Rhythm Diversity: Different Cultures Prefer Different Beat Patterns
A cross-cultural study shows: musical imprinting influences how the brain interprets rhythms. (Picture: Rainer Polak)
The following text is based on an article published by MIT News:
Exposure to different kinds of music influences how the brain interprets rhythm
A study of people in 15 countries reveals that while everyone favors rhythms with simple integer ratios, biases can vary quite a bit across societies.
(Anne Trafton, MIT News Office)
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The human brain appears to be biased toward hearing and producing rhythms composed of simple integer ratios (e.g., 1:1:1). However, these ratios can vary greatly between different cultures, according to a large-scale study including 39 groups of participants from 15 countries. The study was led by researchers from the Max Planck Institute for Empirical Aesthetics (MPIEA) in Frankfurt am Main, Germany, and the Massachusetts Institute of Technology (MIT) in Cambridge/MA, USA, collaborating with 34 researchers from around the world. They recently published their findings in the journal Nature Human Behaviour.
The team tested the reactions of people from urban environments in face-to-face sessions or online, as well as the ones of indigenous populations. Many of the study participants came from societies whose traditional music contains distinctive patterns of rhythm not found in Western music. Despite this, the researchers found similar patterns across groups:
“All participating groups had a preference for integer ratios. Our study thus provides clear evidence of a certain universality in musical perception and cognition,” says first author Nori Jacoby of the MPIEA. “At the same time, however, the results also give us an insight into the differences that occur between different cultures, which can be quite significant.”
The researchers assume that the brain’s preference for simple integer ratios evolved as a natural error-correction mechanism that facilitates maintaining and transmitting a consistent body of music.
“When people produce music, they often make small mistakes. Our results are consistent with the idea that our mental representation is somewhat robust to those mistakes, but it is robust in a way that pushes us toward our preexisting ideas of the structures that should be found in music,” explains senior author Josh McDermott from MIT.
Cross-Cultural Comparisons
The study grew out of a previous one published by Jacoby and McDermott in 2017, in which they compared rhythm perception in groups of participants from the United States and Tsimane' participants, an Indigenous society located in the Bolivian Amazon rainforest. The team played a randomly generated series of four beats and then asked the listeners to tap back what they heard. The rhythm produced by the listeners was then played back to them, and they tapped it back again. Over several iterations, the tapped sequences became dominated by the listeners’ internal biases, also known as priors.
The research team found that both the US participants and the Tsimane' produced rhythms with simple integer ratios—with one difference: most of the rhythms produced by the US participants were commonly found in Western music. However, the ratios preferred by the Tsimane' were different and appeared to be consistent with those documented in the few existing records of Tsimane' music.
“This result provided some evidence that there might be widespread tendencies to favor these small integer ratios, and that there might be some degree of cross-cultural variation. However, we had only analyzed two culturally distinct groups,” Jacoby says.
To get a broader picture, the research team widened the approach: together with scientists from more than two dozen partner institutions worldwide, they surveyed more than 900 people from a total of five continents (North America, South America, Europe, Africa, and Asia).
A Global Approach
“This is really the first study of its kind in the sense that we did the same experiment in all these different places, with people who are on the ground in those locations,” McDermott says. “That hasn’t really been done before at anything close to this scale.”
The team was careful to include not only students or people from urban areas, but also people from traditional societies who are harder to reach. This is significant because much of the research in psychology and music cognition is conducted with students and online participants. They found that participants from the more traditional groups differed significantly from students from the same countries, as well as people who lived in those countries but participated online.
Just as they had in their original 2017 study, the researchers found that in every group they tested, people tended to be biased toward simple integer ratios of rhythm. However, not every group showed the same biases. People from North American and Western Europe, who have likely been exposed to a similar kind of music, were more likely to generate rhythms with the same ratios. However, many groups—for example from Turkey, Mali, Bulgaria, and Botswana—showed a bias for other rhythms. The biases of students and online participants differed far less from Western tendencies than those of traditional groups.
The researchers believe their findings reveal a mechanism that the brain uses to aid in the perception and production of music, and now plan to run additional studies on different aspects of music perception, taking this global approach.
The research was funded by the James S. McDonnell Foundation, the National Science and Engineering Research Council, the National Research Foundation, the National Science Foundation, the Chilean National Research and Development Agency, the Austrian Academy of Sciences, the Japan Society for the Promotion of Science, the Keio Global Research Institute, the Arts and Humanities Research Council, the Swedish Research Council, and the John Fell Fund.
Reprinted with permission of MIT News.
Publication:
Jacoby, N., Polak, R., Grahn, J., Cameron, D., Lee, K. M., Godoy, R., Undurraga, E. A., Huanca, T., Thalwitzer, T., Doumbia, N., Goldberg, D., Margulis, E., Wong, P. C. M., Jure, L., Rocamora, M., Fujii, S., Savage, P. E., Ajimi, J., Konno, R., Oishi, S., … McDermott, J. H. (2024). Commonality and Variation in Mental Representations of Music Revealed by a Cross-Cultural Comparison of Rhythm Priors in 15 Countries. Nature Human Behaviour. Online advance publication. https://doi.org/10.1038/s41562-023-01800-9