That men are on average smarter than women
Wikipedia cites a study by the author which shows there is a difference:
In 1994, Lynn concluded in a meta-analysis that an IQ difference of roughly 4 points does appear from age 16 and onwards, but detection of this had been complicated by the faster rate of maturation of girls up to that point, which compensates for the IQ difference. This reassessment of male-female IQ has been bolstered with meta-analyses with Paul Irwing in 2004[46] and 2005[47] which found a difference of 4.6 to 5 IQ points [5].They saw no evidence that this is due primarily to the male advantage in spatial visualization, and concluded that some research previously presented as showing that there are no sex differences actually demonstrates the opposite. A further study of 1,258 11-year-olds in Mauritius derived a difference of more than 6 IQ points.[48]
Wikipedia also references a critique of that study:
However, last week's publication of Blinkhorn's critique in Nature
represents a major change in attitudes to their claims. He points to a
number of 'serious flaws' in the approach taken by Lynn and Irwing.
For a start, he accuses them of carefully selecting those IQ studies
that they allowed in their meta-analysis.
In particular, he says they chose to ignore a massive study, carried
out in Mexico, which showed there was very little difference in the
IQs of men and women. 'They say it is "an outlier" in data terms --in
other words, it was a statistical freak,' Blinkhorn said.
'It was nothing of the kind. It was just plain inconvenient. Had it
been included, as it should have been, it would have removed a huge
chunk of the differences they claim to have observed.'
In addition, Blinkhorn said the pair were ignoring a vast body of work
that had found no differences. 'Psychologists often carry out studies
that find no differences between men's and women's IQs but don't
publish them for the simple reason that finding nothing seems
uninteresting. But you have to take these studies into account as well
as those studies that do find differences. But Lynn and Irwing did
not. That also skewed their results.'
Blinkhorn also accuses the pair of adopting a variety of statistical
manoeuvres that he describes, in his paper, as being 'flawed and
suspect'.
Last week Irwing defended the study and accused Blinkhorn of
'attacking the men, not the science'. The study they had done 'also
has to be seen in context of our other work which has shown
significant sex differences in IQ. Nor is it true that we played about
with our data.'
For his part, Blinkhorn is unrepentant. 'Sex differences in average
IQ, if they exist at all, are too small to be interesting,' he states
in Nature
It is a stark, unequivocal statement - although it will certainly not
be the last word in a debate that seems likely to dog psychology for
years to come.
The Wikipedia article titled Sex differences in human psychology starts by saying,
Most IQ tests are constructed so that there are no differences between the average (mean) scores of females and males.[1] Areas where differences in mean scores have been found include verbal and mathematical ability.[1]
Its section on IQ mentions several studies which show at least that professor that Lynn is not the only person to report a difference in the mean IQ:
Several meta-studies by Richard Lynn between 1994 and 2005 found mean IQ of men exceeding that of women by a range of 3–5 points.[40][41][42][43] Lynn's findings were debated in a series of articles for Nature.[44][45] Jackson and Rushton found males aged 17–18 years had average of 3.63 IQ points in excess of their female equivalents.[46] A 2005 study by Helmuth Nyborg found an average advantage for males of 3.8 IQ points.[47] One study concluded that after controlling for sociodemographic and health variables, "gender differences tended to disappear on tests for which there was a male advantage and to magnify on tests for which there was a female advantage."[48] A study from 2007 found a 2-4 IQ point advantage for females in later life.[49] One study investigated the differences in IQ between the sexes in relation to age, finding that girls do better at younger ages but that their performance declines relative to boys with age.[50] Colom et al. (2002) found 3.16 higher IQ points for males but no difference on the general intelligence factor (g) and therefore explained the differences as due to non-g factors such as specific group factors and test specificity.[38] A study conducted by Jim Flynn and Lilia Rossi-Case (2011) found that men and women achieved roughly equal IQ scores on Raven's Progressive Matrices after reviewing recent standardization samples in five modernized nations.[51] Irwing (2012) found a 3 point IQ advantage for males in g from subjects aged 16–89 in the United States.[52]
My personal opinion (or 'take-away') on this subject is that a difference of that magnitude is too small to be noticeable in real life (or "too small to be interesting" as is stated above).
That very-high-IQ men are much more common-place than very-high-IQ women
Ibid has some support for that theory:
Some studies have identified the degree of IQ variance as a difference between males and females. Males tend to show greater variability on many traits including tests of cognitive abilities,[54][55] though this may differ between countries.[56][57][58][59] A 2005 study by Ian Deary, Paul Irwing, Geoff Der, and Timothy Bates, focusing on the ASVAB showed a significantly higher variance in male scores, resulting in more than twice as many men as women scoring in the top 2%.
And:
Both Feingold (1992b) and Hedges and Nowell (1995) have reported that, despite average sex differences being small and relatively stable over time, test score variances of males were generally larger than those of females. Feingold found that males were more variable than females on tests of quantitative reasoning, spatial visualisation, spelling, and general knowledge. […] Hedges and Nowell go one step further and demonstrate that, with the exception of performance on tests of reading comprehension, perceptual speed, and associative memory, more males than females were observed among high-scoring individuals.
These studies support the theory that "high-IQ men are more common-place than high-IQ women": for example, "more than twice as many men as women scoring in the top 2%".
I'm not aware of scientific support for the more extreme version of that theory (i.e. 8-to-1 disparity at IQ 145 and above). In the article referenced in the OP, professor Lynn writes,
In recent years, the forces of political correctness have made the reporting of this sort of statistic virtually impossible.
Yet as a psychologist who has dedicated his career to the study of intelligence - and, in particular, to how it differs between the sexes - I can tell you that in my academic circles these IQ figures are barely disputed.
I don't find that argument convincing, because:
- If he has numbers to support his theory, can he really not publish them (except as indirect allegations in the Daily Mail)?
- The alleged consensus among "my academic circles" doesn't convince me, because it's easy to imagine that "his circles" are a self-selecting subset of people who don't disagree with him.