It has been revealed why the IQ of the US population has decreased terribly in recent decades

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It has been revealed why the IQ of the US population has decreased terribly in recent decades
It has been revealed why the IQ of the US population has decreased terribly in recent decades

It is very surprising, but there is a proven reason from several directions that the average level of intelligence has decreased in recent years overseas. The whole thing has nothing to do with education, nor with genetics, the decline was caused by something much stranger, which the sufferers had absolutely nothing to do with

Leaded gasoline may have reduced the IQ of more than half of the US population, reports the New Scientist magazine. Childhood exposure to leaded gasoline was associated with an average IQ decline of 2.6 points for adults in the United States, and 5.9 points for those born in the mid-to-late 1960s.

A new study shows that the body's lead load affects IQ. Of course, the value is still determined by innate and environmental factors, but unfortunately it seems that they are not immovable values.

More than half of the people living in the United States have a slightly lower than average IQ, in part because they breathed in the exhaust fumes of vehicles powered by leaded gasoline as children. Experts believe that the deterioration is most common among those born in the 1960s and 1970s, when the use of this fuel was at its peak.

“Similar effects are likely to have occurred in other high-income countries”

says Aaron Reuben of Duke University in North Carolina. "In the last century, the practice of using lead in gasoline was very similar in developed countries."

In the 1920s, lead was added to gasoline to make car engines work better. If the substance gets into the brain, it can disrupt nerve signaling and destroy brain cells at higher levels. Young children are especially sensitive to the effects of metal that disrupts the development of the brain.


Using data from a national survey, Reuben and colleagues analyzed the lead levels of more than 11,600 children aged 1-5 years from blood samples taken between 1976 and 2016. Blood lead levels for the period between 1940 and 1975 were also estimated based on the lead content. This data was then linked to a previously established formula showing how lead exposure affects IQ.

Their findings suggest that half of the current US population had elevated blood lead levels during childhood. Nationwide, it is estimated that lead exposure may have caused an average IQ drop of 2.6 points, with those born in the mid-to-late 1960s losing an average of 5.9 points.

In the 1970s, it was recognized that tiny particles of lead in exhaust gases could enter people's bloodstreams, and that higher environmental levels of the metal were linked to poorer school performance in children.

The use of leaded gasoline in road vehicles was finally banned in the United States in 1996 and in the United Kingdom in 2000.

“Recent study proves lasting effects of certain environmental toxins”

– pointed out Mathew Hauer of Florida State University, who participated in the work. "The effects can last for a long time and can also exist for other toxins," the expert says.

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