Nobody is born an expert and starts creating music or playing chess straight out of the womb. So let's not stretch the argument all the way down ad absurdum. Assuming some basic skill development (like familiarizing with the rules of the game) has taken place and some basic abilities  (like understanding the rules of the game) are present, one can then ask a more interesting question- which of the two factors- on the one hand- genetic/ fixed in nature like intelligence or ability; versus on the other hand, environment and self-driven/ malleable in nature like an enriched environment/ deliberate practice, are more instrumental in eminent performance and exceptional expertise.  

I am the first one to shy away from pitting one thing vs. other and thinking in the frames of dichotomies; but the recent debate in Intelligence is framed in these terms so despite believing in nature via nurture etc. etc., I will take the bait.

First off, though I intend to read the full debate, but reading the introduction by Detterman was good enough to make me think and come up with a rejoinder, so still haven’t moved beyond the introductory artcile. If you hate Ericsson or the argument for deliberate practice, please stop reading now.  You have been warned.

Detterman makes the argument that finding no correlations between IQ and many expertise outcomes is methodically flawed and short-sighted.  He illustrates this with an example of NBA (basketball) players. He did some study of NBA players and found no correlation between height and salary and also between height and points scored. Instead of being humbled by these outcomes and recognizing that after a threshold of height, not having which could act as a limiter/ constraint, beyond that threshold of height, height provides you with a zero discriminatory advantage over those who may be similarly endowed, he takes a to-me-comical stance that this proves that low correlations of IQ with say chess expertise or musical expertise is explained similarly and experts in these depend critically on Intelligence to thrive.

A crucial part of his muddled argument is that we should consider mean effects. Basketball players have significantly higher mean height than standard American population, but also crucially (to me) a greater variance. If height was crucial to basketball success, I would have expected the variance in height to be much less than the general population, but obviously its otherwise, and Detterman choses to gloss over this fact. The logic of focusing on means is to challenge the deliberate practice paradigm, showing that on average the NBA basketball players have greater heights than sample population, and similarly that expert chess players have higher IQ than normal population. Thus proving that its intelligence that matters and not parctise.

Let me turn the argument around. What does Detterman think is the average deliberate practice a normal American puts in say practicing basketball or say practicing music/ chess? I would assume it should be close to double digits , say 100 hours, with a wide variance. What about experts – again As Anders has shown it should be in the range of 10,000 hrs, with a lot less variation. Again if looks at mean effects , I’m sure 10,000 hours would be at a very high SD, than the mean of population, assumed as 100 in our case. Relying solely on mean also, would make a strong case for the importance of deliberate practice (which is mix of hard work, strategy, motivation and a growth mindset imho) over the ability side of the debate. Just like Detterman makes the case that it is hard to find a person with a height of 70 in.(which is the American national average and deviates remarkably from 79 in. height which is NBA average) in the NBA sample, I challenge him to find a player in NBA who got in their by fluke, without putting in the hard work and deliberate practice to the tune of at least 100 hours ( the assumed national average). If one cannot find such a player on should gracefully acknowledge that minimum thresholds of both deliberate practice and ability may be required but beyond a threshold, things change and perhaps given the other overwhelming data, beyond those thresholds deliberate practice (motivation included) is much more relevant and differentiator for expert performance than supposedly ‘innate’ ability.

To illustrate by another example (which may resonate with Plomin et al, another set of contributors to the current debate), assume that height is largely genetic. Then genetic or innate factors would be crucial for extraordinary (big/small) height.  Of course there is an interplay with environment in the sense that if we don't provide the raw materials on which genes can build (the right environment), then the maximum height may be limited by environmental factors- thus in poor countries with low nutrition, not only should mean height be low, it should also have less variance as people are limited by the environmental constraint- here whatever low variance should exist should be explainable by environmental factors; in rich countries, on the other hand,  where environmental factors become immaterial, the height is totally under genetic control  and all the variance should be genetic in nature and explainable by genes. Also the mean should be higher now.

Now assume a trait, say being an expert in basketball, is totally under environmental control. Genetic or innate differences are totally immaterial, unless a gene, say causing muscular dystrophy, prevents you from playing basketball. In this case, the early exposure and deliberate practice you receive as a child should be instrumental in shaping whether you end up and expert and continue putting the 10,000 hours. Expertise may still run in families (like the musical gharanas) , but be totally inexplicable by genetic factors, but more by early exposure and shared environment.  Also because expertise & abilities are domain specific, while actually putting in 10,000 hrs of deliberate practice a domain general phenomenon, one can study expert twins and siblings, and see if they are indeed more experts in twins than in siblings, and experts in the same domains or different domains to tease apart whether shared environment is behind expertise or its more about genetic and innate factors. 

But returning back to the original thought experiment, assuming basketball playing expertise is environmental, and assuming no underlying genetic differences at play between different nations' populations, one would assume that the basketball team which would be at advantage in international competitions, would be that which can provide the right environmental trainings etc. to its participants. I am totally ignorant about sports, but have a hunch that rich and developed nations, that are willing to invest more in training of their teams, typically fare better than poor and developing nations. If someone from developing nation, in these conditions is able to make a name for herself, it may be paradoxically because her genes may provide her an advantage. Assuming a common genetic human pool across nations, the fact that some nations win more Olympic medals than others should be explainable by no facts other than the environmental ones- right trainings, coaching etc. in the nations that win versus poor ‘infrastructure’ (an enabler of deliberate practice) in countries that don't do so well.

The point I want to make is, that is should be obvious to anyone that thresholds of both ability and expertise are required for exceptional performance or expertise; beyond that threshold, its equally clear to me, that the differentiator and enabler is the right amount of deliberate practice, right motivation, hard work and a growth mindset.

Now waiting for the backlash from the IQ fundamentalists!

About the Author

Sandeep Gautam

Sandeep Gautam is a software developer and science writer at The Mouse Trap.

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