Evolutionary psychologist Geoffrey Miller recently published Spent: Sex, Evolution, and Consumer Behavior, a book on signaling, psychology, and consumerism. It's very up LW's alley - it reads almost as if Robin Hanson had written a book. (Actually, Hanson has never published a book, has he? Has anyone ever seen them in the same place? Hm...)

Sam Synder has written an overview/summary of the book, which I can attest hits many of the interesting points. (I would also praise the pervasive humor, which kept it readable and furnish many good examples of the 'reversal test', and the exercises at the end of the book.)

Some of the most interesting chapters to me were the ones dealing with Openness, which one will remember was recently shown may be changeable by psychedelics  - possibly the first such tweakable member of the Big Five, leading to the suggestion that it may be worth considering changing it. Hold this thought.

First, Miller discusses the signaling of Openness (starting on page 108 of the PDF, logical page 207):

Wherever you stand on the openness spectrum, those less open than you seem boring, dull, conventional, and conformist, whereas the more open seem eccentric bizarre, disruptive, threatening, or even psychotic. Given this diversity of openness levels, and the resulting diversity of preferences for different degrees of openness in family, friends, and mates, there is less incentive for people to fake their openness than their intelligence, If you pretend to have higher openness than you really do, you may be transiently attractive to those more open than you, but you'll be less attractive to those less open than you, The net result will be no higher social or sexual popularity. In fact, given the bell curve of openness, the more you deviate from an average level of openness, the fewer people you are likely to attract.
This means that where openness is concerned, consumers can sometimes display cheap, reliable openness badges that are fairly credible, also means that consumerist capitalism caters very well to the whole
range of openness. There are highly open cities.... There are some highly open musical genres (indie, alternative, jazz, world, hip·hop) and more conventional genres (pop, country, gospel, classic rock), There are more open genres of fiction (contemporary, science, erotic) and more conservative forms (romance, mystery, military history, fantasy). There are highly open magazines (Seed, Wired, Prospect, Icon, Harper's, Unzipped), and more mainstream magazines (Time, Money, Stuff, Today's Christian Woman)....

Why is Openness negative at its extreme? (Miller has remarked before this in Spent that despite what one might think, one of the other 6 psychological traits he covers, IQ, essentially has no bad amount to have - you have to be in the top percentile before IQ starts being a potential negative, and much marketing is covertly appealing to people's desires to look smart.)  On the potential biological negatives of novelty-seeking:

Each person's lymphocytes learn to fight off the particular varieties of parasites that are common within his own local group, which gives him an immunological memory of the parasites he has already encountered. (Immunization is simply the process of teaching the lymphocytes about a new kind of pathogen by exposing them to safer, deactivated forms of the pathogen.) However, the immune system's learned parasite resistance is highly localized, People from other kin groups, clans, tribes, ethnic groups, or races-even if they live just a few miles away-may host other varieties of parasites that evolved slightly different ways of being transmitted to hosts, infecting them, and making them sick.
Thus, any interaction with outsiders brings a high risk of acquiring a new kind of parasite that may be especially hard for one's locally adapted immune system to fight off. The higher the parasite load the greater the number, variety. and severity of parasites surrounding one's local group the higher that risk is and the more cautious people should be about strangers. They should develop a more proactive "psychological immune system" to avoid getting their mouths, noses, genitals, or skin anywhere close to potential sources of infection. They should be much more averse to contact with other groups, including not just their human members, but also their food, clothing, shelters, animals, social customs, hygiene practices, and purification rituals-anything associated with possible parasite transmission. In other words, people in high-parasite regions will benefit from becoming more xenophobic (fearful of out-groups) and ethnocentric (focused on their own in-group).

Recent research shows something very curious: group Openness inversely correlates with parasite load, even after controlling for all the obvious confounds like health and longevity. (I haven't looked up this research yet; he attributes it to "Corey Fincher and Randy Thornhill at University of New Mexico, and Mark Schaller and Damian Murray at University of British Columbia".)

For example, in a 2008 paper. Schaller and Murray suggested that openness and extraversion would be lower in territories where people suffer from higher parasite loads. They gathered data on average Big Five Five personality scores from three previous studies that had each analyzed thirty,three, fifty, or fifty-six of the ninety-eight territories for which the parasite loads were known. Across the seventy' one territories for which had both parasite-load data and personality data, they that people from territories with the highest parasite load indeed had substantially lower openness and extraversion scores on average.
For the twenty-three territories where Big Five scores could be averaged across all three previous studies (yielding the most accurate estimates), the correlations were guite strong: -.6 between parasite load and openness, and about the same for extraversion. These correlations remained substantial even after controlling for differences across territories in average annual temperature, distance from the equator (absolute latitude), life expectancy, GDP per capita, or political attitudes (individualism versus collectivism).
Collectivists make stronger distinctions between in-group and out-group, are warier of contact with strangers and foreigners, and highly value tradition and conformity. Relatively "collectivist" cultures include China, India. and countries in the Middle East and Africa; relatively "individualist" cultures include the United States and the nations of western Europe, especially Scandinavia. The researchers gathered data on average individualism/collectivism scores from four previous studies that had each analyzed sixty, eight, fifty, eight, fifty-seven, or seventy territories for which parasite loads were known. Across the ninety-eight territories, the various measures of collectivism correlated strongly with current parasite load (correlations ranging from .44 to 59), and even mare strongly with historical parasite load from about a century ago (correlations ranging from .63 to .73).... Even controlling for the four variables known from previous research to predict collectivism across cultures--life expectancy, population density,  GDP per capita, and the Gini index of economic inequality-parasite load still predicted collectivism quite strongly.

The evolutionary researchers Dan Fessler, David Navarette, and Mark Schaller have found that "perceived vulnerability to disease" - an individual's self-rated susceptibility to getting colds, infections, and communicable diseases--does predict that individual's xenophobia. Also, looking at photographs of parasites and disease symptoms has been shown to make people more xenophobic, at least temporarily. A final piece of evidence relies on the fact that women's immune systems grow adaptively weaker during first-trimester pregnancy, so that their bodies don't reject the fetus as an alien parasite. Women in the first trimester also show higher xenophobia, as if they unconsciously realize that their weaker immune systems will have more trouble fighting off new infections from outsiders; this xenophobia becomes weaker as their immune systems become stronger in the second trimester. More generally, people's openness, extraversion, and individualism tend to peak in young adulthood when their immune systems are strongest, and tend to decline throughout middle age as their health declines.

Incidentally, a good deal of LW's userbase could be described as 'young adults'; and it does seem relatively rare for old people to become transhumanists, as opposed to young or very young people. The next step, some anthropological observations which certainly look as if they are costly signalling something:

 Especially in areas with high parasite loads [eg. Papua New Guinea?], many tribal people open their skin to infection when they arc young adults, through scarification or tattooing or forced genital mutilation, to show that their immune systems are strong enough to survive the wounds. (The 5,300-year·old body of "Otzi the iceman," discovered in the Italian Alps in 1991, had fifty-seven tattoos.) If you are a healthy, energetic young male or woman covered in well-healed self-inflicted scars, despite living in a high·parasite area, you have credibly demonstrated that your health is very strong. Potential mates and friends may not consciously understand the connections between costly signaling theory, microscopic parasites, scarification using unsterilized tools, and individual differences in the number and efficiency of the lymphocytes that constitute the adaptive immune system. However, they can unconsciously assess that you would not be looking healthy or energetic after having endured so many cuts if you were weak and sickly. Biologists such as W. D. Hamilton and Anders Moeller have argued that in many other animal species, sexual ornaments have evolved as indicators of parasite resistance.

The final step - applying this idea to us:

In developed countries, we have less to fear from infectious parasites, but much more to fear from infectious memes. So, instead of opening our bodies to ambient germs, we open our minds to ambient culture, to determine if we can stay sane throughout the onslaught.  When you see teenagers and young adults posting their interests in music, books, and film on their MySpace websites, consider the costly signaling principles at work. If they have exposed themselves to a lot  of death metal, Chuck Palahniuk, and David Lynch, and they are  still sane enough to sustain a reasonable conversation through email  or instant messaging, they have credibly proven their openness and psychosis-resistance....Certain extreme ideas may present minimal danger to those with  strong antipsychosis defenses, who can therefore afford to act highly open. But those same ideas may present genuine dangers to those with weaker defenses, who must minimize their openness. If these outlandish speculations have any merit, then people who are low in openness prefer to associate with One another in part to protect their sanity. They seek out communities, jobs, lifestyles, malls, friends, and products that will not challenge their antipsychosis defenses. They prefer the familiar to the novel, the conventional to the radical the predictable to the challenging. They prefer goods and services that are heavy on matter and habit, and light on cognition and imagination.They move to comfortably anti-intellectual communities: rural towns or ethnically homogeneous suburbs around provincial cities, such as Indianapolis, Indiana. or Augsburg, Germany; large, progressive, multicultural cities are just too threatening. In this way, the less-open can thrive for years in meme .. excluding bubbles. avoiding as much as possible disturbing thoughts and social encounters. For them the unexamined life is ... the easiest way to avoid psychosis.

Why Don't We All Want Maximum Openness?

Openness is a dangerous trait in several ways. It can lead to social embarrassment - when one's behavior is too weird or novel. It to one's brain getting infected by maladaptive memes-false information, dumb ideologies, conspiracy theories. It can lead one cult, enroll in art school or move to Santa Fe.

For example, while openness is strongly correlated with creativity, it is also correlated with psychosis (loss of contact with reality). To study correlations, my colleague Ilantt Tal and I asked University of New Mexico students to complete six tests of verbal creativity and eight tests of drawing creativity, along with measures of the Central Six traits.
We found that openness has moderate positive correlations with both general intelligence (30) and positive schizotypy (.29). Openness predicts both verbal creativity (.34) and drawing creativity (.46).
Intelligence also predicts both verbal creativity (35) and drawing creativity (.29). Schizotypy predicts creativity very weakly, but once you control for openness, it does not predict creativity at all, Thus, creativity is best predicted by positive responses to openness questions, rather than schizotypy questions. The implication is that there is a link between madness and creativity, as philosophers have speculated for millennia, but the link is mediated by openness. Openness has creativity benefits and extreme openness shades over into psychosis, but the psychosis is not generating any creative work; It's just a harmful side effect. This is yet more evidence that very high openness is a dangerous game, with potentially high payoffs in creativity, but potentially catastrophic effects on mental health. In a complex, media-rich society, perhaps only people with very good mental health can tolerate a high degree of openness without losing their equilibrium.
The highly open expose themselves to new experiences, cultures, people, relationships, norms, ideas, worldviews, art, music, sexual practices, and drugs, They can get infected by nasty, maladaptive, memes; they might end up believing in astrology, homeopathy, or Scientology, They might find themselves joining the open-marriage scene, which almost always leads to divorce; or the methamphetamine scene, which leads to psychosis; or both, which leads to spousal homicide.
Cultural disgust to bizarre new ideas protects low-openness people not only from psychosis, but from maladaptive memes. They may not adopt useful new ideas very quickly, hut neither do they join suicide cults [like Heaven's Gate, to name an example I was reading about recently]

The weak correlation with IQ has the troubling implication - what happens when you are highly Open but not especially intelligent, and you are confronted with memes & products optimized on the free market?

Highly open consumers can be highly profitable, because they can be highly gullible. For example, the more than averagely open constitute the main market for complementary and alternative medicine.
Without them, there would be no market for:
• auricular point therapy (acupuncture of the outer ear)
• Bach flower essences (ingestible wildflower essences)
• colonic irrigation (having gallons of warm water pumped through your colon via anal tubing)
• dolphin therapy (emotional healing through "energy transfers" from contact with dolphins)
• Gerson therapy (drinking vast amounts of fruit juice, plus coffee enemas

I am a little troubled because as a child I was interested in such alternative things and the Occult as well - I seem to recognize this pattern in myself. My inner Hanson asks me, 'why are you so sure you aren't still mistaken and that you aren't so Open your mind finally fell out?'

A closing link: 'the valley of bad rationality'.