Based on the idea of building mental representations, I decided here to switch from taking notes sequentially as I read to creating my own summary of the arguments after reading, and then skimming the book again to correct details and fill in anything I missed. I don’t have any way to evaluate the effectiveness of different note-taking strategies, but this certainly produced a more readable reference. It does mean that I miss out on the detailed criticism I usually record, so maybe I should add an extra pass to check references and look for counter evidence.

(Author is psych professor. Studies expertise, and introduced the term deliberate practice.)

Expert performance is not as much a product of innate talent as is widely believed. First, the existence of prodigies usually turns out to be a myth - on further investigation every world-class expert has thousands of hours of practice/training behind them. Second, there are cases where effective training techniques have been able to raise arbitrary individuals to world-class levels eg:

Physical adaptability has only been explored in last 50 or so years - consider the huge difference in Olympic performance in that time, a result of better understanding of how to train athletes.

Mental adaptability even less well explored. Vast improvements in chess and music performance in the same time period though.

Adaptability is highest as a young child, but possibly much higher in adults than previously believed eg:

General adaptability is lower in adults, but still high enough to reach expert level performance in many cases. What absolute limitations does an adult have? Not much known yet, except that:

Brain physically changes. London cabbies, mathematicians, glider pilots, musicians, divers display measurable increases in sizes of certain parts of the brain.

Not free eg London cabbies get worse at abstract spatial memory, expert string musicians have worse sensation in the palm of their left hand.

Requires upkeep eg retired London cabbies show partial shrinkage.

Mental representations. Chunking. Build mental structures specific to domain of expertise and use ‘pointers’ to these to reduce load on working memory. Eg:

Hallmark of expertise is the ability to see patterns where beginners see chaos. Eg

Effective practice is the process of building and honing mental representations. Good mental representations also make practice more effective - by making one better aware of what to strive for and better able to notice and debug mistakes.

Deliberate practice:

Better to train at 100% effort and stop when exhausted, rather than less effort over more time.

This is hard! Motivation and engagement. Can come from:

Ensure you always have positive feedback by dividing training into manageable milestones, and measuring yourself against those regularly.

Environment is partially under your control. Sleep well, maintain health, remove potential distractions, surround yourself with motivated peers.

Is grit/willpower innate? Open question, but:

Mental representations don’t have to be built form scratch. Well-developed fields build up an understanding of how to transmit representations, and what kind of practice methods are good at honing them. For such a body of practice to build up, there must be:

So ideally, deliberate practice also involves:

Failing that:

Examples of deliberate practice:

In response to plateaus:

(Incidental rebuttal of the popular 10000-hour rule, which was popularized by Gladwell based on a misinterpretation of the authors work. ‘World-class’ is a measure that is relative to others in the same field, so the amount of time it takes to reach depends as much on the maturity of the field as anything. The first subject in the authors experiments digit span experiments reached what was at the time world-class performance after ~200 hours.)

Skills, not knowledge. Knowing something alone is not enough to build the mental representations to employ that knowledge effectively. Focus practice/training/education on what skills/abilities should be developed, not on what knowledge should be learned.

You pick up the necessary knowledge in order to develop the skills; knowledge should never be an end in itself

Given the drastic improvements in sports, chess and music in the last century, it’s natural to wonder what improvements could be achieved in other fields by applying the same principles.