This is
obviously a topic on which I have some slight familiarity and am quite aware of
the sex differential. That it has now
improved is good news. Other noted
differentials are better ascribed to changes in nurture and the lack of
available role models for boys in particular.
Yet genius potential is all about real processing speed.
Your brain
must be naturally quicker to start with.
That is still
not good enough as I have met many could have been types as well. Two other things must occur. The brain must be wired properly through an
excellent intense training in mathematics as an adolescent. Then you also must feed the monkey huge
amounts of data and as many ideas as much as possible. There are other mental skills that can be
usefully optimized. Those include a
photographic memory which I do not have but now know how to acquire.
For the bulk
of humanity slow but steady works pretty well.
Cleverer
still
Geniuses are getting brighter. And at genius
levels of IQ, girls are not as far behind boys as they used to be
Dec 22nd 2012
SCIENCE has few more controversial topics
than human intelligence—in particular, whether variations in it are a result of
nature or nurture, and especially whether such variations differ between the
sexes. The mines in this field can blow up an entire career, as Larry Summers
found out in 2005 when he spoke of the hypothesis that the mathematical
aptitude needed for physics and engineering, as well as for maths itself, is
innately rarer in women than in men. He resigned as president of Harvard
University shortly afterwards.
It is bold, therefore, of Jonathan Wai,
Martha Putallaz and Matthew Makel, of Duke University in North Carolina, to
enter the fray with a paper that addresses both questions. In this paper, just
published in Current Directions in Psychological Science, they describe
how they sifted through nearly three decades of standardised tests administered
to American high-school students to see what had been happening to the
country’s brightest sparks.
They draw two conclusions. One is that a
phenomenon called the Flynn effect (which weighs on the “nurture” side of the
scales because it describes how IQ scores in general have been rising over the
decades) applies in particular to the brightest of the bright. The other is
that part, but not all, of the historic difference between the brainiest men
and women has vanished.
The three researchers drew their data from
Duke University’s Talent Identification Programme, TIP, which is designed to
ferret out especially clever candidates early on: all the participants had
scored in the top 5% of ability when confronted with exams designed for much
older students. TIP, in turn, draws on three national exams: SAT, EXPLORE and
ACT. Altogether, Dr Wai, Dr Putallaz and Dr Makel looked at data from 1.7m
children. Those data spanned the years between 1981 and 2010.
In the general population boys are well
known to do a bit better than girls in maths. Girls, in turn, edge out boys on
tests of verbal reasoning. The result is similar overall IQ scores. Among the
best young mathematical brains, however, that equality does not pertain. Here,
boys do a lot better at maths than girls—but less better than they used to, as
the researchers discovered.
In the early 1980s, the ratio of males to
females in the top 0.01% of maths scores in SAT, the Scholastic Aptitude Test,
was around 13 to 1. By the early 1990s it had fallen to four to one. After
this, however, it remained obstinately unaltered (see chart). The other two tests,
both of which post-date the period in which the SAT shows those huge changes,
indicate less lopsided sex ratios of between two and three to one. But neither
shows girls making much recent progress towards equality.
Nurturing talent
This study is not perfect. Its most
interesting result rests on data from just one of the three sets of exams it
looked at and its sample sizes are, necessarily, small. But it chimes with the
findings of a much older investigation, carried out in 1983 by a group of
researchers at Johns Hopkins University, which also discovered a male-to-female
sex ratio of 13:1 among the most able young mathematicians.
Why a dramatic rise in the aptitude of
America’s brightest young female mathematicians should then be followed by two
decades of stagnation is not obvious, and, not being experts in mine-clearance,
the researchers offer no hypothesis. It is clear that the rise itself must be
“nurture” of some sort—possibly a change in teachers’ attitudes towards girls
who are interested in maths—but the subsequent stasis could have either
explanation. A line of reasoning in favour of “nature” is that put forward by
Simon Baron-Cohen, a psychologist at Cambridge University. This connects the
extreme systematising patterns of thought which make a good mathematician with
the preponderance of men among those with Asperger’s syndrome, a form of autism
that does not harm a person’s general intelligence. But the disparity could
equally well be the result of some as-yet-unelucidated difference between the
ways girls and boys are brought up.
The nature of the beast
That such unelucidated environmental
influences can have real effects on IQ is eloquently illustrated by the Flynn
effect. This phenomenon, brought to the world’s attention in the 1980s by James
Flynn of the University of Otago, in New Zealand, is that average IQs around
the world have been rising at the rate of 0.3 points a year for the past eight
decades. Using the TIP data, Dr Wai and his colleagues showed that this is as
true of the brightest youngsters in American society as it is of lesser
mortals, suggesting that even they can have their abilities boosted by whatever
is causing the Flynn effect. Once again, the changes seem to be mainly in
mathematics. Scores in the brightest children’s verbal-reasoning and reading
abilities demonstrate no clear trend, but all three national tests show
sustained improvements in their mathematical ability over the past three
decades.
No one knows what causes the Flynn effect.
Theories range from better nutrition, via a more stimulating general
environment (thanks to such things as television, radio, the internet and video
games), to the phasing out of lead in petrol and paint. What is clear is that
it cannot be a change in gene-given ability, which is what most people mean by
“nature” in this debate, because too few generations have passed for natural
selection to have had any meaningful impact.
Featured comment
J. KempDec 21st 2012, 04:48
There are several effects in the mix here
which bear mentioning:
1. Mate selection (in Darwin's words,
"sex selection") can easily drive up IQs over time. This amounts to
one or the other (or both) members of a couple selecting their reproduction
mate on the basis of intelligence. If people are selecting against lower-IQ
individuals as mates, while selecting in favor of higher-IQ individuals, this
can drive up IQ much, much faster than classic "Darwinistic
selection".
2. Breastfeeding, which has made a strong
comeback in the Western world during the past 30 to 40 years, has been shown to
have positive impacts on IQ across populations on a genetically modified basis.
See, for example:http://www.pnas.org/content/104/47/18860.full.pdf
3. SAT tests have been very substantially
dumbed down over the past 4 decades. In fact, the American Mensa organization
ceased accepting high-threshold SAT scores as a pathway to gain Mensa
membership as of 1994. Prior to that, there was a sufficiently solid
correlation between IQ and SAT scores. After 1994 there is not. Thus, SATs are
likely not presently doing much by way of measuring the capacities of the very
highest ability individuals. In other words, if IQ is not longer very
correlated with SATs, this implies that many people can simply be
prepared/trained to do well on these exams somewhat independently of their true
native ability. (By contrast, the Miller Analogies is likely a far better tool
for distinguishing different levels of ability among the very highest IQ
individuals.)
4. There are strong indications that a major
structural factor at work in male vs. female intelligence is the reality that
there are key intelligence-impacting genes on the X-chromosome, of which men
have only one while women have two. All female mammals are mosaics with respect
to the X-chromosome, meaning that their tissues are a patchwork quilt in which
one or the other of their X-chromosomes is turned on (and the other off) in
each patch. This creates a situation where it is easier for males to win the IQ
lottery if they happen to get a single very strong version of the relevant
genes on their X-chromosome. For a woman to have that same gene in all of her
tissues, she would have to inherit the rare, very strong allele/s from both of
her parents, which is statistically far less likely to occur. Similarly, males
are also far more likely to lose this lottery, and wind up mentally retarded,
which is where women pick up the dividend of having two X-chromosomes: X-based
mental retardation is far less common among women as their risk is diversified
by having two X-chromosomes, and thus a good chance of having one more helpful
allele on one of their X-chromosomes to offset any harmful allele.
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