The Risks We Dread: A Social Circle Account

Fear of threats associated with social circle size: Risks that can wipe out social circle of about 100 individuals just as feared as those that can kill 1,000

Humans’ fear level toward threats is associated with the typical size of our social circles, according to a report published April 11 in the open access journal PLoS ONE. People fear threats that would kill 100 people more than those that would kill 10 people, but equally fear those that would kill either 100 or 1,000 people, the authors report.

Social groups tend to be on the order of about 100 people. The researchers, Mirta Galesic of the Max Planck Institute for Human Development in Berlin and Rocio Garcia-Retamero of the University of Granada in Spain, also determined that this effect was not due to lack of differentiation between 100 and 1,000.

"We hypothesized that this relationship of dread and size of typical social circle has an evolutionary origin: loosing one’s group might have been deadly in ancient human history. As the extant literature and our own data suggest that people tend to maintain active contact with no more than 100–150 people, threat to this number of people would be expected to evoke maximum dread. Our results are in accord with this hypothesis," says Galesic.

The authors conclude that the work could have important implications for raising awareness about specific risks to the general public.