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Homo (Sans) Sapiens: Is Dumb and Dumber Our Evolutionary Destiny?

The views expressed are those of the author and are not necessarily those of Scientific American.

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James R. Flynn’s observation that IQ scores experienced dramatic gains from generation to generation throughout the 20th century has been cited so often, even in popular media, that it is becoming a cocktail party talking point. Next stop a New Yorker cartoon. (An article about Flynn and the Flynn effect has already been published in The New Yorker.)

A recent report in Trends in Genetics (part 1 and part 2) takes a bleaker view of our cognitive future—one that foresees the trend line proceeding inexorably downward. Gerald Crabtree, a biologist at Stanford University, has put forward a provocative hypothesis that our cushy modern existence—absent the ceaseless pressures of natural selection experienced during the Paleolithic—makes us susceptible to the slow creep of random genetic mutations in the the 2000 to 5000 genes needed to ensure that our intellectual and emotional makeup remains intact. The implications of this argument are that we as a species of the genus Homo are over many generations slowly losing our sapiens.

The press justifiably had a field day with this one:

Why did Petraeus do it? Maybe humans are evolving to be dumber.

We’re getting, like, dumber

Homo уже не тот sapiens

The really clever part of Crabtree’s argument rests on the contention that a Stone Age Fred Flintstone may have been more of a dynamo in some ways than a 20th century Albert Einstein—our pre-historic forebears performed  the evolutionary heavy lifting that led to the swollen heads that we still avail ourselves of, at least until the inevitable decline predicted by Crabtree sets in.

Expansion of the human frontal cortex and endocranial volume, to which we likely owe our capacity for abstract thought, predominately occurred between 50 000 and 500,000 years ago in our prehistoric African ancestors, well before written language and before we had the modern voice-box to produce sophisticated verbal language, but after the first tools. Thus, the selective pressures that gave us our mental characteristics operated among nonverbal hunter-gatherers living in dispersed bands or villages, nothing like our present-day high-density, supportive societies.

In line with Crabtree’s take, the transition to survival through wiles—in place of speed and physical strength—required adaptations that appeared to rival or outpace the most lofty contemporary intellectual achievements like writing a symphony or cogitating on higher math. One small error in gauging the aerodynamics and gyroscopic stabilization of a spear and one of our would-be ancestors became a canape for a saber-tooth tiger.

Many kinds of modern refined intellectual activity (by which our children are judged) may not necessarily require more innovation, synthesis, or creativity than more ancient forms: inventing the bow-and-arrow, which seems to have occurred only once about 40,000 years ago, was probably as complex an intellectual task as inventing language. Selection could easily have operated on common (but computationally complex) tasks such as building a shelter, and then computationally simple tasks, such as playing chess, became possible as a collateral effect.

Flintstone vs. Einstein smarts are contrasted most starkly by considering the case of artificial intelligence. AI has achieved major strides in emulating certain aspects of intellect: playing chess or Jeopardy and finding patterns in large collections of data, a field dubbed “deep learning.” But the remaining and still immense challenges AI confronts lie elsewhere, as Crabtree points out:

AI promised household robots that would wash dishes, mow the lawn, and bring us freshly cooked croissants and coffee in the morning. Needless to say we do not have these robots now and none of the readers of this piece will probably ever see them, despite the immense financial impetus to build them.

The things at which AI excels—playing chess, Jeopardy or keeping an airplane on course—are, in fact, a cognitive piece of cake compared to washing dishes and putting them away in the right place. I remember roboticist Rodney Brooks demonstrating this during a talk at MIT in which he simply put his hand in his pocket and pulled out some change, an extraordinarily tough task for the current generation of R2-D2s.

Without the rigors of strong selection in our extended urban conglomerates—no more necessity of getting it right the first time on that spear throw—the slow but relentless decline of those 2,000 to 5,000 cognition-related genes has already begun—as this argument goes. Crabtree begins the first part of  his essay by asserting that the average citizen from Athens circa 1,000 B.C.—or anyone from Africa, India, Asia or the Americas millenia back—would be among the “brightest and most intellectually alive of our colleagues and companions, with a good memory, a broad range of ideas, and a clear-sighted view of important issues”—personal qualities supplemented by an astonishing emotional aplomb. This hyper-fit type would have prevailed even before the rise of civilization:

A hunter–gatherer who did not correctly conceive a solution to providing food or shelter probably died, along with his/her progeny, whereas a modern Wall Street executive that made a similar conceptual mistake would receive a substantial bonus and be a more attractive mate. Clearly, extreme selection is a thing of the past.

Maybe this explains our fascination with post-apocalyptic Mad Max-style fantasies?  But where’s the proof for Crabtree’s musings and what about contradictory evidence?  Crabtree proposes a test of his hypothesis and he also dismisses the Flynn effect that suggests that we have been getting progressively smarter generation after generation. Better IQ scores, Crabtree posits, are not a result of natural selection, but rather may have resulted from getting rid of lead and other heavy metals from gasoline and paint, from elimination of hypothyroidism by putting iodine in salt and from learning how to take tests better. Notwithstanding the Flynn effect, our slow genetic decline continues apace.

And what does the author of the Flynn effect  think about the Crabtree effect?

Crabtree suggests that our genetic IQ is in decline and proposes a direct genetic test of his hypothesis. We should await the results without  sharing his pessimism.   As he says, the environment that pressures us to perform intellectually is competition with other people, which could be argued to be at its maximum today. He “fears” it is not enough and that is not a solid foundation foundation for his speculations.  A much more direct test of trends is reproductive patterns.  Only recently have the better educated been out-reproduced by the less educated.  One can imagine events that would reverse this, so it is premature to panic.

Meanwhile, noted British anthropologist and evolutionary psychologist Robin Dunbar questions the premises of any postulated slow slide toward imbecility:

Crabtree’s argument is built on the assumption that the selection pressure for big brains (aka IQ) was solving instrumental problems (how to survive in the world by building better weapons, better tools, etc). In fact, the selection for larger brains across all mammals and birds (and specifically primates) is the complexities of the social world, and this remains at least as complex as it ever was — in fact, the social world may have even become more complex than it ever was due to a combination of higher population density and urbanization. The ability to build clever tools or novel hunting techniques appears to be a by-product of the [neural] software needed to handle a complex world (they both use the same logic and cognitive processes). So we haven’t in fact lost the selection process that kept the pressure on.

The question, as often happens in evolutionary biology, is how to distinguish assertions like Crabtree’s from a Rudyard Kipling “just so” story. Crabtree has thought of a test that would sequence whole genomes of carefully selected individuals—ones whose genes could be traced back through an involved analysis to ancestors who lived at different times during the past 5,000 years when the transition from hunter-gatherer lifestyle to agriculture was taking place. The test would look for an increase in mutations for those individuals with genes linked to ancestors who lived more recently along the 5000-year continuum, a confirmation of the gradual decline in intellectual ability.

Finding these people might require more than posting notices on Twitter and Facebook and Crabtree’s  proposal is probably not going to get pegged high on the NIH’s funding priorities for the 2014 federal fiscal year. But the Stanford professor still does not despair. He ends this entropic projection of our evolutionary future on an optimistic and self-deprecatory note. Science, he says, may yet find a way to counteract this trend. “One does not need to imagine a day when we could no longer comprehend the problem, or counteract the slow decay in the genes underlying our intellectual fitness, or have visions of the world population docilely watching reruns on televisions they can no longer build.”

We may still have a few hundred years before we lose the modifier denoting “intelligent” in Homo sapiens and science may yet find a way to save us “by socially and morally acceptable means. In the meantime [Crabtree volunteers], I’m going to have another beer and watch my favorite rerun of Miami CSI (if I can figure out how to work the remote control).”


Image Source: Nevit Dilman




Gary Stix About the Author: Gary Stix, a senior editor, commissions, writes, and edits features, news articles and Web blogs for SCIENTIFIC AMERICAN. His area of coverage is neuroscience. He also has frequently been the issue or section editor for special issues or reports on topics ranging from nanotechnology to obesity. He has worked for more than 20 years at SCIENTIFIC AMERICAN, following three years as a science journalist at IEEE Spectrum, the flagship publication for the Institute of Electrical and Electronics Engineers. He has an undergraduate degree in journalism from New York University. With his wife, Miriam Lacob, he wrote a general primer on technology called Who Gives a Gigabyte? Follow on Twitter @@gstix1.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. DaveG 12:15 pm 11/26/2012

    I’ll believe there’s no more ‘strong selection’ when we all have the same number of children and grandchildren.

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  2. 2. rshoff 12:33 pm 11/26/2012

    It makes sense that evolution would not actively favor any particular trait over another. As a passive process, the more successful traits will evolve, whereas, the less useful traits will linger or fade. As such, who ever said that intelligence would be one of more successful traits? The dinosaurs were not all that bright yet the species survived for millions of years. As for humans. Well…

    Perhaps our species’ intelligence will be or was required for a moment in time.

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  3. 3. jtdwyer 12:59 pm 11/26/2012

    I suspect to many ‘humanities’ scientists have been generalizing test results derived from specific populations. I doubt it’s been definitively determined that I.Q. test scores are diminishing worldwide.

    By focusing on evolutionary changes to brain physiology its easy to overlook the fact that the human population is not thousands of times larger than during the early, sustenance, hunter-gatherer days. The evolutionary blip of electronic interaction and dense populations offer greater potential for enhancing human capabilities than any biological change of the past few hundred thousad years.

    Even if individual capabilities become limited or more narrowly focused, human societal capabilities have been enormously enhanced by technological developments in the past 100-200 years, especially the past few decades.

    Now, if humanity can only survive the consequences of these developments on the biosphere, perhaps we will continue our relativistic pace of development.

    Of, course, I still prefer the good old days when there were only a couple of billion people on this little rock…

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  4. 4. jtdwyer 1:01 pm 11/26/2012

    commentary erratum:
    “… the human population is not thousands of times larger…”
    should read:
    “… the human population is NOW thousands of times larger…”

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  5. 5. ansutherland 1:55 pm 11/26/2012

    I know that mainstream scientists tend to shy away from socially or politically insensitive topics or conclusions, but “absent the ceaseless pressures of natural selection experienced during the Paleolithic—makes us susceptible to the slow creep of random genetic mutations in the 2000 to 3000 genes needed to ensure that our intellectual and emotional makeup remains intact.” would, at least in part, support the notion that if dumb people out breed smart people, we should get steadily dumber over time.

    The ability of less capable people to out breed others is an example of “absent the ceaseless pressures of natural selection”. Now, is it true that intellectually inferior people out breed the rest? That I do not know, but there is some evidence in support of this assertion; correlational though it may be. IQ does correlate with educational achievement and educational achievement does correlate with the choices one makes concerning children (more educated people have few children and usually later in life).

    The problem however with using IQ as the arbiter of objective intelligence is that entire countries and cultures are likely to experience differentials in IQ expression. As an example, religiosity is inversely correlated with IQ. Is the Middle East therefore less intelligent than the west? In terms of IQ, probably! Perhaps a better way to think of IQ is to see it as a culturally dynamic means of assessing intellect based upon modern, but limited, assertions of what intelligence is.

    The real question then becomes, how do the 2000-3000 aforementioned genes relate to our impression of what intelligence is? If IQ = intelligence and IQ is culturally specific, as I believe the evidence would show, would Mr. Crabtree expect to see genetic differences relating to intellect on a cultural level? If no genetic relevance to IQ, as it relates to culture, can be found, then it would seem that much of what IQ tests measure as disparity across populations is the result of a social construct and therefore best measured epigenetically, not genetically.

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  6. 6. RDWalker 2:03 pm 11/26/2012

    This same idea occurred to me years ago. Many intelligent people have few or no offspring these days, where as many people (In America, especially) with low to average intelligence seem to just crank kids out at alarming rates. You don’t have to be smart to breed, you just have to have sex. During the stone age, intelligence was vital to survival of an individual. It isn’t anymore. Humanity, in some places, is breeding itself stupid, and we are devolving, up to a point, in my opinion, tragically.

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  7. 7. sparcboy 3:49 pm 11/26/2012

    I’m hoping that at one point this debate will be meaningless as humans will have learned how to manipulate genes and every person born has an IQ that would make Einstein look a little on the slow side.

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  8. 8. MadScientist72 4:14 pm 11/26/2012

    First off, people shouldn’t make the mistake of equating education with intelligence. Intelligence is only one among many factors that influence academic achievement. Access to educational opportunities is at least as big a factor. Many intelligent people never get significant formal education, because they’re poor, or they live in an area without they necessary resources, or in some places simply because they’re female. The people having the most kids these days may be poorly educated (and just plain poor), but that doesn’t mean they’re stupid.
    Second, “the selective pressures that gave us our mental characteristics” may have “operated among nonverbal hunter-gatherers living in dispersed bands or villages”, but “our present-day high-density, supportive societies” are a function of those mental characteristics and, as such, strongly favor their continuation.
    Third, Crabtree’s prevalent use of terms like “probably”, “possible”, “may not necessarily” and “could easily have operated”(aka “weasel words”) reveal his conclusions as nothing but speculation.
    Finally, the “ceaseless pressures of natural selection” that spawned our intelligence have NOT absented themselves, they’ve merely changed form. Instead of needing to properly time a spear-throw to avoid winding up in the jaws of a sabertooth, we have to properly time merging with traffic to avoid winding up in the grill of an 18-wheeler. Canape or pate, you’re just as dead.

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  9. 9. TTLG 4:37 pm 11/26/2012

    The idea that people are getting dumber is absurd. The world we have created is vastly more complicated than anything our ancestors had to deal with. Which is more difficult to invent or utilize, a stone ax or an automobile? Which threat is more difficult to identify, a lion hiding in the grass or a frayed power cord?

    The social environment has become even more complicated. Thousands of years ago, if a group of people could not get along with the others in their tribe, they could simply move away and form another tribe. If 911 has shown us anything, it is that there is that not managing to get along is no longer an alternative.

    The only real question I see is whether or not we are getting smarter fast enough.

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  10. 10. rshoff 4:38 pm 11/26/2012

    @jtdwiyer – I like the idea that you introduced …”interaction and dense populations offer greater potential for enhancing human capabilities than any biological change”…

    Might that also imply that intelligence is not married to humans? We can hand it off. First to human networks within populations then to artificial intelligence, thereby making ourselves obsolete in this arena. Intelligence itself is evolving and expanding at a more rapid pace that it’s traditional hosts (ourselves).

    Of course, then we have to ask again, “What is human intelligence, anyway?” And why is artificial intelligence considered ‘artificial’…

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  11. 11. alan6302 4:57 pm 11/26/2012

    The fact that intelligence is dropping ,can be accredited to skillful doctors. Fluoridated water, Fluoride toothpaste, deliberate iodine deficiency, crap food ,vaccinations, brain washed school teachers.

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  12. 12. windone 4:59 pm 11/26/2012

    Assuming the observation that, at least in the western world, the better to do in a social and economic sense, are having less to few to no children, and the poor to do socially and economically are having more to many children, ( it looks that way in the western US), it then appears that western ethic and value of “feeding the starving” or providing more for those less fortunate, is contributing to or causing diminished cultural values of self sufficiency, do more to get ahead, or make a better life for you and yours.
    Perhaps out of the ‘goodness of our collective hearts’ we are supporting the ‘breeding’ of less capable and in that sense less intelligent population as a whole.

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  13. 13. rshoff 5:08 pm 11/26/2012

    @TTLG – I’m not sure we are getting ‘dumber’, but I do think that our ancestors were at least as intelligent as we are. The world in which we live is one of their creation, not ours. Thinking of jtdwyers comment, it has been a long haul for generations of humanity to get to this point. Our current civilization is the result of aggregate intelligence and knowledge for which no one person, community, or generation can take credit.

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  14. 14. jgrosay 5:58 pm 11/26/2012

    Am I right if I remember that Neanderthals had bigger brains than sapiens, and the stone age sapiens had bigger brains than contemporary average mankind? It was said that brain has limits in size because of bigger brains being too much slower, but the biggest brain is in some whales, around 7 liters, thus making us thing that giants may have been possible after all.

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  15. 15. jtdwyer 6:39 pm 11/26/2012

    rshoff – Thanks for the interest. However, as a old time information systems analyst I spent a couple of decades reading about AI research – that was 20 years ago. However, while AI related methods and techniques may be applied to computer systems, when it comes to general intelligence I really don’t think researchers know enough to ask the right questions yet. IMO, computers of some kind may someday be capable of some form of general intelligence, but it won’t be in any way human.

    I do think that we’re leveraging the capabilities of computers to enormously enhance our own intellectual capabilities, which I think is more important. Machines, no matter how intelligent, should be tools…

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  16. 16. YangHui 7:23 pm 11/26/2012

    This is actually a reasonably testable hypothesis; there are still groups of people who live in hunter-gathering societies and who lack ancestors that have experienced the transitional to agriculture. If the IQs of those people are higher than those in modern societies (after controlling for non-genetic variables such as exposure to toxins), that is fairly solid evidence that this is the case.

    That said, even if this is the case it is unlikely it will cause society to break down as a whole; there is no selection AGAINST intelligent people, genetic draft will cause random change and a divergence in society. Though the average person may be less intelligent than before, there will be a few who are as intelligent as their forebears. If these people become a minority in society, their skills will become valuable, and natural selection will probably once again work in their favor. It is more likely it will reach an equilibrium in the proportion of the population that is intelligent rather than intelligent people dying out.

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  17. 17. vagnry 2:40 pm 11/27/2012

    Average IQ may drop, but the top won’t!

    Unfortunately, people, especially women, who take a higher education (and supposedly are cleverer than average) have fewer kids, while the uneducated (supposedly dumber) get more kids.

    So, on average, IQ may well drop, but the intelligencia marry other clever people, and their IQ may rise.

    I think the future of mankind is more dependent on the +130 IQs, than on the -90 IQs.

    Just like the inequality of wealth is increasing, no rich person marries a pauper!

    I know there are exceptions to these rules, but they are hardly statistically significant:-;

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  18. 18. mwagner17 3:44 pm 11/27/2012

    This is a little like saying that modern medicine allows inferior genes to survive and reproduce.

    While this may be true, modern medicine also allows intellectually superior genes to thrive and reproduce even if the individual possesses inferior genes against disease.

    Natural selection favors intelligence. We see that again and again. As a species, are we TOO SUCCESSFUL? Perhaps. After all, as our numbers increase, we displace many other species.

    Our technology has eliminated many of the natural threats to our survival but it has also led to other threats to our survival.

    Antibiotics have saved millions of lives but also contributed to heartier bacteria which can survive our antibiotics and kill us anyway.

    Humans spend as much on healthcare on their last year of life as they do in all their preceding years put together.

    Global warming is our doing. Nature provides natural barriers to over-population through disease and famine but we have the technology to eliminate those barriers.

    People are starving in Africa because their leaders choose tribal war over feeding the hungry and treating the sick.

    It is certainly true that most human beings living today could not survive living in the open grasslands of the Serengeti but the collective knowledge of the human race means that they don’t have to either.

    Human beings have the power to solve these ills that plague the human race. Humans also have the power to make the world unlivable for any except themselves.

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  19. 19. samlehmanwilzig 4:17 pm 11/27/2012

    Astonishingly, neither the article’s author nor the readers’ comments mention the most obvious argument against the “dumbing down” thesis: we are about to use genetic and neuro-tech knowledge to enhance our brain power, not to mention human brain / AI synthesis. True, these will not carry higher intelligence forward to the next generation gentically, but barring some unforeseen (and highly unlikely) massive disaster, those technologies will be available to all future generations, and will improve from generation to generation. So it makes no difference if we will be “naturally” slightly dumber or slightly smarter — our cognitive-enhancing technologies will ensure LOTS of greater smarts.

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  20. 20. bongobimbo 4:17 pm 11/27/2012

    Why use IQ? It’s a baaaaad test, always favoring those who are consider data (even trivia) accumulation and lifeless analysis better than deep reasoning and synthesis. Seems to me a CQ (creativity quotient) would be a better measure of survivability. Can the person be faced with challenges and lose childhood brainwashing to become flexible and pragmatic? Can s/he create workable solutions–not just technology, but sensible processes such as practical ways to roll back CO2 and methane emissions? And so on. In my 76-year experience the ones who seem best at this are the ones snickered at as nerds, but just wait. Their survival may be the real Revenge of the Nerds.

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  21. 21. jtdwyer 4:09 pm 11/28/2012

    Re. the “… hypothesis that our cushy modern existence—absent the ceaseless pressures of natural selection experienced during the Paleolithic—makes us susceptible to the slow creep of random genetic mutations in the the 2000 to 5000 genes needed to ensure that our intellectual and emotional makeup remains intact,” perhaps there’s additional external factors at work here.

    Perhaps the slow pace of random mutations has been accelerated. Please see

    While this study focuses on protein encoding changes affecting the susceptibility to disease, even diseases can affect intelligence. More direct implications for intelligence are also possible…

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  22. 22. mikegtu2005 5:23 pm 11/28/2012

    We are still evolving, lifes challengers are still with us just as surely as they challenged our brain size in surviving half a million years ago or 100000 or 500 . Where it takes us is the big question. My sense is at the moment life challengers are currently shaping slightly different areas of our make up than in the past . I dont think dumb and dumber is where the human race is heading , perhaps physically weak and weaker. ????

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  23. 23. Spin-oza 5:31 pm 11/28/2012

    Yeah… it may be a speculative hypothesis that our genetic basis for intelligence is weakening, but i think it to be a valid hypothesis, from a Natural Selection point of view.
    Dysfunctional mutations and genetic illness meant an early death and no reproductive chance modern medicine or the convenience of society’s props… or certainly significantly less chance of being considered a “fit” mate. Consider the single example of myopia… just one of myriad examples… now extremely common, but a survival risk in spades in our early evolutionary path.
    Moedern life is governed by a hive (versus individual) intelligence… social networking and media… myriad disjointed factoids… and the many distractions of leisure time (yep… that Nascar n’ NFL gonna make ‘em couch-taters smarter… right?).
    I mean you can get along pretty well today with mental and physical disabilities that would have been a genetic dead-end millennia hence.
    That said, perhaps pre-implantation genetic screening will reverse that trend, if societies will ever put value on quality (of life) over quantity, the latter of which is dispoiling the planet at an alarming rate.
    Sooo… where’s the silver lining?
    It’s likely on humanities Star Trek (and no… i’m no “trekkie”). Only the brightest and emotionally well adjusted will be venturing forth to colonize… oh… i don’t know… say… Mars? And they will… ahem… likely reproduce and… ahem… spawn a favor genetic line. It will be a form of selection pressure that will be absolutely counter to the dumbing-down among masses, often spawning while adolescents, high on drugs or alcohol.
    It’s also clear that with autism rates… Fragile X & Down’s syndrome… ADHD… environmental toxins and all the rest… the genetic hurdles are only looming larger vis a vis a Home with Sapiens.

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  24. 24. Spin-oza 5:49 pm 11/28/2012

    Oh… just “proof read my post” and should read:
    “Dysfunctional mutations and genetic illness meant an early death and no reproductive chance BEFORE modern medicine or the convenience of society’s props…”

    Another thought: any darn fool (from a genetic standpoint) can exist and even reproduce (think drug addict having her 7th kid, destined for foster care) in the bowels of urban living and social “safely nets”… whist it takes a particular fit person (physically as well as mentally) with the ability to think and plan, and make correct judgments and often time-pressured decisions, to be able to function as a “survivalist”, even with modern “gear” (compass, machete, proper clothing, etc.)… which is a close a comparison as we can imagine in modern times vis a vis the evolution of Homo (to Sapiens) and the brain connections/specialization underlying what we now term “intelligence”.

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  25. 25. dantevialetto 5:54 pm 11/28/2012

    If we are looking what men have done until now with pride and greed – global warming, overpopulation, fanaticism – it is easy to see how it wll be our evolutionary destiny: exactly dumb and dumber!

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  26. 26. ecoligist 5:57 pm 11/28/2012

    Monitoring some trait averaged over a whole population is not likely to show much. But subsets might be more fruitful. I.e.: universities are the breeding grounds for marriages among those accepted. Assuming a preponderance of brighter lights among university students versus the non-college folks, we can see that there is an on-going massive selection process within the industrialized world. It should be expected that within only a few generations IQ scores should begin to show two lobes – one lobe steadily moving up and away from the main group. I would not be surprised that even within this “university-educated” subset, there would be further subsets – actors marrying actors, mathematicians marrying fellow classmates. Even if this is only 15% true within the college set, it is nonetheless more selective than what would be going on in the non-college set. (Wasn’t there are recent movie based on this idea?)

    True, maybe our domesticated brains might be smaller than those of wild-men, but don’t overlook the fact that because we are social and domesticated, we have opted to spread our wits not only among our neighbors but also now with other types of memory – from books to electronic chips. In a sense, previous wild-man has now outsourced a significant amount of memory to other specialized repositories. Memories have, of course, hugely expanded in content over time – libraries have grown and grown, data bases are now into the zillions of super-bytes.

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  27. 27. billfalls 6:19 pm 11/28/2012

    Crabtree and some commenters here seem to be mired in 19th- and early 20th-century errors about evolutionary theory: for instance, that evolution “progresses” in a linear way and that “inferior” people – immigrants, minorities, and other targets of the old eugenics movement – are diluting the gene pool when they bear children.
    Even if these claims made evolutionary sense (they do not), there is no way to prove that humans are evolving toward greater or lesser intelligence: no DNA evidence, no test (as others noted here, what IQ tests measure is not even one kind of intelligence, let alone all the kinds that help us succeed), and no way to show a shift in intelligence for groups of people, let alone all of humanity.

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  28. 28. endo_alley 9:01 pm 11/28/2012

    Crabtree assumes that human reproduction shall continue in the future as it has in the past. But as leaps and bounds are made in understanding the human genome and its connection to heritable diseases improve, surely the technologies that could make genetic modifications capable of ridding these diseases shall also improve and become ever cheaper. And when government is responsible for the healthcare of its citizenry, those in power may perhaps make the calculation that ridding disease in the genotype is far cheaper than treating it in the phenotype. And so some genetic enhancements, if not compulsary, will at least be smiled upon. Given enough time for bioethics itself to evolve, it is not inconceivable that other, more elective traits will also be spliced into genes for socially conveniant reasons. And from there the connection between natural selection and evolution in humans (and the evolution of plants and animals we rely on) may never be quite the same.

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  29. 29. GreenMind 11:45 pm 11/28/2012

    In his speculation, Crabtree seems to be simply ignoring the selection pressures that we can see every day in the newspapers.

    First, people in poverty handle life-threatening conditions every day, from drive-by shootings, to paying the rent, to avoiding temptation like drugs, etc., so I am personally convinced that they are pushing the intelligence of the human race upward, not downward. Don’t assume that the fact that someone is in poverty means that they got there by being dumb. They are far more likely to have been born there, or their mother got a divorce from an abusive dad, or the bank redlined their neighborhood, or the only available were at Walmart, etc. Just surviving and raising children in poverty with no access to doctors, wholesome food, clean water, education, etc, puts a strong premium on having good genes. IMHO, If you want to find the genes for the highest intelligence, go to the areas of deepest poverty. Thing is, they may not look too intelligent because of lack of education, but their genes will be better.

    Second, toxins like lead increase the selection pressure. If someone is reasonable functional with a load of lead in their brain, their genes are probably pretty good.

    Third, violence in the world puts an enormous premium on intelligence. Some people flee war-torn areas. Others stay put, or are even attracted to them. We have plenty of warriors in the world and plenty of refugees. I’d say the refugees are probably a lot smarter than the warriors, and a lot less likely to be killed.

    Fourth, adolescents die from a lot of stupid things. Car accidents, drinking games, dares, playing chicken, drug overdoses, gang wars, etc. I think there is plenty of selection pressure pushing intelligence up and impulsiveness down.

    Fifth, only in the last hundred years has cheap literature been available to the most developed societies, and it is still rare in developing countries. All of a sudden, being literate is the norm in the wealthy countries, and not being able to read in a literate society is a huge liability in finding a spouse and avoiding danger. Again, huge selection pressure on greater intelligence, and more to come in the rest of the world as literacy spreads.

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  30. 30. 13inches 12:05 am 11/29/2012

    Crabtree states:

    “AI promised household robots that would wash dishes, mow the lawn, and bring us freshly cooked croissants and coffee in the morning. Needless to say we do not have these robots now and none of the readers of this piece will probably ever see them, despite the immense financial impetus to build them.”

    Current technologies could build robots to easily perform ALL the tasks Crabtree lists here…but WHY ? Has Crabtree never heard of dishwashing machines ? Is Crabtree too lazy to get off his butt and put his croissant into a microwave oven ? The Roomba robot currently vacuums floors and laser guided lawn mowers can now robotically mow lawns. Does Crabtree just wanna lay in bed all the time and physically do NOTHING but take up space ? I think Crabtree himself is proof he is dumber than his own parents, so at least within his own family his theory has some creedence.

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  31. 31. sjfone 8:59 am 11/29/2012

    Who needs frontal lobe activity when you have apps, game controllers and Facebook.

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  32. 32. Charles Lyell 10:11 am 11/29/2012

    We not getting “dumber.” Our species’ problem is that dopamine influences choices by rewarding expectations.

    Unfortunately, there’s a serious glitch in the dopaminergic system that has helped countless “dumb” animals survive long enough to pass on their DNA. The glitch is that the system evolved to reward both logical and illogical expectations. Unlike “dumb” animals, who don’t get to reproduce if they keep making illogical choices, Homo sapiens who can’t resist choices based on illogical expectations have children who instinctively “go for the dopamine” — regardless of the consequences.

    A simplistic but helpful example of logical and illogical expectations that receive dopamine rewards:

    Logical expectations that keep “dumb” animals and smart people ingesting moderate portions of wholesome foods.

    Illogical expectations of future mouthfuls that keep food addicts so preoccupied with ingesting the next (and the next and the next) mouthfuls that they don’t taste what they’re eating and end up obese, sick, unhappy, and craving the next mouthful.

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  33. 33. canoehead 10:16 am 11/29/2012

    I’d just take a look in the cattle lots of Texas (or Alberta). are captive bred populations such as these less intelligent than wild bovinity? I’d bet that they are. a smart cow won’t easily let it self be herded, coralled, and killed.

    perhaps a study of the relative intelligence of some captive (read “genetically recycling and survival assisted”) populations of otherwise wild-related species, compared to the same groups in the wild, could give us an accelerated feedback on this theory.

    happy, unsuspecting, cooperative herding entities with a modicum of earning capacity is exactly what good consumer-based economies need. just look at the self-arranging lines of people at big-box store checkouts, next time you join in!

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  34. 34. Andira 10:19 am 11/29/2012

    These ideas are in no way new. They are also without scientific support. The idea that a lack of competition and caring for the weak would undermine the human species became popular in the late 1800′s and formed the basis for Francis Galtons ideas of eugenics, which later formed a basis for castrating the poor or mentally handicapped. The whole thing is racist speculation, and nothing else. People who grow up today face a highly intellectually competitive social environment. Rather than hitting each other with clubs, we compete for the girls in other ways.

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  35. 35. grousehunter 12:18 pm 11/29/2012

    Has the issue of genetic memory ever been considered? Maybe IQ is increasing because of a build up of genetic memories being supported by individuals having children at a later age (thus more accumulated knowledge). This supports the conclusion that higher IQ was being driven by the higher (and later) breeding rate of intelligent members of the group. It also supports the conclusion that IQ’s may have been lower in the past due to the earlier breeding practices of Hominids, thus a much slower accumulation of genetic memory. If less intelligent individuals (less accumulated knowledge) are again out breeding the intelligent (more accumulated knowledge), late breeders, then one would expect to see a fall in IQ’s based on the concept of genetic memory.

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  36. 36. johnmenninga 7:16 pm 11/29/2012

    Since the paleolithic, evolution of our intelligence has been driven, not by our natural environment but by our social environment. This continues to get more complex and demanding. I don’t see the evolutionary pressure easing any time soon.

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  37. 37. kevinl4000 2:36 am 11/30/2012

    Makes sense. Smart educated people are having one or two kids (if any). High school dropouts are having four or five. The smart genes are dying out and the dumb genes are expanding.

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  38. 38. Knyaz 7:19 am 11/30/2012

    Перед генетическим модифицированием человека,что означает в дальнейшем смену цивилизаций,будет научное и моральное одурмание человечества.Генетически модифицированный человек будет умнее,красивее,здоровее,чем мы но он на генетическом уровне не будет человеком и будет на этом уровне удаляться от нас с каждым годом.Благими намерениями устлана дорога в ад,мы уних будем гастайбайтерами.

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  39. 39. rugeirn 3:18 pm 11/30/2012

    How odd. I had the impression that this publication was devoted to science. Now, here, I find that it is instead devoted to nonsensical speculation devoid of the slightest trace of anything one would call evidence. Whoever OK’d this piece should be ashamed of themselves.

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  40. 40. bucketofsquid 4:27 pm 11/30/2012

    While I really enjoyed the movie “Idiocracy”, I find people proposing that the average IQ is dropping to be rather unintelligent. We know that in the western nations the average IQ is increasing rather than dropping as education systems become more effective. A number of studies have also shown that the mental development of a child is primarily driven by direct contact and activity with their parents. Most of the intelligent people in the western world do not come from the more privileged castes of society. Try actually doing some real research. Birth rates are tied directly to wealth and the ability to buy birth control (or toxic chemical laden perfumes and air fresheners) and NOT intelligence.

    It is also nice that the pompous, arrogant, loser, idiot, narcissists have a nice forum here to post self congratulatory braggery to keep them busy. We wouldn’t want them to spend much time in the real world fouling things up for the rest of us. My congratulations to the few that actually discussed the article rationally.

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  41. 41. bucketofsquid 4:31 pm 11/30/2012

    One other thought; try and make a stone tool with your bare hands. It is very difficult. I have an in-law that works for the Feds demonstrating a paleolithic lifestyle. He makes all of his own stone tools. He makes everything he uses in his job himself with only stone and bone tools.

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  42. 42. Bob Grumman 11:11 am 12/1/2012

    The fact that IQ tests, which measure a combination of shallow thinking and intellectual conformity, the antithesis of intelligence, seem to be rising tends to support the notion that we’re getting dumber, but I find Crabtree’s speculations unpersuasive.

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  43. 43. jtdwyer 3:48 pm 12/1/2012

    samlehmanwilzig – while some form of genetic manipulation of intelligence and/or electronic augmentation of computational capabilities will become increasingly technically possible, it certainly remains to be seen whether these factors will contribute in any significant way to average individual or societal intellect.

    The availability of such ‘brain’ enhancements could just as well be used to implement societal control systems. Even if our wonderful government would never consider such violations of individual human rights, some government somewhere might well take advantage – arguably for the benefit of humanity. Once such systems are in place, for what ever intended reason, they can potentially be systematically controlled…

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  44. 44. tucanofulano 5:10 pm 12/3/2012

    It seems animals in the wild truly needs their wits about them to survive. City animals apparently get by just as well with fewer wits, and therefore lower numbers of kilocalories daily to maintain life + brain as brain shrinks.

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