Can't grow new brain
Uhm....unlike lack of athleticism or hight or skill, etc, changing your mindset is what a mentor is actually for. The human brain is highly plastic. If Young has the desire and the right mentor, he can totally change his mindset on how he approaches the game, and improve his basketball IQ.
Good point. There is a mental health model of performance that highlights the impact of mood states on athletics. The majority of sports psychology are actually consultations for anxiety-related performance issues, though. The treatment modalities used are common for anxiety in clinical patients - relaxation, imagery, cognitive restructuring (my favorite) - but minus a few individual studies and one meta-analysis (that tested different models, not tx efficacy), I have not come across many effectiveness studies. Have not come across any studies that looked at pre- and post-brain activity differences, either.
I think Young could have benefited from coming along when Rondo and Perk did. I think both were probably pretty significantly influenced by their environment, benefiting from the modeling of the Big 3. For Perk, perhaps work ethic and just literally finding a home where his talents would fit with the team's needs. I'd guess Rondo for mood-related issues and he may be a better, though loose comparison of how the culture can help someone develop in the face of personal difficulties.