Rehearsing a new alternative with emotional intensity creates a new highway in the brain. (Robbins, Anthony. Awaken the Giant Within. p 136-140. NY: Fireside, 1991.)
We have to work harder and longer to change a habit than when we learned it in the first place. (Goleman, Daniel, PhD, with Richard Boyatzis, and Annie Mckee. Primal Leadership. p 104-105. Boston: Harvard Business School Press, 2002.)
The more higher skills (e.g., bike riding, cognition) are practiced the more automatic they become. Initially these routines require mental strain and stretching—the formation of new synapses—but mastered, the mental processing becomes easier. Neurons initially recruited for the learning process are freed to go to other assignments, the fundamental nature of learning in the brain. (Ratey, John J., MD. A User’s Guide to the Brain. p 34-35. NY: Vintage Books, 2002.)
Estimates are that 10,000 hours of practice is required to achieve world-class level of mastery, in music as well as any field of endeavor. (Sternberg, Barbara, PhD. Music & the Brain. p 20-21. CA: Institute for natural Resources, Home-Study #2320, 2009).
According to Ericsson, the highest levels of performance and achievement appear to require at least 10 years of intense prior preparation—sometimes referred to as the Ten-Year Rule. (Restak, Richard, MD. The New Brain. p 23. PA: Rodale, 2003.)