Some animals seem to appreciate music. What does that mean for human evolution?

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6 hours ago

Ronan the sea lion can dance to a lot of different songs, but there is something about 'Boogie Wonderland,' by Earth, Wind and Fire that really gets her going.
It didn't take more than a few days for Peter Cook, a marine mammal sciences professor at the New College of Florida, to train Ronan to bop her head to music. Using fish as a reward, he taught her the movement. Then he taught her to move when a metronome played. Over the course of the next two months, he gave her a fish every time she synchronized her head bops to the beat of the music. Once that clicked, she could do it 60 times in a row within a couple of days, he said.
Before long, she was able to do this with music recorded live in a studio with natural fluctuations, complex instrumentation and syncopation, meaning different beats were emphasized in different measures, Cook explained. And it wasn't just Earth, Wind and Fire that got her moving, but also the Backstreet Boys and other rock songs.
'Once she understood the task, she seemed to be able to transfer that knowledge over to even complex musical types of stimuli, which do have things like meter,' Cook told Salon in a phone interview. 'The thing is, we're just not sure how she thinks about or understands things like meter, syncopation or anything like that.'
Historically, many thought that humans were the only animals that could recognize an external beat and synchronously move to it. But in 2007, Snowball the cockatoo went viral for dancing to the rhythm of the Backstreet Boys. Then, in 2013, Ronan the sea lion similarly acquired world-fame for moving her head rhythmically to the beat of music.
These two case studies are part of a growing field of research set on trying to understand which animals have the capacity to be musical, providing clues on how and why music evolved in humans.
In 1871, Charles Darwin wrote: "The perception, if not the enjoyment, of musical cadences and of rhythm is probably common to all animals.' Darwin suggests that if music gives us pleasure, it has an evolutionary purpose. And if all animals share a common ancestor, it could be something that is evolutionarily shared. But that isn't easy to investigate.
'We have this problem in studying the origins of musicality … Music doesn't fossilize,' said Henkjan Honing, a professor of Music Cognition at the University of Amsterdam. 'Cross-species work is a way of resolving that problem because the assumption is that if you share a certain trait with a genetically close species, then the common ancestor might also have had that particular skill.'
In a way, all animals make rhythms, whether in the form of fireflies flashing, birds chirping or even a tiger pacing back and forth. Some of these rhythms are influenced by pure physiology: Walking, swimming and having a heartbeat are all rhythmic. Yet defining what constitutes music is challenging because it is inherently subjective. Plus, we don't know if animals experience music as music, or if that is our own human experience we are projecting onto them.
In one study released last month, eastern and western chimpanzees — which are two different subspecies — were observed in the wild to have distinct drumming patterns. These patterns are short, structured and rhythmic, but they are thought to be used more for communication purposes than for music, said study author Vesta Eleuteri, who studies the evolution of social cognition and communication at the University of Vienna.
'Some chimpanzees drum with isochrony [occurring at the same time], but we didn't find evidence of other core musical rhythms that are present in humans,' Eleuteri told Salon in a video call.
Musicality generally implies that animals have control over the rhythm they are making and use it flexibly. One way to determine if an animal is musical is to see if they have the ability to identify a note's pitch in relation to other notes. Another way, which has been studied more, is to see if they are capable of synchronizing to beats in a rhythm, Honing said.Human children have been shown to do this before they can walk or talk, though it's unclear whether this ability is learned or innate. Children aren't perfectly synchronized to the beat at younger ages and they improve over time, suggesting that it could be something that is socially learned. On the other hand, one 2009 study found evidence in baby's brains that they were detecting rhythmic patterns as young as seven months old, which could indicate that this ability is already functional at birth.
Nevertheless, in a study published in May, Ronan the sea lion was shown to perform better than adult humans when tasked with moving in sync to a beat. Although Ronan doesn't perform this task outside of her training sessions on her own, she does get a fish regardless of whether or not she moves to the music in training sessions, indicating she is voluntarily moving to the beat, Cook said.
It's unclear what motivates Ronan to perform this activity, but Cook said sea lions are kind of like the Border Collies of the sea and can quickly learn new tasks. As such, it could have something to do with mastering a task, he explained.
'I think she enjoys the cognitive challenge and the opportunity to sort of master something and then practice that mastery,' he said. 'I just don't know if it's about groove the way it is with humans.'
Looking at similarities and differences between our closest living relatives, primates, can provide clues into whether music shares a common ancestral origin. In humans, if we are walking or typing and listening to music, we naturally sync up to the rhythm. In studies conducted by Yuko Hattori, an assistant professor at Kyoto University's Primate Research Institute, chimpanzees were able to synchronize their movement to a variety of rhythms. Similar findings were also reported in another study with a bonobo, in which the bonobo was also able to synchronize its drum beats to a human in the experiment.
Movements from primates in these studies are not as precise as humans, but one hypothesis used to explain the origins of music could help explain the differences. It suggests that in humans, our ability to move in time with a beat stems from vocal learning. It could be that humans' ability to refine that beat synchronization evolved along with our vocalization abilities, Hattori said.
'The monkeys are a more distant evolutionary distant species, and so perhaps that there is some gradual development in the course of primate evolution,' Hattori told Salon in a video call.
This hypothesis could explain why birds like Snowball and humans can move to a rhythm, although it raises questions about Ronan the sea lion's ability to move to the beat. Sea lions don't naturally adapt their calls to external stimuli in the wild, although seals do, which share an evolutionary root with sea lions more than 20 million years up the ancestral tree. However, it could be that this shared ancestor is related to some degree of vocal learning in sea lions.
It's rare to get a brain scan of chimpanzees or sea lions due to ethical reasons, so what is happening neurologically when these animals move to the music is also unknown. However, experiments in birds like the zebra finch help provide some answers as to why this species sings.
Although zebra finches sing their own songs and do not move to external rhythms, they do at some point learn those songs from other zebra finches, so there is some degree of learning and internalization related to music.
In one 2017 study, Ofer Tchernichovski, who studies animal behavior at Hunter College, and his team set up an experiment in which birds had to get an unpleasant air puff in order to reach a peep hole where they could see a singing bird. What they found was that males were always willing to 'pay' to hear any song, whereas females were only willing to hear the song if they were presented with the song of their mate. When females were presented with the song of her mate, dopamine levels went up.
'The thing is, the females are not very sensitive to songs, so this was exactly the opposite of what we thought,' Tchernichovski told Salon in a video call. 'What we think is that for females, the song is really about sex, whereas for male zebra finches, it's more social.'
Another study released earlier this year found dopamine activity increased in young zebra finches when they sang songs that were closer to their eventual adult song versions compared to when they sang songs that deviated further away from them.
Other studies have shown male zebra finches 'self-evaluate' their songs when practicing alone with songs they sing better activating the dopamine system more than songs they sing worse. However, when singing for females, their dopamine system is activated by a social response based on the cues they receive from the female.
Studies show that the dopamine system in humans is also activated when we listen to music. In one study, people listened to their favorite music while under an fMRI machine. In anticipation of that moment, the dopamine system was activated in the brain.
Furthermore, studies have also shown that musical training in adolescence increases empathy and prosocial behaviors. In other words, it brings us together — which we see when we clap to the beat at a concert or sing the lyrics to popular songs. One 2014 study found infants were more likely to help someone if that person rocked them synchronously versus whether they did so out of rhythm.
'One of the theories that is important for the origins of musicality is that it could be a way of social bonding, of increasing the social cohesion of the group,' Honing said. 'You see the same thing with Snowball: He likes to dance when his owner is there … She always dances with him, and that's what the bird likes.'
'Enjoyment is the key,' Honing added. 'If you get pleasure out of something, that means it's important biologically, so it might be an adaptation.'