Thanks to @[email protected] for the links!
Here’s a link to Caltech’s press release: https://www.caltech.edu/about/news/thinking-slowly-the-paradoxical-slowness-of-human-behavior
Here’s a link to the actual paper (paywall): https://www.cell.com/neuron/abstract/S0896-6273(24)00808-0
Here’s a link to a preprint: https://arxiv.org/abs/2408.10234
Look up Pete Magadini on YouTube. He’ll explain how to do this. You really must start by being able to count 2 over 3 (or 4 over 6, same thing). Tap out 6 on one leg and 4 on the other, using the “cheat” that everyone learns (i.e., playing in one meter only). This is not yet a polyrhythm. Then COUNT OUT LOUD, 1-2-3-4, 1-2-3-4-5-6, alternating, several measures, while your hands continue to tap out both counts. This is how you internalize polyrhythms.
Also, learn Afro-Cuban rhythms. Those are claves of African origin and many are polyrhythmic. If you want to take it to the extreme, study Virgil Donati, man is sick.