RealClearScience Journal Club

Science Figures Interpreted and Analyzed by RealClearScience

A Spider in Madagascar Engages in Oral Sex

Ross Pomeroy - May 2, 2016

Darwin’s bark spiders produce the toughest known silk in the entire world. The stuff is ten times more resistant to breakage than Kevlar! But the arachnids' silk-making prowess rates second to their sexual prowess, apparently. A new study published to Scientific Reports shows that males of the species perform oral sex on females up to 100 times during copulation.

Researchers from the Scientific Research Centre of the Slovenian Academy of Sciences and Arts and the Smithsonian's National Museum of Natural History traveled to Andasibe-Mantadia National Park in Madagascar to get up-close and personal with Darwin's bark spiders, the males of which measure in at roughly 6 millimeters long, while the females stretch about 20 millimeters. The team intently observed 29 separate matings in both the laboratory and the wild. In all instances, the smaller males performed cunnilingus on the vastly larger females. As the authors arousingly described:

"Typically, a performing male first hooked one of his cheliceral fangs to female’s copulatory opening, turned his body perpendicular to the female, then orally secreted fluids into the copulatory openings."

Marvin Gaye couldn't have said it any better.

The researchers suggest two likely hypotheses for the behavior. First, oral sex may signal mate quality -- to the better-skilled and more physically able male go the spoils! Second, enzymes in the males' saliva may render the environment inside the females' genital organs more hospitable to their sperm.

Oral sex is well documented in mammals. Notable givers include macaques, lemurs, bonobos, hyenas, cheetahs, lions, dolphins, bats, and (of course) humans. But throughout the rest of the animal kingdom, the act is not as well known. Male fruit flies lick female genitalia, an action that's rewarded with longer mating bouts. Also, there are spotty reports of oral sex occurring amongst widow spiders.

The researchers also observed bark spiders engaging in other risqué sexual acts, including sexual cannibalism, where the female eats the male, and mate-binding, in which the male envelopes the female in silk to avoid said cannibalism. Believe it or not, these acts weren't nearly as surprising as the oral sex.

Source: Gregorič, M. et al. Spider behaviors include oral sexual encounters. Sci. Rep. 6, 25128; doi: 10.1038/srep25128 (2016).

Raising Income Taxes Won't Fix Wealth Inequality

Ross Pomeroy - April 27, 2016

The top 10% of Americans control roughly three-quarters of the nation's wealth, and the minority of Haves are continuing to accumulate more than the majority of Have-Nots.

This is wealth inequality in the United States. And though it doesn't attract as much attention as income inequality, it's arguably far more important, imposing economic instabilities and social strife.

To decrease wealth inequality, pundits, politicians, and economists often suggest raising income tax rates on top earners to as high as 50, 70, or even 90 percent.

The idea sounds plausible, but according to a new study published to PLoS ONE it probably won't work in practice.

To distill the finding, a team of researchers based out of Tel-Aviv University first developed an algorithm to model wealth inequality in the United States between 1930 and 2010. Primarily based on income from wages, income from wealth (profits, rents, dividends, etc.), and changes in capital value (property, shares, etc.) the resulting model correlated closely (p=.96) with historical data on wealth inequality.

The researchers then used their model to predict the future. What would happen, they wondered, if income inequality was varied? In their model, income inequality was tied to a metric called the Gini index, a statistical measure of inequality used for decades. They found that altering income inequality to a Gini index of 0.1 (very low inequality) resulted in the top 10% controlling 78.6% of wealth in 2030, while raising income inequality to a Gini index of 0.9 (very high inequality) resulted in the top 10% controlling 79.3% of wealth in 2030, hardly a significant difference.

According to the researchers, the lack of effect isn't actually surprising.

"When income tax is increased, the top earners, who are not necessarily the wealthiest individuals in the population, have a larger difficulty of accumulating wealth, with respect to the wealthiest. On the other hand, it barely affects the wealthiest individuals. Therefore, such an increase might even deepen the wealth gap."

"Progressive taxation, which might have a significant effect on the distribution of income, will have a small effect on wealth inequality," they add.

The team behind the current study is not the only group to return such a result. Just last year, experts at the Brookings Institute created their own model and found that increasing the top tax rate from 39.6% to 50% wouldn't even dent income inequality, let alone wealth inequality.

As is the status quo with most economic models, the researchers' model suffers from a couple key limitations. Specifically, it did not address economic mobility, nor did it include inheritance taxes.

Taxes on inheritance and capital gains would likely have more of an impact on wealth inequality, as they directly tax wealth, not income.

Source: Berman Y, Ben-Jacob E, Shapira Y (2016) The Dynamics of Wealth Inequality and the Effect of Income Distribution. PLoS ONE 11(4): e0154196. doi:10.1371/journal.pone.0154196

(AP Photo/Janerik Henriksson, File)

Soccer Players Conveniently 'Get Injured' When Their Team Benefits From It

Ross Pomeroy - April 15, 2016

Watching a soccer match can be very much like watching a sitcom with terrible acting. To gain an advantage and help their team win, players regularly engage in acrobatic, unsporting antics, which may include flamboyantly falling to draw a foul, feigning an injury to waste time, or crying out in pain while clutching their neck after beingly lightly tapped on the shoulder.

Savvy futbol fans, of course, aren't buying it. In Seattle, the 40,000+ Sounders faithful chant in unison, "Let him die!" when they deem the "injured" player to be a faker. Now, a new study published to the journal Frontiers in Psychology has confirmed what Seattle fans -- and all other soccer fans -- suspected: footballers are huge floppers.

Researchers based out of the National University Singapore and the University of Birmingham watched thirty Euro 2008 soccer matches, 90 English Premier League matches and 63 World Cup 2010 matches, charting injuries for each team over the duration of every match. The timing of injuries was divided into six periods: 0-15th minute, 16-30th minute, 31-45th minute (including first-half stoppage time), 46-60th minute, 61-75th minute and 76-90th minute (including second-half stoppage time). The injuries themselves were categorized based upon whether they would benefit or not benefit the team of the injured player. For example, if a player suffered an injury when his team was up by a goal, that would constitute a "benefit" injury, as it would slow the game down and give his teammates a break.

The researchers focused only on consequential games. Thus, forty-nine of the 183 matches were discounted because their outcomes were meaningless in the context of the competition or they were blowouts, in which one team led by three or more goals.

When the researchers tallied and categorized the injuries, the results were clear: Towards the end of a game, players on teams that would benefit from an injury were far more likely to suffer an injury. What a coincidence!

Of course, this is almost certainly not a coincidence -- the players are simply faking their injuries.

The researchers interviewed three anonymous managers in the English Premier League about the obvious tactic.

"None of the three managers admitted to actively instructing players to feign injury but all were somewhat ambivalent in their condemnation of such behaviour," the researchers wrote. "One described it as 'clever', another admitted that players did it, 'to take the steam out of the game' and the third admitted they might tell a player to stay down, 'and take a breather.'"

Source: Derbyshire SW, Angel I and Bushell R (2016). When pain brings gain: Soccer players behaviour and admissions suggest feigning injury to maintain a favourable scoreline. Front. Psychol. 7:613. doi: 10.3389/fpsyg.2016.00613

(AP photo)

Study Reveals Habits of Sexually Satisfied Couples

Ross Pomeroy - April 11, 2016

It's not always easy to keep the passion alive in a long-term relationship, but many couples manage to do it. In a recent study published to The Journal of Sex Research, scientists sought to learn the secrets of partners in sexually satisfying relationships. What do they do that those in sexually dissatisfying relationships do not?

Led by Chapman University Professor David Frederick, the team of researchers examined a massive data set of over 38,000 men and women who reported being in a relationship for at least three years. The subjects completed an in-depth, anonymous survey hosted on NBCNews.com back in 2006, in which they responded to a host of questions about their backgrounds, their relationships, and their sex lives.

From the data, the researchers discovered a number of habits associated with a sexual satisfaction. Men and women in sexually satisfying relationships were far more likely to try new sexual positions, talk dirty during sex, wear titillating lingerie, bathe together, give each other massages, go on romantic getaways, try anal stimulation, use sex toys, and say "I love you" during sex.

Most importantly, sexually satisfied men and women were far more likely to communicate openly about their sexual desires. The vast majority of men and women who said they were dissatisfied with their sex lives indicated that it was important to them to have an exciting sex life, yet over sixty percent of them agreed with the statement, "I feel that my partner doesn’t know how to excite me." That is a problem that can be solved by maintaining an open and honest dialogue about sex.

The survey benefited from its placement on a popular website -- the study group was immense and diverse. However, the study is limited by self-selection -- subjects weren't chosen at random.

During a recent interview on the Savage Lovecast, lead author David Frederick cautioned that the data is correlational. Merely adopting the habits of sexually satisfied couples isn't guaranteed to transform a sexually dissatisfying relationship, but it just might.

"For the dissatisfied couples, it's something they can take a look at and say 'Why don't we try this and see what happens?'"

Source: David A. Frederick, Janet Lever, Brian Joseph Gillespie & Justin R. Garcia (2016): What Keeps Passion Alive? Sexual Satisfaction Is Associated With Sexual Communication, Mood Setting, Sexual Variety, Oral Sex, Orgasm, and Sex Frequency in a National U.S. Study, The Journal of Sex Research, DOI: 10.1080/00224499.2015.1137854

(Image: Shutterstock)

Link Between Exclamation Points and Knowledge

Alex B. Berezow - April 1, 2016

We have noticed a striking (and disturbing) inverse relationship between the use of exclamation points in Internet comments and knowledge of the subject at hand.*

*Note: This is not based on a real study, but it's nonetheless true. Happy April Fools' Day!

When Societies Make Women's Health a Priority, Everyone Benefits

Ross Pomeroy - March 31, 2016

In an exhaustive systematic review published to the journal PLoS ONE, researchers based out of the Chan School of Public Health at Harvard University find that investing in women's health produces economic, societal, and humanitarian benefits that persist for generations.

Kristine Husøy Onarheim, Johanne Helene Iversen, and David E. Bloom scoured a number of databases for research pertaining to "women, health, and economics" published between 1970 and 2013. The trio screened 20,834 papers before eventually settling on 124 relevant, high-quality articles for their review. Pouring through every single study, the reviewers uncovered a great many positive outcomes that come from prioritizing women's health. Here are some highlights:

  • Meeting one-third of the need for family planning in Kenya, Nigeria, and Senegal could increase per capita income in each country by 8 to 13 percent. Meeting all of the unmet need for contraception could result in income gains of 31 to 65 percent.
  • In a study conducted in Tanzania, "children of mothers living in areas with iodine supplementation programs attained an estimated 0.35–0.56 years of additional schooling, compared with children living in areas without supplement programs."
  • The availability of oral contraception in the U.S. is associated with a greater number of women pursuing higher education and professional careers.
  • "Greater access to abortion in the U.S. is associated with higher rates of college graduation, lower rates of single parenthood, and lower odds of welfare receipt."
  • "Poor maternal health is associated with diminished child health, with implications for birth weight, neonatal survival, cognitive development, child behavior, school performance, and adult health and productivity," the reviewers found, and these negative effects can spiral into a vicious cycle (displayed below). Programs that remedy maternal malnutrition and poverty benefit mothers, children, and indeed all of society for decades to come.

The reviewers arrived at four primary conclusions:

"First, healthier women contribute to better-educated and more productive societies. Second, ensuring women’s control over their own fertility can boost the pace of economic growth and development. Third, maternal health is crucial to the health and economic wellbeing of subsequent generations through intergenerational spillovers. Fourth, further study is needed on women’s health and household and societal productivity."

"These results demonstrate the necessity and efficacy of investment in initiatives that address women’s health," the reviewers write. "Societies that prioritize women’s health will likely have better population health overall, and will remain more productive for generations to come."

Source: Onarheim KH, Iversen JH, Bloom DE (2016) Economic Benefits of Investing in Women’s Health: A Systematic Review. PLoS ONE 11(3): e0150120. doi:10.1371/journal.pone.0150120

The Girl Who Injected Herself With Mercury

Ross Pomeroy - March 29, 2016

Silvery, shiny, and the only metal that's liquid at room temperature, Mercury is a mesmerizing element. But despite its entrancing nature, you don't want to inject it into your body. And yet, according to a new case report in BMC Research Notes, that's exactly what a 15-year-old Sri Lankan girl did.

Had the girl known that Mercury is toxic, inhibiting key enzymes that counteract oxidative damage and in turn producing a host of concerning symptoms eventually resulting in death, she probably wouldn't have injected both of her forearms with roughly 2 milliliters of the element. Alas, her unfortunate action was inspired by a movie giving the impression that injecting liquid metal can produce superhuman strength. As she found out, it doesn't.

Thankfully, the girl is alive, well, and almost entirely unscathed by the incident. A week after her ill-advised experiment, her parents brought her to the National Hospital of Sri Lanka with a 3-day history of high fever and a conspicuous rash. These symptoms might have mystified the attending physicians, but luckily, the girl wisely revealed her mercurial exploits of seven days past. A quick x-ray (shown above) confirmed her story, and tests placed her blood mercury levels at fifty times normal levels! Otherwise, she was in good health.

Doctors administered a chelation agent called dimercaprol to expunge the elemental mercury from her bloodstream. The chemical reacts with mercury and coverts it to a compound which can be excreted by the body. They also operated on the girl's forearms to manually remove some of the larger deposits of metal that had accumulated in her muscles, which can be clearly seen in the image below (apologies to the squeamish).

The girl stole the mercury from her science enthusiast father, who kept a small stash for conducting the odd experiment. Thankfully, elemental mercury is not as acutely dangerous as its compounds, such as methyl mercury or mercuric chloride. Still, if the girl had not received treatment when she did, she may have suffered permanent damage to her central nervous system, or even death.

Source: Thanuja Nilushi Priyangika et al. "A rare case of self-injection of elemental mercury." BMC Res Notes (2016) 9:189 DOI: 10.1186/s13104-016-1992-8

Money Makes Men Think Their Partners Are Less Physically Attractive

Ross Pomeroy - March 22, 2016

Money does funny things to the mind. Merely thinking about it can alter perceptions of pain and feelings of social rejection. Thoughts of cash also boost feelings of self-sufficiency, resulting in an increased desire to be independent. Wealth even triggers a response akin to addiction.

As new research published to the journal Frontiers in Psychology shows, money also messes with our minds when it comes to mating. Turns out, if you give a man some money, he'll think his partner is less attractive.

Researchers based out of Beijing Normal University in China invited 182 heterosexual college students (121 women, 61 men) in committed relationships into the lab and primed them to feel either rich or poor using two different forms of a questionnaire about financial status. Afterwards, participants rated their satisfaction with their romantic partners across various attributes, including job prospects, family background, and physical attractiveness. The ratings were completed on a 1 to 9 scale (1 = does not match my ideal at all, 9 = completely matches my ideal). Subjects also answered demographic questions about gender, age, and monthly income.

When the researchers examined the subjects' answers, they found that men primed to feel wealthy were less satisfied with their partners' physical attractiveness than men primed to feel poor. The difference was highly significant, a full point on the 9-point scale. Women did not display any differences.

The study replicates a similar effect seen in a study conducted in 2012. Researchers in Singapore exposed men and women to stacks of paper, a sum of money equal to $84, or a sum of money equal to $2,100, then asked them about their requirements of a potential mate. Men who handled the largest sum of money desired mates who were far more attractive. Women's requirements were unchanged.

According to the researchers behind the current study, both results are in line with expectations of evolved human mating strategies.

"Whereas both men and women prefer an attractive mate, men are more likely to value a mate’s physical attractiveness, which signals a woman’s fertility and reproductive value, than women. On the other hand, women are more likely to attach importance to a mate’s resources than men."

The study was carried out on Chinese college students in dating relationships, so the results may not apply to denizens of the Western world or to married couples. Moreover, just 61 males took part, making sample size a potential issue.

Source: Li YM, Li J, Chan DK-S and Zhang B (2016) When Love Meets Money: Priming the Possession of Money Influences Mating Strategies. Front. Psychol. 7:387. doi: 10.3389/fpsyg.2016.00387

(Image: Shutterstock)

Should We Save 'Endangered' Cultures?

Ross Pomeroy - March 14, 2016

Though hard to imagine for residents of the technologically developed world, there remains hundreds of tribes cut off from global civilization, who, in many ways, live as our ancestors did thousands of years ago. Largely indigenous to forested regions in South America, New Guinea, India, and Central Africa, these native peoples evoke wonder whenever they emerge from their homes in the wilds.

For decades, state and international policy has largely protected these tribes, granting them the right to live their lives in isolation. There's good reason for this. History has taught us that when cultures separated by an ocean of differences come into contact, the results can be disastrous. Disease and misunderstanding can rapidly wreak havoc on a smaller, uncontacted society.

But what if an isolated society is already on the verge of extinction? What then? Is it not global society's moral duty to try to bring them back from the brink of death?

According to a trio of academics, the answer is "yes." Moreover, the team recently published evidence that shows seven different isolated tribes in South America to be critically endangered.

In a recent issue of the journal PLoS ONE, Professor Robert Walker, Dr. Dylan Kesler, and Professor Kim Hill argue that no-contact policies should not ignore the well being of the very societies they are designed to protect.

"If populations are small and declining, or not growing as a result of external threats, then current policy approaches should be deemed ineffective," they write, further contending that well-organized contact is preferable to allowing a unique culture to fade from the Earth forever.

Making their arguments more pressing is new data from aerial surveys and satellites. Walker, Kesler, and Hill examined images from NASA, Google Earth, and DigitalGlobe (among other sources), looking for signs of purposeful forest clearings and human-made fires over the last 10-14 years from eight different uncontacted tribes in Brazil, Peru, Ecuador, and Colombia.

They found that only one ethnicity, the Yaminawa of Brazil, demonstrated clear growth over the study period, with a burgeoning population of 400. All of the other tribes had populations of fewer than 120 individuals and showed no signs of growth.

Threatening these peoples are individuals engaged in dodgy activities like illegal logging, mining, squatting, poaching, and narcotrafficking, who pay no heed to the welfare of isolated societies. Tromping through the rain forest, these miscreants threaten to spread disease and inflict harm upon native peoples.

Walker, Kesler, and Hill argue that well-organized and well-funded efforts to contact critically endangered isolated cultures are vastly preferable to the malicious contact they currently receive. The trio also insists that the desire to leave cultures isolated is misguided.

"In our experiences from interviews with people after contact, there is a unanimous consensus that people stay isolated mostly because of fear of extermination and slavery. People want to trade, particularly for access to steel machetes and axes, and they crave exposure to new ideas and new opportunities. Humans are a gregarious species that intrinsically desire and benefit from outside interactions with other groups."

Source: Walker RS, Kesler DC, Hill KR (2016) Are Isolated Indigenous Populations Headed toward Extinction? PLoS ONE 11(3): e0150987. doi:10.1371/journal.pone.0150987

(Image: Gleilson Miranda / Governo do Acre)

Brain Scans of Dogs Reveal Neural Region Associated with Recognizing Faces

Ross Pomeroy - March 3, 2016

When dogs see human faces, a region of the brain called the temporal cortex becomes activated, a new study published to PLoS ONE shows.

The invention of functional magnetic resonance imaging (fMRI) in the 1990s revolutionized how scientists study the brain. The surprisingly simple technique grants a glimpse inside the skull, allowing researchers to examine blood flow within the brain, which is intimately linked to brain activity. Want to know which regions of the brain are activated in response to varying stimuli? You simply follow the blood. 

For more than three decades, fMRI has fueled a great many studies leading to a number of incredible insights about the human brain. But only recently has the method been adapted to study man's best friend. In 2012, Emory University neuroscientist Gregory Berns trained two dogs, including his own canine companion Callie, to sit still and remain attentive within an fMRI scanner. He then cued the dogs with the indication of a food reward (a delicious hot dog) and watched as an area of their brains called the caudate nucleus "lit up."

In the current study, researchers from the National Autonomous University of Mexico adopted Berns' methods and trained seven dogs -- five Border Collies, one Labrador Retriever and one Golden Retriever -- to sit still in a "sphinx" position within an fMRI scanner, their ears adorably adorned with soft ear muffs to protect them from the loud, startling sounds of the machine.

When each canine's training was complete, the researchers presented the dogs with pictures of either human faces or everyday objects and closely watched the canine's brain activity. While everyday objects did not induce much activity at all, human faces elicited a ton of activity (see figure below), primarily in the bilateral temporal cortex, but also to a smaller extent in the frontal cortex, the caudate nucleus, and the thalamus.

"This portion of the temporal cortex in dogs could be anatomically and functionally similar to regions found in other species, like humans, non-human primates and sheep, which suggests a high degree of evolutionary conservation of the ventral visual pathway for face processing," the researchers write.

"The recognition of human faces by dogs could be an essential factor for establishing attachment with humans," they add.

The experiment confirms a similar study published last year by Berns and his colleagues, which also identified the temporal cortex as a region in dog brains where facial recognition takes place.

Berns' study showed that this activity occurs in response to both human and canine faces. The current study applied a bit more magnification, showing that human faces elicit activity in the caudate nucleus, a region associated with reward. On a neurological level, this could indicate that the relationships dogs have with humans are even more satisfying than the relationships they form with members of their own species.

Source: Cuaya LV, Hernández-Pérez R, Concha L (2016) Our Faces in the Dog's Brain: Functional Imaging Reveals Temporal Cortex Activation during Perception of Human Faces. PLoS ONE 11(3): e0149431. doi:10.1371/journal.pone.0149431

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