The argument from authority is of questionable merit. Yes, some people know far more than others, but how does one establish that? Happily, there are publication and citation metrics available to help us, and a reasonable case can be made that experts exist. That does not preclude the possibility that they are all wrong. One really good study might conceivably show that they had all missed an important point. Although rare, this does happen from time to time, just to make things interesting.

In 1987 Synderman and Rothman reported on a survey of 1020 intelligence experts, data having been collected in 1984. The experts were in agreement (99.3%) that intelligence involved “abstract thinking or reasoning�. As regards the burning question: “what is the source of the black-white difference in IQ?� 45% said both genetics and environment, 15% entirely environmental, 14% did not respond, and 1% said entirely genetic. So, strong environmentalists were far more common than strong geneticists. Looking at the references in that paper shows you that experts at that time were reading SJ Gould and Leon Kamin, and their arguments may have increased the environmentalist tendency.

Who are the intelligence experts now?

Men, mostly. That 83% of them are male could be because of male standard deviation advantage, in that exceptional ability is more likely in males (as is the exceptional lack of it). Even more precisely, it would fit the hypothesis that men are also 3 points ahead of women. They are of middle age, which is what one becomes after reading all the required literature (same pattern as in 1984). However, if 30 year olds bother to do the reading they can quickly contribute to it. 7 people over 70 are still publishing. The experts are well-published; and left-wing. The last point may come as a surprise. They tend towards liberal rather than conservative opinions. They are left of centre by 2 to 1. They are strongly in favour of gay marriage, in favour of more social democratic policies and of immigration. They are less keen on, though not totally opposed to “strong affirmative action�.

They come from middle class backgrounds, as one would expect of the children of better educated and probably brighter parents. They are mostly European, and often Jewish. They studied psychology, have PhDs, and are mostly in universities. Two thirds of them are not religious. 75% regard themselves as Jensenists, meaning that IQ has a general factor and is heritable.

Experts sometimes talk to the media, but have a generally poor opinion of it. As of 2013/2014 they rated two particular bloggers far more highly. They find the public debates about intelligence are mostly (two thirds) based on ideology. They have often hesitated to give their opinions in public. They also think that intelligence research could be abused in political settings. On balance, they think that 51% of the black-white difference in intelligence in the US is caused by environmental factors.

Figure 10 shows the range of opinions:

Environmental hardliners are nearly three times as common as hereditarian hardliners. Since the Snyderman and Rothman study in 1987 there has been a shift towards accepting genetic components. Unfortunately, these judgments are strongly related to political perspectives r = -.49 as will be seen below.

One assumes that political perspective came first, and provided a powerful interpretative filter. Age did not have much effect, but gender was almost as powerful r = .48 . There were only 10 women and their average estimate was that 77% of the genetic group difference was environmental, compared to the male average estimate of 39%.

So, here we have another projective test. Is the question of group differences all down to opinion, or do facts matter? It seems to be a case of “Who? Whom?” versus “What? When? Why? How?”. From my perspective, the political affiliations come as a partial surprise. It is informative that this group put the genetic contribution at 49% despite the fact that they lean left. I hope this finding about a willingness to countenance (anonymously) a genetic compontent will not feed them to the wolves.

Having heard the details of the expert’s backgrounds, if you judge people by their demographics, then you may find lots to object about, and might even want to expel those with right wing opinions. If you judge people by their arguments, then you might wish to ignore the revealed political bias, and concentrate on the actual arguments and the supportive evidence, to examine the deeper foundations of the debate. I would favour that approach, but would warn you that, if you are not middle aged now, you will be middle to old aged by the time you have done the necessary reading.

Here is the slide deck presenting the results of the survey.

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