I really hate this article. Pretty much everything I've ever accomplished in my life is because I speak it into existence and hold myself accountable. But then again, if you're the type of person who makes things happen, you don't rely on crappy psychology studies to tell you how to live your life.
I've seen a lot of these "successful people do this thing!" stories, but after years of reading them and watching how people act, I've come to the conclusion that those people are successful by nature first, and all these things they do are helpers, not enablers. Doing that thing won't turn people into successes.
These things are crutches that successful people use to improve themselves, not something that they learned in order to be successful. They'd be successful either way, this is just easier.