Progress Daily

In every society at all historical times, men’s tendency to commit crimes and other risk-taking behavior rapidly increases in early adolescence, peaks in late adolescence and early adulthood, rapidly decreases throughout the 20s and 30s, and levels off in middle age.

The same age profile characterizes every quantifiable human behavior that is public (i.e., perceived by many potential mates) and costly (i.e., not affordable by all sexual competitors). The relationship between age and productivity among male jazz musicians, male painters, male writers, and male scientists is essentially the same as the age-crime curve. Their productivity quickly peaks in early adulthood, and then equally quickly declines throughout adulthood. The age-genius curve among their female counterparts is much less pronounced; it does not peak or vary as much as a function of age.

Both crime and genius are expressions of young men’s competitive desires, whose ultimate function in the ancestral environment would have been to increase reproductive success.

“Ten Politically Incorrect Truths About Human Nature,” by Alan S. Miller Ph.D., Satoshi Kanazawa Ph.D.

In a study of East Asians, Europeans and Africans, Jonathan Pritchard found 700 regions of the genome where genes (some of which are active in the brain) appear to have been reshaped by natural selection in recent times.

In East Asians, the average date of these selection events is 6,600 years ago.

The genetic changes occurred around the same time as the beginning of the Neolithic revolution, when societies switched from wild to cultivated foods, such as rice.

“Since it looks like there has been significant evolutionary change over historical time, we’re going to have to rewrite every history book ever written,” said Gregory Cochran. “The distribution of genes influencing relevant psychological traits must have been different in Rome than it is today. The past is not just another country but an entirely different kind of people.” 

John McNeill said that “human nature is not a constant” and that selective pressures have probably been stronger in the last 10,000 years than during any other epoch.

Oxytocin increases a person’s level of trust, at least in psychological experiments, & these levels are known to be under genetic control in other mammals.

In societies where trust pays off, generation after generation, the more trusting individuals should have more progeny and the oxytocin-promoting genes would become more common. If conditions should then change, and the society be engulfed by strife and civil warfare for generations, oxytocin levels might fall as the paranoid produced more progeny.

Napoleon Chagnon for many decades studied the Yanomamo, a warlike people who live in the forests of Brazil and Venezuela. He found that men who had killed in battle had 3 times as many children as those who had not. Since personality is heritable, this would be a mechanism for Yanomamo nature to evolve and become fiercer than usual.

“The Twists and Turns of History, and of DNA,” by Nicholas Wade

The largest contributor to happiness is the genetically determined set point (or set range). According to KM Sheldon, Sonja Lyubomirsky and David Schkade (Pursuing Happiness, 2003),”The set point likely reflects immutable interpersonal, temperamental and affective personality traits, such as extraversion, arousability and negative affectivity, that are rooted in neurobiology,… are highly heritable… and change little over the lifespan.”

Current estimates suggest that this genetically determined set range accounts for around 50% of an individual’s happiness.

In general, married, well paid, secure, healthy and religious believers are more likely to report themselves as being happy.

Ed Diener and Shigehiro Oishi (Money and Happiness, 2000) surveyed 7167 students across 41 countries. Those who valued love more than money reported far higher life satisfaction scores than those who seemed to be money focused.

The correlations between such variables as money, job security, marriage, etc. and happiness are relatively small. Sheldon et al argue that in total all circumstances account for only around 10% of the variations in people’s happiness.

Schkade and Daniel Kahneman (”Does living in California make people happy?“) show that whilst “living in California” was an appealing idea for many Americans, it didn’t actually boost long run happiness. That is to say, people living in California were about as happy as other Americans on average. So whilst moving may provide a temporary increase in happiness, it is soon adapted into the perception of the “norm.”

David Blanchflower and Andrew Oswald (Money, Sex and Happiness, 2004) find that sexual activity enters strongly into happiness equations.

People are happiest when they achieve their aims, so set yourself goals which stretch you, but are achievable.

“If It Makes You Happy,” by James Montier

In 1956, the average teenager’s weekly income/allowance was $10.55, equal to the disposable income of a family in the early 1940s.

About 10% of burials in NYC in 1889 were in potter’s fields. In 1900, 1.75 million children between the ages of 10 and 15 — almost 1/5 of all children in that age cohort — were in the work force. Children provided 1/4 to 1/3 of the incomes for working-class families, which spent more than 90% of their household earnings on food, shelter and clothing. In 1900, Americans spent nearly twice as much on funerals as on medicine, and less than 2% of Americans took vacations.

By the end of the ’50s, the number of Americans enrolled in colleges exceeded the number of US farmers.

A 1962 Gallup poll found that only 10% of mothers hoped their daughters would emulate the choices they had made in their lives.

More than two-thirds of women who turned 18 during the ’50s claimed to have slept with only one man by their 30th birthday. Compared to only 2% of women who reached adulthood during the ’70s.

“Land of Plenty,” George F. Will’s review of Brink Lindsey’s The Age of Abundance

Men with higher levels of serum testosterone (T) have lower-status occupations, as indicated by archival data from 4,462 military veterans in six U.S. census occupational groups. Higher T, mediated through lower intellectual ability, higher antisocial behavior, and lower education, leads away from white-collar occupations. T levels are heritable and available early enough to affect a number of paths leading to occupational achievement. Prior research has related testosterone to aggression in animals and men, and high levels of testosterone presumably evolved in association with dominance in individual and small-group settings. Ironically, T, which evolved in support of a primitive kind of status, now conflicts with the achievement of occupational status.

T has been associated with dominance (Mazur 1985), aggression (Bernstein, Rose & Gordon 1974; Rose 1978), antisocial behavior (Dabbs & Morris 1990), sensation seeking (Daitzman & Zuckerman 1980), automaticity and perseverant responding (Broverman et al. 1964; van Hest, van Haaren & van de Poll 1989), libido (Morris et al. 1987; Sherwin, Gelfand & Brender 1985), and low verbal intelligence.

“Testosterone and Occupational Achievement” by James M. Dabbs Jr.

A study published in Psychological Science has found a link between a set of genes involved with immune function and mate selection in humans.

Vertebrate species and humans are inclined to prefer mates who have dissimilar MHC (major histocompatibility complex) genotypes, rather than similar ones. This preference may help avoid inbreeding between partners, as well as strengthen the immune systems of their offspring through exposure to a wider variety of pathogens.

The study investigated whether MHC similarity among romantically involved couples predicted aspects of their sexual relationship. “As the proportion of the couple’s shared genotypes increased, womens’ sexual responsivity to their partners decreased, their number of extra-pair sexual partners increased and their attraction to men other than their primary partners increased, particularly during the fertile phase of their cycles,” says Christine Garver-Apgar, author of the study.

This is the first to show that compatible genes can influence sexual relationships.

“New Study is First to Link Romantic Relationships to Genes,” by Sean Wagner

A survey released on January 23, 2007, by Prince & Associates in collaboration with Hannah Grove found that 70% of today’s multimillionaires said being wealthy gave them “better sex.” (You can request a free copy via email here.) A majority also said wealth gave them “more adventurous and exotic” sex lives.The survey polled nearly 600 men and women with net worths of more than $30 million and a mean net worth of $89 million. The survey polled men and women who were the financial “principals,” meaning they were the primary decision makers in their households.

More than 80% of both the men and women surveyed were married, although the women’s wealth was independent of their husbands’. Nearly 3/4 of the women surveyed (about 150) said they’d had affairs, compared to about 50% of the men. While the male numbers are in keeping with findings for the broader American population, the figure for women is almost twice as high as the national average. More than 1/2 of all the men and women surveyed had been divorced at least once.

63% of rich men said wealth gave them “better sex,” which they defined as having more-frequent sex with more partners. That compares to 88% of women who said more money gave them better sex, which they defined as “higher quality” sex.

The women in the survey were almost twice as likely than their male counterparts to have “more adventurous and exotic” sex lives than they did before they were wealthy. 72% of the female respondents said they were “mile-high-club” members (meaning they’ve had sex on an airplane), compared to 33% of the men. (All the survey respondents owned jets or shares in jets.)

“The Rich Libido,” by Robert Frank

Daniel Gilbert has found that we overestimate the intensity and the duration of our emotional reactions to future events. On average, bad events prove less intense and more transient than test participants predict. Good events prove less intense and briefer as well.

One experiment of Gilbert’s had students in a photography class at Harvard choose two favorite pictures from among those they had just taken and then relinquish one to the teacher. Some students were told their choices were permanent; others were told they could exchange their prints after several days. As it turned out, those who had time to change their minds were less pleased with their decisions than those whose choices were irrevocable. This experiment challenges our common assumption that we would be happier with the option to change our minds when in fact we’re happier with closure.

Another study asked whether transit riders in Boston who narrowly missed their trains experienced the self-blame that people tend to predict they’ll feel in this situation. They did not. This experiment demonstrates that we tend to err in estimating our regret over missed opportunities.

And a paper waiting to be published, ‘’The Peculiar Longevity of Things Not So Bad,‘’ shows our failure to imagine how grievously irritations compromise our satisfaction. Our emotional defenses snap into action when it comes to significant problems, such as a divorce or a disease, but not for lesser problems.

Tim Wilson: ‘’We don’t realize how quickly we will adapt to a pleasurable event and make it the backdrop of our lives. When any event occurs to us, we make it ordinary. And through becoming ordinary, we lose our pleasure.'’

Wilson and Gilbert and others have shown that we’re generally unable to recognize that we adapt to new circumstances and therefore fail to incorporate this fact into our decisions.

A large body of research on well-being seems to suggest that wealth above middle-class comfort makes little difference to our happiness. And having children does nothing to improve well-being — and it drives marital satisfaction dramatically down. We often yearn for a roomy, isolated home (a thing we easily adapt to), when, in fact, it will probably compromise our happiness by distancing us from neighbors. (Social interaction and friendships have been shown to give lasting pleasure.)

In a recent experiment, George Loewenstein tried to find out how likely people might be to dance alone to Rick James’s ‘’Super Freak'’ in front of a large audience. Many agreed to do so for a certain amount of money a week in advance, only to renege when the day came to take the stage. This gets at the fundamental difference between how we behave in ‘’hot'’ states (those of anxiety, courage, fear, drug craving, sexual excitation and the like) and ‘’cold'’ states of rational calm. We cannot seem to predict how we will behave in a hot state when we are in a cold state.

Data from tests in which volunteers are asked how they would behave in various ‘’heat of the moment'’ situations — whether they would have sex with a minor, for instance, or act forcefully with a partner who asks them to stop — have consistently shown that different states of arousal can alter answers by astonishing margins. ‘’These kinds of states have the ability to change us so profoundly that we’re more different from ourselves in different states than we are from another person,'’ Loewenstein says.

Loewenstein has done a great deal of work showing that nonpatients overestimate the displeasure of living with the loss of a limb, for instance, or paraplegia.

“The Futile Pursuit of Happiness” by Jon Gertner

Some good genes can’t be passed on.

Female flies that pick mates “fitter” than themselves have very little chance of passing that fitness on to their daughters, and the same goes for males that mate with women fitter than themselves: sons born from such a union are actually less fit than sons born to low-fitness ladies. In the genetic war between the sexes, genes that are good for one sex aren’t necessarily good for the opposite-sex children who inherit them. Alison Pischedda and Adam K. Chippindale discovered this by forcing fruit flies to have sex in various combinations of fit and unfit. Fitness was measured by how many offspring a fly could have.

Conventional wisdom holds that sexual selection is usually good for a species: it creates babies that are stronger, prettier, fitter, since sexual creatures tend to be attracted to mates who are fit in one way or another.

But Pischedda and Chippindale found that seeking out the perfect mate can be detrimental to offspring.

It turns out that certain fitness genes shared by male and female flies on the X chromosome express themselves differently depending on sex. So a gene on a male’s X chromosome might make him an incredibly prolific father, but that same gene expressed in his daughter would prevent her from reproducing in large numbers. Because males only pass along their Y chromosome to male babies, they never pass along their beneficial X genes to sons either.

Pischedda and Chippindale speculate that these genes are acting selflessly. They’re keeping the population diverse. Imagine if fit parents bred only fit children. If their children inherited the fitness gene, they would also spawn lots of children, and so on.

By cutting off fitness after one generation, we’re guaranteed a population whose genes come from a wide variety of sources. If Pischedda and Chippindale are right, sometimes genes work for the good of the species rather than the good of individuals.

Interestingly, the fittest fruit flies come from parents who are not very fit themselves.

“When sex sucks” by Annalee Newitz

In comparing differences between the sexes, researchers use a statistical measure called d. This indicates how far apart the averages of two groups (in this case men and women) are, taking into account the range of values that contribute to each average. The value of d for adult height is around 2. There is no arguing that in any given population men, on average, are taller than women. For behavioral and psychological phenomena, a value of d greater than 0.8 is considered large, of 0.5, moderate, and of 0.2, small. Any d less than 0.2 is a negligible difference.

Janet Hyde collected all the important meta-analyses that have been conducted on differences between the sexes. (Pdf file here.) (A meta-analysis combines many studies by treating the result of each as a single piece of data for statistical purposes.) Of the 124 effect-sizes she calculated, 30% had a value of d close to zero and in a further 48% of cases, d was small.

The largest gaps were in physical attributes such as throwing velocity (d=2.14) and throwing distance (d=1.98). And sexuality — for example, frequency of masturbation (d=0.96) and attitudes about sex in a casual relationship (d=0.81). Men and women reported the same degree of sexual satisfaction.

On average men were physically more aggressive (d=0.6). But a study done in 1994 hints that if women think nobody is watching and judging them, and there are no physical consequences, they might be more aggressive than men.

In this study, participants played a video game in which they defended themselves from attackers, and the number of bombs they chose to drop was a measure of aggression. When participants thought they were known to the experimenter and were having their performance assessed, men dropped more bombs than women did. But when those same participants were given the impression that they were anonymous, women became the more enthusiastic bombers.

Women have as many, or more, angry thoughts as men. In a study carried out in 2004, Robin Simon and Leda Nath found no difference between the sexes in the reported frequency of incidents of feeling angry over a period of time. However, women tended to report anger that was more intense and prolonged.

Nicole Hess and Edward Hagen read study participants, who were undergraduate students, an “aggression-evoking scenario.” They were told they had just overheard a physically smaller classmate of the same sex making false and serious attacks on their reputation to a teacher. Women usually said that they would get their own back with gossip. Men were more evenly divided, with roughly half wanting to punch the slanderous classmate.

In animals such as humans, where there is a lot of maternal care, females find physical aggression less affordable. Research suggests that girls find such indirect or social aggression much more hurtful than boys do.

Males and females of any age are equally good at computation and at understanding mathematical concepts. However, after their mid-teens, men are better at problem solving than women are.

Males also have better spatial abilities than females. If asked to imagine rotating a three-dimensional object, a skill useful in engineering, the difference is quite large (d=0.73 and 0.56 in different studies). The limited evidence available suggests the difference is related to the post-birth testosterone surge in boys. Women who were exposed to high levels of testosterone in the womb do not do noticeably better in spatial-rotation tasks.

Men and women are equally good at navigating. Women tend to rely on remembering landmarks, whereas men rely on their geometric skills to work out direction and distance.

There are relatively few women professors of math and science, yet there is little or no difference in average ability. A study of IQ, covering everyone born in Scotland in 1932, showed that there were more women in the middle of the distribution, but more men at both of the extremes — both more idiots and more prodigies.

Spatial ability is amenable to training in both sexes. The difference between the trained and the untrained has a d value of 0.4, and one programme to teach spatial ability improved the retention rate of women in engineering courses from 47% to 77%.

“The mismeasure of woman,” The Economist