Forget “Peak Oil” and “Peak Credit” … Are We On the Downslope of “Peak Intelligence”?


Scientists say that we have much smaller brains than our ancestors had 20,000 years ago … and we might have gotten stupider since agriculture became widespread.

Huffington Post reports that we’ve probably gotten dumber than even our Victorian ancestors:

A provocative new study suggests human intelligence is on the decline. In fact, it indicates that Westerners have lost 14 I.Q. points on average since the Victorian Era.


As for Dr. te Nijenhuis and colleagues, they analyzed the results of 14 intelligence studies conducted between 1884 to 2004, including one by Sir Francis Galton, an English anthropologist and a cousin of Charles Darwin. Each study gauged participants’ so-called visual reaction times — how long it took them to press a button in response to seeing a stimulus. Reaction time reflects a person’s mental processing speed, and so is considered an indication of general intelligence.


In the late 19th Century, visual reaction times averaged around 194 milliseconds, the analysis showed. In 2004 that time had grown to 275 milliseconds. Even though the machine gauging reaction time in the late 19th Century was less sophisticated than that used in recent years, Dr. te Nijenhuis told The Huffington Post that the old data is directly comparable to modern data.


This new research was published in the April 13 issue of Intelligence.

The Daily Mail notes that we’ve gotten dumber since the 1950s:

Richard Lynn, a psychologist at the University of Ulster, calculated the decline in humans’ genetic potential.

He used data on average IQs around the world in 1950 and 2000 to discover that our collective intelligence has dropped by one IQ point.

Dr Lynn predicts that if this trend continues, we could lose another 1.3 IQ points by 2050.

What’s Making Us Dumber?

There are several theories for why we are getting dumber, including the following:

(1) Toxic chemicals in the environment can reduce intelligence.

Modern man is surrounded by toxic chemicals which have been shown to reduce intelligence.   Examples include flame retardant, lead (found in many lipsticks), certain pesticides (and see this and this),  fluoride (more).

Radiation can also reduce intelligence.  For example, radiation can reduce brain size.

Brian Moench, MD notes:

Many epidemiologic studies show that extremely low doses of radiation increase the incidence of  … diminished intelligence.

And a very well-established resource for doctors (the Merck Manuals) state:

The fetus is sensitive to damage from radiation because fetal cells are dividing very quickly and also differentiating from immature into mature cells. In the fetus, exposure in excess of 300 mGy during 8 to 25 weeks after conception may cause reduced intelligence and poor school performance.

(2) Humans evolved to eat a lot of Omega 3s:

Wild game animals have much higher levels of essential Omega 3 fatty acids than domesticated animals. Indeed, leading nutritionists say that humans evolved to consume a lot of Omega 3 fatty acids in the wild game and fish which they ate (more), and that a low Omega 3 diet is a very new trend within the last 100 years or so.

In other words, while omega 3s have just now been discovered by modern science, we evolved to get a lot of omega 3s … and if we just eat a modern, fast food diet without getting enough omega 3s, it can cause all sorts of health problems.

So something just discovered by science can be a central fuel which our bodies evolved to use.

Omega 3s – in turn – boost intelligence and help prevent cognitive decline.

(3) Similarly, Science Daily notes:

Exposure to specific bacteria in the environment, already believed to have antidepressant qualities, could increase learning behavior, according to research presented at the 110th General Meeting of the American Society for Microbiology in San Diego.

Mycobacterium vaccae is a natural soil bacterium which people likely ingest or breath in when they spend time in nature,” says Dorothy Matthews of The Sage Colleges in Troy, New York, who conducted the research with her colleague Susan Jenks.


“We found that mice that were fed live M. vaccae navigated the maze twice as fast and with less demonstrated anxiety behaviors as control mice,” says Matthews.

In a second experiment the bacteria were removed from the diet of the experimental mice and they were retested. While the mice ran the maze slower than they did when they were ingesting the bacteria, on average they were still faster than the controls.

Obviously, we don’t get in as much soil as our ancestors did.

(In addition, some bacteria in our gut greatly influence brain function. Most native cultures ate fermented foods containing healthy bacteria.)

(4) Exercise boosts intelligence … and our ancestors got a lot more exercise than we do!

“Even our most highly trained athletes pale in comparison to” farmers  7,000 years ago.

(5) In addition, high levels of cortisol – the chemical released when one is under continuous, unrelenting stress – and poverty can physically impair the brain and people’s ability to learn.

Hunter-gatherers had more leisure time – and a more playful attitude – than we do today.

(6) [For this and the next theory, we quote from HuffPost.] Dr. Jan te Nijenhuis points to the fact that women of high intelligence tend to have fewer children than do women of lower intelligence. This negative association between I.Q. and fertility has been demonstrated time and again in research over the last century.

(7) “The reduction in human intelligence … would have begun at the time that genetic selection became more relaxed,” Dr. Gerald Crabtree, professor of pathology and developmental biology at Stanford University, told The Huffington Post in an email. “I projected this occurred as our ancestors began to live in more supportive high density societies (cities) and had access to a steady supply of food. Both of these might have resulted from the invention of agriculture, which occurred about 5,000 to 12,000 years ago.”

Postscript:  Relaxing activities like meditation and prayer have been shown to increase brain mass and connectivity in certain areas of the brain.  And sex makes you smarter and causes brain growth.

Category: Psychology, Think Tank, Web/Tech

Please use the comments to demonstrate your own ignorance, unfamiliarity with empirical data and lack of respect for scientific knowledge. Be sure to create straw men and argue against things I have neither said nor implied. If you could repeat previously discredited memes or steer the conversation into irrelevant, off topic discussions, it would be appreciated. Lastly, kindly forgo all civility in your discourse . . . you are, after all, anonymous.

8 Responses to “Is Modern Life Making Us Dumber?”

  1. Joe_T. says:

    (8) Talk Radio. Produces a constant high level of cortisol, combined with the inherent dumbing effect of negative information dispersal.

  2. orsogrigio says:

    chemicals, bacteria, radiations, food … any possible (if hardly conceivable) cause, but NOT the way we ‘live’ our brain. The eternal is not MY fault. I am old enough to have started my learning on books, paper and pencil, and then to have lived thru computers, huge machines at the beginning, doing pinpointed, specialistic tasks, up to finding out telephone numbers and timetables today. I was quite smarter when I was figuring out something with paper, pencil and midnight oil, making a complex, merciless program (a comma out out place, a few hundred dollars of machine time gone) to run a wider simulatation and improve my model than today. Today a brood of chips finds out anything for me, and I may replace brainwork with blind power. I am not surprised my IQ decays. Instead of informatics we should teach ourselves how to reason, how to use the time that the blind force of computational machines frees to deepen, improve our reasoning. But, for me at least, this is very tiring, and so I look (randomly) for solutions using computing power …

  3. A says:

    Social media is kind of like what the car has been.

    We have always known that there is that segment of the population that offers something short of a measurable IQ.

    And the above two ‘vehicles’ let us know who they are more readily.

  4. wjm23 says:

    And another theory, which I like best, is from Mark Pagel in “Wired for Culture”. Basically he notes that domesticated animals are always “dumber” than their wild cousins as they’re selected to be calm and cooperative. e.g. dogs -vs- wolves, etc.

    He theorizes that we humans are being “tamed” by our culture. You can’t build cities if you’re still a wild hunter gatherer at heart who’s constantly finding reason to kill his neighbors. Instead, culture selects us to be more calm and cooperative than our wild ancestors.

    Essentially he talks of culture as a new, acquired form of DNA that shapes our development at the same time we shape our culture. And like DNA, culture doesn’t care what’s good for us but only what allows it to propagate.

  5. orsogrigio says:

    wjm23, ever overheard about Athens, Rome, Alexandria, Rhodes … ? Our writer discusses a time spell from late XIXth century to today. Mankind built and is still used to live in towns & cities since about three thousand years, so we are pretty domesticated … or not ? I still stress my point: the culprit is a silicon poisoning, or better the dishearting fact that we are not able to control our gadgets because we are not able to control ourselves. Blame no one else

  6. howardoark says:

    Reaction times may be slowing, but general intelligence has been increasing steadily since the 1830s when it was first measured with IQ tests (the Flynn Effect)

    So, this is nonsense.

  7. Biffah Bacon says:

    More fruitcakery from Washingtonsblog. Some counterthoughts:
    what if smaller brains are better, just as smaller microchips have higher circuit density allowing greater speeds at lower voltage?
    What if increased reaction times are a result of people thinking before they react?
    What do IQ tests really measure besides degree of acculturation to the collective norms dictated by a small group of psychology researchers from east coast Ivy League schools? Do IQ tests really measure anything substantial or are they a farcical notion designed to reinforce the status quo by dividing out people of different backgrounds, cultures and experiences? Is Charlie Murray in the house?
    Are starving people stressed? Lots of hunter gatherers have starved to death while chasing omega 3s across the tundra, taiga, steppe and grassland. Malnutrition causes much more distress than not getting your fish oil gelcap. Imagine how stressful it is to leave a baby or a beloved family member out to die because they are holding back the rest of the family.
    Intelligence, finally, is not the be-all and end-all of human existence. Reproduction is. Making babies and expanding your family and your kin network so your babies can have babies as soon as possible in numbers such that they survive and in turn propagate is the definition of biological success. No one cares in the tupiq if you generated mad alpha; but if you have sons to hunt for you and daughters to marry off to neighbor groups who may save your life in starvation times is better than all the bond portfolios in the world.
    Rephrasing the question-is the world getting dumber or are fewer people agreeing with how you think things ought to be?

  8. econ1 says:

    There is a great (well good) movie called “Idiocracy” that may explain some of the IQ loss.

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