Average IQ scores during the last 8 decades have increased by some 25 point. This is an incredibly huge gain observable throughout the whole world, including developing countries. If you were able to travel back in time to the turn of the century a person of average intelligence then would appear to be mentally retarded using modern standards and norms. This phenomenon was noted by several researchers including Richard Lynn, a British Professor of Psychology who has written extensively on controversial issues related to racial and national differences in intelligence. However, the person who has done the most research on the subject of IQ gains over the last century is James R. Flynn. Some people have called the increase in IQ over time phenomenon the Lynn-Flynn effect but the majority abbreviate the same as the Flynn effect.
James R. Flynn is a native of Washington DC who later on in life immigrated to New Zealand. Curiously, his research emphasis was intelligence testing, but his PhD was in political sciences rather than psychology. His conclusions and perspectives on this phenomenon have been summarized in popular books including: “What is Intelligence?: Beyond the Flynn Effect” published in 2007, and “Are we Getting Smarter?: Rising IQ in the Twenty-First Century” published in 2012.
James Flynn (1934- )
To summarize the Flynn effect, there is a clear trend indicating that individual’s IQs have gained about 3 points per decade. The gain is seen regardless of intelligence tests used and has been noticed throughout all examined countries of the world. Again, such a change in IQ is astronomically large!
The Flynn effect stands in clear opposition to the view of researchers that claim that genes are your destiny, or that intelligence is defined primarily by your genetic constitution, or even that intelligence is fairly stable throughout your lifetime. There is plenty of evidence from the literature to support many of the latter arguments. Modern studies now seem to tie intelligence to a large number of genes (Note: similarly autism is tied to about 5,000 risk genes, that is one out of every 4 genes from our genome). So critics of the role of genetics in intelligence welcomed with open arms the Flynn effect because such drastic changes over a few generations could not occur as the sole effect of genes. A change in IQ worldwide suggests that social factors are somehow related to the phenomenon.
If you are thinking the same way I am thinking (hopefully you are), you will notice an analogy to the rising prevalence rates in autism. In both instances noted changes denote a significant increase that can’t be the effect of genetic changes alone. It is impossible for genetic mutations to create evolutionary changes worldwide over the short span of 2 or 3 generations. Naysayers, people trying to explain away the phenomenon, have considered that appropriate norms (whether intelligence tests for the Flynn effect or diagnostic criteria for autism) have changed considerably during the studied period in question. However, numerous studies have shown that the numbers do not add up and we are left with a significant increase despite changing diagnostic criteria. Other possible explanations for the Flynn effect include how modern industrialized nations offer exposure to enriched environments since early childhood to our brooding population. Society is changing recruitment of the workforce towards jobs that require better visual skills (see Thinking Like Einstein by Thomas West). Consider the role of television and video games in the everyday life of our children. Consider the types of toys that were available 80 years ago and those that are available now. While playing video games our children are practicing cognitive skills unavailable to our generation. Also reflect on the general nutritional status of our population and the availability of supermarkets across the country. Read the science and math books your high school child takes for his/her school and compare the same to the ones you used. The Flynn effect is not unexpected, we can see it in everyday life.
Now consider other analogies between the Flynn effect and autism. In both the role of society seems to play a major role. Our environments have changes, we are now exposed to byproducts of industrialization (e.g., pollution) and to new practices (e.g. use of repeated ultrasounds during pregnancy). It is interesting that the new DSM-V criteria accept diagnosis of autism spectrum disorders at later points in life whenever environmental exigencies surpass the capacity of the subject. This means that a person working within limited capacity at younger ages may display symptoms much later when first going to mainstream school or even later on when joining the Army. This fact would increase the total number of people with a diagnosis of autism spectrum disorders that were otherwise previously confined to more severe cases – those who were symptomatic in the first few years of life.
Another important factor is that the Flynn effect is greatest in the bottom 10% of IQ scores. Meaning that IQ has increased within the population, because those individuals at the lower tail end of the IQ distribution have improved their scores. Otherwise the highest IQ quartile of individuals have not gained as much. This is somewhat similar to autism where parts of the increase in prevalence (now 1 in 50) may be due to the inclusion of a fraction of individuals, primarily ASD children who were previously unrecognized (Blumberg et al., 2013).
The rise in prevalence in autism and the Flynn effect still await explanations. As many issues that draw upon a variety of social sciences disciplines it is doubtful whether we will be able to obtain concrete answers. There will always be groups of skeptics. However, the questions these phenomena pose makes it of utmost importance that we pursue them. Curiously acceptance of the role of society and diminished role of genetics have been readily welcome and entertained in the scientific arena for the Flynn effect. The same phenomena in autism has drawn dire criticisms, polarized researchers, and remains a contentious issue. In autism a line has been drawn in the sand which provides little or no room for a compromise. Maybe we could stand to learn from other areas of science.
Blumberg SJ, et al. (2013) Changes in prevalence of parent-reported autism spectrum disorder in school-aged U.S. children: 2007 to 2011-1012. National Health Statistic reports 65.