A very good article. It points out that when it comes to learning skills, it's not how many hours you practice that counts but how you pracitce. Since the blogger doesn't allow copying and pasting, please click the link and visit the site to read this good article.
http://colormalinsu.pixnet.net/blog/post/33104260勤能補拙的神話 20120210
編譯 高英哲
The following is the cited passage in English by Gary Marcus, the psychologist who learned to play the guitar, as mentioned in this article. It could shed some light on why practice doesn't make perfect.
"But practice alone is not enough. Hundreds of thousands of people took music lessons when they were young and remember little or nothing. The second prerequisite is what Ericsson calls "
deliberate practice",
a constant sense of self-evaluation, of focusing on one's weaknesses rather than fooling around and playing to one's strengths. Studies show that
practice aimed at remedying weaknesses is a better predictor of expertise than raw number of hours; playing for fun and repeating what you already know is not necessarily the same as efficiently reaching a new level. Most of the practice that most people do most of the time, be it in the pursuit of learning the guitar or improving their golf game, yields almost no effect. Sooner or later, most learners reach a plateau, repeating what they already know rather than battling their weaknesses, at which point progress becomes slow."