By: Kai Wang
Humans aren’t the only ones that can move to the beat, rats can do it too. They had been observed bopping their heads in time with the music of Mozart, Lady Gaga, Queen, and others, researchers report on November 11 in Science Advances.
“Some of us believe that music is very special to human culture. But I believe that its origin is somehow inherited from our progenitors,” says Hirokazu Takahashi, a mechanical engineer at the University of Tokyo, who studies how the brain works.
Perceiving the beat of a song and following it with the movement of the body is called beat synchronization. It’s a puzzle why some species have the ability and some don’t.
For Rats in Takahashi and his colleague's lab, they sped up, slowed down the tempo, and kept the regular speed. Not only did they observe the rat’s motion, but also surgically placed wireless accelerometers on the rats.
The team hypothesized the size of the body might dictate the tempo that the rats started bopping their heads.
“There are lots of reasons to think maybe [rats] would prefer faster rhythms. But that’s not what they found. And that’s intriguing,” says Aniruddh Patel, a psychologist at Tufts University in Medford, Mass., who was not involved in this research. He studies music cognition, the mental processes involved in perceiving and responding to music.
For both rats and humans, the head-bopping was about 120 to 140 bpm. When played faster or slower, there was no head-bopping. This information suggests that there is something about how the brain is tuned to respond to rhythm.
“I think that that study actually raises more questions than answers in some sense,” Patel says. Humans and parrots show beat synchronicity with big movements like bobbing, dancing, or foot tapping. Rats showed small movements.
“Music stimulus is very appealing to the brain,” Takahashi says. “But it is not evidence [that] they enjoy or they perceive music.”