The Role of Deliberate Practice in the Acquisition of Expert Performance

by James Somers, February 9, 2010

I have just finished reading a famous paper by Ericsson, Krample, and Tesch-Romer called “The Role of Deliberate Practice in the Acquisition of Expert Performance” (1993, Psychological Review).

The paper’s key claim is that performance—be it in chess, or swimming, or violin—is a monotonic function of accumulated deliberate practice. More deliberate practice equals better performance.

So what is “deliberate” practice, and how is it different from the regular kind?

The most cited condition concerns the subjects’ motivation to attend to the task and exert effort to improve their performance. In addition, the design of the task should take into account the preexisting knowledge of the learners so that the task can be correctly understood after a brief period of instruction. The subjects should receive immediate informative feedback and knowledge of results of their performance. The subjects should repeatedly perform the same or similar tasks.

So there should be an “active search for methods to improve performance,” immediate informative feedback, structure, supervision from an expert, and “close attention to every detail of performance ‘each one done correctly, time and again, until excellence in every detail becomes a firmly ingrained habit.’” Deliberate practice is demanding and can be quickly exhausting. It’s usually not enjoyable in its own right.

Here’s an example from chess:

In informal interviews, chess masters report spending around 4 hr a day analyzing published chess games of master-level players. Selecting the next moves in such games provides an informative learning situation in which players compare their own moves against those selected in an actual game. A failure to select the move made by the chess masters forces the chess players to analyze the chess position more carefully to uncover the reasons for that move selection. There exists also a large body of chess literature in which world-class chess players explicitly comment on their games and encyclopedias documenting the accumulated wisdom on various types of chess openings and middle-game tactics and strategies. An examination of biographies of world-class chess players… shows, contrary to the common belief that chess players have developed their chess skills independently, that these elite players have worked closely with individuals… who explicitly taught them about chess and introduced them to the literature.

Now that youngsters have access to cheap and super-powerful chess software, in which every position can be meticulously analyzed and moves can be compared across vast historical databases, it’s no wonder that grandmasters are getting better faster. Structured deliberate practice is now easier to come by.

(As it is in poker. All these kids playing online can not only play many orders of magnitude more hands than their veteran predecessors, but they also—like chess players—have continuous access to analytics and hand histories which make perfect fodder for intense study. They can play at a dozen tables simultaneously and work hard on various techniques, situations, and methods, all the while collecting data and keeping track of metrics like percentage of limp-ins, % of hands played off the small blind, % flops seen, etc., for themselves and everyone else at the table.)

Anyway, that 4-hour figure cited above is actually quite common. In fact, the profile of top performers in every field the paper surveyed is remarkably consistent:

  • They start practicing seriously at around 8 years old (sometimes younger), usually after showing unusual “promise” or interest.
  • They seek out and work individually with a handful of mentors or teachers.
    …it is generally recognized that individualized supervision by a teacher is superior. Research in education reviewed by Bloom (1984) shows that when students are randomly assigned to instruction by a tutor or to conventional teaching, tutoring yields better performance by two standard deviations.
  • In addition to coaches / trainers / tutors, they regularly compete on a local or regional level. Doing well in these competitions validates their and their parents’ expense (of time, money for transportation / travel, etc.). So intense practice continues.
  • The duration and frequency of practice sessions gradually increases. (If you immediately started training at an expert’s pace, you’d burn out.) Top performers practice about 4 hours per day in 80-120 minute sessions. There are decreasing marginal returns after the first hour and a half of a session.
  • Athletes work most intensely in the mid-afternoon. Scientists and novelists almost uniformly prefer the morning. These choices make sense from a biophysical perspective.
  • Experts are totally immersed. In addition to practice, they spend 50-60 hours per week on domain-related activities, like lessons, competitions, study, group practice / performance, individual play / performance, etc.
  • Before producing their best work, they need to have completed about 10 years or 10,000 hours of deliberate practice.

It’s hard to overstate the importance of an early start. It’s simply not possible for late bloomers to catch up, since they won’t even be able to practice as much as the elites who started early:

…it is impossible for an individual with less accumulated practice at some age to catch up with the best individuals, who have started earlier and maintain maximal levels of deliberate practice not leading to exhaustion. As noted earlier, the amount of possible practice appears to slowly increase with accumulated practice and skill. Hence, individuals intent on catching up may suddently increase the amount of deliberate practice… Within months these individuals are likely to encounter overuse injuries and exhaustion… Furthermore, the difference in accumulated deliberate practice in late adolescence for the good and best violinists [the two groups in one study, the latter of whom started earlier] is remarkably large and to eliminate this difference the good violinists would have to practice an additional 5 h per week beyond their current optimal level of weekly practice for more than 8 full years.

There are some exceptions. Scientists in particular don’t start intense research until their late teens or early twenties, which is why they often produce their best work in their mid-thirties. The key for them is to write:

In support of the importance of writing as an activity, Simonton (1988) found that eminent scientists produce a much larger number of publications than other scientists. It is clear from biographies of famous scientists that the time the individual spends thinking, mostly in the context of writing papers and books, appears to be the most relevant as well as demanding activity. Biographies report that famous scientists [like Darwin, Pavlov, and Skinner] adhered to a rigid daily schedule where the first major activity of each morning involved writing for a couple of hours.

Why is writing so useful? Writing is hard, structured, and it clarifies thinking. It’s also one of the most effective ways for scientists to get feedback. This is part of the reason why consistent academic blogging can be so effective, especially if the blogger has a decently large audience. (And it makes one yearn for the writerly equivalent of chess or poker software, like a program that spat out a quality metric for each of your sentences as you typed.)

Anyway, the overall picture that emerges from this (quite long) paper is that innate talent counts for very little—even things like lung capacity, heart size, capillary density, dexterity, etc., that we might take to be genetically endowed, turn out to change considerably with years of deliberate practice. Or to take another example, excellent pianists don’t have faster reaction times than amateurs; they only outperform the amateurs on tests specifically related to training on the piano. Nor is there a clean relationship between chess ability and IQ. And so on.

Which is why the authors are right to instruct us to think of “expert performers not simply as domain-specific experts but as experts in maintaining high levels of practice and improving performance.” These are people who have what Sir Francis Galton called “an adequate power of doing a great deal of very laborious work.”

So you want to become good at something? Use the Archimedean method:

Archimedes taught us that a small quantity added to itself often enough becomes a large quantity (or, in proverbial terms, every little bit helps). When it comes to accomplishing the bulk of the world’s work, and, in particular, when it comes to writing a book, I believe that the converse of Archimedes’ teaching is also true: the only way to write a large book is to keep writing a small bit of it, steadily every day, with no exception, with no holiday.

- Paul R. Halmos, I Want to Be a Mathematician