Run for your life!

The behaviour of people facing this same decision was analysed by PhD graduate Mignon van den Berg from the Faculty of Civil Engineering and Geosciences while she worked on her doctorate. Rather than focus solely on real-life evacuations, she turned her attention to a mock disaster created within an experimental video game environment dubbed Everscape. It was created as part of a collaboration between researchers at TU Delft and Tokyo’s National Institute of Informatics.

Everscape and slightly different scenarios were used during a series of experiments conducted in late 2013 and early 2014. In each one, a group of participants were led into a computer lab and given a series of instructions before they dived into Everscape to begin their virtual journey to a concert on a small island. During the performance, an earthquake occurred and they were warned that a tsunami would likely soon engulf the venue and the surrounding area.

There were a few different ways for them to reach high ground: by car, train or helicopter. During some of the experiments, all of the participants were allowed to choose whichever method of escape they deemed best. In others, a few of them were selected to play as ‘spooks’ and either quickly flee the venue or stubbornly remain and get washed out to sea. Van den Berg was interested in monitoring the effect of herding behaviour during emergencies like this one and whether or not people panicked or kept their cool.

“On average, 10 – 15% of people remained calm and rational,” she said. “75% reacted semi-automatic. Another 10 – 15% responded in a way that was uncontrolled and inappropriate.”

Van den Berg concluded that herding behaviour definitely played a major role in whether people decided to stay or leave the venue. The more concertgoers a participant saw leaving, the more inclined they were to join them.

“From research, it is known that people tend to follow other people through herding behaviour,” she said. “They use each other as a source of information.”

Once they left, most participants tried to leave by car because it gave them a greater sense of control. In total, 11% of them didn’t survive for reasons ranging from not taking the threat of the tsunami seriously and delaying their departure to getting stuck on the train platform after each carriage was filled to capacity.

Van den Berg, Mignon, The Influence of Herding on Departure Choice in Case of an Evacuation, Promoters: Hoogendoorn, S.P., Defence: December 12, 2016