This is a great question! I’m not really sure of the answer. Even if people who read a lot or play music have different or more developed brains, it would be hard to tell whether they have different brains BECAUSE they do this, or whether they read or play music BECAUSE their brains are different. This is a constant struggle for scientists, to work out which way round a relationship is!
People who a lot of certain activities can often get more connections in certain parts of their brain, so this would probably be the case for people who read, or play music. But I wouldn’t say brains were more developed, just different. And everyone’s brain is different.
Hope this answers your question, there are better ‘brain experts’ in this group who can hopefully give you more detail/a better answer 🙂
It is a very difficult answer, you may know that the left side of the brain controls the right side of the body and vice versa. So when you do complicated 2 handed tasks such as playing an instrument you form stronger connections over the bridge between the 2 halves of your brain, which is thought to be a good thing. However, just as Suzi said, it is almost impossible to say this gives you a ‘better’ brain, just different.
Apparently, some doctors even tell their patients with Alzheimer’s Disease to do puzzles in the hope of keeping it at bay, since I don’t think it can be cured at the moment. So, in a way, that helps their brain to stay ‘better’, maybe?