Tuesday, November 11, 2014

Do Humans and Animals Share Musical Tastes?

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.


Branden Kelly said...

Hey Brian,

The title of your post alone is intriguing and your summary and reflection were both very interesting to read. When I read this, This I immediately thought about how we communicate with dogs, for example. We don't talk to them with words necessarily, but we use voice inflections to communicate our emotion with them. We raise our voice in an excited manner to communicate happiness, and articulate, forceful language when we want to communicate anger. I always enjoy asking my dog if she wants a treat, but asking her in a negative, forceful tone. Or telling her how bad of a dog she is, and using a gentle tone. They always respond to the tone more than the words. Except, now through these experiments, my dog can now detect the word "treat" no matter how I say it. Maybe something to contradict this statement on inflection of tone towards dogs would be this video: https://www.youtube.com/watch?v=XjtEOpkoK8Y, a dog who understands the word "dog catcher", it always cracks me up!

Stacey U. said...

Thank you for an intriguing article and unusual subject matter. I recall initially reading something similar in the Jourdain (1997) book, except he explains the building of the scale in terms of frequencies that sound “right” to our ears (pp. 69-74). Perhaps some animals, or in this case these particular birds, perceive and experience pitch in the same way, where singing and hearing certain frequencies is more pleasing than others. I noticed you also raise this idea of pleasure in your reflection, which is terribly interesting—how do these birds, or other animals, experience pleasure in terms of sounds and/or music? I also find your suggestion about evolution compelling—maybe the nature of animal ears themselves can be more closely investigated. And after all, we are all part of the same physical world where frequencies are constant across the board, so somehow similarities between our music and that of the animals’ are not surprising.

Doug Brenton said...

Loved this posting - thank you for it! I agree with your reflections and I cannot help but think of Judy Collins who is a biomusicologist and creates CD's with animal sounds/music. In the last half-century, Judy Collins has sung with humpback whales and CDs with titles like “Sounds of the Rainforest”. I believe that these are simply biological functions that animals create.
I have read that natural sounds such as whale and bird songs can be identified as music, but that their songs may be part of a “universal music” that provides an intuitive musical concept to many animals—including humans. We can look at the evidence and I think we can give more credit to animals. We can then look at humans and be less impressed with humans. This brings up my point that the similarities between human and animal sounds and the innate desire to create music that the similarities suggest is a topic now being explored by the evolving field of biomusicology. Biomusicologists argue that not only are the sounds of some animals pleasing, but they are also composed with the same musical language that humans use. Whales, for example, use many of the musical concepts found in human music, including similar rhythms, phrase lengths, and song structure. They, too, continue to use music as way to communicate emotions. Overall, this is a great post!

Veronica V said...

Thank you for sharing this Brian. It was surprising to me that the male hermit thrush can sing up to ten different song types and that they overlap with the major, minor and pentatonic scales! It makes you wonder about different scales that are used in different cultures. I once watched a documentary where they performed a study in North Cameroon with people who have never heard Western music before. Researchers wanted to see if they could distinguish between music that was happy, sad, and scary which would help them determine whether music is learned, or within us. They found that the people in North Cameroon could in fact, successfully identify the three excerpts. This was an interesting find!

I agree also agree with Branden. When I first this post, I also immediately thought about how humans communicate with dogs. I thought about my dog as well and how much he used to respond to the inflections of my voice, and I also would play around with my words and inflection, for example, calling him a different name all together, but using the same voice that I normally do. He would still respond to me. However, my dog used to go nuts and grab his leash and bring it to your feet whenever anyone said the word “walk”. I’m not sure how he learned to distinguish that, because it didn’t matter how you said it, whether in an excited voice, mad voice, loud, or soft. Thank you as well Branden for sharing that video in your response! Very funny video.