Sportive Thoughts

I've previously written on my suspicion that linguistic factors influence test-scores and that genes have a direct effect on linguistic ability. Now I want to take these musings a step further, and ask whether an open class of genes-- call them i-genes --are responsible for achievement in the classroom.

Before I start, I should clarify that I do not see a causal connection between i-genes and a child's first language. To argue that there is such a connection is ludicrous; very obviously, children are not programmed by genetics to speak a given language. We know this based on what we already know about language acquisition: it occurs uniformly in a stage spanning from 12months through 4 years. All humans learn their first language during this period from their home environment. However they do it, they do it at the same time and nearly the same pace without regards as to which language they learn. Local, regional, and global differences in language use only become an issue as the child grows up and demonstrate proficiency to adults who may use a slightly different language.

With that said, while there is no way i-genes can select which language a child speaks, it is plausible if not discoverable that i-genes can show a child's ability to speak any language to be greatly improved. Thus the central claim here is i-genes are directly related to basic cognitive ability.

That much is undoubtedly true. We see children inherit very many traits from their parents, and if we do not question whether height or eye-color is a direct expression of inherited genetic material, then we must accept that some amount of cognitive ability is also inherited. The major questions are how much? and does inheritance explain the existence of racially based student achievement gaps?

How Much Intelligence is Inherited?

The science of genetic inheritance is very old, and we need not learn much of it to understand how parents' intelligence can be passed on to sons and daughters. In the simplest terms, we can imagine four different i-genes: a dominant ("S") and recessive ("s") smart i-gene, and a dominant ("D") and recessive ("d") dumb i-gene.

Let's say Adam is quite average, with the following i-genetic makeup:

sd

Nothing spectacular about Adam; he's got a recessive version of both genes. Now let's consider his partner Eve, who has a different i-gene expression:

SD

Eve is an exact average with a dominant smart gene and a dominant dumb gene. Now we can determine all the possible inheritances of Adam and Eve's children:

Ss, Sd, Ds, Dd

Here we can see, with our oversimplified version of things, that Adam and Eve will have a 50%-50% shot at intelligent children.

Because Adam and Eve's prospects are so simplified, they more or less represent what to expect from the children of very average people. Now let's consider yourself, you very smart person:

SS + SS = SS, SS, SS, SS (100% smart)

SS + SD = SS, SD, SS, SD (50% smart, 50% average)

SS + Ss = SS, Ss, SS, Ss (100% smart)

SS + Sd = SS, Sd, SS, Sd (100% smart)

SS + ss = Ss, Ss, Ss, Ss (100% smart)

SS + DD = SD, SD, SD, SD (100% average)

SS + Dd = SD, Sd, SD, Sd (50% smart, 50% average)

SS + Ds = Sd, Ss, SD, Ss (75% smart, 25% average)

SS + dd = Sd, Sd, Sd, Sd (100% smart)

So it looks like, even if your partner is extremely dumb, the expectation is that your children will be average (assuming the interaction between two different, dominant traits is the exact average). According to our simplified model, you won't have dumb children.

Now, it turns out that the results are analogus in case you are extremely dumb yourself. If your i-gene pair is "DD", then the highest intelligence your children will show is "SD", or the exact average. More than half your partners will give you children as dumb as you; only one special someone is guaranteed to give you the averge child you hope for. Suddenly things look quite a bit less optimistic.

What does all this mean?

At best it means that if i-genes are simply passed down, then a basic intelligence level will be kept in the family until it is bred out *unless* a couple starts at average to begin with (like Adam and Eve). In other words, at face value it looks like the prospects of improving children's intelligence relies on selecting for  "smart", dominant i-genes. That means we are going to have trouble justifying efforts to close any achievement gap between races, if indeed i-genes coding different levels of intelligence are more predominant in one race over another. The pure genetics argument is daunting.

Why Genes Cannot Explain the Achievement Gap

If you are depressed, about to pop the champagne cork, or asking the NAACP to sue me to oblivion--stop. The simple picture I drew above has many holes in it, that upon closer examination, prove the genetics argument to be unsound.

William Dickens of the Brookings Institute has the following to say on the topic:

If researchers were able to identify all the genes that cause individual differences in school readiness, understand the mechanism  by which they affect readiness and the magnitude of those effects, and assess the relative frequency of those genes in the black and white populations, they would know precisely the extent to which genetic differences explain the black-white gap. But only a few genes that influence cognitive ability or other behaviors relevant to school readiness have been tentatively identified, and nothing is known about their frequency in different populations. Nor are such discoveries immanent.

So much for the direct arguments. We don't know any relevant facts about the genetic component of intelligence; therefore if we were to support even the oversimplified genetic argument above, we would have to do so relying on circumstantial and indirect evidence. Traditionally, this evidence has been test scores, including standardized tests and IQ exams. Many have tried arguing backwards from the results of such testin to the genetic root. However, there is ample evidence to suggest that such a backwards supposition would be incorrect.

Dickens writes:

Over the past century, dozens of countries around the world have seen increases in measured cognitive ability over time as large or even larger than the black-white gap... The score gains have been documented even between a large group of fathers and sons taking the same test only decades apart, making it impossible that the gains are due to changes in genes. Clearly environmental changes can cause huge leaps in measured cognitive ability.

The case seems to be shut; genes don't exclusively predict academic achievement. But to say that is only to refute an explanation, not provide one. Genes may exhibit predisposition to cognitive ability, but, given the fact that they do not explain the major differences between the intelligence of two groups, something else must account for the gap between minority and white achievement on exams.

In my next post, I will present Dickens alternate model, which stipulates that "multiplier processes" are available to Whites, and this difference in environment accounts for exaggerated differences in test scoring.