A shockwave, an explosion, a fire. The boat lets in water and topples over, passengers hang on to life boats or jump into the waves. Few circumstances have the tragic intensity of a shipwreck, which takes mere seconds to throw human beings into life-threatening situations, where the cruelest of decisions have to be made: who is a priority and who can wait?

Two economists from the University of Uppsala in Sweden studied 18 naval catastrophes in order to analyze the attitudes and actions of people in those situations. Their results, published in the Proceedings of the National Academy of Sciences, put to rest the chivalrous idea that "women and children first" is an ironclad rule.

Two exceptions

Do social norms of helping behavior still hold during shipwrecks? Or do they give way to survival of the fittest, where it’s every man for himself? To answer these questions, the authors looked at the survival rates of different categories: crew members and passengers, men and women, adults and vulnerable people (seniors or children).

Until now, only two shipwrecks had been scientifically examined in this way: the Titanic, in 1912, and the Lusitania, in 1915. The first, which has been ingrained in collective memories, had a 70 percent survival rate for women and children, and only 20 percent for men. As dramatic and chaotic as the evacuation operations were, they were a victory for chivalry and the famous exhortation to save "women and children first." But this accident was just one tragedy among many others.

The Lusitania presents slightly different evidence, as the proportion of saved men is approximately equal to that of women, but the scientists found an explanation for this lack of altruism: the suddenness of the tragedy. The Titanic sunk in two hours and forty minutes, whereas its unfortunate successor only took 18 minutes. In such a short period, humans don't have time to collect their wits, say psychologists. In medical terms, the adrenalin rush that brutally awakens the selfish survival instinct has no time to dissipate.

Survival of the fittest

A larger sample was required to find out more. The two Uppsala researchers gathered documentation on a series of shipwrecks that took place between 1852 and 2011. They used four criteria to make their choices: the ship carried passengers, it had least 100 people onboard at the moment of its demise, it sunk in peace time (except for the Lusitania, which was torpedoed during World War I) and it left behind sufficiently detailed passenger records (which excluded some of these past years' worst tragedies, such as the MV Doña Paz and the MV Le Joola, which caused respectively 4,000 and 1,800 deaths in the Philippines and Senegal).

Eighteen ships were chosen, with one test sample containing all of them, and one "main sample" excluding the Titanic and the Lusitania.

On the Titanic, crewmembers had a 23.8% survival rate, which was inferior to the passengers (38 percent), even though their knowledge of the ship and of evacuation procedures should have favored them. Here, the sailors seem to have obeyed the code of conduct that orders them to leave a sinking ship after their guests. But in the overall sample, the proportions were reversed. The survival rate is much higher among crewmembers (61.1 percent) than among passengers (31.9 percent). Survival of the fittest prevailed.

Similar results emerged from comparing man and women survival rates. The first usually have an advantage because they are stronger physically; and as underlined by the authors of the study, "during the evacuation of a sinking boat, success is typically determined by the capacity to move quickly in halls and stairs, on tilted surfaces that are littered with people and debris."

Other important factors have to come into play to counter this masculine superiority, as with the Titanic, where the survival rate was 74.6% for women and 16.9% for men. But once again, this is the exception. In the main sample, 37.4% of men survived, as opposed to 26.7% of women.

Why so un-chivalrous?

The authors then tried to understand how these results came to be, and put forward several hypotheses. The first is that people react more selfishly when they are taken by surprise and have no time to react to a rapid sinking, as was the case on the Lusitania. But in the overall sample, the suddenness of the tragedy had no effect on the identity of the survivors.

A second hypothesis looked at the number of women on board, the idea being that the fewer there are, the easier it is to save them, as men are more inclined to respect the "women first" rule if there aren't too many to jeopardize their own survival. The reasoning seems logical, but data points to the exact contrary: the fewer women there are on board, the more they risk being abandoned.

A third attempt to explain the results looks at the feeling of sympathy and postulates that people are more inclined to help and even sacrifice for each other if they know each other. According to this hypothesis, altruism should be stronger when the number of passengers is lower and the cruise is longer. But once again, statistics showed the opposite: the survival rate for women is modified in neither case.

The researchers finally discovered two factors that exert decisive influence on events. The first is the attitude of the leader. When the captain gives orders to save "women and children first," he is sufficiently obeyed to modify the survival rates. On the five ships where such an order was given, the proportion of surviving women increased by 9.6 percent.

Contrary to many catastrophes, shipwrecks take place in societies with a strong hierarchy, where commanders have the power to punish. The selfish impulse to go before others thus hits against the interest of not provoking a superior's wrath. On the Titanic, according to some witnesses, crewmembers went as far as to shoot an uncooperative person.

The second factor that influences the survival rate is women emancipation. Women pull through much better since the First World War. Before this great political and social turning point, they hardly benefited from the protection men were supposed to offer them at sea. However, after the war, they were able to perform better in disaster situations. How? By adopting a lifestyle that used to be reserved for men, which led them to improve their swimming skills and enabled them to wear less cumbersome clothes.