Responding to David Shenk's The Genuis in All of Us

On the heels of Richard Nisbett's egalitarianism opus last summer comes another blank slatist treatise from David Shenk entitled The Genius in All of Us: Why Everything You've Been Told About Genetics, Talent, and IQ Is Wrong. Well, one surely can't admonish him for lack of ambition. I've read or listened to a number of interviews where he expounds on his banal and idealistic thesis. This post will be organized in bullets for clarity.

Confuses Necessity and Sufficiency: This is the primary problem with Shenk's argumentation strategy. Any high scoring LSAT student is assuredly familiar with the logical distinction between these two notions. For a given principle to apply, there are necessary conditions, those which must be achieved but may be achieved despite failure of the larger objective, and sufficient conditions, those that guarantee satisfaction of the given principle.

In this Bloggingheads conversation with Will Wilkinson, Shenk makes this rather elementary error, asserting that work ethic isn't merely a necessary condition but a sufficient one:

Everyone in the NBA is an extraordinary athlete and has spent years and years working their butts off and has worked very very hard and has all the qualities that you just stated. But Michael Jordan did stand above them in not just in his ability, but in all of these ingredients that we look at. We know that his drive and his ambition, we look at how he got to be where he is, it's just documented...So there is a difference in the quality of how people practice.

OK, so Jordan practiced really hard. That doesn't undermine the notion that a basic component of success is genetic (Wilkinson gives the fantastic example of Michael Phelps' body dimensions). It's pretty simple: Independently, hard work and proper genetics are necessary but not sufficient conditions for the highest levels of achievement. This anecdote brings me to my next point:

Using Anecdote and non-Quantitative Studies: In the Bloggingheads interview and in these two essays (WSJ and The Atlantic), Shenk employs what one could appropriately deem the "Gladwell strategy". His arguments are primarily buttressed by personal anecdote, individual instances, and a noticeable lack of quantitative corroboration. For example, take his comments on Michael Jordan whereby he appeals to this book from David Halberstam. Let's just assume this secondary source offers a reasonably accurate representation of Jordan's pugnacity. Yes Jordan's work ethic was legendary, but where are the books detailing the lives of Patrick Ewing, Clyde Drexler, Hakeem Olajuwon, Charles Barkley, and Karl Malone/John Stockton (the last pair of whom had an almost telepathic connection on the court - lots of practice perhaps?). We have absolutely no means by which to quantify Jordan's work ethic and appropriately compare it to a control group or cohort of individuals achieving a reasonably close measure of success.

In The Atlantic article where Shenk broaches cognitive ability, he points to a number of studies yet provides not one number allowing readers to gauge the practical implications. He discusses a study attempting to connect amount of verbal exercise during early childhood to adulthood intelligence:

Head Start wasn't getting hold of kids early enough. Somehow, poor kids were getting stuck in an intellectual rut long before they got to the program-- before they turned three and four years old. They devised a novel (and exhaustive) methodology: for more than three years, they sampled the actual number of words spoken to young children from forty- two families at three different socioeconomic levels: (1) welfare homes, (2) working-class homes, and (3) professionals' homes. Then they tallied them up.

Children in professionals' homes were exposed to an average of more than fifteen hundred more spoken words per hour than children in welfare homes. Over one year, that amounted to a difference of nearly 8 million words, which, by age four, amounted to a total gap of 32 million words. They also found a substantial gap in tone and in the complexity of words being used. As they crunched the numbers, they discovered a direct correlation between the intensity of these early verbal experiences and later achievement.

Of course, Shenk provides no actual data from the study. Contrastingly, Charles Murray provides data from a US study that controlled for home environment (middle class) and found that some underlying factor distinguishing siblings (genetics?) had a substantial effect on adulthood achievement.

Each pair consists of one sibling with an IQ in the normal range of 90-110 ,a range that includes 50% of the population. I will call this group the normals. The second sibling in each pair had an IQ either higher than 110, putting him in the top quartile of intelligence (the bright) or lower than 90, putting him in the bottom quartile (the dull). These constraints produced a sample of 710 pairs. In 1993, when we took our most recent look at them, members of the sample were aged 28-36. That year, the bright siblings earned almost double the average of the dull: £22,400 compared to £11,800. The normals were in the middle, averaging £16,800.

Additionally, Shenk never actually quantifies the magnitude of improvement. He uses ambigious phrases like" positive influence", "importance of", and "growth mindset", but never distinguishes between minimal mutability such as passing algebra and gross malleability such as getting a physics PhD. The former of which has little implications beyond personal appeasement and confirming erudite theories of educational philosophy. (In Real Education, Murray alludes to studies where intense academic intervention engendered about a 5% gain in test scores). Then when Shenk does provide an appeal to specific data, he forgets to qualify his optimism through a modicum of critical thinking.

The same dynamic applies to talent. Something crazy happened to the world's violinists in the 20th century: they got better faster than their peers had in previous centuries. We know this because we have lasting benchmarks, like the effervescent Paganini Violin Concerto No. 1 and the concluding movement of the Bach Violin Partita No. 2 in D Minor—14 minutes of virtually impossible violin work. Both pieces were considered nearly unplayable in the 18th century but are now played routinely and well by a large number of violin students. (The Bach is now routinely included in the repertoires of music schools and competitions).

Does he consider that perhaps, with expedited travel and the spreading of classical music throughout the civilized world, there are simply more people playing violin? Let's say in the 18th century, only 100 people in the entire world played violin seriously. If only 1% (and thus 1 person) of the violin-playing population had the genetic gifts to master such an arduous task, then yes, one could justifiably conclude this piece was virtually impossible. But 200 years later, let's say 10,000 people play violin seriously. Now there are 100 who can play and thus it would seem to be relatively routine. And remember, the repertoires of music schools and competitions, especially in the highly competitive suburbs, are for the best of the best.

As for the supposed increased talent of our runners and tennis players, on the scale of human ability (from the fat kid in 4th grade huffing his way after one lap to Usain Bolt), the improvements gained through fastidious study of experts are picayune.

Attacks Genetic Determinism Strawman: As with most blank slatists, Shenk argues against a concocted framing of the hereditarian argument. By showing environment and work ethic are important factors in achievement, Shenk believes he undermines the genetic argument.

That's because genes interact with their surroundings, getting turned on and off all the time and, even more amazingly, saying different things depending on whom they are talking to. "There are no genetic factors that can be studied independently of the environment," explains McGill University's Michael Meaney, in his article "Nature, Nurture, and the Disunity of Knowledge." "And there are no environmental factors that function independently of the genome. [A trait] emerges only from the interaction of gene and environment."

Let me repeat this rather obvious point: No sane person asserts that genetic predilections define a rigid trajectory of one's successes and failures. As stated above, merely illustrating the influence of environment does not invalidate the hereditarian viewpoint. My conception of the nature/nurture dichomoty is that genes define a reasonable interval for one's potential achievement. Then, environment and work ethic, amongst other non-biological factors, pinpoint one's position on that interval. This squares much better with the available evidence than Shenk's specious claims.

I've skimmed over a number of other interviews and articles. Shenk basically keeps repeating the assertion that the genetic hypothesis is an antiquated myth promulgated by the likes of Francis Galton. He rarely provides actual scientific support besides referencing some intrepid group of "scientists" or innovative rat studies! He also quite predictably engages in standard IQ denialism deriding the Bell Curve and positively citing Robert Sternberg's drivel. I don't feel like regurgitating these easy arguments countering this romanticism.

Finally, if intelligence is a pliable attribute, then surely our decades of educational reform would have spurred a mild improvement in academic achievement. We must have hit something right in the last forty years. If so, please explain the chart above. What we really need is a "Skinner Box" experiment on a bunch of kids. But I doubt that will happen any time soon.

[If you have any other studies that show stability in human traits, cognitive, physical, or otherwise, please include them in the comments and I will add them to the post.]