The basic human physical response to music (grooving) is shared with other species according to researchers.
Two reports (one and two) published online today in Current Biology, reveal that birds – cockatoos and parrots in particular – can bob their heads, tap their feet, and sway their bodies along to a musical beat.
Aniruddh Patel of The Neurosciences Institute in San Diego, lead author of one of the studies, said that they've discovered a cockatoo named Snowball that dances to the beat of human music.
"Using a controlled experiment, we've shown that if the music speeds up or slows down across a wide range, he adjusts the tempo of his dancing to stay synchronized to the beat. One of Snowball's favorite dancing tunes is none other than the Backstreet Boys' "Everybody," he said.
In the video below, which is associated with the report, a sulphur-crested cockatoo, Snowball, can be seen to adjust its movements so that they remain synched to a changing musical beat.
Experimental Evidence for Synchronization to a Musical Beat in a Nonhuman Animal
Patel and his team set out to test the hypothesis that only vocal learning species (such as humans and some birds, cetaceans, and pinnipeds, but not nonhuman primates) are capable of synchronizing movements to a musical beat. They found that such synchronization is not uniquely human and suggest that animal models can provide insights into the neurobiology and evolution of human music.
The study included experiments carried out to suppress any manipulation of the musical tempo and imitation of human movement.
The other study, which took place at Harvard University and was led by Adena Schachner, a doctoral candidate in psychology, has a similar conclusion. It found that entrainment is not unique to humans and that the distribution of entrainment across species supports the hypothesis that entrainment evolved as a by-product of selection for vocal mimicry.
"For a long time, people have thought that the ability to move to a beat was unique to humans," a. "After all, there is no convincing evidence that our closest relatives, chimpanzees and other apes, can keep a beat, and there is similarly no evidence that our pet dogs and cats can line up their actions with a musical beat, in spite of extensive experience with humans. In this work, however, we found that entrainment [to music] is not uniquely human; we find strong evidence for it in birds, specifically in parrots," Schachner said.
Spontaneous Motor Entrainment to Music in Multiple Vocal Mimicking Species
Light is shed on just how the cognitive processes needed for both vocal mimicry and entrainment in a press release that details this study:
"In both vocal mimicry and entrainment," says Schachner, "you're taking in auditory input, and constantly monitoring not only your output but also the sound input. This allows you to fix your output in real time, to better resemble or line up with what you hear. For example, if you are tapping to a beat, you constantly monitor the sound and your taps, so that if you become misaligned with the beat, you immediately change your timing. If you are imitating a sound, you constantly monitor your memory of the sound you are trying to imitate, as well as the sound you are producing, so if you notice a difference, you can change your vocalization. So it seems plausible that vocal mimicry and keeping a beat might rely on some of the same mechanisms."
She added that the current findings lend plausibility to the idea that the human entrainment capacity evolved as a byproduct of our capacity for vocal mimicry.
The two movies above were published online in Current Biology on Thursday, April 30.