At the end of the 20th century, a trend of increasing scores on intelligence quotient (IQ) tests was detected worldwide when comparing successive generations. This phenomenon is known as the Flynn effect and it is especially important in populations with 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 surpassed it, making the current trend in these places towards a decline in average intelligence.
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 IQ that occurs with generation changes a phenomenon that has been detected in numerous parts of the world and that Flynn helped spread.
The Flynn effect occurs in fluid intelligence, crystallized intelligence, spatial intelligence, and global IQ, but it is particularly notable in fluid IQ scores. Compared to crystallized intelligence, which depends on experience, fluid intelligence is defined as the ability to solve new problems and is mainly attributed to biological factors.
Various studies and meta-analyses carried out worldwide confirmed the cross-cultural nature of the Flynn effect. However, it seems to occur almost exclusively in populations of low socioeconomic level which most likely indicates that it is related to environmental factors.
Likewise, the magnitude of the Flynn effect has decreased over time, at least in rich countries. Added to this are other phenomena that influence the fact that currently the global trend has reversed and is now negative; We will talk about this later.
Explanations of this phenomenon
Since 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, Proposed explanations for the Flynn effect focus primarily on the environment
1. Improving schooling
Some authors have proposed that the Flynn effect is simply due to an increase in literacy rates, which are associated with improved IQ. On the other hand, access to high-quality schooling, especially for children of low socioeconomic status, could also explain part of this phenomenon.
2. Compensation for nutritional deficiencies
Nutritional deficiencies interfere with physical development of children, and therefore also in the cognitive. In places where infant nutrition is inadequate, as was the case in most of the world a century ago or in many African countries today, IQ scores are generally lower.
It is important to keep 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 for intellectual development in very early stages of life.
3. Advances in medicine
Like 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 not treated properly.
4. Enrichment of the environment
Flynn himself defended it in his book “What is intelligence?” (2007) that recent changes in society have increased the abstract reasoning capacity of the world’s 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 academic and work demands and the decrease in the number of children per family, which would allow an improvement in the attention and care that children receive.
5. Familiarity with IQ 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 allows us to obtain higher scores on instruments that measure intelligence.
In the same sense, the test format has expanded significantly during the last decades as a form of educational testing, including tests with verbal and mathematical items very similar to some IQ tests. This may also have influenced familiarity with this type of testing.
Are we getting smarter?
Although the Flynn effect remains significant at low socioeconomic levels and in poor countries, studies carried out in recent decades confirm that the influence of this phenomenon is reducing worldwide. This means that Nowadays the average IQ level tends to decrease even maintaining the Flynn effect.
According to various research, the Flynn effect has been overcome by other factors that favor a reduction in the average IQ in countries such as the United Kingdom, Norway, Denmark or Australia. Experts further predict that This decline will continue at least for 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 met to a lesser extent, such as Latin America, East Asia, Arab countries, Africa and India.
At the moment it has not been possible to determine the exact causes of this phenomenon. There are those who relate it to the arrival of immigrants from countries with a lower average IQ, but research does not support this hypothesis. At a historical level, the decline in intelligence has been attributed to the fact that People with higher IQ tend to have fewer children
