Black Brain, White Brain?

There came out recently a book called Black Brain, White Brain -- by  Gavin Evans.  It seems to have got some acclaim so I thought I might say a bit about it.  That task seems to be facilitated by an article by Evans under the same heading which appeared just over a month ago.  The article seems to summarize the main points of the book and thus spares me the time of reading the book.  But if there are things in the book which undermine any of the things I day below, I would be delighted to hear of it.

The main point of the book seems to be an accusation that it is racist to discuss the black/white IQ gap.  And like all other efforts in that direction that I know of it does a lot of huffing and puffing and declaring things obvious rather than providing proof of them.  The abusive and intemperate writing by Evans may be judged by his reference to "racist science that has been spewing out of the computers". Do computers spew? His use of abusive language like that is certainly a strong indication that he has a weak case that he is trying to cover up. "fester" and "dangerous" are other emotive words he uses.  Abuse in lieu of facts is a very familiar Leftist modus operandi.  And a few of Evans's  assertions do seem to be simply wrong.

And in the best Leftist style, his writing is almost entirely an appeal to authority.  Quite illogically, he thinks that because other people have declared something wrong then it must be wrong.  That many people have declared genetically-oriented treatments of the black/white IQ gap to be wrong and mistaken proves nothing at all.  It simply shows that most academics are Leftist.  For Evans to have written in any sort of scholarly way, he would have to list the main points where the genetic writers were found to be in error.  He does not do that.

He seems to think that he has made a great point by saying that no one gene for IQ  has been discovered.  So what?  IQ researchers have for decades accepted with perfect calm that  IQ is polygenetic.  Whether one gene or many is behind a difference may make research more or less difficult but it does not take away from the fact that the difference is genetic. And the genes that do contribute to IQ differences are being discovered all the time.  I must make a list of the studies concerned some time. I have noted quite a few on this blog.

He then goes on to claim that intelligence has not evolved for 100,000 years.  That completely ignores the work of Bruce Lahn, who showed a major evolutionary change in brain size about 5,000 years ago, a change which coincided with the birth of civilization and which is almost unknown in Africa. Pesky!

Another claim by Evans:  "Other studies have also shown that the IQs of children adopted into middle class homes rise significantly and that these increases can persist into adulthood".  He is right about the first part but wrong about the second part. Manipulations of the environment can improve IQ scores in childhood and even into the teens but by about age 30, all those improvements are lost.  By age 30 most environmental influences have washed out and the genetic endowment comes to the fore.

And then Evans gets on to the good ol' Flynn effect. So much has been written about that that I hesitate to write any more but in summary, the Flynn effect seems to be an artifact of increasing years of schooling and the test sophistication that engenders.  On important IQ subtests -- such as vocabulary -- where being test-wise does not help -- there has been very little movement in scores.  And in some advanced countries -- such as Nederland -- the rise has petered out, as one would expect if it was just a one-time artifact that had approached an asymptote (maximum value).

Finally, I am amazed by his assertion that "black American IQs are rising at a faster rate than those of white Americans".  I know of no evidence for that.  In fact, on some indices, the black/white gap is increasing.  So I guess I will have to "fester" away in my conclusion that there are real and inborn differences between the average IQs of blacks and whites.

And let's not have the old nonsense that IQ tests measure something limited and mysterious.  They measure general problem-solving ability, which is why researchers tend to use the term 'g' instead of 'IQ'.

And I may note that my view of IQ is no longer academically marginalized stuff at all. I don't quite know whether to be pleased or disappointed but it seems that mainstream psychology is catching up with what psychometricians such as myself have been saying for years: That IQ is highly general, highly central, highly hereditary and of overwhelming importance in determining people's life-chances. Not so long ago any claim to that effect would be very marginal within psychology and would expose anyone making it to all sorts of nasty accusations.

But you can now read it all not in some obscure academic journal or some Rightist source but in a 2004 issue (vol. 86 no. 1) of the American Psychological Association's most widely-circulated journal -- the Journal of Personality and Social Psychology.

Article after article there sets out the importance of IQ. And for social psychologists to be taking an interest in such evidence is really amazing. Psychometricians have known all that stuff for years. It is the social psychologists who have been most resistant to such ideas.  I guess that even an organization as Leftist as the American Psychological Association has to come to terms with the evidence eventually.

And note that the APA conceded some time ago that "African American IQ scores have long averaged about 15 points below those of Whites".  15 points is one standard deviation, which is a huge difference -- accounting for 34% of the distribution.  So it looks like I've got a lot of company in my "festering", as Evans calls it. Evans is fighting a lost battle.