Nice, if conventional, refutation

A nice piece in yesterday's NYT by psychologist Richard E. Nisbett on the race/intelligence controversy sparked by The Bell Curve and reignited recently by James Watson. (Thanks to Michael Bowerman for pointing it out).

Nisbett cogently and concisely deflates the claims that intelligence has been proven 60-80% "heritable" by twin and adoption population studies. By the end of the piece, the reader is left with the strong impression that those studies are flawed and misleading. They don't stand up, even on their own terms.

What Nisbett doesn't do -- understandably, because it's a lot trickier -- is explain how those population studies also fly in the face of our modern understanding of genetics. It's not biologically possible for someone to directly inherit, via genes, a certain level of intelligence. Genes don't work that way. Everything about our genes is mediated through interaction with the environment. The dichotomy of "nature vs. nurture" actually does not exist.

Our popular discussion of genetics, intelligence, talent etc is stuck in a very strange place. We use terms, concepts and metaphors which lead us astray. In order to get unstuck, we're going to need a whole new way to frame the discussion. That's what I'm working on (struggling with) in my book.

Comments

[Pat Mathews]

One way to mediate the entire intelligence debate is to teach people that they can beat out the natively gifted by doing work. (Of course, they have to believe it, and be faced with people who will be convinced by the results of doing work.)

I was about to explain the entire proposition and go into detail when I realized Aesop had gotten ahead of me 3,000 years ago. "And the gold medal for the marathon goes to - the Turtle!"

[notkevinnealon]

I think that the easiest way to frame the idea is a concept that I was taught in my chiropractic education - about the expression of your potential. My understanding has always been that the genes that your parents passed to you gave you the POTENTIAL CAPACITY to achieve certain traits. From conception on, your environment has shaped the ACTUAL CAPACITY of these traits.

Whether it's the capacity to perform complex mathematical calculations (or map spatial relationships or bench press 250 lbs or combine the fine motor, gross motor and cognitive abilities to hit a drive 290 yds down the center of the fairway) in each instance, your genetics determined your ultimate capacity for each component needed to acquire a skill. Over time, a multitude of factors interplay to fill the void with talent.

Thus, when considering intelligence, talent or any other measure, in terms of genetics, I think that it is easiest to frame the heritability portion of the discussion (nature) in terms of how big of a bucket were you given (potential capacity). The environment's effect on this(nurture) leads to the ultimate expression of each trait in terms of how much will each of your buckets get filled up (actual capacity).

An addendum to this is that there are some instances by which you may artificially enlarge or shrink the size of each bucket. Anabolic steroids can magnify the effect of your genetic expression (potential capacity) for strength, speed etc, and depending on whether you put the time in at the gym or not, you can potentially increase the actual capacity for the trait (strength). Chronic alcoholism can affect your cerebellum, thereby diminishing your potential for fine motor skills, in effect shrinking your bucket.

Either of these (increasing or decreasing the size of the bucket) may or may not have an effect on the ultimate expression of the traits (actual capacity), depending on how much work is put into developing the particular traits.

At the end of it all, it comes down to: A)what size is each bucket for each trait? B) have you added any externalities that can artificially increase the size of any of these buckets? and C) how much have you filled each bucket up?

[Riz]

I have been looking to the field of 'Epigenetics' to provide some of the answers to the nature/nurture debate. I consider it the potential connecting bridge between these two worlds and am optimistic that the more we learn, the more we will come to realise that nature and nurture and more tightly meshed than we previously comprehended.