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The Flynn effect: are we getting smarter?

The Flynn effect: are we getting smarter?

March 25, 2024

At the end of the 20th century, there was a worldwide tendency to increase the scores in IQ tests when comparing successive generations. This phenomenon is known as the Flynn effect and it is especially important in populations of low socioeconomic status.

However, increases in IQ due to the Flynn effect have recently been reduced in rich countries, to the point that other factors have overcome it, causing the current trend in these places to be towards the decrease in average intelligence.

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What is the Flynn effect?

The researcher James Robert Flynn (1934-) has defended during his professional career the fact that intelligence depends largely on environmental factors, which make it unnecessary to resort to intergroup explanations, such as the genetic superiority of certain social groups.


The term "Flynn effect" was coined by Richard Hernstein and Charles Murray in the book The Bell Curve (1994). These authors used it to describe the increase in the IQ that occurs with generation changes , a phenomenon that has been detected in many parts of the world and that Flynn helped to spread.

The Flynn effect occurs in fluid, crystallized, spatial, and global IQ intelligence, but it is particularly noticeable in the scores on the fluid IQ. Faced with crystallized intelligence, which depends on experience, fluid is defined as the ability to solve new problems and is attributed mainly to biological factors.


Several studies and meta-analyzes carried out worldwide confirmed the transcultural nature of the Flynn effect. However, it seems to occur almost exclusively in populations of low socioeconomic status , which indicates in all probability that it is related to environmental factors.

Likewise, the magnitude of the Flynn effect has been reduced over time, at least in rich countries. To this are added other phenomena that influence that currently the world trend has reversed and is now negative ; We'll talk about this later

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Explanations of this phenomenon

Given that the increases in intelligence that have been detected have occurred too quickly (sometimes up to 10 IQ points in 30 years) to be due to genetic variations, the explanations proposed for the Flynn effect focus mainly on the environment .


1. Improvement of schooling

Some authors have proposed that the Flynn effect is simply due to an increase in literacy rates, which are associated with an improvement in IQ. On the other hand, access to high-quality schooling, especially in children of low socioeconomic status, could also explain part of this phenomenon.

2. Compensation of nutritional deficits

The nutritional deficits interfere with physical development of children, and therefore also in the cognitive. In places where infant feeding is not adequate, as it was in most of the world a century ago or in many African countries today, the IQ scores are generally lower.

It is important to bear in mind that these effects overlap with educational improvements after a certain age. In any case, it is believed that nutrition may be more relevant to intellectual development in very early stages of life.

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3. Advances in medicine

As the improvement in nutritional conditions, medical progress has allowed the healthy development of many people. According to some studies, it is particularly important the reduction in the number of infectious diseases , as well as in its severity; This type of alteration can affect the brain if it is not treated properly.

4. Enrichment of the environment

Flynn himself defended in his book "What is intelligence?" (2007) that recent changes in society have increased the capacity of abstract reasoning of the world population. These variations can be mainly technological or social.

Among the relevant factors Flynn highlights familiarization with new technologies , which can be stimulating for the brain, the increase in the academic and work requirement and the decrease in the number of children per family, which would allow an improvement in the attention and care received by the children.

5. Familiarity with CI tests

In addition to the popularization of IQ tests, this factor is related to the increase in literacy rates and the improvement of formal education. Schooling enhances the capacity for abstract thinking and therefore it allows obtaining higher scores in instruments that measure intelligence.

In the same sense, the test format has extended significantly during the last decades as a form of educational test, including tests with verbal and mathematical items very similar to some IQ tests. This may also have influenced the familiarity with this type of evidence.

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Are we getting smarter?

Although the Flynn effect remains significant at low socioeconomic levels and in poor countries, studies conducted in recent decades confirm that the influence of this phenomenon is decreasing worldwide. This means that currently, the average IQ level tends to fall , even keeping the Flynn effect.

According to several investigations, the Flynn effect has been overcome by other factors that favor a reduction of the average IQ in countries such as the United Kingdom, Norway, Denmark or Australia. Experts also predict that this decline will continue at least during the rest of the 21st century in Europe and the United States, if the current trend continues.

However, it is expected that the increase in intelligence will continue to occur in regions where the needs of the population are covered to a lesser extent, as in Latin America, East Asia, the Arab countries, Africa and India.

For the time being, the exact causes of this phenomenon have not been determined. Some people relate it to the arrival of immigrants from countries with a lower average IQ, but the research does not support this hypothesis. At the historical level, the decline in intelligence has been attributed to the fact that people with a higher IQ tend to have fewer children .


Why our IQ levels are higher than our grandparents' | James Flynn (March 2024).


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