During the 20th Century, there was a steady rise in IQ scores among populations. Present trends however show a persistent decline in the same causing concerns.
The new study comes from the researchers at the Ragnar Frisch Centre for Economic Research, Norway. The team analyzed the IQ scores of over 730,000 Norwegian males who were born between 1962 and 1991. For each decade of birth between 1962 and 1975, the IQ scores showed a rise of 3 percent. Thereafter the scores showed a steady decline, the team of researchers noted. The results of the study were published in the latest issue of the journal Proceedings of the National Academy of Sciences (PNAS).
IQ training top view visual puzzle (suitable both for kids and adults): Can you find the top view for every fir tree decorated with red, blue and yellow ornaments? Answer included bottom of page. Image Credit: ratselmeister / Shutterstock
According to lead researcher Ole Rogeburg who is a research fellow at the Ragnar Frisch Centre, this decline is not due to genetics but due to environmental factors. This study was conducted by Rogeburg and Bernt Bratsberg. Same differences in IQ are seen within families explained Rogeburg and so it has more to do with the environment than genes.
The researchers say that environmental factors that could play a role in IQ include the methods of education, time spent online and overall less time spent reading. Changes in nutrition with more unhealthy diets could also be one of the contributors to lower IQ scores, they note. Factors that did not contribute to decline in IQ scores were family size, immigration on the rise and parental education. Lifestyle factors, they write, are the most important causes of declining IQ.
The team writes in their study titled, “Flynn effect and its reversal are both environmentally caused,” that this decline is due to the reversal of the Flynn effect. Flynn effect is a term that is used to define the huge leaps in IQ scores that was seen in the 20th Century in several parts of the world. The Flynn effect is said to have reached its pinnacle in the 1970’s. This study shows that thereafter it has been spiraling downwards.