I mean sure, I'm incredibly skeptical of "baby Mozart" approaches to music. Certainly starting young and practicing early goes a long way towards being successful in anything. Discipline in any field builds discipline towards others.
We can go on and on about the mathematical nature of music but I would argue it's easier for people to do it by not thinking about those things and being in touch with how it feels.
I'm kind of bothered that anything to do with IQ these days is pursued by researchers or is given a fair shake by our dear readers at Hacker News.
Stop trying to max your kids stats. It's incredibly dehumanizing. I get that we all want children to have the best opportunities, but maybe it'd be a more equitable situation if we stopped reducing ourselves to a numbers game.
Maybe they'll be smarter when they learn to do things they feel passionate about and not conditioned to perform like a trained monkey. We already have enough performative identity for careerism in high school kids. Maybe intelligence and success comes from knowing yourself, and not from being told to do things because you get points?
Sorry parents! An essential part of culture and discipline of art and pleasure might not be inherently advantageous to your child's ability to fill out tests so while you're at it make sure they never do anything for themselves beyond the sole purpose of getting in somewhere just so they can realize they don't know who they are!
Edit: Also the use of "put down the banjo". Let's talk about that. This is a study done in Japan and the UK. Are they even playing the banjo? Nothing wrong with the banjo, banjo's great. But specifically going with the banjo as their title and image lends itself to a specific tone for some readers. Not exactly what some people would consider "intellectual" music for vague reasons in class and race perhaps. I'm detecting a bias here against the "utility" of folk music. I wish they'd link the actual paper. Did the researchers give a bunch of banjos as part of a controlled study? I'm so sure a lot of well-to-do parents in Tokyo and London are feeling burned by having to keep up with the competitive nature among children in banjo culture.