Before I started college, there was a sudden rage amongst my male friends. A rage for one specific thing. Not phones or computers or cars or clothes. Nope. It was for a guitar. Most of the guys I knew, in the year or two before college, suddenly became obsessed with the guitar, picking out melodies, trying to match still changing warbling voices to a hopefully tuned instrument.

I couldn't figure it out. What was up with the guitar obsession?! Some of these people were people who never had displayed a musical bent their entire lives, and here they were, sitting experimentally on the benches outside my school with guitars in hand.

Finally, I asked my brother (who also, of course, had taken up the guitar), why every guy seemed to want to play the guitar. Why not the cello or the piano or the trombone or the kazoo? My brother rolled his eyes at my denseness.

"For the GIRLS, of course"

Charlton, et al. "Do Women Prefer More Complex Music around

Ovulation?" PLoS ONE, 2012

(And yes, specifically, they ALL wanted to play this song. I would hypothesize that about 80% of the men I know can pick out this song on the guitar. Considering that a substantial portion of the female populace does indeed have brown eyes, I realize the efficiency of this method, but for those of us with non-brown eyes, this song is IRRITATING BEYOND BELIEF. This has been a public service announcement.)

My brother was right (there, I said it), but he might have been more wise than he knew. After all, what IS the evolutionary point of music?

Is it to summon forest animals with our dulcet tones (to then turn and feast upon them?)

(This is my own personal hypothesis)

Or is it for social group cohesion? Mother-child bonding? Or is it really all to get the chicks?

And it turns out that there is indeed a mate-getting hypothesis for the evolution of music. The idea goes like this:

1. there are sex differences in musical processing.

2. Men like to make music, even when women are allowed to make music (this part gets me no end. Why on earth would women making music prevent men from doing so?!). Female performance in music listening varies during the menstrual cycle.

3. Making music requires some skills, like manual dexterity, creativity, rhythm, etc, which might be useful in a mate.

So humans must have evolved to make music because dudes wanted to attract the ladies with their sexy songs.

I have some issues with this particular hypothesis, but I'll get back to those at the end of the post. The authors of this study were interested in seeing whether this sexy song hypothesis was true. Specifically, they hypothesized that if humans had evolved to make music for males to attract females, then several things would have to be true:

a. females would be attracted to more complex songs than males

b. females would be most attracted to the most complex songs during the time they were most susceptible for mating, in other words, they would prefer the more complex songs during ovulation.

To test this, the authors took 40 women of reproductive age who were not taking hormonal contraceptives. They had them listen to six stages of musical complexity, generated by a computer program.

(You can hear the audio samples with the supporting information, here)

The authors had them listen to the musical strains during low and high fertility portions of their cycles.

The participants had to rate how complex they thought the music was, and how much they liked it.

You can see on the left the complexity rankings. The rankings clearly increased once you got to level 3 or so (which seems to me that we are not very sensitive to complexity in a single solo line). But on the right, you can see the measure of how much they liked the music, based on the menstrual cycle phase. There is no difference. In general, the women liked the higher complexity music more, but it did not vary as a function of lower or higher fertility.

What does this mean? It means that this study does not support the idea of complex music making as a sexual selection strategy. Or rather, it does not support the idea that women prefer more complex music around ovulation. They could, for example, prefer more complex music all the time, for the same reason of sexual selection.

One of the things that always amuses me about people who study evolutionary psychology, mate selection in humans, etc, is how defined we apparently are by a single point in time. That point in time is ovulation, the point at which the women must be wooed and won to get the babymakin' on. And this makes me wonder. Ovulation is a pretty small slice of the time. And it's not in sync with other women and not explicitly signaled by our bottoms turning extra red, so you never know when it's happening. Yet, somehow, all the evo psych comes down to is about how women are most susceptible to x, y, or z at the time of ovulation. Dang, do we really think women only want to be impressed once a month? Sure, in theory you only have to get them to head into the bushes with you for a minute, but I mean, if it's all about providing for the kids and being a good long term partner and high quality mating prospect, wouldn't it be a good idea to impress us ALL the time? And given the social aspects of human development, just taking a girl off for five minutes and leaving her with the kids wouldn't be good social capital, the long term seems much more logical. I do not understand why all people who study this seem to feel that ovulation is the only time during which females need to be impressed.

But this study shows that ovulation time doesn't matter, in terms of music liking, at least. Of course, there are loads of caveats. This was computer generated music, not a human voice. The emotionality of the music was missing. The sound of music in itself is not a song sung directly to you. There are tons of other measures of male attractiveness that may carry a lot more weight than their ability to carry a tune or strum a guitar.

There's also one part of the original hypothesis that bothers me: the idea that, if men make music even though women can also make music...this must mean that there's a sexually selected reason for it. Why? What is the logical step here? If both men and women create music, doesn't this provide more fodder for the group cohesion idea than sexual selection? I admit I don't get this part of the hypothesis.

But I'm still glad to see this study for one particular reason: negative data.

Technically, this data is negative. They showed a significant effect of complexity, but the hypothesis was not upheld. Often, data like this is tossed in the back of a filing cabinet, never to be seen again. The difficulty of getting it published is too high, most journals only want flashy, significant results. But negative data is incredibly important. It is just as important to know what doesn't work as it is to know what does. And without published negative data, you may very well end up doing the same experiments over and over, dozens of labs discovering the same negative result, wasting time and effort. So I'm very glad that PLoS ONE is around, and willing to publish this kind of study.

Charlton BD, Filippi P, & Fitch WT (2012). Do Women Prefer More Complex Music around Ovulation? PloS one, 7 (4) PMID: 22558181