We’ve all been there: a catchy song comes on the radio and we instinctively adapt our movements to the rhythm we’re hearing. This reflex seems so natural that it has made some researchers wonder whether human brains are wired to simply like any and all musical rhythms.

Now, an American-German study published in the journal Nature has examined this phenomenon and indicates that we have a preference for certain rhythms depending on our culture.

Researchers from MIT and the Max Planck Institute for Empirical Aesthetics came to this conclusion after conducting an experiment with 39 groups of participants from 15 countries, some of whom had already participated in a previous 2017 study.

Many of the volunteers came from cultures whose traditional music contains rhythmic patterns not found in western music.

The academics had each group listen to a series of four randomly generated rhythms, before asking them to reproduce what they heard by tapping. They then asked them to repeat the experiment, this time listening to the rhythms they had generated themselves.

The scientists found that the musical sequences produced by the volunteers differed greatly from the original, suggesting that they were influenced by certain biases regarding rhythm.

“The initial stimulus pattern is random, but at each iteration the pattern is pushed by the listener’s biases, such that it tends to converge to a particular point in the space of possible rhythms. That can give you a picture of what we call the ‘prior’, which is the set of internal implicit expectations for rhythms that people have in their heads,” Josh McDermott, associate professor of brain and cognitive sciences at MIT, explained.

Regional variations

The research team found that participants’ rhythmic biases varied, not from individual to individual, but according to their country of origin. Thus, American volunteers tended to produce rhythms with integer ratios such as 1:1:2 and 2:3:3.

The notion of integer ratios indicates the duration relations between different notes or beats. A 1:1:2 ratio refers to a three-note sequence in which the first and second notes have the same duration, while the third is twice as long as the two preceding it. Similarly, the ratio 2:3:3 refers to a rhythmic sequence of three notes in which the last two are twice as long as the first.

Americans’ preference for 1:1:2 and 2:3:3 does not arise out of nowhere: these rhythmic sequences are often used in western music. Volunteers from the Tsimané ethnic group in Bolivia, meanwhile, produced different rhythms, undoubtedly closer to those of their traditional music.

“Our study provides the clearest evidence yet for some degree of universality in music perception and cognition, in the sense that every single group of participants that was tested exhibits biases for integer ratios,” lead author Nori Jacoby outlined.

“It also provides a glimpse of the variation that can occur across cultures, which can be quite substantial.”

All in all, the findings lend credence to the notion that music – and specifically the notion of rhythm – transcends geographical boundaries, even if each culture has its own musical preferences.