# Should humans with low IQ be..... **URL:** \ **Category:** Great Debates\ **Created:** [February 26, 2016, 3:25pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204 "2016-02-26T15:25:12Z")\ **Posts on this page:** 12\ **Page:** 6
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [February 29, 2016, 8:04pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/101 "2016-02-29T20:04:59Z")
> **[Flynn effect](https://en.wikipedia.org/wiki/Flynn_effect)** > > The Flynn effect is the substantial and long-sustained increase in both fluid and crystallized intelligence test scores that were measured in many parts of the world over the 20th century. 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, Test ... It’s been happening for awhile already… EDIT: Sorry, responding to the OP, not the absurd idea that people are getting dumber… They are demonstrably not. Demonstrably, that is, if you think IQ tests measure intelligence, which assumption the OP seems to be taking a priori. ---
**Author:** ![BrightNShiny](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@BrightNShiny](https://boards.straightdope.com/u/BrightNShiny)\ **Post date:** [February 29, 2016, 9:47pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/102 "2016-02-29T21:47:43Z")
We’ve already got a way to increase average IQ across the globe. It’s called early childhood nutrition. Well, we’ve actually got a number of ways to increase average IQ across the globe: childhood nutrition, pre-natal care, immunizations, universal compulsory education, test-taking instruction for IQ tests. Oh, and not dumping lead into the drinking water. Seems like we have a lot of options to increase IQ scores without resorting to eugenics. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [March 1, 2016, 7:56pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/103 "2016-03-01T19:56:51Z")
> [@dougie\_monty](#): > > Well, I confess I wouldn’t know how to do that…do you? It’s not my position to determine if it’s true. It’s yours. The people presenting the claim that people are inevitably getting dumber should present evidence that it is the case. Absent any evidence to the contrary, I will assume people are basically about as intelligent as they have ever been. ---
**Author:** ![dougie\_monty](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@dougie\_monty](https://boards.straightdope.com/u/dougie_monty)\ **Post date:** [March 1, 2016, 9:03pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/104 "2016-03-01T21:03:38Z")
This would be difficult to determine indeed. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [March 1, 2016, 9:25pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/105 "2016-03-01T21:25:55Z")
Well, there is always Google 😛[Here](http://www.livescience.com/37095-humans-smarter-or-dumber.html) is an article on the subject (this article seems familiar so maybe someone linked to it earlier): > [@](#): > > Are Humans Getting Smarter or Dumber? > [@](#): > > Are you smarter than your grandma? > > The world is full of evidence that modern humans have more going on upstairs than their ancestors did: Smartphones. Heart transplants. A basic understanding that germs cause diseases. > > Beyond these technological advances, though, is another hint that humans are getting smarter. It’s called the Flynn effect, named after intelligence researcher James Flynn, an emeritus professor of the University of Otago in New Zealand. > > Since IQ, or intelligence quotient, tests have been revised and standardized several times in the past 100 years, to see the Flynn effect, scientists have their volunteers take tests designed for previous generations. Flynn and his colleagues have found that all around the world, the new generations score higher on the old tests than the original test takers did. > > The increases are no small matter, either — they vary by geography, but tend to be around three extra IQ points per decade. [Creative Genius: The World’s Greatest Minds] > > Flynn and many other researchers suspect that rising IQ scores reflect improving modern environments. IQ is part heritable and part environmental; enrich a young child’s environment with opportunities to learn, and they’ll have a higher IQ later in life. Better nutrition, more schooling and more stimulation could also explain the Flynn effect. > > So could the kind of thinking that people do today. If you asked someone in the 19th century the relationship between a dog and a hare, they’d likely go with something concrete, based on their real-life experience with the two animals, Woodley said. “The dog hunts the hare” might be a typical response. > > Today, people are taught to think more abstractly. A modern person would be more likely to say that both dogs and hares are mammals, for example. > > “These sort of heuristics and modern habits of thought have changed the way people have approached answering IQ tests,” Woodley said. > [@](#): > > The dulling of humanity > > Even as the Flynn effect sends IQ scores skyrocketing, some researchers argue a darker view. Humans aren’t getting smarter, they say. They’re getting stupider. > > In November 2012, Stanford University School of Medicine researcher Gerald Crabtree published two papers in the journal Trends in Genetics suggesting that humanity’s intelligence peaked between 2,000 and 6,000 years ago. > > Crabtree based this assertion on genetics. About 2,000 to 5,000 genes control human intelligence, he estimated. At the rate at which genetic mutations accumulate, Crabtree calculated that within the last 3,000 years, all of humanity has sustained at least two mutations harmful to these intellect-determining genes (and will sustain a couple more in another 3,000 years). Not every mutation will cause harm — genes come in pairs, and some weaknesses caused by mutation can be covered for by the healthy half of the pair, Crabtree wrote; but the calculation suggests that intelligence is more fragile than it seems. > > Furthermore, he argued, intelligence isn’t as evolutionarily important to humans today as it was when the species was hunter-gatherers. Thousands of years ago, failing to grasp the aerodynamics of throwing a spear when a lion was coming at you meant you were toast — no more passing along your genes to offspring. Modern man rarely faces such life-or-death tests of wits, Crabtree wrote. [10 Things That Make Humans Special] > > Another theory holds that humanity’s genetic capacity for intelligence is in decline because of a phenomenon called dysgenic mating. Since the mid-1800s, IQ and reproduction have been negatively correlated, studies have found. To put it bluntly, people who are more intelligent have fewer babies. Because intelligence is part genetic, some researchers argue that, if anything, IQs should be dropping. > > Instead, scores are going up, creating a paradox for the dysgenic mating theory, Woodley said. > [@](#): > > Is humanity getting smarter or dumber with time? The answer may be both. > > While IQ scores are rising at a remarkable rate, humans’ underlying genetic potential for smarts could be on the decline, a new study suggests. The research found that by one measure of intelligence, the Victorians had modern folk beat. > > The findings aren’t without controversy — particularly whether or not the measurements used really reveal intelligence. Still, the study highlights the trouble with measuring intelligence over time: Smarts aren’t defined as just one thing. What makes a person clever on the African Savannah could be nearly useless in the financial centers of Hong Kong. > > “It’s not simply that intelligence is going down or going up,” said Michael Woodley, a psychologist at Umea University in Sweden who led the new research. “Different parts of intelligence could be changing in lots of different ways.” [Life’s Extremes: Smart vs. Dumb] > > Are you smarter than your grandma? > > The world is full of evidence that modern humans have more going on upstairs than their ancestors did: Smartphones. Heart transplants. A basic understanding that germs cause diseases. > > Beyond these technological advances, though, is another hint that humans are getting smarter. It’s called the Flynn effect, named after intelligence researcher James Flynn, an emeritus professor of the University of Otago in New Zealand. > > Since IQ, or intelligence quotient, tests have been revised and standardized several times in the past 100 years, to see the Flynn effect, scientists have their volunteers take tests designed for previous generations. Flynn and his colleagues have found that all around the world, the new generations score higher on the old tests than the original test takers did. > > The increases are no small matter, either — they vary by geography, but tend to be around three extra IQ points per decade. [Creative Genius: The World’s Greatest Minds] > > Flynn and many other researchers suspect that rising IQ scores reflect improving modern environments. IQ is part heritable and part environmental; enrich a young child’s environment with opportunities to learn, and they’ll have a higher IQ later in life. Better nutrition, more schooling and more stimulation could also explain the Flynn effect. > > So could the kind of thinking that people do today. If you asked someone in the 19th century the relationship between a dog and a hare, they’d likely go with something concrete, based on their real-life experience with the two animals, Woodley said. “The dog hunts the hare” might be a typical response. > > Today, people are taught to think more abstractly. A modern person would be more likely to say that both dogs and hares are mammals, for example. > > “These sort of heuristics and modern habits of thought have changed the way people have approached answering IQ tests,” Woodley said. > > The dulling of humanity > > Even as the Flynn effect sends IQ scores skyrocketing, some researchers argue a darker view. Humans aren’t getting smarter, they say. They’re getting stupider. > > In November 2012, Stanford University School of Medicine researcher Gerald Crabtree published two papers in the journal Trends in Genetics suggesting that humanity’s intelligence peaked between 2,000 and 6,000 years ago. > > Crabtree based this assertion on genetics. About 2,000 to 5,000 genes control human intelligence, he estimated. At the rate at which genetic mutations accumulate, Crabtree calculated that within the last 3,000 years, all of humanity has sustained at least two mutations harmful to these intellect-determining genes (and will sustain a couple more in another 3,000 years). Not every mutation will cause harm — genes come in pairs, and some weaknesses caused by mutation can be covered for by the healthy half of the pair, Crabtree wrote; but the calculation suggests that intelligence is more fragile than it seems. > > Furthermore, he argued, intelligence isn’t as evolutionarily important to humans today as it was when the species was hunter-gatherers. Thousands of years ago, failing to grasp the aerodynamics of throwing a spear when a lion was coming at you meant you were toast — no more passing along your genes to offspring. Modern man rarely faces such life-or-death tests of wits, Crabtree wrote. [10 Things That Make Humans Special] > > Another theory holds that humanity’s genetic capacity for intelligence is in decline because of a phenomenon called dysgenic mating. Since the mid-1800s, IQ and reproduction have been negatively correlated, studies have found. To put it bluntly, people who are more intelligent have fewer babies. Because intelligence is part genetic, some researchers argue that, if anything, IQs should be dropping. > > Instead, scores are going up, creating a paradox for the dysgenic mating theory, Woodley said. > > Understanding an intelligence paradox > > Now, Woodley and his colleagues think they may have solved that paradox, and the news is not good. > > To look back at historical intelligence, the researchers turned not to IQ tests, but to reaction time. Simple reaction time (the amount of time it takes to respond to a stimulus) is correlated with IQ, Woodley said, and not nearly as sensitive to cultural influences as IQ tests. > > “The idea is that reaction times represent your ability to engage in very basic and elementary cognitive processing,” he said. [The 10 Best Ways to Keep Your Mind Sharp] > > In the 1880s, English scientist Sir Francis Galton measured reaction times in 2,522 young men and 888 young women from a wide variety of socioeconomic statuses. He found that men’s average reaction time to a stimulus was 183 milliseconds, and women’s was 187 ms. (Galton’s reaction time studies were part of his work as the founder of the field of eugenics, the idea that only the “best” should reproduce. Eugenics was embraced by a variety of high-profile people in the early 1900s, most notably Adolf Hitler, who wanted to establish a “master race” of Aryans.) > > Twelve similar studies to Galton’s conducted after 1941, on the other hand, found an average reaction time for men of 250 ms and for women of 277 ms — markedly slower. A review study detailing those findings was published in The American Journal of Psychology in 2010. > > Woodley and his colleagues expanded on the 2010 work, including additional data and matching the old and new studies to be sure they were measuring the same things. Despite the fact that timers have improved quite a bit since the 1880s, Woodley is confident that Galton’s measurements are accurate. Galton used a pendulum-based machine to time reactions, and such machines are generally accurate within 10 ms, Woodley said. > > Galton’s data also behaves as you might expect it to behave if it were correct, Woodley said. For example, groups with more inbreeding performed worse on the reaction time test. > > The new analysis was “crystal clear,” Woodley said. > > “We found a very, very robust trend with time, toward slowing speeds of reaction,” he said, “which is consistent with the idea that the more stable, the more culturally neutral, the more genetically influenced components of intelligence have been declining rather than increasing.” > > What that suggests is that even as IQ scores rise with education and health, humanity’s capacity to get smarter is shrinking. In essence, the Flynn effect might be hiding an underlying decline, a “psychometric dark matter” not visible on pen-and-paper intelligence tests, Woodley said. ---
**Author:** ![heartsplayer](https://avatars.discourse-cdn.com/v4/letter/h/d9b06d/32.png) [@heartsplayer](https://boards.straightdope.com/u/heartsplayer)\ **Post date:** [March 1, 2016, 10:34pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/106 "2016-03-01T22:34:35Z")
> [@Nansbread1](#): > > Slowly erased from the Earth? > > If a biological mechanism for eradicating humans with low intelligence becomes available in the future and it is painless and (works bypreventing such humans from having children) then is there any valid reason why it should not be implemented to > > A) reduce the worlds population and conserve natural resources > B) allow a more intelligent human race to flourish on earth In my opinion, yes and no. The people with really low intelligence, who add absolutely nothing to this planet, should be eradicated - but most people with a reasonable IQ (i.e. more than 10) don’t need eradicating. ---
**Author:** ![octopus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/octopus/32/3716_2.png) [@octopus](https://boards.straightdope.com/u/octopus)\ **Post date:** [March 1, 2016, 11:22pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/107 "2016-03-01T23:22:44Z")
> [@RickJay](#): > > Well, your beloved Dr. Crane wrote this almost two “Breeding cycles” ago. > > Please provide evidence the average IQ in the Western world has declined. > **[REVEALED: Disturbing Trend In Human Intelligence](https://www.huffpost.com/entry/people-getting-dumber-human-intelligence-victoria-era_n_3293846)** > > REVEALED: Disturbing Trend In Human Intelligence From a 3s Google search. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [March 1, 2016, 11:28pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/108 "2016-03-01T23:28:49Z")
Thanks for pointing to Crabtree again (and did you read the article?) However, see above for the precise opposite claim. There appears to be no scientific consensus on the matter, which a smart person would interpret as meaning that we should not assume it’s happening. ---
**Author:** ![drewder](https://avatars.discourse-cdn.com/v4/letter/d/57b2e6/32.png) [@drewder](https://boards.straightdope.com/u/drewder)\ **Post date:** [March 2, 2016, 1:48am UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/109 "2016-03-02T01:48:29Z")
> [@octopus](#): > > [People Getting Dumber? Human Intelligence Has Declined Since Victorian Era, Research Suggests | HuffPost Impact](http://m.huffpost.com/us/entry/people-getting-dumber-human-intelligence-victoria-era_n_3293846.html) > > From a 3s Google search. 14 IQ points in 120 years? Guy claims this has been happening since the agricultural revolution. Our hunter gather ancestors must have been brilliant. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [March 2, 2016, 3:29am UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/110 "2016-03-02T03:29:01Z")
I guess my answer to the OP would be that if everyone everywhere agreed that being smarter should be our only objective then fine. But otherwise you (impersonal you) don’t get to dictate what should be our priority and you certainly don’t get to kill people to achieve such aims. Anyway, if super-intelligence is your bag then AI and/or artificially augmenting the brain will no doubt arrive there long before natural selection (and killing people with low IQs won’t change that picture). And I think that’s the point I’d make to other people in this thread: I think everyone else is being a bit too loose on the topic of human evolution, pointing out matter-of-factly that dumb people contribute less to the gene pool because they are more likely to die, or that the Flynn effect proves we’re becoming smarter. Just because the OP idea is nonsense doesn’t mean we need to jump to conclusions. ---
**Author:** ![lance\_strongarm](https://avatars.discourse-cdn.com/v4/letter/l/87869e/32.png) [@lance\_strongarm](https://boards.straightdope.com/u/lance_strongarm)\ **Post date:** [March 2, 2016, 2:40pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/111 "2016-03-02T14:40:41Z")
> [@Mijin](#): > > and you certainly don’t get to kill people to achieve such aims. Nor forcibly sterilize them - something that has ACTUALLY HAPPENED in the United States from the 1920s up to the 1970s. ---
**Author:** ![lance\_strongarm](https://avatars.discourse-cdn.com/v4/letter/l/87869e/32.png) [@lance\_strongarm](https://boards.straightdope.com/u/lance_strongarm)\ **Post date:** [March 2, 2016, 2:42pm UTC](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204/112 "2016-03-02T14:42:07Z")
> [@heartsplayer](#): > > In my opinion, yes and no. > > The people with really low intelligence, who add absolutely nothing to this planet, should be eradicated - but most people with a reasonable IQ (i.e. more than 10) don’t need eradicating. Intelligence is not the only thing that adds to the planet though. I know many people with very low IQs. They are better people who add more to the planet than some people I know with high IQs. [Previous page](https://boards.straightdope.com/t/should-humans-with-low-iq-be/747204.md?page=5)