The Musical Tastes of Chimps

Your Random Science News Story From the Month of March

You might have heard that plants like music. Or rather, that playing music helps them grow faster and/or healthier. Despite several studies (and one Mythbusters episode) of varying quality, the jury’s still out due to the difficulty of actually replicating the results of said studies. But music wasn’t exactly composed for plants’ ears. So, how about the species that’s closest to our own – Pan troglodytes, the common chimpanzee?1

Turns out our genetic first cousins appear to have no musical tastes whatsoever.

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Credit: Rennett Stowe, CC BY 2.0

At least that’s what a new paper – published in the journal PLOS One – tells us.

What happened?

Researchers led by Dr. Emma Wallace from the University of York sought to observe whether or not playing music for chimps had positive effects on their welfare, and if the genre of the music mattered. To do this, they conducted three different studies: the first two observed if/how playing music affected the chimps’ use of space (i.e. did they actively approach/avoid it) and their behaviour; the third gave the chimps the power to play the music of their choice (or to turn it off).

Unlike previous studies on chimpanzees, this was the first that gave them the option to leave the music-playing area or choose to turn the music off. It was also the first to study chimps in a non-laboratory setting.2

I know you’re dying to know what kind of music these chimps were subjected to, so here you go:

At the Edinburgh Zoo (observed in periods between 2013-2015)

  • The “Pop/Rock” category (Post-2010 to avoid recognition; apparently, they’ve haven’t been exposed to music since at least that year. So, sorry, guys. No Monkees puns…)
    • Beauty and a Beat – Justin Bieber (ft. Nicki Minaj)
    • ET – Katy Perry (ft. Kanye West)
    • Locked out of Heaven – Bruno Mars
    • One More Night – Maroon 5
    • Rollin’ in the Deep – Adele
    • Too Close – Alex Clare
    • Troublemaker – Olly Murs (ft. Flo Rida)
    • We are Young – fun. (ft. Janelle Monáe)3
  • The “Classical” category
    • Bach – Brandenburg Concerto #2 in G, BWV 1048 – 2. Andante
    • Beethoven – Piano Sonata No. 14 in C# minor Op. 27 No. 2 Moonlight – Adagio sostenuto
    • Chopin – Noctunre for piano No. 16 in E flat major, Op. 55/2, B. 152/2
    • Elgar – BGN
    • Mozart – Clarinet Concerto in A – Adagio
    • Mozart – Serenade in B Flat, Gran Partida – Adagio
    • Richard Stoltzman – Maid with the Flaxen Hair

At the National Center for Chimpanzee Care in Texas (observed in 2006, only for the third study), the paper merely reveals the CDs used: 25 Classical FavouritesBest of 80’s Metal, Vol. 1, and Dance My Children, Dance (an African Folk album by Samite).

I’m quick to note that the tempo of the modern music was consistently – and often significantly – faster than that of the classical music. The paper doesn’t specify why the researchers didn’t choose some faster classical songs to compare against the pop genre; it’s been shown in previous work that non-human primates prefer slower tempo music, so the chimps might have been biased toward the classical music not for the genre, but simply for the tempo. Someone should take this into consideration in future studies…

What’d they find?

During the first study, the chimpanzees neither sought out nor avoided the music; however, they tended to enter the music-playing area when the song had a slower tempo and leave when it was faster4 (Sadly, they don’t provide info for which songs they exited most frequently, so I can’t insult the artist of my choice by saying chimps don’t like them, either…). While music was playing, the chimps were observed to show less abnormal behaviours (e.g. “regurgitation and reingestion”, drinking/eating bodily waste, pulling out fur), but were also less social with one another compared to when no music was playing; the genre made no difference.

Results from the second study – which continuously tracked 3 chimps, rather than checking on the group as a whole every so often – contradicted those of the first. There was no significant change in abnormal behaviour when music was/wasn’t playing.

When the chimps were actually able to control the music using a touchscreen, they showed no preference for a particular genre, or for silence, and grew less interested in interacting with the ‘jukebox’ fairly quickly. This was especially true for the Edinburgh group, who were rewarded with grapes while training to operate the touchscreen, but not once actual testing started. Except for the first experiment session, which saw 18 button presses (12 of them from one likely grape-craving chimp named Edith), the average number of interactions with the touchscreen was about 3 per 60-minute session.

In the individual training sessions, some chimps did appear to show preferences (e.g. Edith chose pop over classical over silence). However, in the group setting where they could choose not to interact with the touchscreen at all – or never be in the music-playing area – there simply wasn’t enough screen-pressing to determine if these were true preferences for genre. The researchers acknowledge the training may not have been enough for the chimps to figure out how to work the system – i.e. which screen button was associated with which genre, or even the difference between music genres, because the chimps were only exposed to 3 seconds of song after touching the correct area of the screen.

So what?

As stated previously, this was the first paper that studied chimps outside of lab-captivity with the freedom to ignore any and all music if they so desired. And, as stated about the plant studies, researchers will need to be to conduct more studies to demonstrate the results of this one (i.e. chimp indifference) can be replicated.

That being said, if we’re looking to improve the welfare of captive chimpanzees, we should look for possible enriching activities other than having them listen to music of any genre. While there don’t appear to be any negative effects on the chimps (Thus, a carer with terrible taste in music will only be torturing their coworkers), the benefits appear quite limited.

Meanwhile, a 2016 paper revealed that orangutans (or at least the ones studied) can’t tell the difference between music and “scrambled non-music samples”5, and preferred silence when given the option. Combining this with Dr. Wallace and her team’s work, it’s not unreasonable to propose that music appreciation is uniquely human.

 

Unless chimps are really into something we just haven’t tested, yet. Like death metal.

Or polka.

 


1. Bonobo, aka Pan paniscus, is the only other species within the genus Pan and therefore also equally related to homo sapiens. Only about 4% of our genome differs from that of Pan species. 
2. Previous studies on lab-captive chimps forced to listen to music showed benefits of listening to slow tempo music in “relaxing genres”.
3. You might be wondering, “Where’s the rock?” Don’t worry, I am too. 
4. Except for Lucy, whose mean exit tempo was much, much lower (52 bpm) than her mean entrance tempo (91 bpm). 
5. Created “by dividing each music sample into 0.5 [second] segments, randomly re-ordering the segments, and playing the randomly re-ordered segments in reverse.”

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