The father of the poet Dylan Thomas used to read rhythmic poetry loudly over his wife's belly before his son was born. He wanted his son to be a wordsmith. It worked, although I'm sure once Thomas was a kid, other approaches worked better. It's weird, but it makes a good story.
The baby Mozart fad of a few years ago petered out, but this research seems valid. Rhythm is so basic to everything. Rhythm, dance, timing, music - they're present in so many things we do. I can decide to take an afternoon nap and tell myself to wake up in 38 minutes, and I will wake up exactly at that time. Our bodies keep time, with really good silent drummers in our brains. What we recognize as rhythm probably comes out that.
I once did a fiction reading in one of those old chrome microphones from the 1940s, still in use in the 80s in a hippy cafe. It had been used in shows there by Bob Dylan and... Mike Naismith. I was impressed by the Monkees connection because like the Beatles cartoons, they'd been childhood TV for me.
There have always been manufactured bands like the Monkees, the Sex Pistols, the Spice Girls and a pile of K-Pop stars. Research into other animals says many get rhythm as we do, so there's probably 'always' been rhythm too, I just wish English had chosen a word that was easier to spell for it.