In my Psychology class, we recently learned about homologous traits. For those of you who don’t know what homologies are, they are characteristics that we share with another species because it derived from our common ancestry. Chimpanzees are usually the most common example used when discussing homologous trails with humans. Although most people already know that we share 98.8% of our DNA with chimps, when reading about our commonalities on the Jane Goodall Institute website, I also found that they’re similar to us because they show similar emotions using facial expressions, they have a similar length of pregnancy (at eight months), they can suffer from depression, and they share a similar central nervous system. I was also curious about what other, less obvious characteristics we have today that came from our ancestors, so I did some research, and found a particular study that really intrigued me.
If only Harambe could share 98.8% of his DNA with us
In this study, Chimpanzees Prefer African and Indian Music Over Silence, researchers tested chimps to see what kind of music they liked. They included three types of music during the test: West African, Japanese taiko, and North Indian raga. In order to conduct the experiment, the researchers hid a speaker in the exhibit, and measured the distance from the speaker. This distance was split into four zones (zone one was the closest to the speaker, and zone four was the furthest away). The scientists hypothesized that if the chimps did not enjoy the music, they would move to zone four, where it was inaudible. However, if they reacted positively to the stimulus, they would remain in zone one (Mingle et al.).
We’re more related than we think
Also mentioned in the study was an example of a previous test that was used to examine a chimp’s music preference, but it only used different types of Western music during the trial. Because we are taught in this class to always look for faults in studies, the researchers in the more modern experiment actually found that all western style music is virtually the same – so their experiment did not prove anything. This could be considered a source of bias. In regards to acoustic patterns, all western music, including classical, rock, and jazz, all follow similar arrangements, while the scientists discovered that music from across the world carry diverse pitches and beats (Mingle et al.).
The researchers eventually concluded that the chimps enjoyed listening to both the African and Indian music, but did not care for the Japanese. In fact, they found that they preferred silence over the Japanese music.
The researchers determined that the chimps didn’t like Japanese and Western music because that music carried protuberant rhythmic configurations, which the chimps could consider threatening (Mingle et al.).
This should be interesting to us because when we study species homogeneous to us, we are, in a way, studying our own psychological behavior and biological structures. Through this study, we now have a more solid understanding of how we learned to distinguish between different pitches of audio. Perhaps now that we know that chimps do like music, we can measure exactly how they react when they hear music they enjoy.
In text citation: Mingle, M. E., Eppley, T. M., Campbell, M. W., Hall, K., Horner, V., & Waal, F. B. (2014). Chimpanzees prefer African and Indian music over silence. Journal of Experimental Psychology: Animal Learning and Cognition, 40(4), 502-505. doi:10.1037/xan0000032