First off, in the musicians community announcing your plans helps get people around them to help get them accomplished. For example, when someone tells me they are starting a new solo project I may know musicians for them. Putting your plans out to the world gets the word out to people so interested parties can come aboard or follow you and keep up to date if they are interested in the results.
It goes deeper then this though. I think the inherent wiring of many performers is a fear of embarrassment. This fear motivates a lot of us to work harder. I personally dread the idea of announcing any of my plans since my fear of failure is so intense, once I tell someone I am going to have to work so hard at it, I will be exhausted every moment of the day. As wel,l this study was not performed on “creative types” it’s main foundation is built on testing law students, whose minds I don’t think could be more different than most musicians.
While I don’t deny this study has merits and can be great advice for some people I think it is important to consider your own personality into the equation before deciding if it is right for you. Over time you start to find what helps motivate you and for me and a lot of my friends it is indeed a intense fear of failure. While this study is interesting and may help some people, use it to raise your awareness of your own patterns of motivation, rather than using it as a definite key to better success in your endeavors.