Back in the years before World War I, the I.Q. test was invented in Europe, first by Francis Galton in England, then by Alfred Binet in France. The idea of I.Q. testing was adapted in the United States for use in sorting millions of recruits for the Army, deciding which ones were officer material and which were the troops headed for the front lines.

After the war, American psychologists enthusiastically endorsed I.Q. testing. They were widely adapted and used in public schools to classify students. For many decades, psychologists believed that I.Q. was inherited and unchanging. Those who had high I.Q. were born that way, and those who had lower scores were born that way. But right after World War I, as some psychologists insisted that certain races and ethnic groups were superior to others, a few dissident psychologists (William Bagley comes to mind) discovered an inconvenient fact: Black students in the North had higher I.Q. scores than white students in the Appalachian South. Bagley and others made the case that environment was powerful in shaping intelligence and that education was key to changing the odds for poor kids. I wrote about this in chapter four of my 2000 book Left Back in a chapter called “I.Q. Testing: “That Brutal Pessimism.” It was Binet, the father of I.Q. testing who wrote in 1909, that we must reject those who “assert that an individual’s intelligence is a fixed quantity, a quantity which cannot be increased. We must protest and react against this brutal pessimism.” (p. 133).

In response to a reader who quoted I.Q. figures by race, I wrote:

You need not bring IQ into the discussion. It is impossible to make accurate generalizations, as impossible as it is to know what part of intelligence can be attributed to nature or nurture.

And in response to me,  Robert Shepherd wrote that scientists are learning more and more now about the effects of environment on intelligence.

He writes:

We are currently experiencing a revolution in our understanding of environmental effects on gene expression, and this emerging field of epigenetics completely invalidates those studies with identical twins on which the notion of IQ being highly heritable is based. It turns out that the environmental conditions experienced by the mother affect the conditions within her eggs which in turn dramatically affect gene expression which in turn dramatically affects the resulting phenotype. And, of course, that makes complete sense evolutionarily. For complex traits involving multiple genes, one should think of the genotype not as immutable inheritance but, rather, as a set of switches set in response to environmental conditions experienced by the mother. And that explains why one can get dramatic evolutionary change in very short time frames; in other words, epigenetics is an explanation for punctuated equilibria. All this science is relatively new, and it is revolutionary–paradigm shifting–and popular notions about genetics (including the vast literature of pop and pseudo-scientific evolutionary psychology to which The Bell Curve belongs) haven’t caught up with it. See the following report on a recent epigenetics conference for more information:

Folks who talk the Bell Curve line about immutable genetic inheritances and high heritability and folks who spout those IQ by race figures are talking antiquated, now-discredited nonsense. But it’s understandable that they still believe this crap because the relevant disconfirming science, here, is very, very recent. Another good current account: