Dr Nikolai Bode

Essentially, crowd behaviour emerges from the interactions of individuals. Information relating to how individuals respond within these situations, therefore, can inform our understanding of how a crowd is likely to behave.

Dr Nikolai Bode

When zombies attack

Absence of herd behaviour

Advice for the zombie apocalypse

















Ever wondered how you’d react in the midst of a zombie invasion? Well, wonder no more because academics have developed a simulator to demonstrate how decision making is impacted by the imminent arrival of the undead.Researchers at the University of Essex have created a computer game in which players must escape from a crowded building that has been breached by zombie hordes. The scientists, whose findings have been published in the journal, used the simulator to gather data about how stress affects decision making.The team asked attendees at the Science Museum’s ZombieLab event to find the optimal route out of a virtual, zombie-infested environment. Whilst some participants were allowed to complete the task at their own pace, others were told that they had to escape the building in record-breaking time.The researchers discovered that when participants were placed under additional pressure, their decisions tended to be poorer than when no extra element of stress had been introduced. Far from focusing their minds, stress caused people to resort to questionable tactics. Rather than attempting to identify novel, more effective exit strategies, for example, individuals attempting to beat target times were more likely to retread familiar routes.Despite its zombie-fuelled premise, the AXA-funded research project could result in practical applications for the field of crowd management. To find out more about the insights provided by this nightmare scenario, I spoke to the study’s lead researcher Dr Nikolai Bode from the University of Essex’s Department of Mathematical Sciences. I began by asking Dr Bode to explain more about his team’s zombie simulator."Participants start off inside one of the rooms of our virtual building," he replied. "They then have to manoeuvre their character into another room by navigating their way through some corridors. Once they’ve reached this room, a countdown begins. At this point, an evacuation is initiated and lots of simulated individuals – we call them zombies – begin to roam the building. Essentially, players have to choose between two exit routes. These paths are identical from the perspective of the building’s layout, but differ in terms of how many zombies are using them."The scientists discovered that participants under pressure were less able to adapt to changing conditions. Instead of considering new strategies, they were more likely to stick to routes that they already knew than those playing under non-stressful conditions. The quality of people’s decision making, it seems, deteriorates in high-pressure situations.I went on to ask Dr Bode, who co-authored 'Human exit route choice in virtual crowd evacuations' with Dr Edward Codling, whether information pertaining to the actions of individuals might be extrapolated to teach us more about crowd behaviour."Essentially, crowd behaviour emerges from the interactions of individuals," he explained. "Information relating to how individuals respond within these situations, therefore, can inform our understanding of how a crowd is likely to behave. In a stressful evacuation situation, for example, our results suggest that a larger proportion of the crowd will retrace their footsteps than we might previously have expected. In that sense, this type of research can help us to better understand the behaviour of a crowd as a whole."One of our project’s more surprising findings was that players didn’t tend to follow other members of the crowd," continued Dr Bode. "This is quite interesting because previous research suggests that this is usually what happens: people exhibit herd behaviour when under pressure. Of course, this was a computer game. The question that we must keep in mind, therefore, is whether or not participants perceive virtual agents as actual people."Dr Bode and his colleagues intend to conduct further investigations to refine their results. His team will use its computer game to inform subsequent real-world experiments."We are in the process of running additional tests with the computer game set up," said Dr Bode. "We would like to learn how people respond to different types of directional information. For example, we are looking into how emergency exit signs and other directional information affect people’s decision making. The computer game paradigm is quite useful in the sense that it allows us to exert precise environmental control. In turn, we are able to identify issues that are worth investigating as part of real-world evacuation drills."Insights into crowd behaviour are not only interesting from an academic perspective; experts can use this type of information to make venues safer in real life."On the one hand, the computer game that we have developed could be used as an educational tool for stewards supervising mass events," explained Dr Bode. "It can teach people how a crowd might behave in a high-pressure situation and what safety issues are likely to arise. Architects could also utilise our findings to make buildings safer. Rather than having one main entrance, for example, it might be a good idea to encourage people to follow several routes into a building. This would limit the pressure on specific routes and reduce the risk of everybody trying to evacuate through a single exit."To end our interview, I brought the conversation back to the undead. What advice would Dr Bode give to a person who happens to get caught in the midst of a real-life zombie invasion?"A real-life zombie invasion?" he asked. "Well, I wouldn’t say that I’m an expert on zombie behaviour but I can offer some general advice for anybody involved in an emergency evacuation. It is always worth taking a moment to identify alternative exit routes. This will help you to avoid falling into the trap of immediately running back the way you came."