The french adoption study, by Capron & Duyme (1989, Table 2; 1996, Table 3), attempted to show that IQ can be improved by adoption. Their numbers displayed an IQ gain of 15 or even 20 points (WISC-R). Jensen (1997) analyzed Capron and Duyme adoption data (1996) with N=38, a study often cited by environmentalists as evidence against the hereditarian hypothesis. Jensen showed that the IQ difference owing to the adoption of children from low-SES parents by high-SES families is not g-loaded while at the same time the IQ difference owing to low-SES versus high-SES biological families loaded in fact on the g factor or PC1. Plus, the SES-difference of adopted families correlated at only 0.099 with SES-difference of biological families.
Author: Meng Hu (Page 5 of 6)
In Bias in Mental Testing (1980, pp. 546-548), Arthur Jensen showed that a congruence coefficient test from a factor analysis of the within- (WF) and between-family (BF) correlations among blacks and whites could yield an identical g factor structure. A similarity in factorial structure for these four groups having been evidenced, he writes :
These correlations are statistically homogeneous; that is, they do not differ significantly from one another. Thus it appears that the g loadings of these seven tests show a very similar pattern regardless of whether they were extracted from the within-family correlations (which completely exclude cultural and socioeconomic effects in the factor analyzed variance) or from the between-families correlations, for either whites or blacks. … This outcome would seem unlikely if the largest source of variance in these tests, reflected by their g loadings, were strongly influenced by whatever cultural differences that might exist between families and between whites and blacks.
Jensen (1980, Table 4) has been replicated by Nagoshi and Johnson (1987, pp. 310-314). I will replicate those earlier tests using NLSY97 and NLSY79. As Jensen (1998, pp. 99-100) noted, the congruence coefficient (CC) can be interpreted as being an index of factor similarity.
In the NLSY97, a Jensen Effect of biracial blacks has been found, using self-reported white ancestry. In the NLSY79, some questionnaires (R00096.00, R00097.00) asked about the respondents’ first and second racial/ethnic origin. When the respondent reported being non-black or white in one of the questionnaires and black in the other, he was categorized as being a multiracial.
In an earlier article, I have shown that the magnitude of sibling correlations among NLSY-ASVAB subtests correlates with the magnitude of g-loadings, but moderately with the magnitude of black-white IQ gaps in those subtests using Jensen’s method of correlated vectors, a possibly imperfect technique in some instances as explained in my previous article. In another post, it has been seen that US blacks having more (self-reported) white ancestry showed a higher IQ level, and that this effect is not mediated by skin color. Here, I will show that the magnitude of the score advantage for blacks with more white ancestry among subtests correlates with the above mentioned variables.
Recently, the GSS released the survey results for the year 2012. And a skin color variable has been included. But rather than using the SDA program, available here, I used the GSS cumulative datafile 1972-2012 for SPSS, available here. This allows more complex analyses to be performed than what is possible with the SDA.
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The IQ differences between blacks and whites lead to differences in sibling regression to the mean. The races regress to different means. Criticisms were made about the hereditarian interpretation of the differential sibling regressions. I will demonstrate that this phenomenon (1) is not a statistical artifact and (2) is consistent with the hereditarian interpretation of it.
Introduction. If color-based discrimination becomes more intense at a later age, when darker-skinned individuals face discrimination in the labor market and thus depressing their economic opportunities at every level, for instance, the colorism hypothesis could have argued that IQ measured at earlier ages would not mediate the IQ-outcome relationship measured at a later age because discrimination would have conditioned later success in life.
Some variables in the Add Health and the NLSY97 allow us to investigate the relationship of skin color with IQ and racial ancestry with IQ (AHPVT scores and ASVAB scores) among the US black population. Given the positive results, a question worth considering is whether or not skin color mediate the relationship between family ancestry and IQ.
I don’t know where to begin. If I have to introduce myself I could say that I’m chinese, that my english is awful, that no one knows who I am, and that the average reader of this blog is probably much older than me. Also, it is clear that Jason Malloy and John Fuerst have followed the IQ-race debate for many years now and I am not as knowledgeable as they are – far from it – but knowledgeable enough to write this. To be honest, around two years ago I didn’t even know that blacks have a lower cognitive ability than any other races, as assessed by IQ tests, until I came across this paper “Thirty Years of Research on Race Differences in Cognitive Ability” – in February/March 2011 if I remember correctly. This has caused a stir in my mind, and struck my curiosity. Since that day, I wanted to be better informed, collecting information and data that either reject or confirm the theory posited by the hereditarians. Gradually I was moving to the dark side. You could say I am a hereditarian now.
Among all the books and papers I have read so far, I would highly recommend Arthur Jensen (e.g., The g Factor, Educability & Group Differences, Bias in Mental Testing). I think he is the one who has made the most devastating criticisms against the environmental-cultural hypothesis, and James Flynn being the toughest opponent of the hereditarian side. I am not particularly interested in the consequences of the victory of one side over the other, but if I have to say a word about my political view, which is not worth discussing, the only thing I would say is that no one (and even asians – at least those who live in western countries) would agree with me. I indeed see all the advantages of an ethnically homogeneous country, regardless of the tenability of the “race realism” thesis, which has become my new obsession. My goal in joining this blog is to pursue what I was constantly trying to succeed in for these two last years : refuting the race realism case. And I have not yet succeeded.
What happens if the Black-White IQ difference is entirely environmental in origin ? I argue here that we cannot be certain that the gap will disappear, and it is even possible that the gap would have increased if the between-group heritability (BGH) of IQ was lower than what it actually is.
Insofar as the socio-economic status (SES) is an index of cognitive stimulation, through wealth, culture, life style, parental expectations, parenting, and so on, it would be useful to examine the magnitude of the IQ gap at different levels of SES.
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