In 1984, New Zealand intelligence researcher James Flynn observed a phenomenon that piqued curiosity like no other: not only had the mean IQ scores of Americans risen exponentially between the 1930s and 70s, but at a noteworthy rate of 13.8 points – which almost amounts to the gap of an entire standard deviation (15 points). Studies conducted in several other countries yielded similar findings: an increase of 3 IQ points was observed per decade during certain times of the 20th century among industrialised Western countries. Such growths were reported to be even stronger in Japan and South Korea, where the increase skyrocketed to around 7.7 points. Beyond cosmopolitan areas, the Flynn effect has also manifested itself in developing corners of the world, such as in rural Kenya.

Many appear confident about the explanation behind this phenomenon – it almost seems too obvious. In particular after World War II, societal circumstances have generally been favourable for creating improved educational environments. A relatively ‘worry-free’ era allows countries to focus on schooling and parents to devote energy to their children’s development. In parts of the developing world, the growth of parental literacy and more stable familial structures have exponentially contributed to more academic support in the home environment. Likewise, improved nutrition is a key factor in the increase of IQ scores, although its role is likely larger in rural than in urban areas. The increasingly competitive local and global labour markets have also stimulated people to reach the highest of their cognitive potentials.

“An explanation for the decline in IQ scores could relate to the increasing comfort of a highly developed society”

Encouraging as it may appear, evidence suggests that the Flynn effect is not bound to last, and that human intelligence might have already begun to plateau. The numbers recount this vividly: IQ points in Norway have fallen by 7 points per generation in post-1975 cohorts. In Denmark, points went down by 1.5 between 1998 and 2003. Many other countries in the industrialised world tell an eerily similar story.

An explanation for the decline in IQ scores could relate to the increasing comfort of a highly developed society. In a digitised world where machines help with providing answers (‘Siri, how do I fix my loose bicycle brakes?’), some skills traditionally assessed in IQ tests – such as technical problem-solving skills – are not practised as often as before in our daily lives. Overall, the developmental trajectory of the Flynn effect and its reversal appears to be a fixed pattern in developed countries. This is illustrated particularly well in the similar ebb and flow of Japan and South Korea’s IQ scores at different developmental stages of their societies.

“We may also benefit from stepping back and revisiting the concept of ‘intelligence’, and what it truly means for our evolution as the human race”

But is the rise and fall of IQ scores something to concern ourselves with? While some scholars do worry, we could perhaps interpret the broader picture in a different light. Firstly, IQ tests themselves are not omnipotent; they tend to test fluid and crystallised intelligence in differently conceptualised constructs, and as scientists argue, an individual’s IQ points could vary exponentially depending on which IQ test they use. Furthermore, when the Flynn effect was observed, sceptics weighed in and argued that the increase in scores could be a temporary reflection on the population’s adaptation to test-taking strategies and test familiarity, or improved literacy rates even. It is therefore unclear what the Flynn effect and its reversal suggest, given that the reasons for both phenomena are not all that straightforward.

We may also benefit from stepping back and revisiting the concept of ‘intelligence’, and what it truly means for our evolution as the human race. There is no denying that reasoning and problem-solving skills are fundamental, but intelligence, as assessed in IQ tests, is not the only key towards building a more enriched global society, nor is it the only path to solving humanity’s greatest problems. IQ tests do not assess the 4Cs that may be more pivotal than general intelligence itself– creativity, curiosity, complex critical thinking, or most importantly, compassion. It is perhaps high time to consider how these other factors interact with the concept of intelligence before we further interpret what may be in store for the future of human brainpower.