Abstract: Woodley
et al. (2013) cite declines in simple reaction time as evidence of dysgenesis.
In this paper it is conceded that these declines are strong evidence for a
dysgenic trend. However, declines in g cannot
be inferred from reaction time declines alone.
Woodley et al.
(2013) are quite correct that the existence of a secular decline in reaction
time suggests dysgenesis. However, the secular decline in reaction time is
probably a poor quantification, per se, of the exact dysgenesis rate. Woodley
(2012) argues that the Flynn effect may be caused by increasing specialization
in cognitive abilities. If specialization has truly increased, one would expect
to see a secular decline in certain such abilities. These abilities are
probably, for the most part, not measured on typical g-loaded tests (Lynn, 1998
gives the example of farming ability), but it is nevertheless to be expected
that some g-loaded tests will show a secular decline. It may be responded that
reaction time’s shared variance with g is
wholly genetic (Woodley et al. cite Rijsdijk et al., 1998 on this matter) and
therefore changes in specialization will have a minor impact. However, even if
the environmental influences on reaction time are different from those on IQ,
there may still be considerable environmental influences. Moreover, reaction
time influences mortality rates (Deary & Der, 2005). Declining reaction
time independent of g fits into
Woodley’s (2012) life-history model because there would be less pressure to
develop a mortality-mediating ability in a less environmentally harsh
environment. It should be noted as well that even though simple reaction time
shows little or no training effect (Kida et al., 2005), there may be other
processes that decrease simple reaction time, such as imprinting (Armstrong
& Woodley, under review).
While Woodley et al. extract declines in g from the declines in reaction time (given a .54 correlation),
simply multiplying the decline in reaction time by the g-loading is not sufficient to establish a decline in g (cf. Dickens & Flynn, 2001 for
discussion of a similar issue). Using a similar procedure on IQ tests for the
Flynn effect would imply high g gains
(say, if performance on a test with a g-loading
of 0.8 has increased by a d of 1, this
procedure would imply that g has
increased by a d of 0.8). However, the Flynn effect is not on g (Woodley, 2011, 2012a, 2012b; te
Nijenhuis & van der Flier, 2013).
A number of similar declines (approximately 1 SD since the Victorian
era) on other highly g-loaded tests or abilities would corroborate Woodley et
al.’s dysgenesis estimate. To the best of my knowledge, though, there are few
tests that have shown a secular decline; the SATs have, but the population has
grown increasingly representative (e.g., Williams and Ceci, 1997; Sailer, 2011a,
2012). Piagetian tasks show a decline (Shayer et al., 2007), and if the decline
in g estimated from secular trends in
Piagetian tasks is comparable to the decline in g estimated from secular trends, this would corroborate a 1 SD
dysgenesis estimate. Likewise, if the decline in IQ among wealthy countries
that are no longer experiencing the Flynn effect (e.g., Sundet et al., 2004)
was similar to the decline measured using reaction time, Woodley et al.’s
estimate would be validated.
Finally, it should be noted that a g decline of 1 SD is difficult
to believe (cf. Charlton, 2013; Flynn, 1987; Guha, 2001 for discussion of a
similar issue).[1]
A community with average levels of g 1
SD higher than modern populations would be supermen. Ashkenazi Jews, who are a
tremendously successful ethnic group, appear to have IQs around 110 (e.g.,
Cochran et al., 2005; Lynn, 2011; Sailer, 2011b). Hence even the most
intellectually successful ethnic group would have IQs five points lower than the Victorians, if Woodley et al. are
correct. This process of devolution is made quite incredible by the fact that
it is hypothesized to have occurred in only 130 years (Cochran, 2012).
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The achievements of Shakespeare and Newton suggests that British IQs have been decreasing for a long time. So there!
ReplyDeletePerhaps I should have said English rather than British. But let me add that the achievements of Hume and Smith suggests that Scottish IQs have been decreasing for a long time too.
ReplyDeleteAnd as for the Greeks, my dears, one can barely bring oneself to contemplate them.
My paper (final paragraph) contains somewhat of an error. It is well-known that the success of the Ashkenazim is not entirely explicable by their IQs, so it is somewhat misleading to use them as an example of the achievements of a high-g population. Nevertheless, my general point (Victorians would have been supermen) still has some merit. It would be interesting, incidentally, to compare the Victorian-modern innovation rate decrement to the American black-white decrement. Blacks aslo have the disadvantage of smaller SDs, though, so this too would be somewhat disanalogous.
ReplyDeletehttp://www.sciencedirect.com/science/article/pii/S0160289613000706
ReplyDeleteIn this study, therefore, the anti-FE has a magnitude of about that predicted by Woodley et al.
I am shifting more toward accepting Woodley et al's conclusion. But if I had to bet my life on it, I don't know what I'd do.