The study, carried out by the university’s department of psychology, involved 200 participants from Christchurch who had lived through the earthquake and were 18 or older at the time.
PhD student Keren Segal said the phenomenon of community bonding after shared trauma had been studied before, but those studies focused on human threats, such as terrorist attacks, rather than natural disasters. Supervising professor Jamin Halberstadt said the study was the first to show the negative events need not be caused by other people. Participants who recalled the earthquake felt more connected to Christchurch if they felt more fear, or if they suffered more harm. The level of harm suffered was stronger than any other measure. Harm was measured by participants’ responses to questions about the quake’s effect on their own situation, which could include their physical or mental state, or on their property or workplace.
"People who suffered more physically and psychologically felt more fused and connected to the city when they recalled the earthquake," Ms Segal said.
"I found that people who were more fused were also more willing to act prosocially and volunteer."
Those who believed the quake was caused by a supernatural influence also developed stronger bonds.
"This is important for us because usually these kind of studies are conducted when you relate to an out-group threat like a terrorist attack or war," Ms Segal said.
"In those situations people tend to fuse because they can say ‘somebody else did it’, so it was interesting to find that intention, even if it is a supernatural one, influenced how strongly people would feel towards the city," she said.
There was no way of comparing the level of fusion demonstrated in the Christchurch study to previous work carried out on terrorist threats and conflict, she said.