From the article:

[] Three of the twelve subjects did not use the recommended high-level language JTS for solving the task, but rather programmed in assembly language instead. Two of these three in fact required the longest working times of all subjects. One might argue that the decision for using assembly is part of the individual differences, but presumably most programmers would not agree that doing the program in assembly is the same task as doing it in a high-level language.

In my experience, making the right decisions like that is the real difference between good and not so good programmers. Good programmers do on average better choices that results in less code, code that is easier to maintain and reason about, and choosing language and architecture that fit the problem at hand. It is not that good programmers develop so much faster usually.