Yes, among the books on the race-IQ controversy that I’ve seen, I agree that these are the closest thing to an unbiased source. However, I disagree that nothing very significant has happened in the field since their publication—although unfortunately, taken together, these new developments have led to an even greater overall confusion. I have in mind particularly the discovery of the Flynn effect and the Minnesota adoption study, which have made it even more difficult to argue coherently either for a hereditarian or an environmentalist theory the way it was done in the seventies.
Also, even these books fail to present a satisfactory treatment of some basic questions where a competent statistician should be able to clarify things fully, but horrible confusion has nevertheless persisted for decades. Here I refer primarily to the use of the regression to the mean as a basis for hereditarian arguments. From what I’ve seen, Jensen is still using such arguments as a major source of support for his positions, constantly replying to the existing superficial critiques with superficial counter-arguments, and I’ve never seen anyone giving this issue the full attention it deserves.
However, I disagree that nothing very significant has happened in the field since their publication
Me too! I just don’t think there’s been much new data brought to the table. I agree with you in counting Flynn’s 1987 paper and the Minnesota followup report, and I’d add Moore’s 1986 study of adopted black children, the recent meta-analyses by Jelte Wicherts and colleagues on the mean IQs of sub-Saharan Africans, Dickens & Flynn’s 2006 paper on black Americans’ IQs converging on whites’ (and at a push, Rushton & Jensen’s reply along with Dickens & Flynn’s), Fryer & Levitt’s 2007 paper about IQ gaps in young children, and Fagan & Holland’s papers (200200080-6), 2007, 2009) on developing tests where minorities score equally to whites. I guess Richard Lynn et al.’s papers on the mean IQ of East Asians count as well, although it’s really the black-white comparison that gets people’s hackles up.
Having written out a list, it does looks longer than I expected...although it’s not much for 30-35 years of controversy!
Also, even these books fail to present a satisfactory treatment of some basic questions where a competent statistician should be able to clarify things fully, but horrible confusion has nevertheless persisted for decades. Here I refer primarily to the use of the regression to the mean as a basis for hereditarian arguments.
Amen. The regression argument should’ve been dropped by 1980 at the latest. In fairness to Flynn, his book does namecheck that argument and explain why it’s wrong, albeit only briefly.
The regression argument should’ve been dropped by 1980 at the latest. In fairness to Flynn, his book does namecheck that argument and explain why it’s wrong, albeit only briefly.
If I remember correctly, Loehlin’s book also mentions it briefly. However, it seems to me that the situation is actually more complex.
Jensen’s arguments, in the forms in which he has been stating them for decades, are clearly inadequate. Some very good responses were published 30+ years ago by Mackenzie and Furby. Yet for some bizarre reason, prominent critics of Jensen have typically ignored these excellent references and instead produced their own much less thorough and clear counterarguments.
Nevertheless, I’m not sure if the argument should end here. Certainly, if we observe a subpopulation S in which the values of a trait follow a normal distribution with the mean M(S) that is lower than for the whole population, then in pairs of individuals from S among whom there exists a correlation independent of rank and smaller than one, the lower-ranked individuals will regress towards M(S). That’s a mathematical tautology, and nothing can be inferred from it about what the causes of the individual and group differences might be; the above cited papers explain this fact very well.
However, the question that I’m not sure about is: what can we conclude from the fact that the existing statistical distributions and correlations are such that they satisfy these mathematical conditions? Is this really a trivial consequence of the norming of tests that’s engineered so as to give their scores a normal distribution over the whole population? I’d like to see someone really statistics-savvy scrutinize the issue without starting from the assumption that both the total population distribution and the subpopulation distribution are normal and that the correlation coefficients between relatives are independent of their rank in the distribution.
Well, if you’ll excuse the ugly metaphor, in this area even the positive questions are giant cans of worms lined on top of third rails, so I really have no desire to get into public discussions of normative policy issues.
Yes, among the books on the race-IQ controversy that I’ve seen, I agree that these are the closest thing to an unbiased source. However, I disagree that nothing very significant has happened in the field since their publication—although unfortunately, taken together, these new developments have led to an even greater overall confusion. I have in mind particularly the discovery of the Flynn effect and the Minnesota adoption study, which have made it even more difficult to argue coherently either for a hereditarian or an environmentalist theory the way it was done in the seventies.
Also, even these books fail to present a satisfactory treatment of some basic questions where a competent statistician should be able to clarify things fully, but horrible confusion has nevertheless persisted for decades. Here I refer primarily to the use of the regression to the mean as a basis for hereditarian arguments. From what I’ve seen, Jensen is still using such arguments as a major source of support for his positions, constantly replying to the existing superficial critiques with superficial counter-arguments, and I’ve never seen anyone giving this issue the full attention it deserves.
Me too! I just don’t think there’s been much new data brought to the table. I agree with you in counting Flynn’s 1987 paper and the Minnesota followup report, and I’d add Moore’s 1986 study of adopted black children, the recent meta-analyses by Jelte Wicherts and colleagues on the mean IQs of sub-Saharan Africans, Dickens & Flynn’s 2006 paper on black Americans’ IQs converging on whites’ (and at a push, Rushton & Jensen’s reply along with Dickens & Flynn’s), Fryer & Levitt’s 2007 paper about IQ gaps in young children, and Fagan & Holland’s papers (200200080-6), 2007, 2009) on developing tests where minorities score equally to whites. I guess Richard Lynn et al.’s papers on the mean IQ of East Asians count as well, although it’s really the black-white comparison that gets people’s hackles up.
Having written out a list, it does looks longer than I expected...although it’s not much for 30-35 years of controversy!
Amen. The regression argument should’ve been dropped by 1980 at the latest. In fairness to Flynn, his book does namecheck that argument and explain why it’s wrong, albeit only briefly.
satt:
If I remember correctly, Loehlin’s book also mentions it briefly. However, it seems to me that the situation is actually more complex.
Jensen’s arguments, in the forms in which he has been stating them for decades, are clearly inadequate. Some very good responses were published 30+ years ago by Mackenzie and Furby. Yet for some bizarre reason, prominent critics of Jensen have typically ignored these excellent references and instead produced their own much less thorough and clear counterarguments.
Nevertheless, I’m not sure if the argument should end here. Certainly, if we observe a subpopulation S in which the values of a trait follow a normal distribution with the mean M(S) that is lower than for the whole population, then in pairs of individuals from S among whom there exists a correlation independent of rank and smaller than one, the lower-ranked individuals will regress towards M(S). That’s a mathematical tautology, and nothing can be inferred from it about what the causes of the individual and group differences might be; the above cited papers explain this fact very well.
However, the question that I’m not sure about is: what can we conclude from the fact that the existing statistical distributions and correlations are such that they satisfy these mathematical conditions? Is this really a trivial consequence of the norming of tests that’s engineered so as to give their scores a normal distribution over the whole population? I’d like to see someone really statistics-savvy scrutinize the issue without starting from the assumption that both the total population distribution and the subpopulation distribution are normal and that the correlation coefficients between relatives are independent of their rank in the distribution.
What would appropriate policy be if we just don’t know to what extent IQ is different in different groups?
Well, if you’ll excuse the ugly metaphor, in this area even the positive questions are giant cans of worms lined on top of third rails, so I really have no desire to get into public discussions of normative policy issues.