Researchers found an interesting trend in intelligence scores. Since the 1970s there has been a drop in the general IQ test scores.
Bernt Bratsberg and Ole Rogeberg, from Ragnar Frisch Center for Economic Research in Norway, conducted the study published in the journal PNAS.
Experts have observed an intelligence boom throughout the 20th century —a phenomenon called Flynn effect. The increase and changes in the intelligence quotient of the population were rapid. On average, the measured intelligence increased by about three points per decade.
Several theories offered possible explanations for the apparent brightening of the human mind, which include improved health care, better nutrition, and education.
The findings of the new study, however, showed a reversal of this trend.
For their study, the researchers analyzed the IQ test results of young men who entered Norway's' national service between the years 1970 and 2009. Based on the results of 730,000 tests, the researchers observed that, on average, the scores dropped seven points per generation.
Although the findings do not provide conclusive proof that people are getting dumber, experts said that the findings of the study are still worrying.
"This is the most convincing evidence yet of a reversal of the Flynn effect," said Stuart Ritchie from the University of Edinburgh, who was not involved in the study. "If you assume their model is correct, the results are impressive, and pretty worrying."
It appears that environmental factors play an important part in the drop in IQ scores. The researchers observed that the IQ score decline occurred among actual families, such as between brothers and son. This suggests that the decline is not due to family factors but to environmental factors.
Lifestyle changes such as modifications in the education system, children playing video games more and reading less, could be responsible for this.
"The trends are not due to a changing composition of families, and that there is at most a minor role for explanations involving genes (e.g., immigration and dysgenic fertility) and environmental factors largely fixed within families (e.g., parental education, socialization effects of low-ability parents, and family size)," the researchers wrote in their study.
"Their influence is negligible compared with other environmental factors.
Earlier studies also came up with similar results. A study conducted by researchers in Britain found that IQ score is falling by 2. 5 to 4.3 points per decade since the end of World War II.