Narcissism levels have been increasing among Western youth, and contribute to societal problems such as aggression and violence. The origins of narcissism, however, are not well understood.

Here, we report, to our knowledge, the first prospective longitudinal evidence on the origins of narcissism in children. We compared two perspectives: social learning theory (positing that narcissism is cultivated by parental overvaluation) and psychoanalytic theory (positing that narcissism is cultivated by lack of parental warmth).

We timed the study in late childhood (ages 7–12), when individual differences in narcissism first emerge.

In four 6-mo waves, 565 children and their parents reported child narcissism, child self-esteem, parental overvaluation, and parental warmth. Four-wave cross-lagged panel models were conducted.

Results support social learning theory and contradict psychoanalytic theory: Narcissism was predicted by parental overvaluation, not by lack of parental warmth. Thus, children seem to acquire narcissism, in part, by internalizing parents’ inflated views of them (e.g., “I am superior to others” and “I am entitled to privileges”).

Attesting to the specificity of this finding, self-esteem was predicted by parental warmth, not by parental overvaluation.

{ PNAS | Continue reading }

Japan’s House Foods Group Inc. said it has developed onions that release extremely low amount of tear-inducing compounds. […]

[T]he resulting onions have the added benefit of not leaving a strong smell on the cook’s hands or the breath of those who eat them.

{ WSJ | Continue reading }

related { 1,000-year-old onion and garlic eye remedy kills MRSA }

art { Max Bill, untitled, 1967 }

The sexual selection concept arises from the observation that many animals had evolved features whose function is not to help individuals survive, but help them to maximize their reproductive success. This can be realized in two different ways:

• by making themselves attractive to the opposite sex (intersexual selection, between the sexes), or
• by intimidating, deterring or defeating same-sex rivals (intrasexual selection, within a given sex).

Thus, sexual selection takes two major forms: intersexual selection (also known as ‘mate choice’ or ‘female choice’) in which males compete with each other to be chosen by females; and intrasexual selection (also known as ‘male–male competition’) in which members of the less limited sex (typically males) compete aggressively among themselves for access to the limiting sex. The limiting sex is the sex which has the higher parental investment, which therefore faces the most pressure to make a good mate decision.

For intersexual selection to work, one sex must evolve a feature alluring to the opposite sex, sometimes resulting in a “fashion fad” of intense selection in an arbitrary direction. Or, in the second case, while natural selection can help animals develop ways of killing or escaping from other species, intrasexual selection drives the selection of attributes that allow alpha males to dominate their own breeding partners and rivals.

{ Wikipedia | Continue reading }

Canine teeth, horns, claws, and the sheer size and strength of certain male animals provide strong examples of physical weapons, and aggression is a behavioral weapon among humans and other animals. A peacock’s tail, which is useless and costly to sustain, is the most famous example of an ornament. Showing off and creativity may be the human equivalents of this ornamentation. Certain polygynous species, such as the elephant seal, become weapon specialists, relying primarily on intrasexual combat to achieve reproductive success. Other species, such as the peacock and numerous birds of paradise, specialize in intersexual selection to produce extravagant male ornaments. Humans are versatile animals who rely on a large brain to facilitate amassing and facultatively employing a large repertoire of survival and reproductive strategies, including weapons and ornaments.

Even though ancestral men may have used intrasexual combat more than intersexual ornaments in acquiring mates and much human female choice may also have derived from male contests, modern men use both intrasexual and intersexual mating strategies as evidenced by much research showing a clear association between mating motivation and various behaviors that constitute weapons and ornaments in men. Specific weapon-like behaviors under mating investigation include physical or direct aggression in response to provocation, social dominance and status, endorsing warring attitudes, and producing a low voice pitch. The studied ornament-like behaviors include conspicuous material consumption, risk taking, humor, being unique and non-conforming, becoming loss averse, making generous financial donations, and exhibiting heroic altruism, all of which are preferred by women.

These studies suggest that, similar to other male animals, men can exhibit weapon-like and ornament-like behaviors, but, unlike many male animals that specialize in either weapons or ornaments nearly to the exclusion of the other, men seem to have developed the versatility to acquire and apply both strategies to facultatively respond to intrasexual and intersexual competition. Men may use weapons and ornaments facultatively as situational responses to intersexual and intrasexual conditions and, over time, may also develop behavioral tendencies in using one strategy more frequently over the other, adding to the vast individual differences along a weapon-ornament dimension.

{ Evolutionary Psychology | PDF }

photo { Jerry Schatzberg }

15 years ago, the neurosciences defined the main function of brains in terms of processing input to compute output: “brain function is ultimately best understood in terms of input/output transformations and how they are produced” wrote Mike Mauk in 2000.

Since then, a lot of things have been discovered that make this stimulus-response concept untenable and potentially based largely on laboratory artifacts.

For instance, it was discovered that the likely ancestral state of behavioral organization is one of probing the environment with ongoing, variable actions first and evaluating sensory feedback later (i.e., the inverse of stimulus response). […]

In humans, functional magnetic resonance imaging (fMRI) studies over the last decade and a half revealed that the human brain is far from passively waiting for stimuli, but rather constantly produces ongoing, variable activity, and just shifts this activity over to other networks when we move from rest to task or switch between tasks.

{ Björn Brembs | Continue reading }

A group of leading biologists called for a worldwide moratorium on use of a new genome-editing technique that would alter human DNA in a way that can be inherited.

The biologists fear that the new technique is so effective and easy to use that some physicians may push ahead before its safety can be assessed. They also want the public to understand the ethical issues surrounding the technique, [which holds the power to repair or enhance any human gene, and] could be used to cure genetic diseases, but also to enhance qualities like beauty or intelligence.

{ NY Times | Continue reading }

Genome-editing technologies may offer a powerful approach to treat many human diseases, including HIV/AIDS, haemophilia, sickle-cell anaemia and several forms of cancer. All techniques currently in various stages of clinical development focus on modifying the genetic material of somatic cells, such as T cells (a type of white blood cell). These are not designed to affect sperm or eggs. […]

The newest addition to the genome-editing arsenal is CRISPR/Cas9, a bacteria-derived system that uses RNA molecules that recognize specific human DNA sequences. The RNAs act as guides, matching the nuclease to corresponding locations in the human genome.

{ Nature | Continue reading }

photo { Darren Holmes }

related { Genetic Origins of Economic Development }

{ American scientist James Stuckey and volunteer Judy Creeden demonstrate the human body’s ability to function as a conductor of electricity during a lecture in New York sponsored by the Atomic Energy Commission, 1966 | photo by F. Roy Kemp }

8,000 Years Ago, 17 Women Reproduced for Every One Man

[A] member of the research team, a biological anthropologist, hypothesizes that somehow, only a few men accumulated lots of wealth and power, leaving nothing for others. These men could then pass their wealth on to their sons, perpetuating this pattern of elitist reproductive success. Then, as more thousands of years passed, the numbers of men reproducing, compared to women, rose again. “Maybe more and more people started being successful,” Wilson Sayres says. In more recent history, as a global average, about four or five women reproduced for every one man.

{ Pacific Standard | Continue reading }

Our eyes are drawn to several dimensions of an object–such as color, texture, and luminance–even when we need to focus on only one of them, researchers at New York University and the University of Pennsylvania have found. The study, which appears in the journal Current Biology, points to the ability of our visual system to integrate multiple components of an item while underscoring the difficulty we have in focusing on a particular aspect of it.

{ EurekAlert | Continue reading }

photo { George Pitts }

The ability to express empathy — the capacity to share and feel another’s emotions — is limited by the stress of being around strangers, according to a new study.

{ ScienceDaily | Continue reading }

related { People in the study were more likely to disclose something personal about themselves after laughing together, although they didn’t realize it. }

Over a decade ago, psychologist Barry Schwartz published what might be the ultimate psychological life-hacking tome, The Paradox of Choice: Why More Is Less. […]

If you ever aren’t sure if you attended the very best party or bought the very best computer, just settle for “good enough.” People who do this are called “satisficers,” and they’re consistently happier, he’s found, than are “maximizers,” people who feel that they must choose the very best possible option. Maximizers earn more, Schwartz has found, but they’re also less satisfied with their jobs. In fact, they’re more likely to be clinically depressed in general.

The reason this happens, as Schwartz explained in a paper with his Swarthmore colleague Andrew Ward, is that as life circumstances improve, expectations rise. People begin comparing their experiences to peers who are doing better, or to past experiences they’ve personally had that were better. […]

Schwartz’ solution […] just settle for something that’s acceptable—even if you know there’s likely something better out there.

{ The Atlantic | Continue reading }

photo { Jeff Mermelstein, New York City, c. 1993-1997 }

For two years the researchers tracked transactions at a supermarket in America. Perhaps unsurprisingly, shoppers who brought their own bags bought more green products than those who used the store’s bags. But the eco-shoppers were also more likely to buy sweets, ice cream and crisps. Psychologists call this sort of behaviour “moral licensing”: the tendency to indulge yourself for doing something virtuous. […]

A study from 2011 on water-conservation in Massachusetts shows how. In the experiment, some 150 apartments were divided into two groups. Half received water-saving tips and weekly estimates of their usage; the other half served as a control. The households that were urged to use less water did so: their consumption fell by an average of 6% compared with the control group. The hitch was that their electricity consumption rose by 5.6%. The moral licensing was so strong, in other words, that it more or less outweighed the original act of virtue.

{ The Economist | Continue reading }

art { Malcolm Levy }

Imagine a virus wipes out everyone on the planet except [a man]. […] He finds the last woman on Earth. […] Can they repopulate the Earth? To do so, their children would have to mate with one another, or mom and dad, in order to rebuild the human race. All the incestuous taboos aside, is this even genetically possible?

Inbreeding has unfortunate genetic consequences due to the increased inheritance of recessive genes, which can result in neonatal death. Inbred children that survive are at increased risk of congenital birth defects, reduced fertility, smaller size, immune deficiencies, cystic fibrosis, and more. These defects are also likely to be passed on to their children as well. […]

Some real-life examples of the consequences of inbreeding can be found in places where there are restricted breeding opportunities — for example, within monarchies, islanders, or closed societies. Hemophilia was notoriously prevalent in European royal families. Some Amish societies have a larger number of children born with extra digits on their hands or feet. Jews of Eastern European descent tend to have higher rates of a number of genetic diseases, including cystic fibrosis. […]

The net result of inbreeding is that the resulting population loses a diverse genetic portfolio, which means they are less resistant to rare diseases and deformities. The smaller the gene pool, the faster it gets dirty. Such individuals would also have less diverse immune systems, making it much easier for a single germ to wipe them all out. […]

In addition to the genetic landmines, the family would likely have a very difficult time overcoming the innate resistance most species have against inbreeding. Evolution knows that inbreeding is not good for the species, so it engineered a built-in “incest taboo” that creates a strong aversion to such behavior. A devil’s advocate, however, could argue that the biological barrier to familial sex could be overcome through artificial insemination.

What about using a sperm bank? Sperm is stored in liquid nitrogen, so it would stay frozen for a short time after the power goes out. However, you’d have to act fast because no one is around to monitor the storage tanks and top off the liquid nitrogen as it evaporates.

There are practical concerns to consider as well. The last man and woman, as well as their kids, would need to have large numbers of children and, unless one of the founders happens to be a doctor, it is hard to imagine many of these babies surviving in such a world. Even if they (and mom) survive childbirth, there are countless opportunities for them to perish in this type of environment before reaching childrearing age.

{ The Scope | Continue reading }

art { Hilo Chen, Beach 166, 2010 }

Recent studies have shown that women are more sensitive than men to subtle cuteness differences in infant faces. It has been suggested that raised levels in estradiol and progesterone may be responsible for this advantage. […]

Thirty-six women were tested once during ovulation and once during the luteal phase of their menstrual cycle. In a two alternative forced-choice experiment, participants chose the baby which they thought was cuter (Task 1), younger (Task 2), or the baby that they would prefer to babysit (Task 3). […]

During ovulation, women were more likely to choose the cuter baby than during the luteal phase, in all three tasks. These results suggest that cuteness discrimination may be driven by cyclic hormonal shifts.

{ Hormones and Behavior | Continue reading }

art { Henri Chopin, La crevette amoureuse, 1967-1975 }

Scientists are increasingly convinced that the vast assemblage of microfauna in our intestines may have a major impact on our state of mind. The gut-brain axis seems to be bidirectional—the brain acts on gastrointestinal and immune functions that help to shape the gut’s microbial makeup, and gut microbes make neuroactive compounds, including neurotransmitters and metabolites that also act on the brain. […]

Microbes may have their own evolutionary reasons for communicating with the brain. They need us to be social, says John Cryan, a neuroscientist at University College Cork in Ireland, so that they can spread through the human population. Cryan’s research shows that when bred in sterile conditions, germ-free mice lacking in intestinal microbes also lack an ability to recognize other mice with whom they interact. In other studies, disruptions of the microbiome induced mice behavior that mimics human anxiety, depression and even autism. In some cases, scientists restored more normal behavior by treating their test subjects with certain strains of benign bacteria. Nearly all the data so far are limited to mice, but Cryan believes the findings provide fertile ground for developing analogous compounds, which he calls psychobiotics, for humans. “That dietary treatments could be used as either adjunct or sole therapy for mood disorders is not beyond the realm of possibility,” he says.

{ Scientific American | Continue reading }

related { Is Neuroscience Based On Biology? }

[O]ne in six serial killers are female. Their crimes tend to go undetected for longer than their male counterparts, likely in part because “our culture is in denial of women’s proclivity for aggression.”

Harrison and her team have profiled 64 US female serial killers active between the years 1821 to 2008. […] The female serial killers had murdered between them at least 331 victims (making an average of 6 victims each). Their victims are of both sexes, but disproportionately male. The women had an average of age of 32 at the time of their first killing, and poisoning was the most common method. […] “the women in our study poisoned, smothered, burned, choked, shot, bludgeoned, and shot newborns, children, elderly, and ill people as well as healthy adults; most often those who knew and likely trusted them.”

Many of the homicidal women had stereotypically female professions, including being nurses and baby-sitters. They tended to be above average in physical attractiveness, which may have helped to engender trust in their victims.

As to motives, the most common was “hedonistic”, a category in forensic psychology that refers to killing for financial gain, lust or thrill, with nearly half the sample fitting this category. The next most common motive was “power-seeking”, which includes killing people in one’s care. […]

Quotes from some of the killers hint at their psychopathological thinking:

“They [the children] bothered me, so I decided to kill them.”

“I like to attend funerals. I’m happy when someone is dying.”

“That is my ambition, to have killed more people – more helpless people – than any man or woman who has ever lived.”

A striking contrast with male serial killers is the relative absence of sexual violence and deviance. Two exceptions were a female serial killer who was a rapist, and another who reportedly barked like a dog during sex. But overall, the researchers highlighted how the women in their study primarily killed for resources, while their male counterparts kill for sex. This follows evolutionary theory, Harrison and her co-authors explained, in the sense that men are said to be motivated more by seeking multiple sexual opportunities, while women are motivated to find a committed partner with sufficient resources. […]

The new analysis points to a worrying trend: a 150 per cent increase in the number of reported cases of female serial killers since 1975.

{ BPS | Continue reading }

Over the past twenty years, DNA analysis has revolutionized forensic science, and has become a dominant tool in law enforcement. Today, DNA evidence is key to the conviction or exoneration of suspects of various types of crime, from theft to rape and murder. However, the disturbing possibility that DNA evidence can be faked has been overlooked. It turns out that standard molecular biology techniques such as PCR, molecular cloning, and recently developed whole genome amplification (WGA), enable anyone with basic equipment and know-how to produce practically unlimited amounts of in vitro synthesized (artificial) DNA with any desired genetic profile. This artificial DNA can then be applied to surfaces of objects or incorporated into genuine human tissues and planted in crime scenes.

Here we show that the current forensic procedure fails to distinguish between such samples of blood, saliva, and touched surfaces with artificial DNA, and corresponding samples with in vivo generated (natural) DNA. Furthermore, genotyping of both artificial and natural samples with Profiler Plus1 yielded full profiles with no anomalies. In order to effectively deal with this problem, we developed an authentication assay, which distinguishes between natural and artificial DNA based on methylation analysis of a set of genomic loci: in natural DNA, some loci are methylated and others are unmethylated, while in artificial DNA all loci are unmethylated.

{ Forensic Science International: Genetics | PDF (2009) }

Psychology journal bans P values

P values are widely used in science to test null hypotheses. For example, in a medical study looking at smoking and cancer, the null hypothesis could be that there is no link between the two. The closer to zero the P value gets, the greater the chance the null hypothesis is false; many researchers accept findings as ‘significant’ if the P value comes in at less than 0.05. But P values are slippery, and sometimes, significant P values vanish when experiments and statistical analyses are repeated. […]

“We believe that the p < .05 bar is too easy to pass and sometimes serves as an excuse for lower quality research,”

{ Nature | Continue reading }

Darwin made a famous distinction between men’s and women’s mating strategies, between choosy, coy females and ardent, promiscuous males. […]

Yet, as also anticipated by both Darwin and Trivers, empirical studies of both non-humans and humans reveal extraordinary flexibility in mating and investment behavior, both within and between the sexes. Reproductive strategies are clearly not an invariant, species-specific characteristic, but rather facultative responses to individual- and population-level social and ecological circumstances, rendering conditional mating strategies optimal. […]

For example, across the ethnographic record, human societies can range from polyandrous to polygynous mating patterns, same-sex marriage can be institutionalized as with woman-to-woman unions in East Africa and men can spend considerable amounts of time and effort in beautifying themselves as in West Africa. […]

Until recently, the study of sex-differentiated reproductive behaviour has relied on the long-standing model of sexual selection developed by Trivers. This model links sex roles directly to the differential investment in young by males and females. In its simplest form, this model posits that because males invest less initially (in sperm), they have a higher potential reproductive rate (PRR) and benefit more from mating multiply than do females. As a consequence, selection typically would favour mate-seeking and competitive behaviour in males, and heavy investment in parental care in females. […]

Using data from eight Makushi communities of southern Guyana, characterized by varying adult sex ratios contingent on migration, we show that even within a single ethnic group, male mating effort varies in predictable ways with the ASR. At male-biased sex ratios, men’s and women’s investment in mating effort are indistinguishable; only when men are in the minority are they more inclined towards short-term, low investment relationships than women.

{ Royal Society Open Science | Continue reading }

Using new data from the United Kingdom’s Annual Population Survey, we find that […] marriage may help ease the causes of the mid-life dip in life satisfaction and that the benefits of marriage are unlikely to be short-lived. We explore friendship as a mechanism which could help explain a causal relationship between marriage and life satisfaction, and find that well-being effects of marriage are about twice as large for those whose spouse is also their best friend.

{ National Bureau of Economic Research | Continue reading }

All galaxies are thought to have supermassive black holes at their center. These start out small—with masses equivalent to between 100 and 100,000 suns—and build up over time by consuming the gas, dust, and stars around them or by merging with other black holes to reach sizes measured in millions or billions of solar masses. Such binge eating usually takes billions of years, but a team of astronomers was stunned to discover what is, in galactic terms, a monstrous baby: a gigantic black hole of 12 billion solar masses in a barely newborn galaxy, just 875 million years after the big bang.

{ Science | Continue reading }

Every 250m years the sun, with its entourage of planets, completes a circuit of the Milky Way. Its journey around its home galaxy, though, is no stately peregrination. Rather, its orbit oscillates up and down through the galactic disc. It passes through that disc, the place where most of the galaxy’s matter is concentrated, once every 30m years or so.

This fact has long interested Michael Rampino of New York University. He speculates that it could explain the mass extinctions, such as that of the dinosaurs and many other species 66m years ago, which life on Earth undergoes from time to time. Palaeontologists recognise five such humongous events, during each of which up to 90% of species have disappeared. But the fossil record is also littered with smaller but still significant blips in the continuity of life.

Many hypotheses have been put forward to explain these extinctions (and the events may, of course, not all have the same explanation). The two that have most support are collisions between Earth and an asteroid or comet, and extended periods of massive volcanic activity. Dr Rampino observed some time ago that cometary collisions might be triggered by gravitational disruptions of the Oort cloud, a repository of comets in the outermost part of the solar system. That would send a rain of them into the part of space occupied by Earth. This has come to be known as the Shiva hypothesis, after the Hindu god of destruction. […]

In his latest paper, Dr Rampino speculates that the real culprit may be not stars, but dark matter—and that this might explain the volcanism as well.

{ The Economist | Continue reading }