Category: Science

Tomorrow I am attending a conference on self-deception, directed by Robin Hanson and me. We will have numerous luminaries, including Robert Trivers and Thomas Schelling, in attendance. By the way, blogging will continue.

Here are a few self-deception pointers for the day:

However much I examine my vanity, I can’t see in it the same disagreeable tone of the vanity of other people, all of which is just a further stage of vanity.

by the poet Carlos Drummond de Andrade.

Or, did you know that Stalin, when revising his official biography for publication, ordered that this sentence be inserted:

Stalin never let his work be affected by the least shadow of vanity, presumption or idolatry.

Thomas More once wrote:

Most men like their own writing best of all.

All of these bits are from Lies We Live By: The Art of Self-Deception, by a very underrated Brazilian economist named Eduardo Giannetti. Few economists are so well-read in the humanities, so ironic at the right moment, and so on the mark in their understanding of human psychology. If anyone out there knows Eduardo’s email address, please forward it to me, I would like to write him.

1. Bushmeat hunters in Africa typically earn in the range of $250 to $1050 a year.

2. In one sampled African market, ape meat cost about twice as much as beef or pork.

3. “In the big cities of Central Africa, it seems relatively easy to find a gorilla head or some hands, or perhaps a chimpanzee hand or two or four, for sale in the medicinal and fetish markets…In a Brazzaville fetish market, a dealer once offered me a gorilla head for the equivalent of $40 and a hand for about $10.”

4. Hunters of ape meat often rely on the trails cut by loggers

5. Ape meat supply has largely gone underground in recent years, although in a given market most people know whom to ask to get the meat.

6. Many village and hunter-gatherer societies have a special word for “meat-hunger.”

7. Central Africans eat at least as much meat per person as Americans or Europeans do.

8. Hunters claim that if a champanzee is wounded and cornered and about to meet his death, that he will beg for his life with the same expressions that a human being would use.

9. One hunter wrote: “It is this lurking reminiscence of humanity, indeed, which makes one of the chief ingredients of the hunter’s excitement in his attack of the gorilla.”

All of these bits are from Eating Apes, by Dale Peterson. This is a remarkably intelligent and disturbing book, the photos are unforgettable. The author is sympathetic to the plight of the great apes but he also understands how markets work, what the life of the poor is like, and why a naive ban on hunting is unlikely to succeed.

By the way, today’s Cnn.com reports that the Orangutan may be extinct within 10 to 20 years.

Today’s Financial Times runs a feature article on neuroeconomics, an offshoot of experimental economics.

Why do people cooperate in experimental games?

…during the games, Prof Smith’s team scanned players’ brains using functional magnetic resonance imaging. The FMRI scan showed that players who co-operated were using parts of their brain called Brodman’s areas 8 and 10. These areas had previously been associated with thinking about the mental activities and the motivations of others, and of delaying gratification to receive higher rewards later. Non-cooperative players did not use these parts of the brain, and neither did those who knew they were playing against computers instead of human opponents.

This, argues Prof Smith, is consistent with the reciprocity explanation: players are thinking about the likely responses of other players and deciding to trust them.

Brain scans are not the only tool of neuro-economists. Other approaches include measuring pulse rates, skin conductivity and hormone levels. And as a result of such experiments, neuroeconomics boasts an eclectic collection of findings – one of them being that ovulating women are less trustworthy than the rest of us…

Would you like to hear more about ovulating women?

Prof [Paul] Zak has also found that women who take part in the trust game while they are ovulating send back substantially less money to their fellow player than other women or than men – crudely, they are less trustworthy. He explains: “The physiological reason is that progesterone suppresses the effect of oxytocin. The evolutionary biological reason is that is that if you’re about to get pregnant, you should be very careful about overreacting to the social signals you receive. In addition, you don’t want to be giving away resources.” Prof Zak points out that since trust is fundamental to economic development, a better understanding of the oxytocin and the physiology of trust could be fundamental for promoting development. The Bangkok Post has already picked up on his work: the newspaper says that since the oxytocin stimulants massage, food and sex are much beloved of Thais, Thailand’s economic development is assured.

For those interested, GMU researcher Kevin McCabe has started a fledgling neuroeconomics blog.

I recommend Ian Deary’s Intelligence: A Very Short Introduction. I am going to buy more books in this Oxford series. We at Marginal Revolution aim to provide value for attention, however, so here is an even shorter introduction.

1) Almost all measures of intelligence correlate with one another and quite a few measures of different aspects of intelligence are highly correlated. It is thus meaningful to talk about general intelligence, g. Howard Gardner’s work on “multiple intelligences” is on the fringes of scientific psychology.

2) Intelligence rankings are stable with age but fluid intelligence, meaning something like pure reasoning power, as opposed to crystalized intelligence peaks in the 20-30s and then declines with age.

3) Connecting IQ scores to brain morphology and activity is still in its infancy but there are modest, but well established, correlations between brain size and IQ (psychometric intelligence) and measures of reaction time (which plausibly measure brain speed) and IQ.

4) Intelligence is in large part genetic and that which is due to environment is primarily not due to the obvious possibilities such as family upbringing.

5) Intelligence matters for work performance and education. IQ is a better forecaster of work performance than just about any other test short of a trial run on the actual work to be performed.

6) IQ has been rising, the Flynn effect. No one knows why.

7) None of the above points are controversial among intelligence researchers.

Aside from Dreary’s book another useful introduction to intelligence research is the authoritative consensus report from the American Psychological Assocation, Intelligence: Knowns and Unknowns, summary here.