Music’s Evolutionary Role In Sexual Selection

Music poses a conundrum for evolutionary theorists because it seems to have no apparent adaptive value. But why does this concern exist with only one form of art amongst the plethora that includes, say, sculpture, poetry, or juggling?

The reason is that music involves a dedicated neural wiring that seems to fill no other purpose than to allow people to sing, play, and make sense of discrete pitch, harmony, and isochronous rhythm. Most art forms, as well as skillful behaviors in general, exploit general abilities that can be applied to many things. Not so with music. Add in the fact that musical ability is heritable, a human universal, and follows a narrow set of structural constraints across virtually all known indigenous cultures around the world, in spite of their apparent but superficial differences, and it becomes hard indeed to explain it away as a cultural artifact.

To cut a long story short, there are about a half-dozen plausible explanations for the existence of music, including attachment to the pre-verbal infant, social bonding, or perhaps helping us express or regulate emotions. It might also be an offshoot of some other faculty, known as a spandrel in the evolutionary psychology community. Entire conferences have been dedicated to the connection between language and music, arguing that one developed before the other, and the other profited from the first (their order of appearance is still a matter of debate). However, remaining murky questions include why neither isochrony nor a small set of fixed pitches are employed in language, and what could have motivated the wide-spread practice of music, given that it serves no practical purpose other than enjoyment.

Here, we tested an explanation based on sexual selection, with songbirds as the prime model. Female songbirds choose a mate based on the proficiency and intensity of his song, even though singing for hours per day exposes him to predators and reduces the time used for finding food. Sexual selection means that one sex prefers features of the other sex that may not be favored by natural selection.

Still, the preference for the debilitating and biologically expensive (but beautiful) tail of the peacock may still lead to greater fitness (many offspring) since the peahen “holds the keys” to that fitness, so to speak. Could it be the same with music, in that our predisposition for it was developed as a means to quickly and reliably communicate to females that a male has excess resources to spend on a totally useless (but beautiful) costly signal?

In all mammals, the female invests more biological resources in the offspring. According to the so-called parental investment theory, this should lead to a range of predictions, most of which relate to sex differences. Two of them are that women would value men’s musical skill relatively higher than men would women’s and that this sex difference would be more pronounced when evaluating a person one is likely to have a child with.

To this end, an experiment was conducted in which people were shown an image of a face at the same time as they heard someone play the drums, saxophone, or violin, and were told that it was played by the person in the image. In reality, the same faces occurred with music played with more or less skill in three levels from beginner to expert. The higher the skill, both men and women generally rated a person of the opposite sex as more attractive, in terms of having sex, a short or long relationship, or going on a date. Musical skill also lead to higher ratings of intelligence, health, and social status, but not parenting skill.

The critical result, however, is that this increase was significantly higher when women rated men than when men rated women. Specifically, the difference between medium and high skill made men more desirable for a long relationship but not for sex, a date, or short-term relationship (all less likely to produce children in the modern world), while there was no such effect on women’s desirability. Similarly, women rated high-skilled men as more intelligent, healthy, and of higher social status, whereas musical skill did not increase men’s ratings of women in these regards.

These results are consistent with and do not refute the hypothesis that music evolved as a costly signal of fitness. This idea cannot ultimately be proven but can be made more or less likely by laying a mosaic of interlocking facts and observations, both from real life, behavioral and genetic studies¹, as well as experiments, like the present one.

Directly related to this study, it needs to be shown whether the effects of music skill are larger or different from other skills and features that also affect social status, which is a central variable in women’s mate choice, be it poetry, cooking, or downhill skiing, or perhaps intelligence or wealth, bearing in mind that these respondents might simply have used music skill as a proxy for intelligence. Whereas this study looked at the evaluation side, it is important to also look at the performance side, for example, whether men become significantly more motivated than women to learn, perform, or exhibit musical skills when single, or as a function of testosterone levels².

Music is such an important part of most people’s lives today and yet remains such a conundrum from an evolutionary perspective. Knowing more about it could have implications for the quality of life and even for its therapeutic applications (see [3] for a few examples).

These findings are described in the article entitled Musical improvisation skill in a prospective partner is associated with mate value and preferences, consistent with sexual selection and parental investment theory: Implications for the origin of music, recently published in the journal Evolution and Human Behavior. This work was conducted by Guy Madison, Jakob Holmquist, and Mattias Vestin from Umeå University.

References:

1. Mosing, M., Verweij, K., Madison, G., Pedersen, N. L., Zietsch, B., & Ullén, F. (2015). Did sexual selection shape human music? Testing hypothesis of music evolution using a genetically informative sample of over 10,000 twins. Evolution & Human Behavior, 36(5), 359-366. doi:10.1016/j.evolhumbehav.2015.02.004
2. van der Linden, D., Dutton, E., Dunkel, C., & Madison, G. (2018). National-Level Indicators of Androgens are Related to the Global Distribution of Scientific Productivity and Science Nobel Prizes. Journal of Creative Behavior. doi:10.1002/jocb.351
3.  Theorell, T., Madison, G., & Ullén, F. (2018). Associations between musical aptitude, alexithymia, and working in a creative occupation. Psychology of Aesthetics, Creativity, and the Arts.
4. Ramji, R., Aasa, U., Paulin J., & Madison, G. (2016). Musical information increases physical performance for synchronous but not asynchronous running. Psychology of Music, 44(5), 984-995. doi:10.1177/0305735615603239
5. Theorell, T., Lennartsson A.-K., Madison G., Mosing M.A., & Ullén F. (2015). Predictors of continued playing or singing – from childhood and adolescence to adult years. Acta Pediatrica, 104(3), 274-284. doi:10.1111/apa.12870
6. Wallert, J. & Madison, G. (2014). Recovery after aerobic exercise is manipulated by tempo change in a rhythmic sound pattern, as indicated by autonomic reaction on heart functioning. Frontiers in Human Neuroscience, 8, 738. doi:10.3389/fnhum.2014.00738
7. Vasionyte, I. & Madison, G. (2013). Musical intervention for patients with dementia: A meta-analysis. Journal of Clinical Nursing. 22, 1203-1216. doi: 10.1111/jocn.12166
8. Madison, G., Paulin, J., & Aasa, U. (2013). Physical and psychological effects from supervised music exercise. American Journal of Health Behavior, 37(6), 780-793. doi:10.5993/AJHB.37.6.7.