowd sizes to assess the leader-to-follower ratios at each level, and it soon emerged that the bigger the crowd size, the smaller the number of decision makers required. In large crowds of 200 or more, 5% of the group was enough to influence the direction in which it traveled!

“There are many situations where this information could be used to good effect,” Prof. Krause of the University’s Faculty of Biological Sciences stated in a recent interview. “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.”

According to Prof. Krause, the study started as part of studying animal grouping behaviour, and as it convincingly demonstrates, there are strong parallels between human crowds and animal flocks, which might be instinctual.

But on a metaphorical plane, does this study explain phenomena like fashion fads and opinion shifts too?


DYER, J., IOANNOU, C., MORRELL, L., CROFT, D., COUZIN, I., WATERS, D., KRAUSE, J. (2007). Consensus decision making in human crowds. Animal Behaviour,75(2), 461-470. DOI: 10.1016/j.anbehav.2007.05.010

Sudip Ghosh, MD

Sudip Ghosh, MD, is a surgeon at the University of Manchester, UK and a medical writer.
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