Stories
Slash Boxes
Comments

SoylentNews is people

posted by n1 on Thursday March 05 2015, @03:08AM   Printer-friendly
from the village-idiot dept.

IQ is rising in many parts of the world. What's behind the change and does it really mean people are cleverer than their grandparents?

It is not unusual for parents to comment that their children are brainier than they are. In doing so, they hide a boastful remark about their offspring behind a self-deprecating one about themselves. But a new study, published in the journal Intelligence, provides fresh evidence that in many cases this may actually be true.

The researchers - Peera Wongupparaj, Veena Kumari and Robin Morris at Kings College London - did not themselves ask anyone to sit an IQ test, but they analysed data from 405 previous studies. Altogether, they harvested IQ test data from more than 200,000 participants, captured over 64 years and from 48 countries.

http://www.bbc.com/news/magazine-31556802

This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 4, Funny) by cmn32480 on Thursday March 05 2015, @03:17AM

    by cmn32480 (443) <reversethis-{moc.liamg} {ta} {08423nmc}> on Thursday March 05 2015, @03:17AM (#153361) Journal

    What I can't understand is why the vast majority of the world seems SO much dumber? Is it just a lack of common sense? Or is IQ not REALLY a good indicator?

    --
    "It's a dog eat dog world, and I'm wearing Milkbone underwear" - Norm Peterson
    • (Score: 4, Insightful) by SlimmPickens on Thursday March 05 2015, @03:32AM

      by SlimmPickens (1056) on Thursday March 05 2015, @03:32AM (#153365)

      I think the main thing is that at memory is a hierarchical-temporal phenomenon. Something may well be in another persons brain but we may not have said it in a way that sets off their memory. Not everyone is blessed with a high degree of transference, and even those that are may still need some time to sift through everything.

      That and human nature, anytime someone doesn't understand us we assume the person is stupid.
       

      • (Score: 3, Informative) by Balderdash on Thursday March 05 2015, @02:32PM

        by Balderdash (693) on Thursday March 05 2015, @02:32PM (#153503)

        That is the reason that so many training courses, covering similar topics but from different speakers, have a fair amount of overlap.

        Each person learns differently, and the delivery method of one trainer may appeal to one person, and a totally different spin on the same topic will resonate with another person.

        --
        I browse at -1. Free and open discourse requires consideration and review of all attempts at participation.
    • (Score: 5, Funny) by frojack on Thursday March 05 2015, @04:02AM

      by frojack (1554) on Thursday March 05 2015, @04:02AM (#153370) Journal

      I think it has to do with your age, and your understanding of IQ.

      When you are young, you tend to think everybody else is dumber than you. You may occasionally find yourself in error, but never in doubt. You are quicker to pick up on new and tech, but have no idea what to do with a maul and a wedge.

      When you are old, (geezerhood) you've seen everything, at least twice, seen three or four generations of technology come and go. You delight in letting the wippersnappers hang themselves with their own rope, and would rather keep your mouth shut and let people think you're ignorant, than start running your mouth and prove them correct. You don't have all the facts on the tip of your tongue, (because the mind is the Second thing to go), but you know where to find where to look it up. You need a password vault to remember all your passwords, and you have that password tattooed on your left foot. You have the words "other foot" tattooed on your right foot.

      --
      No, you are mistaken. I've always had this sig.
      • (Score: 2) by SlimmPickens on Thursday March 05 2015, @04:11AM

        by SlimmPickens (1056) on Thursday March 05 2015, @04:11AM (#153372)

        So memory is a pedantry-temporal-heirarchy?

      • (Score: 1, Insightful) by Anonymous Coward on Thursday March 05 2015, @04:31AM

        by Anonymous Coward on Thursday March 05 2015, @04:31AM (#153379)

        You need a password vault to remember all your passwords

        If I didnt have 200 different passwords I wouldnt bother... If jackasses wouldnt let my password leak I could reuse the samish password everywhere. But nooooooo.....

        • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @07:15AM

          by Anonymous Coward on Thursday March 05 2015, @07:15AM (#153428)

          Lamentation of reality is okay. There are bad actors in the world. If there were no thieves or overly curious then there would be little need for locks. However to point the blame for that reality at the only people that are actively trying to protect you is Greek tragedy levels of unfair.

      • (Score: 2) by aristarchus on Thursday March 05 2015, @07:49AM

        by aristarchus (2645) on Thursday March 05 2015, @07:49AM (#153439) Journal

        Bro! This is our frojack. There are many like him, but this one is ours. At least I think I remember he is.

    • (Score: 1, Insightful) by Anonymous Coward on Thursday March 05 2015, @04:22AM

      by Anonymous Coward on Thursday March 05 2015, @04:22AM (#153374)

      Think of someone you know with an IQ of 100...

      Now, realize that half (more or less) of people are dumber than that.

      Said the wise, dead guy.

      • (Score: 3, Insightful) by Anonymous Coward on Thursday March 05 2015, @04:37AM

        by Anonymous Coward on Thursday March 05 2015, @04:37AM (#153386)

        IQ is a meaningless indicator of intelligence to begin with; pure pseudoscience.

        • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @06:37PM

          by Anonymous Coward on Thursday March 05 2015, @06:37PM (#153588)

          You might want to actually look at the several tens of thousands of papers correlating IQ with various actions we mere humans perceive as being intelligent. Any one would prove you wrong. Sure it is not an objective measure of intelligence and that is why the second word is Quotient. Often relative measurements are the best science can do. That does not mean it is pseudoscience.

          • (Score: 0) by Anonymous Coward on Friday March 06 2015, @04:00AM

            by Anonymous Coward on Friday March 06 2015, @04:00AM (#153719)

            You might want to actually look at the several tens of thousands of papers correlating IQ with various actions we mere humans perceive as being intelligent.

            I am not interested in completely arbitrary definitions of intelligence. I am interested in good science. The field of physics, for example, has lots of good, objective science. The same can't be said for the social 'sciences', where most of the studies are biased, subjective, never replicated, and where arbitrary conclusions are drawn based on often poorly-collected data (which is often gathering using subjective questions).

            Tens of thousands of studies or millions of studies makes no difference if they are faulty. And IQ is still in question.

            Any one would prove you wrong.

            No, they wouldn't, as you later state: "Sure it is not an objective measure of intelligence and that is why the second word is Quotient."

            It's not an objective measure of intelligence; it's completely arbitrary and unscientific, much like much of psychology.

            Often relative measurements are the best science can do.

            Bad science is still bad science even if that's the 'best' we have. It's better to admit that you don't know what intelligence is or have a good way of measuring it rather than relying on trash like IQs.

            The idea that you can measure someone's intelligence using a simple number and arbitrary tests might seem great to the simple-minded, but I suspect the real answer is far more complex than that. We have a long way to go. And I'm tired of hearing about trash like IQ in the media; it's time to put it to rest.

      • (Score: 2) by SlimmPickens on Thursday March 05 2015, @05:28AM

        by SlimmPickens (1056) on Thursday March 05 2015, @05:28AM (#153410)

        Half of people that get tested.

        • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @11:43AM

          by Anonymous Coward on Thursday March 05 2015, @11:43AM (#153470)

          It is a great asshole ratio estimate. Two kinds of people take the test. People too stupid to know they'll suck at it, and people who **know** they'll get a high score.
          Next time someone feigns stupidity you can assume he was malicious.

    • (Score: 2, Touché) by Anonymous Coward on Thursday March 05 2015, @04:44AM

      by Anonymous Coward on Thursday March 05 2015, @04:44AM (#153390)

      Of course it is a good indicator! The entirety of what it means to be human summed into a single number? It doesn't get better than that!

      • (Score: 3, Insightful) by SlimmPickens on Thursday March 05 2015, @06:17AM

        by SlimmPickens (1056) on Thursday March 05 2015, @06:17AM (#153418)

        Nothing more to being human than being smart?

        • (Score: 1) by soylentsandor on Thursday March 05 2015, @07:05AM

          by soylentsandor (309) on Thursday March 05 2015, @07:05AM (#153426)

          Or being dumb, duh.

          Hey if AC says it, it must be true. It can't possibly have been sarcasm.

        • (Score: 1, Informative) by Anonymous Coward on Thursday March 05 2015, @07:57AM

          by Anonymous Coward on Thursday March 05 2015, @07:57AM (#153441)

          > Nothing more to being human than being smart?

          Your poor word choice aside, yes.
          There is nothing unique about the human experience that does not derive from the intelligence of the species.
          Otherwise we'd just be goldfish.

      • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @06:57AM

        by Anonymous Coward on Thursday March 05 2015, @06:57AM (#153425)

        IMO its a little better than the number between 1 and 10 used by men to define women.

    • (Score: 2, Insightful) by Anonymous Coward on Thursday March 05 2015, @11:07AM

      by Anonymous Coward on Thursday March 05 2015, @11:07AM (#153464)

      IQ is just another way of picking out the idiots - if you think IQ means anything more than jack shit, you are an idiot.

  • (Score: 2) by skullz on Thursday March 05 2015, @04:15AM

    by skullz (2532) on Thursday March 05 2015, @04:15AM (#153373)

    Get off my, uh... lawn! That's the word.

  • (Score: 2) by Hartree on Thursday March 05 2015, @04:50AM

    by Hartree (195) on Thursday March 05 2015, @04:50AM (#153394)

    So, you're saying I'll get smarter if I think about Picasso, Mondrian and Pollock?

    (I've got a real weak spot for Salvador Dali, though. Who can't like the Anarcho-Monarchist?)

  • (Score: 3, Insightful) by anubi on Thursday March 05 2015, @04:51AM

    by anubi (2828) on Thursday March 05 2015, @04:51AM (#153396) Journal

    a lot of us have seen the test, and know what its looking for.

    --
    "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
  • (Score: 5, Informative) by mrcoolbp on Thursday March 05 2015, @05:05AM

    by mrcoolbp (68) <mrcoolbp@soylentnews.org> on Thursday March 05 2015, @05:05AM (#153401) Homepage

    As I understand it, that in general the population on average does get "smarter" due to the continual spread and refinement of knowledge, and IQ stands for Intelligence *Quotient*. "The median raw score of the norming sample is defined as IQ 100 [wikipedia.org]."

    The Wikipedia page continues: "Since the early 20th century, raw scores on IQ tests have increased in most parts of the world. When a new version of an IQ test is normed, the standard scoring is set so performance at the population median results in a score of IQ 100"

    It will always be the average, even as people get smarter, with the internet making the spread of knowledge more rapid and rampant, I assume this is just some kind of acceleration of this effect.

    --
    (Score:1^½, Radical)
    • (Score: 1, Interesting) by Anonymous Coward on Thursday March 05 2015, @07:23AM

      by Anonymous Coward on Thursday March 05 2015, @07:23AM (#153432)

      Shh! Don't tell people that. What people say about IQ tests can give you insight as to what their IQ is likely to be.

      People that have not figured out that half the people are dumber than the median give themselves away as being on the wrong side of it! Exceptionally high IQ is given away by statements about IQ tests being not very relevant but better than nothing and mumbling something about r values and correlation.

      • (Score: 4, Insightful) by acid andy on Thursday March 05 2015, @04:47PM

        by acid andy (1683) on Thursday March 05 2015, @04:47PM (#153559) Homepage Journal

        People that have not figured out that half the people are dumber than the median give themselves away as being on the wrong side of it!

        Uhh, that's not how the median works. Which side does that make me?

        --
        If a cat has kittens, does a rat have rittens, a bat bittens and a mat mittens?
        • (Score: 1, Touché) by Anonymous Coward on Thursday March 05 2015, @06:43PM

          by Anonymous Coward on Thursday March 05 2015, @06:43PM (#153589)

          You are thinking of mode, or possibly mean, median separates half the sample set from the other half of the sample set. That means humans. I'm sure you know what side you and the moderators that +4 your post are on. Here is an audience appropriate explanation. [mathgoodies.com]

          • (Score: 2) by acid andy on Thursday March 05 2015, @06:52PM

            by acid andy (1683) on Thursday March 05 2015, @06:52PM (#153596) Homepage Journal

            My apologies. You're absolutely right. That'll learn me to try and apply statistics knowledge that hasn't been used in anger in years. Use it or lose it.

            --
            If a cat has kittens, does a rat have rittens, a bat bittens and a mat mittens?
  • (Score: 4, Interesting) by Snotnose on Thursday March 05 2015, @05:06AM

    by Snotnose (1623) on Thursday March 05 2015, @05:06AM (#153402)

    I've found that those considered the smartest people I've run across in the last 50+ years mostly had phenomenal memories. As in, can quote lines from movies, remember exact dates when they attended concerts, can quote dates in history, atomic numbers of elements, specific facts from a test run 2 months ago, individual lines in a balance sheet, etc.

    Me? My memory sucks. I'm good at concepts. I always struggled in history (fred did something in 1362), but excelled in math (learn 1 concept a day, do 20 problems). This extrapolates out to I can read requirements and crank out better code than (I like to think) 90% of my co-workers.

    I've found that the average person considers those with great memories "smarter" than those of us who can't remember shit, but can solve problems. Are they smarter? eliphino.jpg (I've got the pic if you want it :)

    --
    Why shouldn't we judge a book by it's cover? It's got the author, title, and a summary of what the book's about.
    • (Score: 2, Insightful) by Anonymous Coward on Thursday March 05 2015, @06:19AM

      by Anonymous Coward on Thursday March 05 2015, @06:19AM (#153420)

      A good memory helps synthesis - kind of like a large cache on a cpu. The CPU can be blazing fast but if it has to constantly idle waiting on memory reads - or worse yet paging in from disk - then it gets nothing done. The larger the "working set" the more patterns and inter-relationships you can put together in a reasonable amount of time.

      • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @07:34AM

        by Anonymous Coward on Thursday March 05 2015, @07:34AM (#153436)

        A poor CPU with high storage (ala. SAN) are those people who are walking encyclopedias but can't think themselves out of a paper bag.

      • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @05:25PM

        by Anonymous Coward on Thursday March 05 2015, @05:25PM (#153570)

        I don't think comparing brains to CPUs or making such analogies is very meaningful. Intelligence is far more complex than that, to the point where we can't even really define it in an objective way. There are various ways around the memory problem, such as storing the data elsewhere. Most rote memorization 'geniuses' I've encountered were only good at memorizing information and doing nothing else; they could not innovate.

    • (Score: 1, Interesting) by Anonymous Coward on Thursday March 05 2015, @07:28AM

      by Anonymous Coward on Thursday March 05 2015, @07:28AM (#153434)

      I am like this, high power with low storage. There is an advantage to be leveraged in novel thinking as that is what we end up doing most of the time to make up for low recall ability. It isn't as efficient at tasks that repeat or are similar, so I find that my abilities are appreciated more when the problems are so broad or unexplored in nature that memory isn't viable. Dive in the deep end, go off the map and fight the cognitive dragons, that is what we are good for.

    • (Score: 1) by brocksampson on Thursday March 05 2015, @10:11AM

      by brocksampson (1810) on Thursday March 05 2015, @10:11AM (#153458)

      What you are describing is the difference between declarative and procedural memory (or, probably more accurately, the ease of recall of declarative or procedural memories). If you read something once and remember it, you probably have a good declarative memory and are considered smart. If you do something once and remember it, you probably have a good procedural memory and are considered talented. (And if you can do both, then you're smart and talented!) Whereas many/most standard tests (aptitude, licensing, etc.) skew towards declarative memory, what IQ tests are supposed to get at is "reasoning" or "problem solving" or "thinking" or whatever you want to call it. But there are strange sub-populations of people who score very high or very low, yet seem cognitively normal otherwise, so to some extent and IQ test just measures how good you are at taking IQ tests.

      • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @05:30PM

        by Anonymous Coward on Thursday March 05 2015, @05:30PM (#153573)

        so to some extent and IQ test just measures how good you are at taking IQ tests.

        Since we haven't been able to define intelligence concretely as of yet, I would say that's entirely what they do. IQ tests are arbitrary, and people who think they measure intelligence believe so without good scientific evidence.

    • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @01:01PM

      by Anonymous Coward on Thursday March 05 2015, @01:01PM (#153481)

      Intelligence is defined by the ability to solve general problems. So yes, memory improves your ability to do so, but it's not the only aspect of it. For the mathematically we could say that reasoning = f(memory, natural_aptitude, skill, ...).
      Assuming it's not crippling, you can make up for poor memory to an extent, but, if hypothetically you have the exact same reasoning ability as me and better memory, then you are smarter because you can solve arbitrary problems better than me. That said, not even perfect memory will make you solve problems you are simply incapable of comprehending, so reasoning is the absolute limit since there are methods to compensate for lacking memory (eg notes) but there is very little you can do to improve your raw brainpower.

      tl;dr When it comes to intelligence, memory is important but reasoning is essential.

      • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @05:22PM

        by Anonymous Coward on Thursday March 05 2015, @05:22PM (#153569)

        Intelligence is defined by the ability to solve general problems.

        There is no concrete, objective definition of intelligence.

        then you are smarter because you can solve arbitrary problems better than me.

        Define "arbitrary problems." How exactly does solving arbitrary problems mean you're smarter? Are you using the Pythagorean theorem to solve the same types of problems again and again? That's just tedious nonsense, and I would say it isn't a measure of intelligence (which itself doesn't have an objective definition). So it all depends on what you mean by "arbitrary problems."

  • (Score: 5, Interesting) by RedBear on Thursday March 05 2015, @05:36AM

    by RedBear (1734) on Thursday March 05 2015, @05:36AM (#153411)

    I watched a Ted talk a while back about this exact thing. I couldn't remember who it was who gave the talk. Turns out it's the researcher who the "Flynn Effect" was named after: James Flynn. Pretty good talk. I recommend it to anyone and everyone.

    James Flynn: Why our IQ levels are higher than our grandparents [ted.com]

    The quote that I particularly remember was Flynn talking about discussing the mistreatment of black people with family and friends decades ago (he's white). He would say to them (paraphrasing), "Imagine if you were black, is this how you would want to be treated?" and they would simply reply, "Son, that's the dumbest thing you've ever said." Or something of that sort. They literally couldn't think abstractly in such a way as to be capable of thinking of themselves as not being white. To their brains, that's just not how the universe works. There was simply no discussion to be had over such a silly idea.

    Fast forward a couple of generations later and nearly every person he talks to now is capable of imagining themselves as not being [ white | black | male | female | straight | gay | etc ], and capable of having a discussion about whether they would like to be treated a certain way "if they were X". In other words, abstract thinking, in some ways, has actually measurably improved in just a few short generations. Except of course among those who score very high on the Right Wing Authoritarian scale. High RWAs continue to exhibit a remarkable lack of abstract thinking capability and an inability to identify logical fallacies. [umanitoba.ca]

    --
    ¯\_ʕ◔.◔ʔ_/¯ LOL. I dunno. I'm just a bear.
    ... Peace out. Got bear stuff to do. 彡ʕ⌐■.■ʔ
    • (Score: 2) by mrcoolbp on Thursday March 05 2015, @06:05AM

      by mrcoolbp (68) <mrcoolbp@soylentnews.org> on Thursday March 05 2015, @06:05AM (#153413) Homepage

      This is exactly what I was referring to in my comment above [soylentnews.org], I didn't mention the name which is the "Flynn Effect".

      --
      (Score:1^½, Radical)
    • (Score: 2) by mhajicek on Thursday March 05 2015, @01:55PM

      by mhajicek (51) on Thursday March 05 2015, @01:55PM (#153492)

      I posit that TV and movies may have been significant contributors to the improvement in abstract thought.

      --
      The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
      • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @04:53PM

        by Anonymous Coward on Thursday March 05 2015, @04:53PM (#153561)

        Fans of Survivor, American Idol, and Fox News are significant examples to the contrary.

    • (Score: 1, Touché) by Balderdash on Thursday March 05 2015, @02:38PM

      by Balderdash (693) on Thursday March 05 2015, @02:38PM (#153508)

      I had a dream about being a crippled black lesbian atheist.

      I don't know how it is in real life, but in the dream world you get like $10,000.00 per month in EBT to spend on noodles and diet sodas.

      It was pretty sweet except for the morbid obesity and constant influx of daytime television and talk shows.

      --
      I browse at -1. Free and open discourse requires consideration and review of all attempts at participation.
  • (Score: 2) by PizzaRollPlinkett on Thursday March 05 2015, @12:10PM

    by PizzaRollPlinkett (4512) on Thursday March 05 2015, @12:10PM (#153474)

    To abstract "intelligence" away from intelligence about something is wrong and doesn't work. (My ideas about intelligence are influenced by Wittgenstein.) People are not "intelligent" in general, they're intelligent about some subject. Some people find some subjects easier or more interesting than others. When you try to abstract "intelligence" into its own thing, you get bogosity like IQ tests. This kind of test will only test your ability to take IQ tests. They're so far removed from anything real that they don't test anything but some kinds of pattern recognition. If you're good at those (I've never, for example, been able to look at a list of numbers, discover the formula that generates them, and predict the next number - and that's big on IQ tests), then you have a "high IQ" and are "intelligent". But, otherwise, I guess you're dumb.

    --
    (E-mail me if you want a pizza roll!)
    • (Score: 2) by kaszz on Thursday March 05 2015, @12:55PM

      by kaszz (4211) on Thursday March 05 2015, @12:55PM (#153478) Journal

      Will the ability to figure out the next number aid the capability to create a working fusion device? ;)

      Being good at tests shows remarkable good in school. Being able to push science forward or society is another ballgame.

    • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @09:30PM

      by Anonymous Coward on Thursday March 05 2015, @09:30PM (#153657)

      People are not "intelligent" in general, they're intelligent about some subject.

      I knew right there, thanks to my amazing pattern recognition ability, that this (or some for of why you suck at IQ tests) was about to be next:

      I've never, for example, been able to look at a list of numbers, discover the formula that generates them, and predict the next number - and that's big on IQ tests

  • (Score: 3, Interesting) by kaszz on Thursday March 05 2015, @12:57PM

    by kaszz (4211) on Thursday March 05 2015, @12:57PM (#153480) Journal

    Could it be that every generation creates a more complex world that provides more stimulation for the next one such that they appear more intelligent? And thus that if you stimulate your children right away you can get ahead of this seriously fast?

  • (Score: 4, Interesting) by acid andy on Thursday March 05 2015, @01:21PM

    by acid andy (1683) on Thursday March 05 2015, @01:21PM (#153484) Homepage Journal

    I was under the impression that IQ test scores are normalised so that the population median is 100. If that's the case, how can they compare test scores from generation to generation? I can understand an argument regarding the distribution becoming more skewed so that a greater proportion of the population have above median scores, but if the median moves that still doesn't prove the population as a whole is getting more intelligent.

    Maybe they got hold of data before normalisation but I'd argue that's even more meaningless unless all generations are being given exactly the same test questions. I'm sure this is all clear in their paper but I've not found that.

    --
    If a cat has kittens, does a rat have rittens, a bat bittens and a mat mittens?
    • (Score: 0) by Anonymous Coward on Thursday March 05 2015, @04:36PM

      by Anonymous Coward on Thursday March 05 2015, @04:36PM (#153555)

      You're entirely correct.

      However, they keep having to make successive tests more difficult because people are getting better at them. There have certainly been contributions from
      1) making fuel lead-free
      2) iodated salt (IIRC iodine deficiency used to be the #1 cause of preventable mental retardation)
      3) increased availability of food and
      4) more people receiving education to a higher level

      Probably also important were
      5) increased social pressure to do well in school and go to college
      6) a more carnivorous diet*
      7) vaccines and generally improved medical care in childhood (so the body spends resources on the brain instead of on infections, not to mention the direct damage they can do)
      8) a more stimulating environment (educational tv may suck, but it sure beats nothing)
      9) a society which is generally less hostile to disadvantaged minorities (e.g. if blacks always see themselves portrayed as stupid, it will affect their thinking)
      10) a feedback effect from all of the above, since more intelligent parents can take better care of and better stimulate their children

      * I know there are many loud voices claiming that you must eat only or almost only vegetables. Well, plants contain too little (or none) of several important nutrients (especially cobalamin) vital to brain function. A controversial claim which you are free to disagree with.