For decades various studies of human intelligence levels suggested a general increase since 1935 of about 3 I.Q. points per decade. However, a careful scrutiny of this data, from many nations, suggests mixed evidence, with some scores going up for a while then down, or up and then leveling off. And the trends vary depending on which specific aspect of intelligence is being measured.
In 2001 the present author was asked to develop intelligence tests which children could take over the Internet at the FunEducation.com web site in San Diego. Two tests were developed, a verbal one and a spatial one. They were modeled after the Wechsler Intelligence Scale for Children, third edition. The verbal test proved to be quite popular. It has five sections: arithmetic, vocabulary, comprehension, similarities and information. Each of these tests is as reliable as its corresponding Wechsler test, meaning that the scores provide very dependable estimates of a given individual’s intelligence level.
113,000 children from around the world took the verbal test between 2006 and 2008. When the scores for those children were compared to scores for 163,000 children that took the test between 2009 and 2015, a disturbing trend was apparent. All of the scores for each of the six tests and for the total score were lower for the second group than for the first group, and for all groups of children ages six through 16. The average drop was .81 IQ points per year.
At this rate, in just 37 years, the average world IQ will drop from 100 to 70. 70 is the upper end of the mental retardation range. At that point, half the population of the world will be unemployable because they won’t be smart enough to learn, understand and do basic jobs.
And the few people with the highest intelligence, which will be about 100 compared to current standards, won’t be smart enough to graduate from a challenging four-year college or university program, as we know it now. Nor would virtually any humans be smart enough to complete graduate degrees in medicine, law, physics, chemistry or other subjects. In short, if this trend continues unchecked society as we know it will no longer be possible. There simply won’t be enough intelligent people to keep it going.
Analysis of research by other scientists strongly suggests that the cause of this intelligence drop is toxins in the air. Air is the only thing that humans everywhere in the world consume in the same manner. These toxins come from industry and from fossil fuel combustion. They also come from burning wood, as is done in many developing countries for cooking. When these toxins are breathed in, they cause damage in the brain. For example, studies in highly polluted Mexico City show that children in the city have lower IQ scores from one year to the next than children in the outlying suburbs. Autopsies of the brains of dogs and of humans show more toxins in the brains of those in the city compared to those in countryside. This is just one example of the kind of study that documents the direct relationship between air pollution and cognitive function.
One of the most toxic substances is exhaust from burning diesel fuel. 60 percent of the cancer in California is attributed to diesel fuel exhaust, though diesel vehicles constitute only 2% of California vehicles. The World Health Organization recently reported that more than 90 percent of humans live in communities with unhealthy levels of air pollution.
Thus, it seems critically important that nations work as quickly and as vigorously as they can to stop all pollution of the air from all sources, from industry, wood-burning and fossil fuel burning.
Caged canaries were used in coal mines to warn miners of toxic levels of carbon monoxide gas. Canaries would die quickly at low levels of this gas. This was the signal for the miners to get out. Now, our children’s falling IQ levels are giving us the same signal. They are today’s canaries in the coal mine.
Governments must listen to citizens. The majority of citizens worldwide are concerned about the environment. They need direct say in government policies and programs so that air pollution can be quickly eliminated. During World War II, the United States reduced civilian use of gasoline by 40% simply by rationing gasoline. We must constrain our use of everything that pollutes the air in order for the human species to survive.