Book summary: Pragmatic Thinking & Learning

This is the first part of my summary of “Pragmatic Thinking & Learning”, by Andy Hunt. It’s a book about how the brain works and how to take more advantage of it. It explores many interesting topics, like learning, focusing, the brain modes of operation, etc. Do note that I’ll skip many techniques/lessons in the summary, sometimes because they were less interesting for me (as in, I didn’t think they would work for me), sometimes because I already practise them. This first part will cover the introduction (in PDF), and chapters ”Journey from Novice to Expert” (in PDF) and “This is Your Brain”.


Despite advances in programming languages, techniques, methodologies, …, the defect density has remained fairly constant. Maybe we’re focusing on the wrong things: software is created in your head.

You don’t get taught, you have to learn. Everything is connected, there’s nothing in isolation, so sometimes small things can have unexpectedly larger effects.

Journey from Novice to Expert

The novice needs clear, context-free rules to operate, but an expert is ineffective when constrained by those same rules. Experts don’t just “know more” than novices, they experience fundamental differences in how they perceive the world, approach problem solving, etc. The stages of learning in the Dreyfus model are:

  • Novices. Have little or no previous experience in this skill area (“experience” results in a change of thinking; doing the same for years doesn’t count!). They don’t particularly want to learn, want to accomplish an immediate goal, don’t know how to respond to mistakes and are fairly vulnerable to confusion when things go awry (example of doing taxes for years on p. 20).

  • Advanced Beginners. Can start to break from the fixed rule set a little bit. Can try tasks on their own but have trouble troubleshooting. They want information fast (eg. API reference) and can start using advice in the correct context, but don’t have a holistic understanding and really don’t want it yet.

  • Competent. Can develop mental models and work with them effectively, troubleshoot problems on their own, and begin to figure out how to solve novel problems, as well as seek and take advice from experts. They’re typically described as “having initiative” or “resourceful” and tend to be in a leadership role in the team (formal or not). They’re great to have on your team because they can mentor the novices while not annoying the experts.

  • Proficient. Need the big picture, and thus will seek out and try to understand the larger conceptual framework around the skill. They’re frustrated by simplified information. This is the first level that can correct previous poor performance and revise their approach. They can also learn from the experience of others, which comes with the ability to understand and apply maxims.

  • Experts. Primary sources of knowledge and information in any field, continually looking for better methods and better ways of doing things. Statistically, there aren’t many: probably around 1-5%. Experts work on intuition, not reason. They may be completely inarticulate as to how they arrived at a conclusion. They aren’t perfect though, and have the same cognitive biases as everyone else. They’re also likely to disagree with one another.

Most people, for most skills, never get past the second stage. Plus, practitioners at a lower skill level have a marked tendency to overestimate their own abilities. Note that you want a mix of skills on a team. See “10 years to expertise” on p. 32. The dangers of overreliance on formal models (I’m skipping some in this list!):

  • Confusing the model with reality. It’s easy to confuse the two, but they aren’t the same.

  • Devaluing traits that cannot be formalised. Good problem-solving skills are critical to our jobs, but problem solving is a very hard thing to formalise.

  • Legislating behaviour that contradicts individual autonomy. You want thinking, responsible developers. Don’t reward herd behaviour.

  • Alienating experienced practitioners in favour of novices. Targeting your methodology to novices, you create a poor working environment for the more experienced.

  • Oversimplification of complex situations. Every project/situation is more complex than that.

  • Demand for excessive conformity. What worked great in your last project might be a disaster in the next one.

  • Insensitivity to contextual nuances. Formal methods are geared to the typical, not the particular. But when does the “typical” ever happen?

  • Mystification. Speech becomes so sloganised that it becomes trivial and loses meaning (eg. “we’re a customer-focused organisation”).

This is your brain

You have two “CPUs”: the linear, logical thought and language processing CPU (“L-mode”, for “linear”; the “left part of the brain”); and the searching and pattern matching CPU (The “R-mode”, for “rich”; the “right part of the brain”). They share the same bus so they can’t function at the same time.

R-mode can search “asynchronously” and come up with the response (possibly days) later. It doesn’t do any verbal processing, so the results are not verbal either (eg. trying to describe dreams). Also, it’s not under our direct concious control: as it can give answers anytime, we have to be ready to write down anything that comes up (related: everyone has good ideas, but far fewer track them; of those, even fewer bother to act on those ideas, and even fewer of those have the resources to make a good idea a success). It is very concrete, relating things as they are; it makes analogies and doesn’t require reason or known facts to process input. It’s holistic and wants to see the whole thing at once, perceiving overall patterns and structures. It’s intuitive, making leaps of insight, based on incomplete patterns, hunches, feelings or visual images. It’s very useful for software design.

Synthesis can be good for learning, see “Don’t Dissect the Frog, Build It” on p. 62. Aesthetics also make a difference, see p. 66-67. The brain is wonderfully plastic. There’s no limit to the number of skills you can learn, as long as you believe it (ie. what you think about your brain capabilities physically affects the “wiring” of the brain itself).

And that’s all for now. The next part will cover chapters ”Get in Your Right Mind” and “Debug Your Mind”.

EDIT: read the second part of this summary.