© Illustration RIA Novosti . CC BY 2.0 / hape662 Depositphotos/SarkisSeysianOver the last half century humanity became stupid, scientists have found. Since the mid 1970-ies the performance IQ fell by an average of seven points for each of the next generation. Some experts attribute this to the continuing evolution of man, others to the laws of genetics, and others — with the rapid development of technology. RIA Novosti understood what the reason for the decline of intelligence.
To measure the volume
From upper Paleolithic humans and Neanderthals brains were bigger than ours. On average, men its volume was more than 1500 cubic centimeters against modern 1425. If they were smarter than the current Homo sapiens is a big question, but some researchers find a positive correlation (albeit slight) between the size of this body and level of intelligence.According to Russian anthropologist Stanislav Drobyshevsky, the large size of the brain of ancient people, most likely due to harsh conditions of existence. The CRO-magnons and Neanderthals all the vital information had to be kept in mind as artificial media, such as books, not yet invented, and the wise old men of experience are extremely rare. After all, the average life expectancy was very low.Modern people, on the contrary, was practically in hothouse conditions — clothing, food, information they receive in finished form, and generations of accumulated knowledge is stored on external media. In such circumstances, a large voracious brain, consuming up to 20 percent produced by the body energy, it is not necessary. This is probably why in the last 25 thousand years there has been a gradual shrinkage. In the previous ten thousand years it shrank by nearly five percent.Anthropologists from the University of Chicago attribute this marked reduction of the brain with the mutation, which appeared among the farmers of the Middle East about six thousand years ago. Today most of the human population — its carriers, so the trend apparently will continue.
Progress is not good
According to genetics from Stanford University (USA) Gerald Crabtree for the last three thousand years, humanity has suffered at least two genetic mutations, bad impact on intelligence. In the future, probably, there will be several more changes. That is the conclusion he came to, based on the frequency with which in the human genome there are harmful mutations, and the expected number of “smart” genes.The scientist indicates that the leap in cognitive development and optimization of genes for intelligence, happened before our ancestors came out of Africa. There they had to exist in a fairly harsh environment, so have survived the strongest, smartest and most adapted to the environment. In other words, natural selection worked for the improvement of intelligence.After migration to Europe human life much easier. The development of agriculture, emergence of cities, medical advances have actually negated natural selection. In the population, a large number of individuals with bad mutations in DNA. As a result, the intelligence began to decrease gradually.
The global decline of intelligence
Paradoxically, in the twentieth century, recorded an increase in intelligence. It was discovered in 1984 American psychologist James Flynn, who calculated that from 1932 to 1978 in the USA the average IQ has increased by almost 14 points. His data later confirmed in many countries.But last year, Norwegian scientists analyzed test scores of over seven hundred thousand people, came to the conclusion that since the 1970-ies the average intelligence gradually fall by about seven points for each of the next generation. So, IQ born in 1969 is about three points higher than that of people who are older than them for seven years — 102,3 99,5 against. But then the situation changes: have passed the test volunteers, born in 1989, the average result has less and 99.4 points.This phenomenon can be traced even in some families where older brothers better test for intelligence than younger. So, it’s, apparently, not in demographics or distribution of the less successful genes in the population, say the authors. Probably, the drop in IQ scores, on the one hand, affected by the lifestyle change — the development of technology, changes in education and upbringing, and on the other — the imperfection of the test, which is not able to assess the level of intelligence of modern man.
© Source: Bernt Bratsberg and Ole Rogeberg, Flynn effect and its reversal are both environmentally caused. PNAS June 26, 2018 115 (26) 6674-6678; https://doi.org/10.1073/pnas.1718793115Изменение average IQ by year of birth. We used data of seven hundred thousand Norwegians who were born between 1962 and 1991, kodacrome fact, cognitive ability may decline due to strong environmental pollution, say Spanish researchers. They measured the level of harmful impurities in the air around 39 primary schools in Barcelona and then tested the intelligence of the students. In environmentally favorable areas, the results of pupils on average were better.Similar results were obtained by scientists from Lancaster University (UK), analyzing a sample of 18 thousand young Britons. They found that children with mental retardation more often than their peers living in places with high air pollution.Alfia Enikeeva