When we want to acquire a new skill, we are faced with two choices: trial-error, or instruction. One is experience-driven or practice-based, the other is concept-driven or theory-based.

The trade-offs

Trial-error is the built-in mechanism humans come with to acquire knowledge and skills – our thinking processes are optimized for that. However, it may be expensive and impractical in some situations. For instance, learning to pilot an aircraft by trial-error is risky should you want to keep the chances of learning in the future high. We have developed systems that lower the cost of trial-error, though, such as pilot simulators. It can also be time-consuming: we just don’t have the time to trial-error every piece of knowledge our society is based upon!

Learning by instruction appears to be more efficient: we are presented with models and recipes that work, saving us a lot of time that we can use to advance our knowledge further. Nevertheless, the instruction is not always possible; sometimes the map of knowledge of a certain domain isn’t built yet, so we need to rely on the trial-error approach. Even most important is the fact that internalizing abstract knowledge not based on direct experience seems to be more difficult for humans.
This poses a question: how shall we learn?

The Dreyfuss model

In February 1980, Dreyfuss brothers published a seminal paper on how to teach: «A five-stage model of the mental activities involved in directed skill acquisition». This work was supported by the US Air Force, which was interested in improving their training programs.
What they said is 1) we should recognize the role of the first-hand experience in acquiring knowledge and 2) to become an expert it is necessary to learn the rules, guidelines, and maxims of the particular skill we are interested in.
The rules are the principles that always apply, they don’t depend on anything so they are context-free or non-situational. Examples of rules are the valid movements of a piece in the go game, the set of instructions in programming, the techniques in the Aikido martial art.
The guidelines are the principles that only apply in specifics contexts, so they are context-bound or situational. Things like josekis in the go game (sequences of moves in a specific part of the board), the design patterns in programming, or the katas in Aikido.
The maxims are principles that guide us towards achieving our long-term goal, they help us by assigning a value to guidelines: is this joseki worth it if I’m playing for territory in go? Is the ability to grow new features necessary for this specific part of the application? What specific throw should I use if I want to face the next adversary?
For one to become an expert, rules, guidelines, and maxims should be second nature.
Dreyfuss defines a 5-step process someone goes through to gain knowledge: novice, competence, proficiency, expertise, mastery. Others outline different systems that include three stages. What’s important is to realize that the learning process is at its best when we take a practical approach and theory is presented to the learner as they are prepared to assimilate the next artifact – rules, guidelines, maxims.

Coda

Learning to learn is probably one of the more important skills when we no longer know what’s coming next. The real world ^TM tends to be more chaotic and intertwined than the sequential process outlined by Dreyfuss. Realizing where are you at a particular skill will help you in making decisions about what focus on. For instance, am I a novice at skill X? Well, at this point, I’m better off focusing on learning the rules and imitate what others have done. And so on.
Learning also takes a lot of time – someone has even published a number, about 10.000 hours to become an expert in anything. It’s a lot! It may be discouraging. Luckily, a practice-based approach makes things more rewarding, and time flies when we are enjoying the process.