Advancements in the evolution of the female orgasm

Male orgasm is pretty easy to figure out. Without it, there is no insemination, so evolutionarily if you can’t get off you can’t make babies. Pretty straight forward.

The female orgasm however is more of a mystery. It is unclear why it occurs (and to some, unclear HOW it occurs).

So the recent research on the evolutionary origin of the female orgasm in The Journal of Experimental Zoology… earth shattering.

Read about the results over at the New York Times!


The evolution of human facial diversity

Signalling individual identity is critical in many aspects of human social interaction (click for video!).

We all rely on our ability to recognize other people’s faces to get along in the world. Most people don’t think too hard about this, it’s so fundamental to our existence. But it turns out that in order to stand out in the crowd, you need to be, well different. A recent study shows that human faces are in fact, much more different from one another than other traits, and suggests that this high facial diversity has evolved specifically to signal individual identity. It’s a pretty interesting story, and I look forward to digging into the details.

Check out this NatGeo piece on the work, and the original publication (paywalled).

Literature Cited:
Sheehan, Michael J., and Michael W. Nachman. “Morphological and population genomic evidence that human faces have evolved to signal individual identity.” Nature Communications 5 (2014).

Skeptical that PMS is an adaptive response designed to break up your relationship? Me too.

In a pleasantly surprising turn of events, this week a take-down of some dubious evolutionary psychology was published by the popular media!  The original article, a perspective piece published in Evolutionary Applications, claims that moodiness associated with PMS may have historically served an adaptive role by driving infertile couples apart. 

Premenstrual syndrome (PMS) affects up to 80% of women, often leading to significant personal, social and economic costs. When apparently maladaptive states are widespread, they sometimes confer a hidden advantage, or did so in our evolutionary past. We suggest that PMS had a selective advantage because it increased the chance that infertile pair bonds would dissolve, thus improving the reproductive outcomes of women in such partnerships. We confirm predictions arising from the hypothesis: PMS has high heritability; gene variants associated with PMS can be identified; animosity exhibited during PMS is preferentially directed at current partners; and behaviours exhibited during PMS may increase the chance of finding a new partner. Under this view, the prevalence of PMS might result from genes and behaviours that are adaptive in some societies, but are potentially less appropriate in modern cultures. Understanding this evolutionary mismatch might help depathologize PMS, and suggests solutions, including the choice to use cycle-stopping contraception.

Check out the response, published by The Daily Beast, here:

Here’s the scapegoat unhappy spouses have been waiting for: According to a paper out last week by Michael R. Gillings, premenstrual syndrome (PMS) can ruin a marriage. Gillings claims that PMSing women—in infertile couples in particular—may use feelings of “animosity” as well as risk-seeking and competitive behaviors to leave their husbands and find someone new. I’m sorry to say, but the evidence in favor of this hypothesis is thinner than Always Infinity menstrual pads.