Eating your own placenta. Some people (many of them celebrities) claim that it is a miracle cure-all, helping a new mother overcome everything from postpartum depression to low milk production. But is there actually any proof to these claims? Not that pro-placentophagers (we just made that word up) will likely care, but according to this meta-analysis of the literature, there is little scientific proof for any of these health claims. More specifically, the authors conclude that “studies investigating placenta consumption for facilitating uterine contraction, resumption of normal cyclic estrogen cycle, and milk production are inconclusive.” Sorry, Matthew McConaughey.
“Postpartum women are consuming their placentas encapsulated, cooked, and raw for the prevention of postpartum depression (PPD), pain relief, and other health benefits. Placentophagy is supported by health advocates who assert that the placenta retains hormones and nutrients that are beneficial to the mother. A computerized search was conducted using PubMed, Medline Ovid, and PsychINFO between January 1950 and January 2014. Keywords included placentophagy, placentophagia, maternal placentophagia, maternal placentophagy, human placentophagia, and human placentophagy. A total of 49 articles were identified. Empirical studies of human or animal consumption of human placentas were included. Editorial commentaries were excluded. Animal placentophagy studies were chosen based on their relevance to human practice. Ten articles (four human, six animal) were selected for inclusion. Read More
Think about yawning. Yawn yawn yawn… yawn. Have you yawned yet? If so, it’s probably because you come from a social species. Contagious yawning, unlike spontaneous yawning (the purpose of which might be related to cooling the brain), seems to be related to social coordination and empathy. This type of yawning has only been observed in a handful of animals (for example, dogs may be able to catch human yawns), but never in a non-mammalian species..until now, that is! Here, researchers show that budgerigars (aka parakeets), a social bird species, are able to catch each other’s yawns. These findings lend further support to the idea that contagious yawning serves a social function. (And they also happen to be pretty adorable!)
Experimental evidence of contagious yawning in budgerigars (Melopsittacus undulatus)
“Experimental evidence of contagious yawning has only been documented in four mammalian species. Here, we report the results from two separate experimental studies designed to investigate the presence of contagious yawning in a social parrot, the budgerigar (Melopsittacus undulatus). Read More
Let’s face it–anger is a very real part of everyday life these days. And evidence is piling up that it has very real effects on our health. But how is that evidence gathered? How do researchers collect well-controlled data on how anger changes our physiology? Well, one way is by experimentally inducing anger. And to do that, it sounds like these researchers may have just taken a tip from one of those companies well known for their lack of customer service: “In the harassment condition, EXP2 entered the room after the first minute of the task, claiming that the task should be started over, since the measurements pointed out that the subject did not perform properly. It was stressed that the subject should concentrate and sit still, or otherwise, things would go wrong again. After every next minute of the task, a standardized harassing comment was made through the intercom at an irritated tone, like: ‘can you not sit still now, we have lost time already,’ or ‘it is not going very well; push the button again.’” Yup… that would do it!
“It was investigated whether an angry state, induced by a computer task with harassing comments [see above], would lead to a decrease in cold pressor pain threshold and tolerance in comparison to a neutral situation. It was hypothesized that an increase in cardiovascular activity might partially mediate effects of anger. Furthermore, it was examined whether subjects given the opportunity to express anger would show reduced cardiovascular activity and pain report compared to subjects not given this opportunity.Finally, trait measures for anger expression style and hostility were included. Read More
Yup, you guessed it–according to this case study, a woman was found to have an extra nipple… in her vulva! And guess what else? It produced milk! Although extra nipples aren’t all that common, they usually can be found along the “milk line” (the imaginary line on a person’s torso that correlates with the line between multiple pairs of nipples on other mammals). But extra nipples have also been reported on other places, like the foot. So this extra nipple is unusual for its location. But what makes it really special is that it actually produced milk. It turns out that most extra nipples don’t come with much breast tissue, much less the capacity for milk formation. However, because of the risk of malignancy, this extra nipple was removed after it was diagnosed.
Supernumerary nipple presenting as a vulvar mass in an adolescent: case report
“BACKGROUND: Ectopic breast tissues can be found along the embryonic mammary ridges and can occur in the vulva. While ectopic breast tissue is not uncommon, functional breast with overlying nipple located within the vulva is exceedingly rare. Read More
Facebook. People either love it or hate it. But one thing we can all agree on is that it sucks up a lot of time for a lot of people. Sure, it can be an easy way to keep in touch with large number of friends and family members, but what effect does Facebook have on those who spend hours a day on the site? Well, according to the authors of this study, Facebook has real emotional effects on users…and they aren’t good. The researchers kept in touch with study participants, texting them 5 times per day (!) to find out how they felt, while also keeping track of their Facebook use. Turns out that the participants felt worse and had less life satisfaction after increases in Facebook use. Something to think about before sharing this on Facebook (although we hope you do anyway!).
“Over 500 million people interact daily with Facebook. Yet, whether Facebook use influences subjective well-being over time is unknown. We addressed this issue using experience-sampling, the most reliable method for measuring in-vivo behavior and psychological experience. Read More
When it comes to the evolution of human traits, there’s no issue quite as hot as the “purpose” of the female orgasm. Is it under evolutionary selection, or is it just a developmental byproduct of the all-important male orgasm? Well, according to these authors, if the female orgasm has been selected for, one would expect rates of orgasm to correlate with behaviors related to “fitness”– which in this context doesn’t mean how much you can bench press, but rather how likely it is that your lineage will live on. To test this idea, they gathered information from thousands of Australian twins and looked for possible correlations. It turns out that none of the fitness traits they looked for had a strong correlation with how many orgasms the twins had. Based on their premise, this suggests that female orgasm has not been evolutionarily selected for. But hey, absence of proof isn’t proof of absence!
“Introduction. The criteria for “female orgasmic disorder” (FOD) assume that low rates of orgasm are dysfunctional, implying that high rates are functional. Evolutionary theories about the function of female orgasm predict correlations of orgasm rates with sexual attitudes and behavior and other fitness-related traits.
Aim. To test hypothesized evolutionary functions of the female orgasm.
Methods. We examined such correlations in a community sample of 2,914 adult female Australian twins who reported their orgasm rates during masturbation, intercourse, and other sexual activities, and who completed demographic, personality, and sexuality questionnaires.
Main Outcome Measures. Orgasm rates during intercourse, other sex, and masturbation.
Results. Although orgasm rates showed high variance across women and substantial heritability, they were largely phenotypically and genetically independent of other important traits. We found zero to weak phenotypic correlations between all three orgasm rates and all other 19 traits examined, including occupational status, social class, educational attainment, extraversion, neuroticism, psychoticism, impulsiveness, childhood illness, maternal pregnancy stress, marital status, political liberalism, restrictive attitudes toward sex, libido, lifetime number of sex partners, risky sexual behavior, masculinity, orientation toward uncommitted sex, age of first intercourse, and sexual fantasy. Furthermore, none of the correlations had significant genetic components.
Conclusion. These findings cast doubt on most current evolutionary theories about female orgasm’s adaptive functions, and on the validity of FOD as a psychiatric construct.”
NCBI ROFL: Attractiveness of blonde women in evolutionary perspective: studies with two Polish samples.
NCBI ROFL: Are there different types of female orgasm?
NCBI ROFL: Ovulatory cycle effects on tip earnings by lap dancers: economic evidence for human estrus?
If you bite your tongue or stub your toe, your first instinct is probably to yell. But have you ever wondered why that is? According to this study, being vocal could actually help you tolerate the pain. Here, the authors tested how long subjects could keep their hands immersed in very cold water before they couldn’t take it anymore. The researchers found that saying “ow” during the experiment increased the subjects’ tolerance for pain, but hearing a recording of their own voice or someone else’s voice saying “ow” did not. These results are consistent with a previous study that found that swearing is also an effective way to increase pain tolerance; both studies suggest that the vocalization helps distract you from the pain and could be related to an evolutionarily-preserved “flight-or-flight” response.
“Vocalizing is a ubiquitous pain behavior. The present study investigated whether it helps alleviate pain and sought to discern potential underlying mechanisms. Participants were asked to immerse one hand in painfully cold water. On separate trials, they said “ow,” heard a recording of them saying “ow,” heard a recording of another person saying “ow,” pressed a button, or sat passively. Compared to sitting passively, saying “ow” increased the duration of hand immersion. Read More
Have you ever wondered what exactly is inside your belly button? Well, besides the lint (which is mostly derived from actual lint), there is a whole ecosystem of microorganisms that call the navel their home. The authors of this study used DNA sequencing to identify these organisms, determining that the belly button microbiome is dominated by a few common members (see excerpt below), but the remaining species are diverse. The most surprising result, however, was the discovery of two different types of Archaea (a domain of single-celled organisms often found in extreme environments such as hot springs and not previously reported on human skin) from “an individual who self-reported not having showered or bathed for several years.” Talk about an “extreme environment”– I just feel sorry for whoever had to swab that person’s belly button!
“The belly button is one of the habitats closest to us, and yet it remains relatively unexplored. We analyzed bacteria and arachaea from the belly buttons of humans from two different populations sampled within a nation-wide citizen science project. We examined bacterial and archaeal phylotypes present and their diversity using multiplex pyrosequencing of 16S rDNA libraries. Read More
Rye bread is not for everyone — while it goes great with pastrami, it’s a strong flavor that some people choose to avoid. Well, according to this study, there might be a genetic basis to whether you are a rye person or a…uh…white (bread) person. By studying bread preferences in a large group of Danish and Finnish twins, the authors found that there seems to be a moderate genetic influence on bread preference, with around 20-40% of variation in taste preferences being explained by genetics. While it’s difficult to adequately control for all of the other explanations for why twins may or may not prefer the same type of bread, the authors claim that shared environment growing up is not sufficient to explain the correlations they see. I’ll toast to that!
“Bread is an elementary part of the western diet, and especially rye bread is regarded as an important source of fibre. We investigated the heritability of eating bread in terms of choice of white and rye bread and use-frequency of bread in female and male twins in Denmark and Finland. Read More
The “typical” DUI pullover goes something like this: you get pulled over, the cop conducts a field sobriety test, and you either pass or fail. But what if things go a little differently? What if you try to run? Or you get into a fistfight with a cop? Can the weapons at the police officer’s disposal potentially make you fail, even if you *are* sober? Well, thanks to these scientists, and the pain endurance of their volunteers, we now know! To find out, the volunteers underwent a standardized field sobriety test before and after one of five unpleasant scenarios: five-seconds of zapping with an electrical weapon; a 100-yard sprint; 45-seconds of fighting; a bite from a police dog; or pepper spray in the face. Turns out, after all of that rigamarole, none of these seemed to make a difference to the outcome of the test. But maybe there’s a silver lining; perhaps future officers will use this paper itself as a field sobriety test– it has enough shorthand to make it understandable only to a teetotaler!
“INTRODUCTION: When a law enforcement officer (LEO) stops a suspect believed to be operating (a vehicle) while impaired (OWI), the suspect may resist or flee, and the LEO may respond with force. The suspect may then undergo a Standardized Field Sobriety Test (SFST) to gauge impairment. It is not known whether resistance, fleeing, or actions of force can create an inaccurate SFST result. We examined the effect of resistance, fleeing, and force on the SFST. Read More