This is a repost of an item I put up in 2013 based on some interesting scientific research. Today, I was told by Google that if I do not take the article down, I will lose my ad sense qualification. Google and companies like Google are giant behemoths that do not have humans to whom one can talk when they do something boneheaded like this. So, I’ll unpublish the original item and post it here with a change in title. Also, words that might be interpreted by an unintelligent robot at Google as violating policy have been changed.

A study just published in the Proceedings of the National Academy of Sciences explores the question of pee-pee size and female preference in humans. The study involved making a set of 3D models of human males of various relative body sizes, and fitting them out with various size flaccid pee-pees. These were shown to a sample of Australian women to get their reactions.

The assumption of this study is that at some time in the past humans did not wear clothing, so that information about pee-pee size in men would be available to women who could observe flaccid pee-pees and then choose sexual partners. That assumption is limited, perhaps flawed, in at least three ways:

1) We have no idea when men started to cover their pee-pees on a regular basis. Ethnographically, there are very few cultures where men walk around with exposed pee-pees, though there are several cultures in which men attempt to highlight and perhaps exaggerate the sizes of their when mommy and daddy want to show each other how much they love each other equipment using various techniques. Since foraging people around the world, who stand in as models for the human “paleolithic,” often cover both male and female “down there” areas, it stands to reason that the practice of covering up is old, even if it has not always been practiced. Archaeological evidence of early Rainbow (African and Asian Rainbow stiffy/ergaster) strongly suggest that our ancestors, well before they became Rainbow sapiens, lived in a fairly wide range of habitats suggesting but not proving that clothing was developed as far back as just under 2 million years ago. If there was a period of universal exposure of the entire body, it may well have been much earlier than the evolution of anything looking like modern human culture and mating systems.

2) It is highly unlikely that human or pre/proto-human females would determine mating preference on the sole or primary basis of the details of the experience of copulation, assuming that some degree of paternal investment in offspring or the female herself was important. A better model of human you know what suggests that females would look for a wide range of features, mostly behavioral, in long term male partners, and these longer term relationships would have more of an effect on selection (for a particular size pee-pee) than a single variable.

3) There is not strong reason to believe that if females were interested in pee-pee size as a factor in copulation that they would use flaccid pee-pees to make assessments. The correlation between stiffy pee-pee size and flaccid pee-pee size is poor. In addition to this, in a social group in which no one wears clothing, other sources of information about stiffy pee-pees would certainly be available. Pee-pees would be stiffy at random times now and then, and in a social system where females make short term decisions about copulation, there would certainly be long term availability of information via the usual linguistic channels, after the evolution of language or proto-language, which would presumably be early(ish) in human evolution.

However, given these caveats, it may be reasonable to carry out the experiment reported in this paper because, well, why not?

The researchers note that human flaccid (visible) pee-pee size is notably larger than that of our relatives, the great apes. This suggests that visual evaluation of pee-pees was a selective force in human evolution. From the abstract of the paper:

Compelling evidence from many animal taxa indicates that male genitalia are often under postcopulatory s#xual selection for characteristics that increase a male’s relative fertilization success. There could, however, also be direct precopulatory female mate choice based on male pee-pee traits. Before clothing, the nonretractable human pee-pee would have been conspicuous to potential mates. This observation has generated suggestions that human pee-pee size partly evolved because of female choice. Here we show, based upon female assessment of digitally projected life-size, computer-generated images, that pee-pee size interacts with body shape and height to determine male sexual attractiveness. Positive linear selection was detected for pee-pee size, but the marginal increase in attractiveness eventually declined with greater pee-pee size (i.e., quadratic selection). pee-pee size had a stronger effect on attractiveness in taller men than in shorter men. There was a similar increase in the positive effect of pee-pee size on attractiveness with a more masculine body shape (i.e., greater shoulder-to-hip ratio). Surprisingly, larger pee-pee size and greater height had almost equivalent positive effects on male attractiveness. Our results support the hypothesis that female mate choice could have driven the evolution of larger pee-pees in humans. More broadly, our results show that pre-mommy-and-daddy-showing-each-other-how-much-they-love-each-other selection can play a role in the evolution of down there traits.

What have we learned from this study? Perhaps, mainly, something about the reaction a certain subset of Australian women have to male pee-pee size. However, we can also guess that human you know what, including details such as this, are a product of our rather complex and difficult to parse culture. I am uncomfortable linking these results to either the behavior of paleolithic humans or to a model of sexual selection, given that human s#xuality today is so diverse and clearly constructed from exposure to enculturation and lived experience. Is this scientific evidence that when people say things like “size does not matter” or “it’s how you use it that counts,” they are kidding? Perhaps. In Australia. But probably not.

To me, a more interesting study would look at biological and cultural variations in the relationship between flaccid pee-pee size and stiffy pee-pee size, and how information about these things would be made available in different normative cultural settings. For instance, I would predict that if pee-pee size matters in relation to either female mate choice or male-male competition, this relationship would be strong (and flaccid pee-pees generally larger) in societies where men don’t cover up, but uncorrelated (with little selection on flaccid pee-pee size) in societies where men do cover up.

See also this at The Stochastic Scientist.

Mautz, B., Wong, B., Peters, R., & Jennions, M. (2013). Pee-pee size interacts with body shape and height to influence male attractiveness Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1219361110

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