Flashback Friday: What can 2,914 Australian twins tell us about the evolution of the female orgasm?

By Seriously Science | May 15, 2015 6:00 am

Photo: flickr/Martina Rathgens

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!

Female Orgasm Rates are Largely Independent of Other Traits: Implications for “Female Orgasmic Disorder” and Evolutionary Theories of Orgasm.

“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.”

Related content:
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?

CATEGORIZED UNDER: scientist..or perv?, Sex & Mating

On the purpose of saying “ow” when you hurt yourself.

By Seriously Science | May 13, 2015 12:36 pm
Photo: flickr/Mark Lee

Photo: flickr/Mark Lee

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. 

On the Importance of Being Vocal: Saying “Ow” Improves Pain Tolerance

“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

CATEGORIZED UNDER: feelings shmeelings, told you so

Flashback Friday: Here’s a list of what’s currently living in your belly button.

By Seriously Science | May 8, 2015 9:18 am
Photo: flickr/zeevveez

Photo: flickr/zeevveez

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!

A Jungle in There: Bacteria in Belly Buttons are Highly Diverse, but Predictable

“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

CATEGORIZED UNDER: analysis taken too far

Hate rye bread? According to this study, you can blame your genes.

By Seriously Science | May 5, 2015 10:08 am
Photo: flickr/Jarkko Lane

Photo: flickr/Jarkko Lane

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!

Twin study of heritability of eating bread in Danish and Finnish men and women.

“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

Can the use of force by police change the outcome of a field sobriety test?

By Seriously Science | May 1, 2015 10:13 am
Image: Flickr/Jeffrey Smith

Image: Flickr/Jeffrey Smith

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!

Effect of simulated resistance, fleeing, and use of force on standardized field sobriety testing.

“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

Tired of getting songs stuck in your head? Try this one weird (and delicious) trick!

By Seriously Science | April 30, 2015 6:00 am
Image: Flickr/Jono Haysom

Image: Flickr/Jono Haysom

Earworms. Ugh. We’ve all had them: songs that won’t go away, rattling on and on and leaving our minds on “repeat” for hours, days, and even weeks. There are a number of ways to help get rid of the bastards once they are stuck in one’s head, but what if there were a way to avoid earworms altogether? Well, these scientists think they found a way out of this sticky situation, by means of another! Apparently, chewing on gum reduces the number of “unwanted musical thoughts.” Chew on that!

Want to block earworms from conscious awareness? B(u)y gum!

“Three experiments examine the role of articulatory motor planning in experiencing an involuntary musical recollection (an “earworm”). Experiment 1 shows that interfering with articulatory motor programming by chewing gum reduces both the number of voluntary and the number of involuntary-unwanted-musical thoughts. Read More

CATEGORIZED UNDER: eat me, rated G

Study finds that people with higher incomes have more sex.

By Seriously Science | April 24, 2015 6:00 am

Photo: flickr/tax credits

This study comes straight out of our new favorite journal, the aptly named International Journal of Manpower. Here, the author set out to determine whether there’s a relationship between how much money a person earns and how much sex they have. From a survey of 7,500 people, he found that workers who have sex 2-3 times per week earn on average 4.5 percent more than workers who have sex less often. The direction of causality is still unclear (do people have more sex because they make more money, vice versa, or perhaps there are cases of each?). All we know for sure is that we are submitting our next paper to the International Journal of Manpower.

The effect of sexual activity on wages

– The purpose of this paper is to estimate whether sexual activity is associated with wages, and also to estimate potential interactions between individuals’ characteristics, wages and sexual activity.

– The central hypothesis behind this research is that sexual activity, alike health indicators and mental well-being, may be thought of as part of an individual’s set of productive traits that affect wages. Using two-stage estimations the author examines the relationship between adult sexual activity and wages.
Read More

Want to feel happier? Just smell a happy person’s BO!

By Seriously Science | April 21, 2015 6:00 am
Photo: flickr/littlelovemonster

Photo: flickr/littlelovemonster

Smelling someone’s stinky body odor can really bum you out, at least temporarily. But did you know that BO can communicate emotions directly? According to this study, human body odor may contain chemicals, also known as “chemosignals”, that can carry information about emotional states. To test this hypothesis, the researchers evoked emotions in 12 men by showing them movie clips to make them either happy (e.g., “Bare Necessities” from The Jungle Book), afraid (e.g., clips from Schindler’s List and Scream 2), or neutral (e.g., American weather forecasts). During each condition, the researchers collected sweat from the shaved armpits of the subjects. Later, they asked female subjects to smell the sweat samples, and they measured electrical impulses produced by facial muscles to track the womens’ facial expressions. Turns out that women smelling the “happy sweat” had happier expressions (including smiles) compared with those smelling neutral or fearful sweat (the latter of which elicited a fearful expression). So there you have it — to get a boost of happiness, just find the happiest person in the room and take a whiff!

A Sniff of Happiness

“It is well known that feelings of happiness transfer between individuals through mimicry induced by vision and hearing. The evidence is inconclusive, however, as to whether happiness can be communicated through the sense of smell via chemosignals. Read More

Study examines why dog owners don’t always clean up their pooch’s poop.

By Seriously Science | April 16, 2015 6:00 am
Image: Flickr/David Swayze.

Image: Flickr/David Swayze.

“Sh*t happens.” And, if you’re a regular walker, your shoes (and nose!) are probably very aware that much of it is due to dogs. But how do dog owners normally handle the doodoo? We will let Professor Gross, the author of this poop-tastic study, introduce the topic in his own (very well chosen) words:

“To be sure, at first glance, dog walking seems straightforward. Walk the dog, let it poop, then walk the dog home. But this simple description raises a fundamental question: why it is that the poop falling out of the dog is not taken care of, and if it is, how exactly is this done?”

To undertake this worthwhile endeavor, the author used his daily to commute to carefully study the habits of dog owners: while walking to the train station, he watched what they did (or didn’t do!) with their dog’s poops, and he recorded his observations during the following train ride. Over six months he collected data from hundreds of dog defecations. The results? Well, it turns out that people have three main strategies for coping with canine crap. First, the (terrible, no good, and just plain horrible… not that we judge) dog owner may decide to pretend to not have seen the dog poop, and just leave it there. Secondly, the owner may bag the poop, but randomly drop it on the ground, or tie it to a fence (see the figure from the paper below… WTF?). And thirdly, the (awesome, love-worthy and honorable) owner might bag the poop and properly dispose of it in a trash can. And not everyone consistently does the same thing; dog owners are apparently much more likely to choose option number 3 if someone else is watching. If you find poop funny (and who doesn’t!?!), we highly recommend checking out the witty and well-written full text!

Natural waste: canine companions and the lure of inattentively pooping in public.

“The most organized and regulated societies in Europe have a comparatively high density of pet dogs per inhabitant. Contrary to the general trend in Western societies towards raising standards of hygiene in everyday life, pedestrian areas and urban parks tend to be dog fouling hotspots. Unlike other nonhuman animals, pet dogs are often walked to public places for the sole reason to defecate. Read More

CATEGORIZED UNDER: fun with animals, ha ha poop

This professor measured his fingernail growth for 35 years. The results will amaze you!

By Seriously Science | April 13, 2015 6:00 am

Image:Flickr/Shannon Kringen

Image:Flickr/Shannon Kringen

Have you ever wondered how fast your fingernails grow? And whether they all grow at the same rate? Or perhaps you’ve noticed that your fingernails grow more slowly than they used to? If so, you and William B. Bean have something in common! Professor Bean painstakingly measured the growth of his fingernails for decades, and he published the minutia of these measurements after 20, 25, 30 and 35 years. The full texts of these papers are a delight to read. And the findings? Well, we’ll let Professor Bean speak for himself! (Be sure to check out the fantastically detailed chart of his fingernail growth rates below…)
“When I first began to measure the rate of nail growth, I scored marks on all my nails. Within a few months I found that each nail had its own pace. This was clearly distinguishable even by the rather crude method that I used. Some nails grew rapidly; some, in an intermediate phase, less rapidly; and some, slowly. The differences were small but regular. There was consistency in the variation, so if I applied a ratio I could tell by measuring one nail what the others were doing, and this I did on several occasions. In simple terms, toenails grow more slowly than nails of the hand, and the nail of the middle finger grows more rapidly than the nails of either the thumb or the little finger or the other two middle fingers.”

Nail growth. Thirty-five years of observation.

“A 35-year observation of the growth of my nails indicates the slowing of growth with increasing age. The average daily growth of the left thumbnail, for instance, has varied from 0.123 mm a day during the first part of the study when 1 was 32 years of age to 0.095 mm a day at the age of 67.” Read More


Seriously, Science?

Seriously, Science?, formerly known as NCBI ROFL, is the brainchild of two prone-to-distraction biologists. We highlight the funniest, oddest, and just plain craziest research from the PubMed research database and beyond. Because nobody said serious science couldn't be silly!
Follow us on Twitter: @srslyscience.
Send us paper suggestions: srslyscience[at]gmail.com.

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