April 16, 2008

More on pathogens and personality

Here's the abstract of the new paper I briefly discussed yesterday that claims there is a high correlation between a culture's level of psychological "collectivism" and the local level of infectious disease:

Pathogen prevalence predicts human cross-cultural variability in individualism/collectivism

Corey L. Fincher, Randy Thornhill, Damian R. Murray, and Mark Schaller

Pathogenic diseases impose selection pressures on the social behaviour of host populations. In humans (Homo sapiens), many psychological phenomena appear to serve an antipathogen defence function. One broad implication is the existence of cross-cultural differences in human cognition and behavior contingent upon the relative presence of pathogens in the local ecology. We focus specifically on one fundamental cultural variable: differences in individualistic versus collectivist values. We suggest that specific behavioural manifestations of collectivism (e.g. ethnocentrism, conformity) can inhibit the transmission of pathogens; and so we hypothesize that collectivism (compared with individualism) will more often characterize cultures in regions that have historically had higher prevalence of pathogens. Drawing on epidemiological data and the findings of worldwide cross-national surveys of individualism/ collectivism, our results support this hypothesis: the regional prevalence of pathogens has a strong positive correlation with cultural indicators of collectivism and a strong negative correlation with individualism. The correlations remain significant even when controlling for potential confounding variables. These results help to explain the origin of a paradigmatic cross-cultural difference, and reveal previously undocumented consequences of pathogenic diseases on the variable nature of human societies.

Part of their argument is one that I've been half-jokingly suggesting about the ferociously xenophobic pygmy negritos of North Sentinel Island in the Andamans, off the coast of Indonesia. As I wrote in 2006:

A long time theme here at iSteve.com is defending human biodiversity. Although defending plant and animal biodiversity is extremely fashionable, nobody else speaks up for human biodiversity. Of particular concern to me has been the survival of the pygmy negrito Andamanese of North Sentinel Island in the Indian Ocean (located roughly where Skull Island in "King Kong" would be), one of the last tribes out of contact with the rest of the world. If they ever come into contact with us, most of them will die from diseases for which they have no defenses.

Fortunately, the Sentinelese have no intention of going down without a fight. The Daily Telegraph reports:

Stone Age tribe kills fishermen who strayed on to island

But, it's not at all clear that this evolutionary mechanism, if it exists, could play a sizable role in explaining why, say, the Japanese are more collectively minded.

Certainly, infectious diseases have played a hugely important r0le in the development of cultural and biological differences among humans, but this paper has some major problems. Let's leave aside for now the individualism / collectivism dimension, which clearly is difficult to define, much less measure accurately.

Let's look at their measure of disease. To measure the pathogen burden in about 100 different locations, they look at incidence rates for nine infectious diseases, eight of them from the early or mid-20th Century:

To create our primary measure of pathogen prevalence, we were able to estimate the prevalence of nine pathogens detrimental to human reproductive fitness (leishmanias, trypanosomes, malaria, schistosomes, filariae, leprosy, dengue, typhus and tuberculosis) within each of the 93 geopolitical regions worldwide. By necessity, a contemporary source was used to estimate the prevalence of tuberculosis (National Geographic Society 2005), but the prevalence of the remaining eight pathogens was estimated on the basis of old atlases of infectious diseases and other historical epidemiological information (Simmons et al. 1944; Rodenwaldt & Jusatz
1952–1961).

But, the key point in the war between germs and people is that it's a constant struggle that goes on and on. All this correlation tells us is that during the first six decades or so of the 20th Century, northern Europeans and their offspring tended to be richer, more scientific, and thus had better public health systems than everybody else. Not surprisingly, their traditional high individualism correlates with low levels of infectious disease at that time.

Although European individualism appears to be deeply rooted many centuries into the past, European health and cleanliness most definitely is not. The cultures that emerged from the barbarian invasions of the Roman Empire were among the dirtiest ever.

When Germanic barbarians took over the Roman Empire and couldn't figure out how to keep the supply of clean water flowing to the cities, the population dropped and the survivors dispersed. The English, for example, developed a culture where their upper classes lived in splendid isolation in the healthy countryside, and congregated in London only in summer, when the risk of epidemic was lowest in that northern region.

When 19th Century Europeans finally developed sanitary habits, supported by the wealth of the Industrial Revolution, the populations of their cities finally exploded.

Today, the four countries with the longest life expectancies (a reasonably proxy for low levels of infectious diseases) are cool Andorra (in the Pyrenees), Macau (across from subtropical Hong Kong), temperate Japan, and tropical Singapore). So, psychologically collectivist East Asians are rapidly overtaking Europeans in freedom from infectious disease, and its not clear that Europeans were better off before the 19th Century either. Marco Polo, for example, was impressed by the cleanliness of China, and so were Christian missionaries in 16th Century Japan.

Both Europe and East Asia, having trade contact with each other for millennia, were within the Old World disease complex, unlike the resistance-weak New World.

Pathogen burden is a function of a lot of different factors: climate (warm is typically worse, but cold is worse for some respiratory diseases); density of population; public health measures such as drinking water, sewer systems, mosquito-spraying, and vaccinations; exposure to domestic animals; isolation; and experience with the diseases in generations past leading to selection for resistance or in childhood leading to individual immunity. It's an extremely dynamic feedback system, with only climate being close to a constant over evolutionary time.

My published articles are archived at iSteve.com -- Steve Sailer

20 comments:

Anonymous said...

So you're finally going to give Jared Diamond some credit for that last paragraph? ;)

Anonymous said...

From what I've heard, the Japanese consider the Chinese to be on the dirty side. Certainly the peasant class always was. The Japanese have always been pretty clean.
In her memoirs, a 19th c. missionary wife notes that the Chinese ladies loved to come and visit her western style dwelling and called it "Heaven." Now this was in 1880 and I don't recall from reading the book (which is onl-line) if she even had indoor plumbing, although she may have had. The Chinese were no cleaner than pre-19th c. Euroeans if their mortality rates are any indication. The child mortality rate, until the 1950s, was horrendous in China. There are many on-line memoires of Chinese, mostly women, recounting their lives during the first 5 or 6 decades of the 20th century. Over and over there are accounts of losing most of their 5 or 10 or 12 or 20 children. One woman said plainly that in the old days, most children born, died young. I recall one account were an old lady says "she was the first of a number of daughters in the family to reach foot-binding age" (about 9 for her.) This sort of testimony occurs over and over.
You've really got to look at original sources for information on topics like this.

Anonymous said...

the regional prevalence of pathogens has a strong positive correlation with cultural indicators of collectivism and a strong negative correlation with individualism

What's funny about all of this is that these guys just assume that everyone knows that folks from Afria, Asia, and similar places are more collectivist and xenophobic and less welcoming to outsiders (which is true whether they live in the US or in their homelands). They don't bother proving it, and as real scientists don't even feel they have to.

"It's true, everyone knows it, so there."

The thought police from the "scoial science" side of the campus are probably going nuts over this.

Polistra said...

Fascinating, and you nicely exploded the causality problem with the original. Seems like "touchiness" would be a more important measure than "collectivity" anyway. Are no-touch Japanese more healthy than median-touchy Koreans or high-contact Russians at the same latitude?

Anonymous said...

"The cultures that emerged from the barbarian invasions of the Roman Empire were among the dirtiest ever."

Citation?

Anonymous said...

Part of their argument is one that I've been half-jokingly suggesting about the ferociously xenophobic pygmy negritos of North Sentinel Island

The Sentinelese are hardly pygmies. The average male stands a solid six feet tall. Women average 5.4. Some other Andamanese may qualify as small, but not North Sentinel's wild men.

Anonymous said...

So you're finally going to give Jared Diamond some credit for that last paragraph? ;)

The last paragraph, presumably:

Both Europe and East Asia, having trade contact with each other for millennia, were within the Old World disease complex, unlike the resistance-weak New World.

Diamond failed to explain the decline of the Otttomans and other Muslims, and also the Byzantines, who were who were in the middle of East-West trade and international intermingling for a thousand years or more.

According to Diamond's rather stupid premise, peepul in the middle of Eurasia should have benefitted more from the Eurasian globalism of earlier times.

Diamond's hypothesis: it's geography! See, Eurasia runs east and west and mostly in temperate latitudes, whereas Africa and the Americas are sort of north and south. Therefore geography disadvantages Africans and Native Americans. ( North America mostly temperate also? Uh, Prof. Diamond never seems to have noticed. )

Diamond fails to address these lacunae in his long, dull, unfailingly pee cee "Diamonds and Steel" book.

Anonymous said...

Of particular concern to me has been the survival of the pygmy negrito Andamanese of North Sentinel Island in the Indian Ocean (located roughly where Skull Island in "King Kong" would be), one of the last tribes out of contact with the rest of the world. If they ever come into contact with us, most of them will die from diseases for which they have no defenses

The Jarawa are already experiencing that problem.

Anonymous said...

Off subject, another example of Men with gold chains... a book review in salon about international crime. "McMafia".
http://tinyurl.com/3m99f6

Peter said...

Love reading your movie reviews in AM CON MAG. Would you mind possibly giving our blog a look? Thanks!

GOP Catholics

http://www.gopcatholics.blogspot.com

Anonymous said...

Yellow Fever, Malaria, various forms of Syphilis, were all New World Diseases that took their tolls on European adventurers and conquerors Steve. So I would not give Diamond too much credit.

One of the most dominant environmental factors affecting natural selection in humans is culture. It doesn't just arise in a vacuum or have no effect.

Anon -- various Byzantine, Arab sources recall with horror the dirtiness of the Europeans post-Rome. Chrichton used that in "Eaters of the Dead" which was turned into the film "13th Warrior." The Vikings were extraordinarily dirty.

Matt Parrott said...

I propose that they got this thing perfectly backwards. Consider for a moment that Europeans adapted in the temperate region surrounded by pathogens, immersed in animal waste, and subject to frequent plagues. If that were so, then they would perhaps be uniquely inclined to autoimmune over-responsiveness, would perhaps have a wider array of immune system "signatures", and would be innately less vulnerable to diseases. Culturally, they would have developed strategies for avoiding plagues, such as an aversion of crowds and a strict sexual regimen of monogamy.

Under this model, Africans and other populations which have recently existed in regions which were very sparsely populated, would be going through the bad phase, one Whites already went through.

It seems intuitively obvious to me that isolation is an effective way to isolate yourself from plagues. I'll have to ponder on this for a bit, but it really seems that there are some flawed assumptions here.

Anonymous said...

Yellow Fever, Malaria, various forms of Syphilis, were all New World Diseases that took their tolls on European adventurers and conquerors Steve. So I would not give Diamond too much credit.

Yellow fever and malaria (along with diphtheria, measles, chicken pox, whooping cough, dysentery, and smallpox) were Old World diseases introduced into the New World.

Anonymous said...

"Marco Polo, for example, was impressed by the cleanliness of China...."

He probably spent more time in princely palaces than in peasant hovels. It's possible that europe has gotten a bad rap, when it comes to cleanliness. The medieval scholar Morris Bishop in "The Middle Ages" notes that public baths were quite common in medieval european cities. He claims that medieval europe was not as filthy and squalid as is now commonly presumed. It certainly wasn't clean by our standards, and probably not by the standards of the ancient Romans, but perhaps not as bad as often portrayed (as in James Clavell's "Shogun" for example).

I think that many here are too harsh on Jared Diamond. I found "Guns, Germs, and Steel" to be interesting and alot of it seemed to be quite plausible, especially regarding the influence of geography, domesticatable animals, and cereals. He obviously is horrified at the prospect of group differences, and does his best to suppress such unclean thoughts. I think that intrinsic differences between peoples explains alot of why the history of humanity played out as it did, but probably not all of it.

Anonymous said...

if collective means being comfortable packed together into a subway car, or a crowded village, or a small house with the pigs just outside,with less need for personal space and bodily privacy i'd imagine a collectivist attitude would put you more at risk for disease than the herdsman or trapper or suburbanite or taciturn midwesterner spaced out from the crowd. Only if your highly collectivist herd was successful in keeping out all pathogens would it work. One of the group gets it, everyone will.

they seriously need to define their terms.

Anonymous said...

banallyevilneocon,

Many gentiles would consider a bris "extremely dirty".

Likewise, elements of Muslim personal hygiene.

The claim is that "cultures that emerged from the barbarian invasions of the Roman Empire were among the dirtiest ever", not that some foreign observers commented negatively on them.

As for the Vikings:

Uncleanliness

The image of wild-haired, dirty savages sometimes associated with the Vikings in popular culture has hardly any base in reality. The Vikings used a variety of tools for personal grooming such as combs, tweezers, razors or specialised "ear spoons". In particular, combs are among the most frequent artifacts from Viking Age graves, and one can conclude that a comb was the personal equipment of every man and woman. The Vikings also used soap long before it was reintroduced to Europe after the fall of the Byzantine Empire.

The Vikings in England even had a particular reputation of excessive cleanliness, due to their custom of bathing once a week (as opposed to the local Anglo-Saxons). As for the Rus', Ibn Rustah explicitly notes their cleanliness, while Ibn Fadlan is disgusted by the women sharing the same vessel as the men to wash their faces in the morning. Ibn Fadlan's disgust is thus probably motivated by ideas of personal hygiene particular to the Muslim world (for instance, Muslims are required to wash only with running water), while the very example intended to convey the disgusting customs of the Rus' at the same time records that they did in fact wash every morning.

KlaosOldanburg said...

i think matt's on the right track. monogamy is a great way control the spread of disease (not only STDs)

feminists have sanctified sexual promiscuity, but there were (and still are!) valid *biological* reasons people became so picky about who their peers were hopping into bed with. 'mother nature' punishes sluttiness far worse than 'father god.'

here's a couple of interesting links on collectivism in scandinavian culture:
http://en.wikipedia.org/wiki/Lagom
http://en.wikipedia.org/wiki/Jante_law

--

steve: i know 'a man's blog is his castle,' but i for one vote for more science (and/or social 'science') and less obama (or McSame, or G.I. Hillary).

Anonymous said...

Anonymous, good catch. Maybe Evil Neocon will go away again now. Those Pesky Facts Always Ruining His TheoriesTM.

Anonymous said...

Steve Sailer: The English, for example, developed a culture where their upper classes lived in splendid isolation in the healthy countryside, and congregated in London only in summer, when the risk of epidemic was lowest in that northern region.

I meant to post this on the other thread, but this like as good a place as any.

There's a French sociologist, named Emmanuel Todd, who, back in 1983, caused a minor stir with his book, The Explanation of Ideology: Family Structure and Social Systems (Family, Sexuality and Social Relations in Past Times), [translated into English by David Garrioch]:

Amazon.com, HARDCOVER
Amazon.com, SOFTCOVER
abebooks.com

Todd's thesis was that there was an extraordinary correlation between family structure and political affiliation, so that, very roughly:

Nuclear Family <-> "Libertarian" [classical liberal] politics

Extended Family <-> "Statist" [modern liberal] politics

Anyway, if Todd was right, and if all those statists are indeed huddled together under the same roof, then every time Jr sneezes, it stands to reason that Grandma & Grandpa & all the aunts & uncles & cousins are going to catch the same flu.

PS: I don't know what his politics were back in the day [in the seventies, Todd predicted the downfall of the Soviet Union based on some infant mortality data he had seen, so, at the time, I guess it was assumed that he was a little closer to the libertarian end of the spectrum], but, judging from some recent interviews, lately Todd seems to have devolved into a fairly doctrinaire statist Frog [and Muslim accommodationist].

Or, as Lucianne Goldberg's boy would say, a cheese-eating-surrender-monkey.

Sigh.

Anonymous said...

I think that many here are too harsh on Jared Diamond. I found "Guns, Germs, and Steel" to be interesting and alot of it seemed to be quite plausible, especially regarding the influence of geography....

Sure, if you think it's intellectually rigorous to set out to prove something by adopting an argument that is essentially self-refuting.

Diamond’s thesis stated at page 25 of Guns, Germs & Steel:

Authors are regularly asked by journalists to summarize a long book in one sentence. For this book, here is such a sentence: ‘History followed different courses for different peoples because of differences among peoples’ environments, not because of biological differences among peoples themselves.”

The rather obvious hole in this thesis: environmental differences produce biological differences.

Diamond posits geological differentiation as causing cultural differentiation. Of course, this differentiation results in different selective pressures and, therefore, biological differences.

Humans migrated out of Africa many thousands of years before the advent of agriculture 13,000 years ago (to use Diamond’s date). Thus, if the first migration of homo sapiens out of Africa occurred roughly 110,000 years ago, humans had several thousand generations in which to adapt to new and different environments, even before the advent of agriculture, which accelerated changes in population size, social organization, and technology. And thereafter, humans had another 500 generations to adapt to their diverse geographic environments and their continually diversifying cultural environments.

Although environmental differences started this “feedback loop” (as Rushton terms it), biological differences arose long before the historical events Diamond discusses and have continued to be shaped up to the present.