Progress Daily

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

Givers are happier people than non-givers. According to the Social Capital Community Benchmark Survey, a survey of 30,000 American households, people who gave money to charity in 2000 were 43% more likely than non-givers to say they were “very happy” about their lives.

Similarly, volunteers were 42% more likely to be very happy than non-volunteers. It didn’t matter whether gifts of money and time went to churches or symphony orchestras — givers to all types of religious and secular causes were far happier than non-givers.

According to the University of Michigan’s Panel Study of Income Dynamics, people who gave money away in 2001 were 34% less likely than non-givers to say that they had felt “so sad that nothing could cheer them up” in the past month. They were also 68% less likely to have felt “hopeless,” and 24% less likely to have said that “everything was an effort.”

15% of Americans donate blood at least once each year.

According to the National Opinion Research Center’s General Social Survey, in 2002, 43% of the American adults who gave blood 2 to 3 times during the year said they were very happy versus only 29% of those who did not give blood.

Researchers have conducted experiments in which people are queried about their happiness before and after — sometimes long after — they participate in a charitable activity, such as volunteering to help children or serving meals to the poor. The result: giving has a causal impact on happiness.

In one 1998 experiment at Duke University, adults were asked to give massages to babies — the idea being that giving a baby pleasure is a compassionate act with no expectation of a reward, even a “thank you” — in return. After they performed the massages, the seniors were found to have dramatically lower levels of the stress hormones cortisol, epinephrine, and norepinephrine in their brains.

“Why Giving Makes You Happy,” by Arthur Brooks

Humans have spent most of their time as hunter-gatherers — from at least 85,000 years ago to the birth of agriculture around 73,000 years later.

Human height shrank by nearly six inches after the first adoption of crops in the Near East.

Farmers also had more skeletal wear and tear from the hard work, their teeth rotted more, they were short of protein and vitamins and they caught diseases from domesticated animals: measles from cattle, flu from ducks, plague from rats and worms from using their own excrement as fertiliser.

From the !Kung in the Kalahari to the Inuit in the Arctic and the aborigines in Australia, two-thirds of modern hunter-gatherers are in a state of almost constant tribal warfare, and nearly 90% go to war at least once a year. Usually around 25-30% of adult males die from homicide. The warfare death rate of 0.5% of the population per year that Lawrence Keeley calculates as typical of hunter-gatherer societies would equate to 2 billion people dying during the 20th century.

Richard Wrangham says that chimpanzees and human beings are the only animals in which males engage in co-operative and systematic homicidal raids. The death rate is similar in the two species.

Constant warfare was necessary to keep population density down to one person per square mile. Farmers can live at 100 times that density.

Notice a close parallel with the industrial revolution. The urban poor were overworked and underfed. But 18th-century rural England was a place where people starved each spring as the winter stores ran out, and where where the “putting-out” system of textile manufacture at home drove workers harder for lower pay than the factories would. The industrial revolution caused a population explosion because it enabled more babies to survive.

There is no longer much doubt that hunter-gatherers were the cause of the extinction of the megafauna in North America 11,000 years ago and Australia 30,000 years before that.

At first, modern humans around the Mediterranean relied almost entirely on large mammals for meat. Then they switched their attention to smaller animals, and especially to warm-blooded, fast-breeding species, such as rabbits, hares, partridges and smaller gazelles. The archaeological record tells this same story at sites in Israel, Turkey and Italy.

Human population densities were growing too high for the slower-reproducing prey such as tortoises, horses and rhinos. Only the fast-breeding rabbits, hares and partridges, and for a while gazelles, could cope with such hunting pressure. This trend accelerated about 15,000 years ago as large game and tortoises disappeared.

The belief that hunter-gatherers have plenty of free time turns out to be a bit of a myth. The measurements of time spent getting food by the !Kung omitted food-processing time and travel time, partly because the anthropologists gave their subjects lifts in their vehicles and lent them metal knives to process food.

Even 40,000 years ago, technology and lifestyle were in a state of continuous change, especially in western Eurasia. By 34,000 years ago people were making bone points for spears, and by 26,000 years ago they were making needles. Harpoons, bone spear throwers, and string appeared 18,000 years ago.

15,000 years ago people first domesticated another species — the wolf. 12,000 years ago came agriculture.

Just as we rebounded from the extinction of the megafauna and became even more numerous by eating first rabbits then grass seeds, so in the early 20th century we faced starvation for lack of fertiliser when the population was a billion people, but can now look forward with confidence to feeding 10 billion on less land using synthetic nitrogen, genetically high-yield crops and tractors.

“Noble or savage?,” The Economist

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

Only a decade after their commercial introduction, genetically modified (”GM”) crops are now cultivated in 22 countries on an area more than 4 times the size of Britain, by over 10 million farmers, of whom 9 million are resource-poor farmers in developing countries, mainly India and China. Most of these small-scale farmers grow pest-resistant GM cotton. In India, production tripled last year. GM cotton benefits farmers because it reduces the need for insecticides, thereby increasing their income and improving their health.

Every academy of science — the Indian, Chinese, Mexican, Brazilian, French and US academies as well as the UK’s Royal Society — has confirmed that there is no evidence of risk to human health from GM crops. In 2001, the research directorate of the EU commission released a summary of 81 scientific studies financed the EU, and conducted over a 15-year period: none found evidence of harm to humans or to the environment.

Researchers at PG Economics studied the global effects of GM crops (”Global Impact of Biotech Crops“), and concluded that the “environmental impact” of pesticide and herbicide use in GM-growing countries had been reduced by 15% and 20% respectively. Energy-intensive cultivation is being replaced by no-till or low-till agriculture. More than a 1/3 of the soya bean crop grown in the US is now grown in unploughed fields. Apart from using less energy, avoiding the plough improves soil quality, causes less disturbance to life within it and diminishes the emission of methane and other greenhouse gases. The study concluded that “the carbon savings from reduced fuel use and soil carbon sequestration in 2005 were equal to removing 4m cars from the road….”

James Lovelock has estimated that if all farming became organic, we would only be able to feed 1/3 the present world population.

“The real GM food scandal,” by Dick Taverne