Lead Lowers IQ Levels, Mexican Immigration Lowers America’s Average IQ

I hear news about Flint, Michigan, all the time, about how the lead in the drinking water can lead to lower IQs and how horrible that is. In this type of story, the MSM displays no doubts about the importance of IQ. Also, when it comes to morons getting off the death penalty because they are so stupid, again the MSM believes in the importance of IQ.

What about latino immigration? That lowers America’s average IQ. How come there’s no hand wringing in the MSM about that? When low-IQ folks have more children than high IQ folks, that lowers the average IQ. Why isn’t that a major issue?

Jason Richwine writes for Politico:

My Harvard Ph.D. dissertation contains some scientifically unremarkable statements about ethnic differences in average IQ, including the IQ difference between Hispanics and non-Hispanic whites. For four years, the dissertation did what almost every other dissertation does — collected dust in the university library. But when it was unearthed in the midst of the immigration debate, I experienced the vilification firsthand.

For people who have studied mental ability, what’s truly frustrating is the déjà vu they feel each time a media firestorm like this one erupts. Attempts by experts in the field to defend the embattled messenger inevitably fall on deaf ears. When the firestorm is over, the media’s mindset always resets to a state of comfortable ignorance, ready to be shocked all over again when the next messenger comes along.
At stake here, incidentally, is not just knowledge for the sake of knowledge, but also how science informs public policy. The U.S. education system, for example, is suffused with mental testing, yet few in the political classes understand cognitive ability research. Angry and repeated condemnations of the science will not help.
What scholars of mental ability know, but have never successfully gotten the media to understand, is that a scientific consensus, based on an extensive and consistent literature, has long been reached on many of the questions that still seem controversial to journalists.
For example, virtually all psychologists believe there is a general mental ability factor (referred to colloquially as “intelligence”) that explains much of an individual’s performance on cognitive tests. IQ tests approximately measure this general factor. Psychologists recognize that a person’s IQ score, which is influenced by both genetic and environmental factors, usually remains stable upon reaching adolescence. And they know that IQ scores are correlated with educational attainment, income, and many other socioeconomic outcomes.
In terms of group differences, people of northeast Asian descent have higher average IQ scores than people of European lineage, who in turn have higher average scores than people of sub-Saharan African descent. The average score for Hispanic Americans falls somewhere between the white and black American averages. Psychologists have tested and long rejected the notion that score differences can be explained simply by biased test questions. It is possible that genetic factors could influence IQ differences among ethnic groups, but many scientists are withholding judgment until DNA studies are able to link specific gene combinations with IQ.

How can I be sure all of this reflects mainstream thinking? Because, over the years, psychologists have put together statements, reports, and even books aimed at synthesizing expert opinion on IQ. Many of these efforts were made in explicit response to the periodic media firestorms that engulfed people who spoke publicly about cognitive science. It’s worth reviewing some of those incidents and detailing the scholarly responses — responses that are invariably forgotten before the next furor begins. I’ll place my own experience in that context.
Let’s start 25 years ago, with the publication of The IQ Controversy, a book by Mark Snyderman and Stanley Rothman. The authors surveyed more than 1,000 experts in the field of cognitive science to develop a picture of what the mainstream really looks like. It was very similar to the description I’ve supplied above.
Snyderman and Rothman then systematically analyzed television, newspaper, and magazine coverage of IQ issues. They were alarmed to find that the media were presenting a much different picture than what the expert survey showed. Based on media portrayals, it would seem that most experts think IQ scores have little meaning, that genes have no influence on IQ, and that the tests are hopelessly biased. “Our work demonstrates that, by any reasonable standard, media coverage of the IQ controversy has been quite inaccurate,” the authors concluded.

In conducting the expert survey and contrasting the results with media depictions of IQ research, one would think Snyderman and Rothman had performed a valuable service. Surely public discussion of IQ would now be more firmly grounded in science?
It didn’t happen. Richard Herrnstein and Charles Murray’s The Bell Curve was published in 1994, and real science was hard to find in the media circus that ensued. Herrnstein and Murray’s central claim about IQ differences shaping class divisions continues to be the subject of reasoned debate among social scientists. But non-experts in the media questioned whether IQ is even a valid concept. Intelligence research – psychometrics — is a pseudoscience, they said. The tests are meaningless, elitist, biased against women and minorities, important only to genetic determinists. And even to discuss group differences in IQ was called racist.
In short, the media did everything Snyderman and Rothman had warned against six years earlier. As a consequence, the interesting policy implications explored by Herrnstein and Murray were lost in the firestorm.

About Luke Ford

I've written five books (see Amazon.com). My work has been covered in the New York Times, the Los Angeles Times, and on 60 Minutes. I teach Alexander Technique in Beverly Hills (Alexander90210.com).
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