[Cid_Yama]

Our technology may be getting smarter, but 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.

What exactly explains this decline? Study co-author Dr. Jan te Nijenhuis, professor of work and organizational psychology at the University of Amsterdam, 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.

But this isn't the first evidence of a possible decline in human intelligence.

"The reduction in human intelligence (if there is any reduction) 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."

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.

https://www.youtube.com/watch?v=icmRCixQrx8

[kuidaskassikaeb]

The Flynn effect is the substantial and long-sustained increase in both fluid and crystallized intelligence test scores measured in many parts of the world from roughly 1930 to the present day. When intelligence quotient (IQ) tests are initially standardized using a sample of test-takers, by convention the average of the test results is set to 100 and their standard deviation is set to 15 or 16 IQ points. When IQ tests are revised, they are again standardized using a new sample of test-takers, usually born more recently than the first. Again, the average result is set to 100. However, when the new test subjects take the older tests, in almost every case their average scores are significantly above 100.

Test score increases have been continuous and approximately linear from the earliest years of testing to the present. For the Raven's Progressive Matrices test, subjects born over a 100-year period were compared in Des Moines, Iowa, and separately in Dumfries, Scotland. Improvements were remarkably consistent across the whole period, in both countries.[1] This effect of an apparent increase in IQ has also been observed in various other parts of the world, though the rates of increase vary.[2]

There are numerous proposed explanations of the Flynn effect, as well as some skepticism about its implications. Similar improvements have been reported for other cognitions such as semantic and episodic memory.[3] Recent research suggests that the Flynn effect may have ended in at least a few developed nations, possibly allowing national differences in IQ scores[4] to diminish if the Flynn effect continues in nations with lower average national IQs.

I won't write anything this effect is well known. Culture out runs biology

[KaiserJeep]

Careful, Cid. When I suggested the very same thing here in PO.com a couple of years ago, I was accused of both being a Racist and an advocate of Eugenics.

I have not changed my opinions, but the intelligence decline is but one symptom of many. The widespread use of agriculture, improvements in nutrition and hygiene, medicine devoted to keeping marginal human beings alive and even reproducing, and above all, cheap hydrocarbon energy - these things have combined to produce worldwide not only an enormous population overshoot, but a human species that - almost certainly - is no longer evolving as per Darwin, but is most probably devolving into a less intelligent and less healthy species.

This topic was discussed at length by Robert Heinlein in his early novel Beyond This Horizon(1942). Nobel-prize-winning laureate William Shockley (I heard him speak at an IEEE meeting in the late 1980s) was a leper among his colleagues at Stanford for his views on Eugenics. Further controversy happened in 1994 with the publication of The Bell Curve: Intelligence and Class Structure in American Life by Herrnstein and Murray, because it suggested that there were measurable and quantifiable differences in intelligence, job performance, birth out of wedlock, and involvement in crime from one human race to another - and that such differences were measurable regardless of the individual's social position, wealth, and education. Then in 1990-2003, the Human Genome Project positively linked such racial differences to the "real" racial heritage disclosed by our genes, and not to morphology (i.e. outward appearances such as skin color).

I knew the various girls in my daughter's Girl Scout Troop because my wife was troop leader and I was a frequent troop chauffeur. One troop member got a Doctorate in Sociology and ended up married to a Doctorate in Anthropology. They are fascinating people, my wife still does their taxes. The Anthropologist has voluntarily agreed not to publish his research on human intelligence online - only in print, and only to his colleagues, and only in a limited distribution hardcopy journal. (Politically correct papers are published online without hindrance.) The Sociologist is studying human behavior as relates to Internet usage, social networking, and the like. She has voluntarily refrained from publishing some controversial discoveries because she does not want to impact the group she is studying. Let me summarise by saying: to the vast majority of people today, what they read on the Internet is reality. That their reality is being manipulated by many and edited retroactively by many - at the country level and the corporate level and down to individual blogs - is something that most actually understand, but do not care about - to them the online world is more real than the actual world, if it changes and does not fit their memories, they quickly and uncritically adjust their memory to match the online information. You will see such people here at PO.com, and have probably exchanged comments with them.

Conspiracy theorists have amused me my entire life - which after all is not the same as saying that they are entirely wrong in their beliefs. Trying to change the situation we are in is certainly impossible. The changes necessary to kick start Darwinian evolution again are politically incorrect. Let me just note that the majority of PO.com members seem to hold out some belief - or perhaps faith is a more accurate word - that the human race will get wiser as time passes and save ourselves and the world we live in. You are one of the few that has noticed we are making negative progress towards that goal, and that it will simply never happen. At least, based on this thread, I think you have had such thoughts.

[C8]

A decline in IQ is completely predictable as a result of the growth of social safety net programs and foreign aid. Low IQ people and nations that would have been eliminated by natural selection are being propped up by aid delivered from high IQ folks- who reproduce less. The movie Idiocracy really gets a lot correct.

There is some additional evidence that the rapid spread of smart phone distraction is also inhibiting the ability to concentrate.

[Newfie]

Jared Diamond makes a pretty good case for the decline based on the social safty net and that living is easy now, not a lot of us get eliminated from the breeding pool for dumb mistakes.

[Plantagenet]

We don't live in a democracy. We live in an idiocracy.

[fleance]

Another factor in IQ decline is family's environment so, not merely on genetic factor as the cause of IQ decline.

[EdwinSm]

Is this what H G Wells saw, with the human race diverging into two separate entities, the Eloi and the Morlocks?

I wonder which group we see ourselves as being the ancestors of?

[SeaGypsy]

HG Wells ripped that idea from the Sanskrit Vedas, where it is mentioned many times. Eventually there will be a split between the ignorant & the intelligent, the former will get dumber & uglier as time goes by while the intelligent will become much more so & very beautiful. Given the worship granted to people like the Kardashians apparently there is significant breeding going on between the two groups still. Probably just an oversimplified world view. Good looking & bright guys with no ethics can still sow a lot of wild oats, which probably balances some of the other factors somewhat.

I have thought for decades from a genome view, we are pretty much creating every kind of human hybrid & cross imaginable. When the bottleneck happens, chaos & Darwin take over & the next great experiment of humanity begins.

[Rod_Cloutier]

I took a Mensa test once and I scored 189, you need a test score over 200 to be in the genius group to qualify for Mensa membership.

I found some of the Mensa questions presumptuous. For example one of the questions required a person to have an understanding of prime numbers. This is not something that I studied in school, it is not something that everyone would be aware of, so I got that one wrong.

Take a Mensa test yourself to see if you have an IQ over 200 and qualify for membership in their Genius club:

https://www.mensa.org/workout

[SeaGypsy]

Yep, & 100% sure the few scoring so high would look like morons if transplanted to the jungle or a fishing boat or a 16 gear 3 trailer truck etc.

[GoghGoner]

In an absence of selection why would IQ go down, it could just as well go up. According, to the Flynn effect this has happened. I think this could be completely random movement but part of me would like to believe we have been programmed to become more intelligent.

The argument against high IQ folks not making enough babies has a flaw. We tend to regress to the mean. So if a very stupid person has a baby, that baby will be much closer to the average. If a very smart person has a baby, that baby would also regress to the mean. What happens to the baby's baby, either above or below the mean.

Even with first generation twins, there is substantial variation that has nothing to do with genetics:

Starting around 1990 Professor Bouchard and his team published numerous results from the twin study project. The majority of the conclusions of the twin studies are based on answers to the question of whether identical twins (who were thought to share all their genes) are more similar than those of fraternal twins (who share an average of 50 percent of their genes). It was concluded, among many other things, that identical twins are about 85 percent similar for IQ, whereas fraternal twins are about 60 percent similar. This would seem to indicate that half of the variation in intelligence is due to genes.

[ralfy]

I recall a similar point in Guns, Germs, and Steel, i.e., how a very intelligent city dweller in a jungle environment would probably not last long, etc.

[AgentR11]

While a century seems far too short a time span to draw any conclusions; I do think the hypothesis is probably valid. Intelligence is an expensive trait; thus it seems rational to me that absent some strong, consistent selection pressure over many centuries; average intelligence should slip some.

Civilization has removed most of the selection pressure; and left human evolution strictly up to fecundity.

Adding to this, is the typical amount of time it takes a person to complete their PhD. For a guy, its really no big deal; for a female though, the numbers are friggin harsh. Given that a female can carry to term with good odds from 18 to 35; and your generic PhD candidate finishes at approaching 30 (and not uncommon to be older, if first proposed thesis was just flat wrong....); you've deleted 12+ of the 17 or so really solid reproductive years from your generic smart female. If she naturally spaces fertility, that pretty much locks her down to 2 or 3 offspring, even if she's dedicated to the exercise.

She can of course,roll the dice late and kill/abort any that are slightly defective, but it takes a pretty hard person to do such a thing when the family environment is otherwise conducive. If she gambles early, the uncertainties of a child's early life can easily wreck her prospects of professional or academic success.

OTOH, Jane out of High School? Hooks up with Bob the Welder at 19, and has a solid 15+ reproductively successful years ahead of her, even if she''s an absolutely off the chart moron. Yes, even a person that can be defeated by the assembly instructions for a cheeseburger can successfully deliver and raise a human child. Its not hard.

Now, whether civilization lasts long enough for the above bias to REALLY move the genetics on intelligence, I have no clue at all.

[KaiserJeep]

You seem to be discussing cultural differences between white collar and blue collar folks. While I agree that those exist and that they do amount to the white collar folks reproducing at a lower rate, the rest of us were discussing matters of biology that are species-wide, regardless of country or culture.

Such things as fertility clinics are used to overcome reproductive disfunction. The mentally handicapped also reproduce now, in prior years well into the 20th Century, they would have been forcibly sterilized (which we can all agree is both criminal and tragic). The abundance of food from mechanized agriculture, the intervention of medicine into epidemics (Ebola, Zika, etc.), the prevalence of mosquito control via DDT, modern pharmacology that keeps diabetes patients, HIV patients, Hepatitis patients, etc. alive - all these things impact the 1st, 2nd, and 3rd world countries alike.

Collectively, all these things in concert have stopped, perhaps even reversed, Darwinian evolution of the human species world-wide. They also collectively enabled the population overshoot that dooms us all, the basic problem for which hydrocarbon depletion and climate change are symptoms.

[SeaGypsy]

Traditional Chinese herbal medicine is as affective as IVF in terms of fertility treatments, both fail at least 50% of couples. Also unless the egg & sperm have been frozen in the producer's prime, they are less than ideal. Smart people are often pretty stupid really.

Eg- KJ is so smart he built the internet, but stupid enough to believe his kids have a home booked up on a giant space doughnut when resource depletion destroys the planet.

[JV153]

I took a Mensa test once and I scored 189, you need a test score over 200 to be in the genius group to qualify for Mensa membership.

Is this an enduring, evolutionary intelligence or is it just a flash in the pan ?

[C8]

IQ tests have evolved over the years and are actually pretty good predictors of life success regardless of income level. Recently, models have been made of "real world" problems to see if IQ aligns with this and IQ test scores have been found to be a good indicator of whether a person can solve real world problems also.

See the following article:

https://www.psychologytoday.com/blog/br ... istinct-iq

[Tanada]

While a century seems far too short a time span to draw any conclusions; I do think the hypothesis is probably valid. Intelligence is an expensive trait; thus it seems rational to me that absent some strong, consistent selection pressure over many centuries; average intelligence should slip some.

Civilization has removed most of the selection pressure; and left human evolution strictly up to fecundity.

Adding to this, is the typical amount of time it takes a person to complete their PhD. For a guy, its really no big deal; for a female though, the numbers are friggin harsh. Given that a female can carry to term with good odds from 18 to 35; and your generic PhD candidate finishes at approaching 30 (and not uncommon to be older, if first proposed thesis was just flat wrong....); you've deleted 12+ of the 17 or so really solid reproductive years from your generic smart female. If she naturally spaces fertility, that pretty much locks her down to 2 or 3 offspring, even if she's dedicated to the exercise.

She can of course,roll the dice late and kill/abort any that are slightly defective, but it takes a pretty hard person to do such a thing when the family environment is otherwise conducive. If she gambles early, the uncertainties of a child's early life can easily wreck her prospects of professional or academic success.

OTOH, Jane out of High School? Hooks up with Bob the Welder at 19, and has a solid 15+ reproductively successful years ahead of her, even if she''s an absolutely off the chart moron. Yes, even a person that can be defeated by the assembly instructions for a cheeseburger can successfully deliver and raise a human child. Its not hard.

Now, whether civilization lasts long enough for the above bias to REALLY move the genetics on intelligence, I have no clue at all.

I think your cultural blind spot is showing. Just because a woman is very intelligent does not automatically mean she wants to pursue a PhD. in any field. Add to that the fact that most people on this planet, no matter how bright, do not have both access via location and funding to achieve a PhD. level course of study. The majority of the women on this planet no matter if they are dull or brilliant do not live in a westernized culture that places career far ahead of family life. We in the west are the aberrant culture, not the average culture.