Progress Daily

Katherine Kinzler has demonstrated that preverbal infants as young as 5-6 months of age “prefer” their own native speakers. She found that American infants look longer at someone speaking with an American accent than someone with a French accent, and the opposite pattern occurs with French infants. And when two adults simultaneously offer a 10-month-old the same toy, the baby usually reaches for the one being given to them by the native speaker.

In the ancestral past, neighboring communities were often at war with each other, and the most reliable marker of an out-group member wasn’t what they looked like but how they sounded.

“Babies Don’t Like Foreigners,” by Jesse Bering

Richard Sosis analyzed two hundred 19th-century US communes: 88 religious and 112 secular. He found that communes whose ideology was secular were up to four times as likely as religious ones to dissolve in any given year.

In a follow-up study, Sosis focused on 83 of these communes (30 religious, 53 secular) to see if the amount of time they survived correlated with the strictures and expectations they imposed on the behaviour of their members.

He found that the more constraints a religious commune placed on its members, the longer it lasted (one is still going, after 149 years). But the same did not hold true of secular communes, where the oldest was 40.

Ara Norenzayan has conducted experiments using what is known as the “dictator game,” a test used to gauge altruistic behaviour. Participants receive a sum of money — $10,in this case — and are asked if they would like to share it with another player.

Norenzayan and Azim Shariff primed half of their volunteers to think about religion by getting them to unscramble sentences containing religious words such as God, spirit, divine, sacred and prophet. Those thus primed left an average of $4.22, while the unprimed left $1.84.

An experiment by Jesse Bering subjected a bunch of undergraduates to a quiz. His volunteers were told that the best performer among them would receive a $50 prize. They were also told that the computer program that presented the questions had a bug in it, which sometimes caused the answer to appear on the screen before the question. The volunteers were therefore instructed to hit the space bar immediately if the word “Answer” appeared on the screen. That would remove the answer and ensure the test results were fair.

The volunteers were then divided into three groups. Two began by reading a note dedicating the test to a recently deceased graduate student. One did not see the note. Of the two groups shown the note, one was told by the experimenter that the student’s ghost had sometimes been seen in the room. The other group was not given this suggestion.

The so-called glitch occurred five times for each student. Bering measured the amount of time it took to press the space bar on each occasion. He discarded the first result as likely to be unreliable and then averaged the other four. Those who had been told the ghost story pressed the space bar in an average of 4.3 seconds. That compared with 6.3 seconds for those who had only read the note about the student’s death and 7.2 for those who had not heard any of the story concerning the dead student.

“Where angels no longer fear to tread,” The Economist

According to “Marketing actions can modulate neural representations of experienced pleasantness,” by Antonio Rangel, Hilke Plassmann, & Baba Shiv, if people are told a wine is expensive while they are drinking it, they think it tastes nicer than a cheap one.

The researchers used fmri (functional magnetic-resonance imaging) to scan the brains of 20 volunteers while giving them sips of wine.

Dr Rangel gave his volunteers sips of what he said were 5 different wines made from cabernet sauvignon grapes, priced at between $5 and $90 a bottle. He told each of them the price of the wine in question as he did so. But he lied. He actually used only 3 wines, and served two of them twice at different prices.

The scanner showed that the activity of the medial orbitofrontal cortices (an area of the brain responsible for registering pleasant experiences) of the volunteers increased in line with the stated price of the wine. When one of the wines was said to cost $10 a bottle it was rated less than half as good as when people were told it cost $90 a bottle, its true retail price. When the team carried out a follow-up blind tasting without price information they got different results. The volunteers reported differences between the three “real” wines but not between the same wines when served twice.

Nor was the effect confined to everyday drinkers. When Dr Rangel repeated the experiment on members of the Stanford University wine club he got similar results.

This research suggests that a successful marketing campaign can not only make people more interested in a product, but also make them enjoy it more.

“Hitting the spot,” The Economist

Prior to Eric Turkheimer’s 2003 paper “Socioeconomic Status Modifies Heritability of IQ in Young Children,” scientists had found that genes account for most of the differences in IQ.

Turkheimer found that although the environmental impact on IQ is very small when you look at families with incomes in the moderate range, the reverse is the case when you look at very low-income families.

Impoverished families were underrepresented in most earlier studies.

Two things made Turkheimer’s project possible: the public release of a large, rich database including an unusually large number of children from families of very low socio-economic status; and advances in statistical methods that use computers to carry out huge numbers of computations very quickly.

Research like Turkheimer’s relies on the difference between fraternal twins, who are as genetically similar as any siblings, and identical twins, who share exactly the same genes.

For traits that are primarily determined by genes, identical twins will show no variation, but fraternal twins will. For traits that are determined by environment, identical twins and fraternal twins will show similar patterns of variation in the trait. For traits that reflect an interaction between genes and environment, identical twins will show somewhat less variation than fraternal twins.

Turkheimer found that for the families in the study at the very bottom of the socioeconomic scale, shared environment accounted for 60% of the variance in IQ; and the contribution of genes was close to zero. Non-shared environment, which includes factors such as gender, accounted for the remainder.

Further up the socio-economic ladder, the effects of environment rapidly declined, and genes took on an increasingly important role.

The research does not identify the specific environmental factors that contribute to the variations in IQ among impoverished children.

“New Thinking on Children, Poverty & IQ,” by Jan Richter

The “curse of knowledge” means that once you’ve become an expert in a particular subject, it’s hard to imagine not knowing what you do.

In a 1990 experiment, Elizabeth Newton gave one set of people, called “tappers,” a list of commonly known songs from which to choose. Their task was to rap their knuckles on a tabletop to the rhythm of the chosen tune as they thought about it in their heads. A second set of people, called “listeners,” were asked to name the songs.

Before the experiment began, the tappers were asked how often they believed that the listeners would name the songs correctly. On average, tappers expected listeners to get it right about half the time. In the end, however, listeners guessed only 3 of 120 songs tapped out, or 2.5%.

“Innovative Minds Don’t Think Alike,” by Janet Rae-Dupree

A political prediction market is a bit like the stock market, except that you are buying shares whose value depends on the success of a political candidate, rather than the profits earned by a corporation.

Experimental prediction markets were established at the University of Iowa in 1988, and they have since repeatedly outperformed polls. (See “Results from a Dozen Years of Election Futures Markets Research.”) Economic historians have also documented the impressive forecasting record of prediction markets in the period before scientific polling was adopted. (See “Historical Presidential Betting Markets.”)

In the 2004 primaries, prediction markets pointed to the disintegration of Howard Dean’s candidacy in advance of the fateful Iowa caucuses. In the 2004 presidential election, the market favorite won the Electoral College in all 50 states; in 2006 the markets also picked every Senate race.

Prediction markets have long suggested a strong showing for Hillary Clinton, even as popular commentators had earlier dismissed her as unelectable, much as they did prior to her successful New York senate race in 2000.

Prediction markets tend to be forward-looking, while polls are often backward-looking. For instance, Fred Thompson continues to do well in national polls largely due to name recognition, while prediction markets have discounted this advantage, understanding that candidates like Mike Huckabee will become better known through the campaign. Indeed the markets currently believe that Mr. Thompson is less likely to win the Republican nomination than fringe candidate Ron Paul.

The markets predicted Mike Huckabee’s surge a few weeks before the polls.

On the Democratic side, national polls suggest a landslide for Ms. Clinton, while the markets suggest a one-in-three chance that Obama or Edwards will ultimately win the nomination.

“Best Bet for Next President: Prediction Markets,” by Justin Wolfers

Dr Randy Thornhill manipulated pictures to make people’s faces appear more and less symmetrical, then asked volunteers of the opposite sex rank them for attractiveness. Symetery and attractiveness correlated. His later experiments have shown that all aspects of bodily symmetry contribute, down to the lengths of corresponding fingers, and that the assessment also applies to those of the same sex.

Perfect symmetry is hard for a developing embryo to maintain, so one that can maintain it must have good genes (and luck).

Other aspects of beauty, too, are indicators of health. Skin and hair condition are sensitive to illness and malnutrition.

Leslie Zebrowitz and Gillian Rhodes found 9 past studies on attractiveness and IQ, and subjected them to a “meta-analysis.”

The studies’ researchers had photographed people and asked them to do IQ tests, then showed the photographs to other people and asked them to rank the intelligence of the first lot. The results suggested that people get such judgments right often enough to be significant.

Dr Daniel Hamermesh presided over a series of surveys in the USA and Canada that showed that when all other things are taken into account, ugly people earn less than average incomes, while beautiful people earn more than the average. The ugliness “penalty” for men was -9% while the beauty premium was +5%. For women, the ugliness penalty was -6% while the beauty premium was +4%.

He found the figures for men in Shanghai are –25% and +3%; for women they are –31% and +10%. In Britain, ugly men do worse than ugly women (-18% as against -11%) but the beauty premium is the same for both (+1%).

Dr Hamermesh found that those members of a particular (anonymous) US law school rated attractive on the basis of their graduation photographs went on to earn higher salaries. Moreover, lawyers in private practice tended to be better looking than those working in government departments.

Hamermesh’s study of Dutch advertising firms showed that those with the most beautiful executives had the largest size-adjusted revenues — a difference that exceeded the salary differentials of the firms in question. Finally, he found that attractive candidates were more successful in elections for office in the American Economic Association.

Working in Shanghai, where his research indicated the difference between the ugliness penalty and the beauty bonus was greatest, Dr Hamermesh looked at how women’s spending on their cosmetics and clothes affected their income.

The beauty premium generated by such primping was worth only about 15% of the money expended.

Niclas Berggren’s research team looked at almost 2,000 candidates in Finnish elections. They asked foreigners (mainly Americans and Swedes) to examine the candidates’ campaign photographs and rank them for beauty. The more beautiful candidates, as ranked by people who knew nothing of Finland’s internal politics, tended to have been the more successful — the effect was larger for women than for men.

“To those that have, shall be given,” The Economist

According to new research by Bruce T. Lahn and Sarah Tishkoff, microcephalin and ASPM, two genes involved in determining the size of the human brain, have undergone substantial evolution in the last 60,000 years.

The researchers studied the worldwide distribution of the two genes’ alleles by decoding the DNA of the microcephalin and ASPM in many different populations.

With microcephalin, a new allele arose about 37,000 years ago, although it could have appeared as early as 60,000 or as late as 14,000 years ago. About 70% of people in most European and East Asian populations carry this allele of the gene, but it is much rarer in most sub-Saharan Africans.

With ASPM, a new allele emerged about 5,800 years ago (14,000 to 500 years ago). The allele has attained a frequency of about 50% in populations of the Middle East and Europe, is less common in East Asia, and is found at low frequency in some sub-Saharan Africa peoples.

The ASPM allele emerged about the same time as the spread of agriculture in the Middle East 10,000 years ago and the emergence of the civilizations of the Middle East some 5,000 years ago.

Dr Tishkoff said the statistical signature of selection on the two genes was “one of the strongest that I’ve seen.”

“Brain May Still Be Evolving, Studies Hint,” by Nicholas Wade

For a couple of years, researchers (Ray Fisman, Sheena Iyengar, Itamar Simonson, and Emir Kamenica) ran a speed-dating experiment at a local bar just off the Columbia campus.

Subjects were asked to rate their partners’ intelligence, looks, and ambition after each meeting. Each event had between 10 and 20 daters of each gender, and in the course of the evening, every man met every woman and vice versa.

The researchers collected data on thousands of decisions made by more than 400 daters from Columbia University’s graduate and professional schools.

They found that men put significantly more weight on their assessment of a partner’s beauty, when choosing, than women did.

Intelligence ratings were more than twice as important in predicting women’s choices as men’s. Men tended to prefer women whom they rated as relatively smart and ambitious but they avoided women whom they perceived to be smarter and more ambitious than themselves.

When women were the ones choosing, the more intelligence and ambition the men had, the better.

Women of all races (white, black, East Asian, and Hispanic) revealed a strong preference for men of their own race. But a woman’s race had little effect on the men’s choices.

The researchers found no evidence of a white male preference for East Asian women. But did find that East Asian women did not discriminate against white men (only against black and Hispanic men). So the white man-Asian woman pairing was the most common form of interracial dating. Daters of both sexes from south of the Mason-Dixon Line revealed much stronger same-race preferences than Northern daters.

“An Economist Goes to a Bar,” by Ray Fisman

If the decision to vote is based in part on genetics, James H. Fowler reasoned, identical twins should behave more alike than fraternal twins, because identical twins share all of their DNA, whereas fraternal twins share only half on average.

The researchers matched data from the Southern California Twin Registry with publicly accessible electronic voter registration and turnout records from Los Angeles County. Their analysis of voting histories for 326 identical and 196 fraternal twins suggests that genetics was responsible for 60% of differences in voting turnout between twin types.

Fowler also investigated a larger, more nationally representative database from the National Longitudinal Study of Adolescent Health, or Add Health. This study not only asked if participants voted but also inquired about participation in other political activities, such as whether they contributed to campaigns or attended political rallies or marches. The researchers’ data on 442 identical and 364 fraternal Add Health twins indicate that genetics underlies 72% of differences in voting turnout and roughly 60% of differences in other political activity. Preliminary results from the Twins Days festival in Twinsburg, Ohio, also support the findings.

Fowler hypothesizes that the drive to vote or participate in politics may be linked with genes underlying more ancient behaviors, such as innate dispositions toward cooperation.

Robert Plomin analyzed Fowler’s data, and concluded that genetics was responsible for 40%, not 60%, of differences in voting turnout between twin types. 40% is also the average estimate of heritability seen in twin studies of personality.

Evan Balaban cautions that about two thirds of identical twins share the same bloodstream while fetuses, so greater similarities between twins could be attributable not only to sharing genes but to sharing more similar levels of hormones and other compounds each fetus produces during development.

“The Genetics of Politics,” Scientific American