Search results: "HVGIQ" (page 2 of 2)

HVGIQ: Dominican Republic

The Dominican Republic shares the island of Hispaniola with Haiti, but has a much higher standard of living. Jared Diamond offered some characteristically plausible-sounding reasons for this disparity in his 2005 book Collapse, and these ideas received a fair bit of media coverage following the Haiti earthquake in 2010. While race and human capital both played a part in those explanations, Diamond did not mention intelligence differences (having already rejected this line of thinking as “loathsome” in Guns, Germs, and Steel (1997)). However, the theoretical relevance of this variable is obvious: intelligence and achievement tests are a more direct measure of individual human capital than input variables like education. Jones and Schneider (2006) found IQ to be “the most robust human capital measure” in an expansive dataset of international comparison measures—a better predictor of economic development than variables like educational spending and enrollment.

IQ and the Wealth of Nations (2002) did not include data for either Haiti or the Dominican Republic, but Lynn’s dataset has included one study for the Dominican Republic since the publication of IQ and Global Inequality (2006).

Here I scrutinize Lynn’s use of this reference and introduce a few more small studies. The data available for the Dominican Republic is quite meager. Continue reading

HVGIQ: The Bahamas

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

HVGIQ: Jamaica

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

HVGIQ: Cayman Islands

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


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

HVGIQ: Haiti

Lynn’s international dataset lacks data for Haiti. The Global Bell Curve (2008) simply reports “Nothing is known of the intelligence of the population of Haiti” (p. 147). IQ and the Wealth of Nations (2002) estimates an IQ of 72 by regional comparison with Jamaica. IQ and Global Inequality (2006) estimates an IQ of 67 by comparison with Jamaica, St. Lucia, and Dominica. This is the estimated value still reported in Intelligence (2012).

I have, however, located three intelligence studies for Haiti. Continue reading

Top Ten Human Varieties Posts

In the more than three years of its existence, about 110 posts have been published on this blog. While blogging has unfortunately been light in recent times around here, the upside of the data- and analysis-heavy format of our posts is that they rarely lose their relevance with time, making the perusal of our old posts well worth the time.

To help readers search through our archives, below is a list of what I consider to be some of the best content we’ve published. They’re not necessarily our most popular posts, but I think they offer a good dive into human biodiversity, in particular our perennial favorite topic of IQ differences between groups. The list is in the order of original publication. Continue reading

Ethnic/Race Differences in Aptitude by Generation in the United States: An Exploratory Meta-analysis

An early version of this paper was posted on June 25th. The paper has since been extensively edited and corrected and, subsequently, published at Open Differential Psychology on July 25/26th, 2014. The paper and data files can be found here at the Open Differential Psychology site.



Cognitive ability differences between racial/ethnic groups are of interest to social scientists and policy makers. In many discussions of group differences, racial/ethnic groups are treated as monolithic wholes. However, subpopulations within these broad categories need not perform as the racial/ethnic groups do on average. Such subpopulation differences potentially have theoretical import when it comes to causal explanations of racial/ethnic differentials. As no meta-analysis has previously been conducted on the topic, we investigated the magnitude of racial/ethnic differences by migrant generations (first, second, and third+). We conducted an exploratory meta-analysis using 18 samples for which we were able to decompose scores by sociologically defined race/ethnicity and immigrant generation. For Blacks and Whites of the same generation, the first, second, and third+ generation B/W d-values were 0.79, 0.79, and 1.00. For Hispanics and Whites of the same generation, the first, second, and third+ generation H/W d-values were 0.76, 0.67, and 0.57. For Asians and Whites of the same generation, the first, second, and third+ generation d-values were -0.08, -0.21, and 0.00. Relative to third+ generation Whites, the average d-values were 0.99, 0.84, and 1.00 for first, second, and third+ generation Black individuals, 1.04, 0.71, and 0.57 for first, second, and third+ generation Hispanic individuals, 0.16, -0.18, and -0.01 for first, second, and third+ generation Asian individuals, and 0.24 and 0.04 for first and second generation Whites.

Keywords: Immigrants, group differences, race, ethnicity, aptitude, National IQ

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