Yesterday I posted about the decline in average IQ that has been noted in France, attributed by some scientists to the immigration of lower-IQ peoples. The same phenomenon is also apparent elsewhere in Europe, and for the same reason. The jargon term to search for if you are looking for scholarly work on the subject is "negative Flynn effect".
What's a Flynn effect? It's the general slow rise in IQ scores that has been noted around the world, generally attributed to things like gradual improvements in things like nutrition and education. although the exact cause is unknown. A negative Flynn effect is the opposite: a gradual drop in IQ. This phenomenon is now apparent across much of western Europe.
Although immigration is cited as an explanation by the scientists themselves, the case of Finland shows that it cannot be the only one. In this study, the authors note the "negative Flynn effect" in Finland even though there had been few immigrants in the period under study. Dysgenic effects (environmental influences that cause more intelligent people to have fewer children and less intelligent people to have more children), perhaps arising from welfare systems, may be to blame.
Numerous studies have shown that performance on IQ tests of around 3 to 5 IQ points per decade has improved during much of the twentieth century (Flynn, 1984, 1987, 2012; Lynn, in press). From the mid-1990s these increases went into reverse in Norway, Denmark, Australia, Britain, the Netherlands and Sweden. These negative Flynn effects are summarized in Table 1.
...First, IQs measured by tests of Shapes, Number and Words increased in Finland over the years 1988 to 1997, showing the Flynn effects that have been reported in numerous studies. The largest increase took place in the Shapes test (.46d = 6.9 conventional IQ points), and smaller increases took place in the Number and Words tests (.22d = 3.3 and .12d = 1.8 conventional IQ points, respectively). The larger increase in the non-verbal Shapes test than in the Number and Words tests is consistent with results in numerous previous studies (Flynn, 1984, 1987, 2012; Lynn, in press). The average of the increases from 1988 to 1997 in the three tests is 4.0 IQ points per decade and therefore about the same as that reported for military conscripts in a number of previous studies (Flynn, 1987, 2012). Second, the results show a decline of IQs in Finland for the years 1997–2009.
This confirms the studies noted in the introduction showing that average IQs declined from the mid-1990s in Norway, Denmark, Australia, Britain, Sweden and the Netherlands. The largest declines in the present study took place in the Number and Words tests (−.22d = 3.3 and −.34d = 5.1 conventional IQ points, respectively). The smallest decline took place in the Shapes test (−.18d = 2.7 conventional IQ points) for which scores peaked in 1997, followed by only a small decline and then a plateau thereafter. The 1991 cohort was an anomaly in so far as it was brighter for some unknown reason. The magnitude of the rate of decline of IQ in Finland in the present study calculated as the average of the decline in the three tests was approximately 2 IQ points per decade.
Third, the declines of IQ in Norway, Denmark, Australia, Great Britain, Sweden and the Netherlands may be partly attributable to the large numbers of non-European immigrants with lower IQs who settled in these countries from the mid-1960s onwards. At the end of the first decade of the twenty-first century, 13.1% of the Norwegian population were non-European (Statistics Norway, 2012), as were 11.4% in Denmark (StatBank, 2012), 21% in the Netherlands (CBS StatLine, 2012), 11% in the UK (UK Census, 2011), and approximately 20% in Australia (Australian Bureau of Statistics, 2011). These non-European peoples, with the exception of the Chinese, have average IQs ranging from 10 to 30 points lower than the European average (Lynn, 2006; Lynn & Vanhanen, 2012), so immigrants from these countries are likely to reduce the average IQs in Western nations, and this could explain some or even all of the decline in IQs in Western European nations.
This is unlikely to have been a factor in Finland because there were few non-European immigrants in Finland during the years 1997–2009. In 2012, 4.8% of the Finnish population were immigrants or had at least one immigrant parent (Statistics Finland, 2012) and the great majority of these were Russians and Estonians, whose average IQ is the approximately same as that of the Finns at around 100 (Lynn & Vanhanen, 2012). Those of non-European, including American, origin made up just 1.8% of the Finnish population in 2012 (Statistics Finland, 2012). Thus, the decline of IQs in Finland cannot be attributed to the arrival of significant numbers of immigrants who may have had lower average IQs than the indigenous population.
The most probable reason for the declines in IQs that have now been recorded in a number of countries is the presence of dysgenic fertility, i.e. the negative association between intelligence and numbers of children that has been reported in Sweden (Nystrom, Bygren, & Vining, 1991), Denmark (Nyborg, 2012), Finland (Dutton, 2012) and a number of other countries reviewed in Lynn (2011). For Denmark, Nyborg (2012), employing a combination of simulations involving demographic changes and interpolation based on theoretical IQ losses due to the negative fertility-IQ correlation, estimates the decline in IQ attributable to the combined effects of both within and between population dysgenic fertility for the period 1979– 2010 at 3.11 points equivalent to approximately one point per decade.