What would you do?

The psychology of human behaviour in times of disaster has become an essential discipline used by engineers to reduce the risk that people will die when a building is hit by fire, earthquake or terrorist attack. What became clear is that more lives may well have been saved had people reacted differently. Rather than dash for the nearest exit, most did the opposite: they prevaricated. A study by the US National Institute of Standards and Technology (NIST) found that even those who managed to escape from the towers waited an average of six minutes before heading for the stairs. Some dallied for half an hour. These findings lent credence to a theory already gaining support among risk experts: that when disaster strikes, people behave in unexpected and irrational ways. About half of the interviewees said they hung around before deciding to escape, either waiting for more information about the situation from colleagues or officials, or collecting things to bring with them, changing their shoes, locking things into safes, going to the toilet, finishing emails, filing papers, making phone calls or shutting down their computers. When they did leave, they descended the stairs without great urgency and considerably more slowly than the building's safety engineers had forecast, apparently because of congestion from the large number of people trying to descend, even though the building was far from full.