It was previously thought that the sense of rhythm and timing in music is an exclusively human trait. However, new research demonstrates that rats also possess this ability. This discovery deepens our understanding of animal minds and the origins of music and dance.
Researchers from the University of Tokyo in Japan have found that rats, like humans, cannot resist rhythmic musical compositions, demonstrating their innate sense of rhythm. “Rats exhibited natural — that is, without prior training or exposure to music — synchronization of movements,” noted Dr. Hirokazu Takahashi.
“Music has a significant impact on the brain, as well as on emotions and cognitive processes,” added Takahashi. Although there have been previous instances of animals dancing to music — many examples can be found on social media — the study by Japanese scientists is one of the first scientific works dedicated to this phenomenon.
In a paper published in the journal Science Advances, ten rats were fitted with wireless miniature accelerometers to track even the slightest head movements. They were then played one-minute excerpts of Mozart's Sonata for Two Pianos in D Major at four different tempos: 75%, 100%, 200%, and 400% of the original speed. Twenty volunteers also participated in the study.
The scientists hypothesized that the rats would prefer faster musical pieces, as their bodies, including heart rate, function at a faster pace than humans.
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However, the results showed that both rats and humans exhibited optimal movement synchronization at music tempos in the range of 120-140 beats per minute (120-140 bpm), which is close to the original 132 beats per minute in Mozart's composition. The research group also noted that rats and humans nodded their heads in unison, and the level of head movement decreased with increasing music speed. “We hypothesized that the short-term adaptation of the brain is related to the tuning of beats in the auditory cortex. We were able to explain this by fitting our neural activity data to a mathematical model of adaptation,” the researchers report.
“Furthermore, our adaptation model showed that in response to random sequences of clicks, the highest predictive efficiency of movements in rats was observed when the average interval between stimuli (the time between the end of one stimulus and the beginning of another) was about 200 milliseconds (one thousandth of a second), which corresponds to the statistics of inter-note intervals in classical music,” the scientific paper explains.
Now the team plans to study how other musical aspects (melody and harmony) affect brain dynamics. “As an engineer, I am also interested in using music to create a happy life,” concluded Takahashi.
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