The old idea that the brain is fixed and doesn’t change after a certain young age has now been completely debunked. In the last decade there have been huge advances in the understanding of how the brain works. Perhaps the biggest advance is that we now know that the brain is very “plastic” or malleable. Rather than being fixed by a certain age, the brain is constantly changing, dependent on how we train it. In fact, we can continue to grow new brain cells throughout the lifespan and are constantly creating new pathways that underpin new behaviors and mental function.
There has been a lot of research on this topic. For example, musicians who play stringed instruments have motor areas of the brain responsible for fine movement that are far more developed than the rest of us. Trainee taxi drivers learning the complex geometry of London streets actually showed development of the spatial areas of their brains.
In one famous case a blind boy, Daniel Kish, taught himself echolocation — the ability to navigate around physical space by listening to the echoes of sounds he emitted, like dolphins do. When Daniel was examined, the visual areas of his brain had created new connections with the areas responsible for sounds, effectively enabling him to “see” sounds. Despite being blind he can ride a bike and do many things that would be unthinkable to someone who had no sight.
So, we now fully accept that not only can the brain be retrained, this is happening all the time through our own actions and behaviors.