(John Vibes) A study conducted in China by researchers from the Yale School of Public Health in the United States has shown that air pollution causes a “huge” reduction in intelligence. While the research did take place in China, which is known to have very serious pollution problems, the researchers suggest that 95% of the global population is breathing unsafe air at levels that would cause a significant reduction in intelligence.
(Mayukh Saha) What is the right determinant of success? Most would say intelligence. After all, we have been taught that intelligent people are often smart and can find their way in life quite easily. They will race to their goal faster and more efficiently than those who have less IQ and are less intelligent. However, a study at Stanford University claims that it is not IQ but the attitude that can be a determinant of success.
(John DiPrete) I recently took a Rationality Test and discovered that I was surprisingly rational. (I took it twice to be sure.) How could that be? I wondered. It’s a plain fact that I’ve committed millions of stupid errors, in my life, and was STILL making them! What’s more, few people would ever call me a world class intellect, in terms of intelligence tests or other abstract-thinking measurements. Logically speaking — Mr. Spock I am not.
(Alex Pietrowski) To date, there are at least 53 known international scientific studies concluding that fluoride consumption is harmful to the development of intelligence in children, it impairs their learning and memory capacity. Children are commonly exposed to fluoride from municipal water supplies, dental treatments, environmental pollution, and in-utero.
Throughout the 20th century, IQ scores steadily climbed. But a one study shows that for the past few decades there has been a downward trend in IQ scores, and “environmental factors” are believed to be one of the causes.
For the study, researchers from the Ragnar Frisch Centre for Economic Research in Norway examined the IQ scores of approximately 730,000 Norwegian men born between 1962 and 1991. They found that IQ scores grew by almost 3 percentage points every decade among men born between 1962 and 1975. However, researchers saw a decline in IQ scores among those born after 1975.
The downward trend is in stark contrast to the Flynn effect, a term used to describe the rise in IQ scores over the 20th century. Rogeburg and his colleagues found that the Flynn effect peaked in the mid-1970’s and has dropped steadily ever since.
The study points out a few of the environmental factors driving down IQ scores:
Changes in the education system
Spending WAY more time online
Yes, there may be a genetic component to all of this, but researchers believe whatever that component is, it holds less clout than our environment. There was a substantial variance in IQ between parents and their children, but also a variance in siblings born to the same parents.
Ole Rogeburg, a senior research fellow at Ragnar Frisch Centre and co-author of the study, said:
“It’s not that dumb people are having more kids than smart people, to put it crudely. It’s something to do with the environment, because we’re seeing the same differences within families.”
These are just guesses for now. More research needs to be done to zero in on the environmental factors that may be influencing IQ scores.
Processed foods have been around since the late 1800’s, but there has been a a 92% increase in per capita intake since 1970 of oils, fats, and grains, according to The Washington Post. That fact alone isn’t too concerning, but Americans are eating significantly more added fats and oils, flour and cereal products – the same kinds found in processed foods.
In 2014, Jeanine Bentley, the social science analyst responsible for the USDA’s food availability database, told the Post:
“It’s hard to pinpoint why exactly it’s increased. But it probably comes from an increase in processed and fast foods.”
Then, there’s fluoride. The vast majority of the United States has fluoridated water, but that’s far from the only source of the chemical. The government allows a number of foods to be fluoridated, including iceberg lettuce, citrus fruits, potatoes, and raisins. Then, you brush your teeth with fluoridated toothpaste. You might not give much thought to how much fluoride you come into contact with on a daily basis, but this list will open your eyes.
When it comes to fluoridated water, a major Harvard University study published in 2012 found the following:
A report in the journal Environmental Health Perspectives reveals thatprenatal exposure to flame retardants may lead to lower IQ test scores in children. Further, the more of the chemicals a pregnant woman is exposed to, the more likely she is to give birth to a child with lower intelligence. 
In the meta-analysis, researchers calculated that every tenfold increase in exposure to flame retardants called polybrominated diphenyl ethers (PBDEs) was associated with a 3.7 point decline in kids’ IQ test scores.
Based on that calculation, PBDEs are even more detrimental to fetuses than lead – every tenfold increase in the neurotoxin is associated with “just” a 7-point decline in IQ scores, by comparison.
Study co-author Tracey Woodruff said:
“Even the loss of a few IQ points on a population-wide level means more children who need early interventions, and families who may face personal and economic burdens for the rest of their lives.” 
The meta-analysis summarizes and evaluates the full collection of relevant research on the safety of PBDEs. Ten of the studies the researchers included show a link between flame retardants and intelligence.
The team analyzed an additional 9 studies that searched for an association between exposure to flame retardants and attention-deficit hyperactivity disorder (ADHD). Juleen Lam, an associate research scientist at the University of California San Francisco, said the 9 papers don’t provide enough evidence of a connection between the chemicals and ADHD. 
However, the link between flame retardants and intelligence is undeniable, according to Lam.
“The evidence strongly suggests that PBDEs are damaging kids’ intelligence.”
Knowing this, Lam said, children should be protected from these chemicals to “prevent intelligence loss.”
“We’re really seeing this as a wake-up call to policymakers.”
Researchers are trying to tease out how PBDEs lower intelligence. So far, the evidence suggests the chemicals impair the activity of the endocrine system, the body’s systems of hormone-producing glands which play a role in the body’s circadian rhythm, sexual development, metabolism, and other functions. When a woman is pregnant, her endocrine system heavily influences the development of her fetus’ brain.
There are multitudinous types of PBDEs, and several of them have already been banned in the United States. Most new furniture doesn’t contain those chemicals, said Arlene Blum, a scientist with the Green Science Policy Institute, who wasn’t involved in the study.
Nevertheless, Woodruff, a professor at UCSF, said that “everyone is exposed to PBDEs, so this means that there are potentially millions of IQ points that are lost across the population.” Moreover, “children can be affected for generations to come.” 
Banned But Still Prevalent
Another study led by Hurley, published in March, 2017, showed a gradual plateau in bodily levels of flame retardants – even an increase in some people. Hurley believes that’s likely because as people have disposed of or incinerated their old furniture, PBDEs have made their way into the environment. 
Now, Hurley theorizes, the chemicals are getting into the food supply, as old furniture and foams containing PBDEs have been tossed into landfills or incinerated, causing the chemicals to leach into runoff and/or spewed into the air.
Whether or not flame retardants actually make fires less deadly is up for debate. Bryan Goodman, a spokesman for the industry group American Chemistry Council, said that flame retardants help save lives by providing individuals with a critical layer of fire protection. He added that “the major manufacturers of flame retardants have spent millions of dollars on research both before and after their products go on the market.”
However, some past studies seemed to suggest that flame retardants actually give rise to toxic fumes. Ami Zota, an environmental health scientist at George Washington University who studies flame retardants but wasn’t involved in the paper, said their efficacy is “not really backed up by well-supported data.”