Human Varieties

Year: 2013 (Page 4 of 6)

HVGIQ: The Bahamas

March 12, 2013 / / 5 Comments

The Bahamas is one of the most prosperous nations in the world (Third highest GDP per capita in the Americas, behind the US and Canada), with an economy, much like the Cayman Islands, primarily dependent upon tourism and finance. The population, not much larger than 350,000, is 85% black, 12% white, and 3% Asian and Latin American.

IQ and the Wealth of Nations (2002) does not have a study for The Bahamas, but estimates an IQ of 78 by using the score from Barbados (p. 74). IQ and Global Inequality (2006) estimates an IQ of 84 by averaging the scores from Cuba and the Dominican Republic (p. 55), and this is the estimate still reported in the most recent book (Lynn & Vanhanen, 2012, p. 20).

Here I discuss measured IQ data for The Bahamas from two different studies. Continue reading

Color Differences: Ubiquitous Yet Understudied

March 6, 2013 / / 0 Comments

Note: Our analysis has been updated and extended. Refer also to: Color Differences: Corrections and Further Analysis. Part 1

(or Colorism: Game Over)

Introduction

Following up with Dalliard’s pioneering post on colorism, we looked at the relationship between skin color, cognitive ability, and educational attainment in the full NLSY 97 sample (across all racial and ethnic groups). Our purpose was to test what we term “Strong Colorism”. According to “Strong Colorism”, color discrimination is a unifying explanation for sub-population differences in the US and beyond; it is a generalized phenomenon that can account for pigment related outcome differences. Lest readers suspect that a straw position is being constructed, below is an excerpt from an article, recently published in the journal of Industrial and Organizational Psychology, discussing this model (which the authors take to be established):
Continue reading

HVGIQ: Jamaica

March 1, 2013 / / 16 Comments

IQ and the Wealth of Nations (2002) cites one study for Jamaica (Manley, 1963 ). The sample size is nearly two thousand school children, and the reported IQ is 72 (p. 209). Lynn’s various updates to that book have included five additional references. However, in another anomaly, the most recent book contains only two references, both with relatively small sample sizes, and omits the large study altogether. The IQ estimate for Jamaica has also been lowered to 67! (Lynn, 2012, p. 403)

Here I review over 20 intelligence test studies from Jamaica. I find that Lynn’s numbers were not accurately reported, and that IQ is significantly higher in Jamaica than his books have claimed. Continue reading

Colorism in America?

February 22, 2013 / / 4 Comments

Previously, we established that skin color and intelligence are correlated in the NLSY97 sample as predicted by hereditarian theory. Continuing this investigation, we looked into how these variables go together within and between African American families in the same sample. In other words, we wanted to know if lighter-skinned individuals tend to be smarter than their darker-skinned siblings just as the average light-skinned black in the general population is smarter than the average dark-skinned black. Continue reading

Gildea (1992): A lost IQ study of transracially adopted Koreans

February 16, 2013 / / 7 Comments

In 2005 one of my co-bloggers at Gene Expression posted an excerpt from a Wall Street Journal article asserting that large US ethnic performance differences in spelling bees were due to dubious cultural values. My response was Is it Really Bee-cause of Culture?, which argued that cultural arguments for ethnic differences (at least in their standard formulations) are empirically false. First of all, it’s one thing to argue that “correlation does not imply causation”, but most claims about, say, Asian super-parents or black anti-intellectualism don’t even rely on real correlations, but ex post facto rationalizations: Asian parents must be amazing, because look at how well their kids perform! Research has disconfirmed many of these supposed ethnocultural advantages and disadvantages. Second, behavior geneticists have looked at full siblings, half siblings, adopted siblings, etc; even where real correlations between outcomes and home variables exist (e.g., children with high IQs come from homes with more books), these correlations are demonstrably the result of shared genetic background between parents and their biological offspring, not due to the influences of home environment. Third, and this will be my primary focus here, transracial adoption research is able to test these claims even more directly. Do people from ethnic group Y, that are raised by parents from ethnic group Z, grow up to become like people from biological group Y or from cultural group Z? Again this research has not been kind to culture theory. (“Culture”, of course, could also be transmitted through other hypothetical social influences, but it is not my intention to discuss this all in great detail right now).

Shortly after writing that post, I decided that more needed to be written about transracial adoption research as a behavior genetic experiment. Arthur Jensen, Richard Lynn, and J. Philippe Rushton have all cited the Minnesota Transracial Adoption Study, as well as several IQ studies of transracially adopted Asians, in support of the hereditarian position. And Richard Nisbett has referenced several other adoption studies that suggest no racial gaps. However, I suspected there was more data for transracially adopted children than what this small cadre of scientists had already discussed (at the very least for important variables other than intelligence); research that could give us a more complete picture of what these unusual children become, and what this can tell us about the causes of ethnic differences in socially valued outcomes.

So I spent a number of months during 2006 doing research for an E-book idea (tentatively titled Race Differences & Transracial Adoption). And there were indeed a number of novel and revealing finds in that process. Unfortunately—as usual—I could not obtain all the existing research I wanted, so I never proceeded with the project. Even worse, I never shared what I had discovered with a wider audience. Human Varieties can now serve as an appropriate platform to share those discoveries.

This post heralds the grand new epoch of sharing by summarizing an unpublished doctoral dissertation on IQ and academic achievement in a sample of transracially adopted Koreans (Gildea, 1992 ). According to Google Scholar, no one has previously cited this paper. Here be dragons! Continue reading

HVGIQ: Cayman Islands

February 7, 2013 / / 2 Comments

The Cayman Islands is a British Overseas Territory. In global comparison, this tiny dependency ranks near the top in standard of living and per capita GDP (currently sandwiched between the U.S., Ireland, Japan and Iceland). Lynn and Vanhanen’s books include data for Bermuda—another Overseas Territory—but do not mention the Cayman Islands.

At least one psychologist has administered intelligence tests to Cayman Islands school children (1960 Curti ), and this forgotten study is noteworthy because it is also one of the relatively rare instances where black and white IQ scores have been compared outside of the United States, Britain, and South Africa. Continue reading

More than Just “Colorism”: Part 1.

February 2, 2013 / / 0 Comments

The meaning of a Jensen Effect on the Color Effect

Dalliard showed that IQ correlates with color in both the American Black and Hispanic populations (a color effect) and, importantly, that the IQ-color correlations are positively related to a subtest’s general intelligence loading (a Jensen effect). In short, he showed that there was a Jensen effect on the IQ color effect. This is significant for reasons elaborated elsewhere. Generally, if an IQ difference is strongly positively correlated with g – is g(+) – biological causation is implicated; alternatively, if an IQ difference is strongly negatively correlated with g – is g(-) – cultural causation is implicated. Here, “biological causation” refers to psychophysiological influences on mental states that do not act through sensory informational pathways, while “cultural causation” refers to psychophysiological influences on mental states that act through these pathways; as an example of the general biological versus cultural causal schema, with respect to personality, differences induced by pharmacological agents would be classed as “biological causal” while differences induced by psychotherapy would be classed as “cultural causal.” This schema, of course, isn’t perfect – but it has utility and is not infrequently employed in psychology.
Continue reading

HVGIQ: Cuba

January 31, 2013 / / 6 Comments

There are several intelligence studies for Cubans, including at least two Raven standardizations, some international assessment data, and a few different test measures for Cuban Americans. The message of all these test results is complicated and leaves us with a few puzzles.

IQ and the Wealth of Nations (2002) and IQ and Global Inequality (2006) both list one intelligence study for Cuba: a large Standard Progressive Matrices standardization (Alonso Garcia, 1973 ). In another anomaly, however, this reference has disappeared from the latest version of the dataset (Lynn & Vanhanen, 2012). Cuba is missing from their list of ‘National IQs’ (p. 391), and the reference is not in the bibliography. But this omission is clearly a mistake, since one table (p. 22) still features a ‘Measured IQ’ score for Cuba—85—the same score paired with this study in the previous books. Continue reading

Spearman’s hypothesis and the NLSY97-ASVAB, part 2

January 29, 2013 / / 0 Comments

Skin color is a (very imperfect) proxy for white ancestry in African Americans and Hispanics. If racial and ethnic gaps in intelligence have a genetic component, we would expect lighter skinned individuals to have higher IQs, on the average. Further, because g is the main heritable component of intelligence, tests with higher g loadings should show larger associations with skin color.

We investigated these hypotheses in the NLSY97 sample. It contains interviewer reports on facial skin tone of the respondents as measured on a scale of 1 (lightest) to 10 (darkest). The interviewers used a “color card” as a reference.

All the correlations below are significant at conventional levels unless otherwise indicated. Because of the way skin color is coded in this analysis, negative correlations between skin color and test performance are expected if the hereditarian hypothesis is correct.

I found that among blacks, the correlation between g scores and skin color (darkness) was -0.133 (N=1856), whereas T scores were unrelated to skin color (r=-0.012, ns; N=1856). Among Hispanics, g scores correlated with skin darkness at -0.123 (N=1051), while T scores were unrelated to skin color (r=0.062, ns; N=1051). Therefore the results are about as expected. (See the previous post for information about the T factor.)

Applying again the method of correlated vectors (MCV), we found that vectors of skin color-test gap correlations were strongly and significantly associated with g loadings within populations. In other words, lighter-skinned individuals tended to outscore darker-skinned coracials/coethnics more on tests with higher g loadings. Among blacks, the correlations were r=-0.84 and rho=-0.75, and among Hispanics r=-0.60 and rho=-0.59 (correcting for unreliability would make all these correlations somewhat stronger).

The MCV results could be interpreted in terms of genetic effects: tests with higher g loadings are more heritable, and skin color is a proxy for white ancestry and thus presumably better “IQ genes”. But why would these within-population color analyses produce the expected correlations between g loadings and race markers (i.e., skin tone) when the between-population MCV analysis, presented in the previous post, did not? It appears that on the ASVAB g is the major source of racial/ethnic differences, but the T factor also contributes to the gaps. (Cohen’s d’s on the g scale were B-W 1.124, B-H 0.368, and H-W 0.759, while on the T scale they were B-W 0.561, B-H 0.261, and H-W 0.306.) However, T is not associated with skin color within populations, which suggests that its heritability is low and it is linked to race and ethnicity for non-genetic reasons. This would explain why the MCV results from within- and between-population analyses differ.

In the NLSY97, higher g is associated with lighter skin among blacks and Hispanics. This is in accord with hereditarian theory, but nurturists would of course argue that these correlations are due to colorism. These competing hypotheses could be tested by comparing skin color-IQ associations within and between families, as was done here.

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