Measuring Cooperation and Defection using Shipwreck Data

In Liars and Outliers, I talk a lot about social norms and when people follow them. This research uses survival data from shipwrecks to measure it.

The authors argue that shipwrecks can actually tell us a fair bit about human behavior, since everyone stuck on a sinking ship has to do a bit of cost-benefit analysis. People will weigh their options -- which will generally involve helping others at great risk to themselves -- amidst a backdrop of social norms and, at least in case of the Titanic, direct orders from authority figures. "This cost-benefit logic is fundamental in economic models of human behavior," the authors write, suggesting that a shipwreck could provide a real-world test of ideas derived from controlled experiments.

Eight ideas, to be precise. That's how many hypotheses the authors lay out, ranging from "women have a survival advantage in shipwrecks" to "women are more likely to survive on British ships, given the UK's strong sense of gentility." They tested them using a database of ship sinkings that encompasses over 15,000 passengers and crew, and provides information on everything from age and sex to whether the passenger had a first-class ticket.

For the most part, the lessons provided by the Titanic simply don't hold. Excluding the two disasters mentioned above, crew members had a survival rate of over 60 percent, far higher than any other group analyzed. (Although they didn't consistently survive well -- in about half the wrecks, there was no statistical difference between crew and passengers). Rather than going down with the ship, captains ended up coming in second, with just under half surviving. The authors offer a number of plausible reasons for crew survival, including better fitness, a thorough knowledge of the ship that's sinking, and better training for how to handle emergencies. In any case, however, they're not clearly or consistently sacrificing themselves to save their passengers.

At the other end of the spectrum, nearly half the children on the Titanic survived, but figures for the rest of the shipwrecks were down near 15 percent. About a quarter of women survived other sinkings, but roughly three times that made it through the Titanic alive. If you exclude the Titanic, female survival was 18 percent, or about half the rate at which males came through alive.

What about social factors? Having the captain order "women and children first" did boost female survival, but only by about 10 percentage points. Most of the other ideas didn't pan out. For example, the speed of sinking, which might give the crew more time to get vulnerable passengers off first, made no difference whatsoever to female survival. Neither did the length of voyage, which might give passengers more time to get to know both the boat and each other. The fraction of passengers that were female didn't seem to make a difference either.

One social factor that did play a role was price of ticket: "there is a class gradient in survival benefitting first class passengers." Another is the being on a British ship, where (except with the Titanic), women actually had lower rates of survival.

Paper here (behind a paywall):

Abstract: Since the sinking of the Titanic, there has been a widespread belief that the social norm of “women and children first” (WCF) give women a survival advantage over men in maritime disasters, and that captains and crew members give priority to passengers. We analyze a database of 18 maritime disasters spanning three centuries, covering the fate of over 15,000 individuals of more than 30 nationalities. Our results provide a unique picture of maritime disasters. Women have a distinct survival disadvantage compared with men. Captains and crew survive at a significantly higher rate than passengers. We also find that: the captain has the power to enforce normative behavior; there seems to be no association between duration of a disaster and the impact of social norms; women fare no better when they constitute a small share of the ship’s complement; the length of the voyage before the disaster appears to have no impact on women’s relative survival rate; the sex gap in survival rates has declined since World War I; and women have a larger disadvantage in British shipwrecks. Taken together, our findings show that human behavior in life-and-death situations is best captured by the expression "every man for himself."

Posted on August 14, 2012 at 1:16 PM • 14 Comments

Comments

martinoAugust 14, 2012 3:33 PM

A little off-topic but...

The whole "gentility" thing...

That makes me wonder how a feminist (or equal-rights advocates or whatever you want to call 'em) would handle being told "Women and children first" these days?

My curiosity here lies in whether equal rights means:
A - When it's convenient
vs.
B - Equal rights all around (take the good with the bad)

i.e. one spot left on the rescue boat and there are two people left to rescue - one is a man, one a woman. Flip a coin or push/shove and winners survives or women and children first or...?

It's a little bit of a double-standard to stand up for equal rights but to demand to receive preferential treatment or accommodation based on your sex (when it's convenient to do so). No? Yes? I dunno...? What do you think?

CarolynAugust 14, 2012 4:55 PM

martino: Votes for women, boats for men was the Edwardian feminist response to that argument.

It was, indeed, an argument made against women's suffrage - men will naturally take care of women, so they don't need the vote, or rights to own their own property. Personally, I'd rather have a right to run my own life rather than a supposed right to rescue over a man that is more the exception than the rule.

Jay from BKKAugust 14, 2012 10:11 PM

Did the authors control for the ridiculous costumes women were/are often expected to wear? Swimming to lifeboats or flotsam in skirts and petticoats vs. swimming in trousers has got to be worth a few percentage points.

partdavidAugust 14, 2012 10:22 PM

martino:

I suspect you're trolling; but since the study shows that chivalry in such a situation is a myth, there is no such "double standard."

In other words, women neither demand nor receive preferential treatment, in this context, based on sex, so they are giving nothing up in demanding equal rights.

bobAugust 15, 2012 3:51 AM

@martino

Equal rights are not the same thing as good manners.

Unskilled workers have the same rights as professionals, is this wrong? Should we treat them as Untouchables?

Fried ApeAugust 15, 2012 4:40 AM

Perhaps what this shows is that survival in a shipwreck or other disaster can depend on physical strength and aggression. Successfully saving oneself may require selfish acts, such as climbing over other passengers to get the spaces or get to the exit. There may be some who, having reached a position of nearly saved (one foot in the lifeboat or stood on the plane wing outside the door) will pause to help others. There is probably also the conflict of saving oneself versus helping a spouse or children. Perhaps women are more cooperative so less likely to survive at the expense of others?
Perhaps behaviour varies with the type of disaster? I think I would be more inclined to offer assistance in a slow(ish) boat sinking than if there was a fire burning at my back. And that may be because I know I can swim, but I also know that I'm not fireproof.

Rich ground for theories about cooperation and selfishness and the perception of risk.

AtkAugust 15, 2012 4:52 AM

Regarding crew survival rates: might that be because the crew are helping others to survive? I mean, the crew steer the lifeboats, as passengers are not expected to know how. So each lifeboat should have 1 crew... Did the research compare ratio of lifeboats to crew, crew per lifeboat, and same ratios to affecting survival of passengers?

RyanAugust 15, 2012 4:58 AM

Men are typically stronger. So 'Women First' may work to level the survival odds.

karrdeAugust 15, 2012 11:25 AM

Is the survival rate changed by the underlying ship/lifeboat technology?

Three centuries of shipwrecks covers the age of Sail, the age of Steam, and (possibly) both the pre-Titanic and post-Titanic eras.

If the study includes the Titanic, then the 3-century timespan covers times before and after the advent of wireless communications.

Did any of these factors affect survival rates?

Did the study cover shipwrecks on the high seas? What about shipwrecks on inland lakes? Would other factors affect survival ratios in those environments?

Not that it's a bad study. But the study design may be ignoring other factors...

TerryAugust 15, 2012 2:50 PM

Class is important and often ignored. Class is extends privilege and rights as was the case in this study. The so called "lower" class is more expendable as they do not hold wealth and influence. The point is interesting as I don't see it having changed to date. We still hold the wealthy in higher regard although they score no higher in morales or ethics than more "average" persons. That's one reason why social engineering works, if you appear to be wealthy or influencial, this powerful bias will often get you in the door...

nateAugust 15, 2012 4:21 PM

What about fitness? If many of these events are historical, then I wouldn't be surprised at all if survival was heavily influenced by fitness for the passengers as well as the crew. Were women as fit as men a hundred years ago?

Dirk PraetAugust 15, 2012 7:31 PM

I'm not particularly surprised by the "every man for himself" conclusions. In the end civilisation, altruism and chivalry are just a very thin layer that tends to peel off rapidly in live or death situations. It's one thing both heroes and terrorists have in common: they're very rare and in most cases also incredibly stupid.

MartinoAugust 16, 2012 5:50 AM

Time of year probably plays a big role in the effects of hypothermia and survival rates too (if it wasn't already mentioned).

Shark infested waters might reduce survival chances (ok, kidding on that one, most likely a non-factor at all, just an over-hyped fear).

But the point of the article is looking at cooperation and defection, not directly at the shipwreck stats and data for the sake of determining survivability of assengers I think.

@partdavid: No, not trolling. I wanted to know if it is offensive to some people if I say/act 'ladies first', and by the looks of it...Chivalry is dead or dying in part because some don't want it (some do, like my wife for example and I gladly fulfill what I feel is my role). There are of course other reasons but this obviously sends mixed messages to some guys, that's all. Just look at the responses in the article Bruce posted about the sexual harassment at *Con. Wow!

@bob
Yes, agreed. I didn't exactly phrase my feedback/question well by the looks of it but at the same time it reveals that the equal rights and fairness/gender-equality 'movement' is alive and well. Great!

So the translation of crew having higher survival rates could be the have's vs. The have nots in society? Or the 'in' group of people controlling things (I.e. Gov't bodies?)?

@Terry,
Very true! I've found that if you act the act and dress the role you go places (by observation). Being knowledgeable and skilled helps you pull it off and sustain it of course, heh...

vasiliy pupkinAugust 16, 2012 10:39 AM

@ Dirk Praet:
"In the end civilisation, altruism and chivalry are just a very thin layer that tends to peel off rapidly in live or death situations". That statement is true regardless you like it or don't. On the other hand, in biology genetic programs tend to act towards survival of the pack, e.g. black widow spider uses his mate as food, and 'cases' of altruism is just subordinate tenedency to thatas well: bees are fighting to death for the queen bee safety. Regarding men v. women, it was research conducted that found out all of us could be genetically traced back to three females. I guess that survival genetic memory may affect decision in some situations, i.e.
save egg-holders first.

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