Rats can bop their heads to a musical beat
This discovery may shed light on how brains evolved to perceive rhythm
Rats’ rhythmic response to human music doesn’t mean they like to dance, but it may shed light on how their brains — and ours — evolved to perceive rhythm.
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Humans aren’t the only animals that move to music. Parrots have been known to do it. And now rats have been observed bopping their heads in time with the tunes of Mozart, Lady Gaga, Queen and others. What’s more, the animals seem to respond to the same tempos that get humans’ feet tapping.
A team at the University of Tokyo in Japan made this discovery. The researchers played lab rats a sonata by Mozart — at normal speed, as well as sped up or slowed down. Meanwhile, the team recorded the rats with a motion-capture camera. Wireless sensors on the rats’ bodies also tracked their movements.
The rats’ head bobbing was more pronounced when the sonata played at its usual tempo. That’s around 132 beats per minute. The same was true for 20 people who listened to the song through motion sensor–equipped headphones.
For both humans and rats, the head bopping was consistent when the music was played at about 120 to 140 beats per minute. When the music was played faster or slower, there was no head bopping.
The team also played some of their favorite pop songs for the rats. Lady Gaga’s “Born This Way,” for instance. And Michael Jackson’s “Beat It.” As with Mozart’s music, rats bopped along to the same tempos of pop songs as people do. That is, about 120 to 140 beats per minute.
These findings suggest there is something similar about the way human and rat brains are wired to respond to rhythm, says Hirokazu Takahashi. A mechanical engineer, he uses his expertise to study how the brain works. Takahashi and his colleagues shared the rat rhythm research November 11 in Science Advances.
Aniruddh Patel is a psychologist who studies how the brain perceives and responds to music. He works at Tufts University in Medford, Mass. Rats do seem to prefer beats that humans like, Patel says. But he is not convinced that the rats can match their motions to the beat like humans do.
Humans and parrots respond to beats with big, voluntary movements. Think head bobbing, dancing or foot tapping. To do this, people predict the timing of a beat and move predictably to it, Patel says. “So, we land right on beat or a little ahead of it.”
The rats, meanwhile, showed very tiny movements in response to music. So, it’s not clear if rats can predict a beat or if their bodies just react to it. Both Takahashi and Patel stress that this study does not show that rats like to dance to human music. Still, it could help reveal how humans and some other animals evolved a sense of rhythm.
