The long-standing question of whether the musical tones and scales that humans prefer are happy accidents, biologically determined, or constructed culturally still remains unanswered. Some hypotheses suggest that music has developed based on human physiology and depends on features of human voices and hearing. Others believe that music can be explained mathematically. Still another group of theories argue that music is just a sociocultural construction.
A recent study by Doolittle and colleagues (2014) aims to see what commonalities exist between the musical tones and scales of humans and the songs of animals. The study investigated the singing of Catharus guttatus, commonly known as the hermit thrush (see Hermit Thrush 2009 for an example of thrush songs). This North American species is well known among birders for its songs, but until now, the hermit thrush’s singing has not been rigorously analyzed.
The male hermit thrush is particularly canorous and can sing up to ten different song types that have been observed to overlap with the major, minor and pentatonic scales. American composer Amy Beach (1867-1944) composed two works for piano inspired by the songs of the hermit thrush (see for example Joy Morin Plays Amy Beach: A Hermit Thrush at Morn, Op. 92 No. 2 2011). An early hypothesis was that the thrushes might use resonant frequencies of their vocal tracts to generate a harmonic overtone series similar to the way these are produced in tube-like instruments, but the spectrograms produced in this study showed that this was unlikely (Doolittle et al. 2014, 3). Rather, the authors find that the pitch selection of C. guttatus maps onto the same mathematical formulas that dominate human musical scales. While the findings are not conclusive, one possibility is that the predictability of these kinds of musical scales are easily remembered by male thrushes and can likewise be predicted by females as an “objective yardstick” (Doolittle et al. 2014, 4) for evaluating potential mates.
The findings of this study seem to suggest that human music aesthetics are not accidental or socially constructed. Our musical tastes might depend on certain evolutionary motor and neural characteristics that are shared among other species, including birds.
As Doolittle et al. (2014) discuss, there are several hypotheses that explain the origins of musical tones and scales. For instance, many features of music can be understood with mathematics, like the fact that doubling a 100Hz pitch produces the same note (200Hz) at a higher octave. This explains why notes can be consonant or dissonant with each other and why we find the combination of some tones pleasing and others undesirable. Other fundamental musical features such as rhythm and meter can also be understood mathematically and can be expressed numerically. While math may explain these kinds of fundamental features of music, it falls short when it comes to explaining other qualities of music, such as why certain modes evoke certain feelings in people, or why we like “blue” notes.
The idea that humans share certain musical tastes with animals opens up many interesting research hypotheses. For example, there has long been an assumption that animals use musical-sounding tones to communicate. This suggests to me that perhaps pre-lingual human ancestors might have used song-like tones to communicate. We know that Homo sapiens have been crafting musical instruments since at least 42,000 years ago, even though we do not know exactly what purpose music served for early humans (BBC 2012). Some believe that along with other forms of art, music set Homo sapiens apart from the Neanderthals, and might have contributed to the success of Homo sapiens as a species.
Even though modern humans have developed complicated language systems, we continue to use music as way to communicate emotions. A possible explanation might be that music is a fundamental communication system that uses rhythmic and melodic entrainment. This type of research has interesting implications, not only for understanding how certain animal species communicate amongst themselves, but also how humans might better learn how to communicate with some of our animal companions.
BBC. 2012. “Earliest Music Instruments Found,” May 25, sec. Science & Environment. http://www.bbc.co.uk/news/science-environment-18196349.
Doolittle, Emily L., Bruno Gingras, Dominik M. Endres, and W. Tecumseh Fitch. 2014. “Overtone-Based Pitch Selection in Hermit Thrush Song: Unexpected Convergence with Scale Construction in Human Music.” Proceedings of the National Academy of Sciences, November, 201406023. doi:10.1073/pnas.1406023111.
Hermit Thrush. 2009. https://www.youtube.com/watch?v=o49U8NH_YuY&feature=youtube_gdata_player.
Joy Morin Plays Amy Beach: A Hermit Thrush at Morn, Op. 92 No. 2. 2011. https://www.youtube.com/watch?v=gYFmsmhduWY&feature=youtube_gdata_player.