Children of older fathers have lower IQs | Hacker News Reader

Children of older fathers have lower IQs

guardian.co.uk

18 pointsksvs45 comments

With an average difference of only 3 IQ points that this study found, these children appear to be missing out on little with regards to intelligence.

I would be more inclined to believe any differences in intelligence, if there really are any, are due to the environment in which the child was raised, rather than genetic advantages and disadvantages. In today's world, I would guess that children born to 50 year old men are being born into a family where the wife is not the father's first wife, and the father is not as likely to be as dedicated a father as the younger fathers plan to be. This is a sweeping generalization, but I would wager that for those 50 year-olds who are remarried (once, twice, or more), by the fact that they did not care to keep the family intact the first time (excluding cases where the wife died), these men and their current wives would be less likely to provide a nurturing environment compared to a young father.

A sweeping generalization, but my gut feeling, based on the likely fact that many of those 50 year old fathers are remarried once, twice, or more, indicating to me that they are not as good a father as the SOME of the 20 year olds will be.

Also, statistics on society's accepted geniuses do not seem to show a correlation between fathers' ages and the intelligence of the offspring.

Here is a list I have compiled. IQ scores may be disputed, but the intelligence of these people generally are not.

Genius IQ Father's age

------ -- ------------

Einstein about 160 31

Galileo 185 44

==========================================

Bobby Fischer 187 Likely father, Paul nemenyi: 48

                         Birth certificate father, Hans-Gerhardt Fischer: 35

                         http://www.nndb.com/people/455/000024383/

==========================================

Madame de Stael 180 33

Ludwig Wittgenstein 190 42

Blaise Pascal 195 35

Gottfried Wilhelm Leibniz 205 49

John Stuart Mill 200 33

Emanuel Swedenborg 205 34

Johann Wolfgang von Goethe 210 39

As you can see, one of the highest IQ's, Leibniz's, had a father who as 49 years old.

Einstein's, considered the lowest at 160, had a father of 31, the youngest in this list.

So this is opposite the study's findings. However, I don't really see a correlation overall.

With the study's difference of only 3 IQ points on average, I am inclined to believe that age makes no difference in the intelligence of their offspring, especially in those families that provide a nurturing environment, regardless of the parents' ages.

Wow! Pretty excellent research.

Question, because I'm certain somebody knows: is that story of 100 IQ - 60 = 180 - 140 in terms of relative intelligence true? Or is that just metaphorical and not actually representative of "people doing such-and-such are on different planes of existence"?

is that story of 100 IQ - 60 = 180 - 140 in terms of relative intelligence true?

Short answer: no.

Longer answer: http://news.ycombinator.com/item?id=407083

----

Also: as katz mentioned above, IQs of historical figures are complete nonsense. I can't believe it actually got so many upvotes here on HN.

Question, because I'm certain somebody knows: is that story of 100 IQ - 60 = 180 - 140 in terms of relative intelligence true?

Not really. "180 IQ" is taken to mean two different things. Precociousness is the first; a 6-year-old with the cognitive performance of an 11-year-old has a "183 IQ". It's not terribly meaningful, though, because this says nothing about his adulthood performance, which will probably be closer to the average (usually 135-150). The second is extreme cognitive ability in adults or near-adults, on an "absolute" rather than age-graded scale, which we can't measure using an IQ test.

In general, IQ tests become less meaningful (correlating less strongly to what we consider "intelligence") after 125, and are unreliable after about 150. Many distinguished professors, even in math and the sciences, score in the 120s to 130s when tested. It's not that these people are "only" 98th percentile; the test simply isn't great at measuring the high range.

Also, for case in point about the diminishing utility and relevance of IQ: consider a relationship between a person with an IQ of 125 and one at 100. Someone at 100 is unlikely to finish college, and 125 is the average IQ of Ivy League students. Their relationship would be unlikely to last due to the extreme disparity of intelligence, as well as the different schools and jobs they would be likely to have. On the other hand, if the disparity were 150/125, they'd probably be considered to be well-matched; they'd have gone to similar schools and have similar educational/job experiences; although the disparity would be present, it wouldn't be such that the 150 would end up completely dominating the 125.

That list of people is the most interesting part of this thread.

> I would be more inclined to believe any differences in intelligence, if there really are any, are due to the environment in which the child was raised, rather than genetic advantages and disadvantages.

Intelligence measured by the general intelligence factor is highly heritable. The general intelligence factor is a factor analysis of intelligence and is a measure of “innate” intelligence and attempts at “boosting” this fails. The test that measures this the best is Raven's progressive matrices which is culture and language negative. The general intelligence factor is highly correlated with IQ and highly correlated with future success. The performance of a person in these tests has to do with the physical make-up of the brain (there are a lot of online articles by (dr/prof) Haider that is fairly readable that sheds light on this subject.)

> Here is a list I have compiled. IQ scores may be disputed, but the intelligence of these people generally are not.

A note about your cited IQs – it is probably not correct. The popular press like to “guesstimate” the IQ of historic persons – but this is of little value. Rigorous intelligence tests (such as IQ tests) is a 20th century phenomenon. Leibniz lived in the 17th century – well before these tests. So to try and determine any IQ or measure of intelligence from him is a waste of time.

Also – you collected only a point sample - I bet someone could get the same example with selecting a different group of famous persons. You also only selected the top 1% and not the general populations – so to draw assumptions of this sample to the general population would be wrong.

I do agree with you that the study is somewhat worthless. Here are several conflating factors:

People involved in menial labour (i.e. without tertiary qualifications) generally get children at a younger age. A lot of older financially secure men would generally marry younger less intelligent women (trade-up/Russian bride phenomenon). The age of child bearing of different social classes differs significantly.

Also - a three point IQ difference with all these conflating factors would probably fall under the heading "not statistically significant".

The test that measures this the best is Raven's progressive matrices which is culture and language negative.

I've attended a lecture by John Raven, the publisher of that test, and he doesn't make that claim.

The long, careful examination of what the Raven tests show, in conjunction with other evidence, can be found in James R. Flynn's excellent book What Is Intelligence?, which is about to come out in a new, expanded edition.

http://www.amazon.com/What-Intelligence-Expanded-PB-Beyond/d...

Also very good for reconsidering the importance of IQ tests is Keith Stanovich's What Intelligence Tests Miss.

http://yalepress.yale.edu/yupbooks/book.asp?isbn=97803001238...

http://www.amazon.com/What-Intelligence-Tests-Miss-Psycholog...

> I've attended a lecture by John Raven, the publisher of that test, and he doesn't make that claim.

I never said that he made that claim. Several other people compared RAPM and other intelligence tests to determine the g-loading. It was found by other people (not Dr. Raven) that RAPM has a high g loading. Testing for the general intelligence factor and the use of RAPM is widely accepted. Here is an example of a recent article: “Just one g: consistent results from three test batteries”, (Wendy Johnson, Thomas Bouchard, etc...) 2004. Using Google scholar you can find several other results. Even if you reject RAPM as a measure of g, there are less g-loaded tests (such as IQ) that can be used that predicts more or less the same thing (heritability of intelligence, etc...).

> The long, careful examination of what the Raven tests show, in conjunction with other evidence, can be found in James R. Flynn's excellent book What Is Intelligence?, which is about to come out in a new, expanded edition.

My problem with most of Flynn's books is that he is a political scientist and a passionate left-wing campaigner. He is basically a Gould-light – distorting science to fit his own world view.

I usually prefer to read papers or books on intelligence matters from people with a PhD in areas such as educational psychology or neurology when it concerns brain structure (e.g. prof. Haier).

My problem with most of Flynn's books is that he is a political scientist and a passionate left-wing campaigner. He is basically a Gould-light--distorting science to fit his own world view.

There are a lot of Ph.D. psychologists who disagree with that statement. Here is what Arthur Jensen said about Flynn quite a few years ago, and he hasn't retracted this statment: "Now and then I am asked . . . who, in my opinion, are the most respectable critics of my position on the race-IQ issue? The name James R. Flynn is by far the first that comes to mind." Modgil, Sohan & Modgil, Celia (Eds.) (1987) Arthur Jensen: Concensus and Controversy New York: Falmer. Here's what Charles Murray (all right, not a psychologist nor a geneticist) says in his back cover blurb for Flynn's book I mentioned in this thread: "This book is a gold mine of pointers to interesting work, much of which was new to me. All of us who wrestle with the extraordinarily difficult questions about intelligence that Flynn discusses are in his debt." As Mackintosh (1998, p. 104) writes about the data Flynn found: "the data are surprising, demolish some long-cherished beliefs, and raise a number of other interesting issues along the way." Flynn has earned the respect and praise of any honest researcher who takes time to read the primary source literature. Robert Sternberg, Ian Deary, Stephen Pinker, Stephen Ceci, Sir Michael Rutter, and plenty of other eminent psychologists recommend Flynn's research.

As for what we can conclude about the Raven Progressive Matrices test, one thing we certainly can't conclude is that it is not influenced by the cultural background of the test-taker. The test publisher says culture matters in Raven scores.

http://www.eyeonsociety.co.uk/resources/RPMChangeAndStabilit...

> are the most respectable critics of my position on the race-IQ issue?

The race-IQ issue is separate from the issue of general intelligence and neuroscience of the brain. Even if he is a successful political scientist, it would not make him an educational psychologist or neuroscientist. Much of the popularity of Flynn is his opposition to certain views of Intelligence - not his research.

> one thing we certainly can't conclude is that it is not influenced by the cultural background of the test-taker

With language and cultural negativeness I meant that there is no cultural specific references. One of the main complaints of the IQ test was that it contained western concepts and examples and language (i.e. it was culturally loaded). For example – the pictures in RPM are the same and contains the same meaning from whatever culture you are. Here is a quote from “How Biased are Culture-Loaded Tests?” (Jensen, A):

> Probably the best known and most widely used of such tests s Raven's Progressive Matrices (citations). Such nonverbal tests are expressly designed to reduce item dependence on acquired knowledge and to keep cultural and scholastic content to a minimum while getting at basic processes of intellectual ability.

Also note that that study did not just use RPM but included a verbal section.

The study you gave me showed differences in RPM between what they labelled “cultures” - other authors used other “labels” to try and explain the difference between groups. Here is a quote from the study you gave me:

> On the one hand, the absence of cross-cultural differences in RPM scores between cultures which do differ on a variable

Thanks for the reply. My friendly response to the suggestion that I should consider mostly what subject a person has earned a Ph.D. in as the basis for whom to believe on what subject is that sometimes good ideas for one subject come from people who learned another subject. Sometimes that's the best way to make progress in a subject that has become stuck in outmoded theories. I observe that Ph.D. psychologists

1) were taken by surprise by Flynn's research on IQ test score trends over time, having initially predicted precisely the opposite trend,

2) proposed very stringent standards for acceptable data before believing the trend was real (and Flynn credits Jensen, who has just the sort of credentials you have recommended, as being especially tough in demanding certain kinds of evidence),

3) reviewed his publications before allowing them to appear in the leading journals in the field of psychology,

4) invited Flynn to attend major conferences written up in specialized monographs with acknowledged experts in psychology,

http://www.amazon.com/Nature-Intelligence-No-233-Novartis-Fo...

5) praised his work in standard textbooks on human intelligence,

6) devoted whole monographs specifically to his findings,

http://books.apa.org/books.cfm?id=431712A

and generally accorded Flynn greater honor as a researcher on psychological phenomena than most psychologists gain in a lifetime.

http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=978...

Anyway, scientific issues aren't decided by credentials, but by data. Flynn found and analyzed some very important data that caused a lot of psychologists to reexamine their assumptions. John Raven takes care to write, "The results surprise many psychologists. Eductive ability has turned out to be more easily influenced by appropriate educational and developmental experience than reproductive ability." In other words, what Jensen and others took as a "culture fair," "g-loaded" IQ test turns out to reflect modifiable educational experiences that children have or do not have.

I agree with you that my comparison of Flynn with Gould was not entirely fair. Flynn found the Flynn effect which is an important part. But a book by Flynn is not peer reviewed and may be influenced by his political views (he is author of “How to Defend Humane Ideals: Substitutes for Objectivity” after all).

> Anyway, scientific issues aren't decided by credentials, but by data.

This is true – but data in peer reviewed journals not books.

> In other words, what Jensen and others took as a "culture fair," "g-loaded" IQ test turns out to reflect modifiable educational experiences that children have or do not have.

The majority of psychologists believe that the g-factor is an innate and immutable property. The g-factor correlates with reaction times, glucose metallisation rate and is highly heritable. This indicates that the g-factor most likely have a neurobiological basis (see articles by Haier for example).

In a recent article the g-factor also appeared in a battery of 42 tests (Johnson,W Bouchard, TJ, “Just one g: consistent results form three test batteries”). Here is a quote from the abstract:

> The concept of a general intelligence factor or g is controversial in psychology. Although the controversy swirls at many levels, one of the most important involves g's identification and measurement in a group of individuals. If g is actually predictive of a range of intellectual performances, the factor identified in one battery of mental ability tests should be closely related to that identified in another dissimilar aggregation of abilities. We addressed the extent to which this prediction was true using three mental ability batteries administered to a heterogeneous sample of 436 adults. Though the particular tasks used in the batteries reflected varying conceptions of the range of human intellectual performance, the g factors identified by the batteries were completely correlated (correlations were .99, .99, and 1.00). This provides further evidence for the existence of a higher-level g factor and suggests that its measurement is not dependent on the use of specific mental ability tasks.

A definitive reply to most of that outmoded thinking about g can be found in Nisbet's new book,

http://www.psychologicalscience.org/convention/program_detai...

or in Stanovich's.

http://yalepress.yale.edu/yupbooks/book.asp?isbn=97803001238...

Stanovich is very clear on the distinction between "intelligence" (he is a mainstream psychologist in calling "intelligence" what I would simply call "IQ") and "rationality," an aspect of human cognition hardly tapped at all by most IQ tests. Stanovich comes at these issues from the framework of cognitive science, which also informs much of current behavioral economics. He previously wrote a textbook on understanding psychological research that has gone through a number of editions.

> A definitive reply to most of that outmoded thinking about g can be found in Nisbet's new book,

If you feel that these views are outmoded – give me peer reviewed research articles (not books). I do not have immediate access to books and books are not peer reviewed. The article that I referenced above was written in 2004 – you can find more recent articles in Google Scholar if you want to. I did not see that the above article (or any of the others) have been refuted. I doubt that you can refute thousands of research articles (a lot of them recent) and a discovery that is probably the hallmark of modern psychometrics with a simple reference to a book (calling anything that you oppose “outmoded”).

> Stanovich is very clear on the distinction between "intelligence" (he is a mainstream psychologist in calling "intelligence" what I would simply call "IQ")

Also I think you are confusing “intelligence” with the general intelligence factor (g) (also intelligence does not equal IQ. IQ is just a standardised intelligence test that is fairly well correlated with the g factor). The general intelligence factor is a factor that is common to almost all different tests on intelligence. While the general intelligence factor is immutable other parts of intelligence can be changed by training/learning (i.e. by the environment).

> "intelligence" (he is a mainstream psychologist in calling "intelligence" what I would simply call "IQ") and "rationality," an aspect of human cognition hardly tapped

The purpose of intelligence tests is to test intelligence – not factors such as rationality, emotion and inter-personal skills such as Stanovich's book suggest. The latter are all factors that is undoubtedly environmental and the value of such tests are doubtful to the intelligence debate.

Why is it people don't understand that all groups have different means given large enough N. Statistical significance has nothing to do with the magnitude of difference. Effect size is what you are looking for which looks at the magnitude of the difference in means taking into account the groups variance.

Also, 3 may well be statistically significant, and perhaps have a large effect size. This does not mean it is clinically significant.

IQ scores may be disputed, but the intelligence of these people generally are not.

The IQ scores claimed for these historical figures would have to be very strenuously disputed, because most of those persons never took an IQ test. The book Terman's Kids

http://www.amazon.com/Termans-Kids-Groundbreaking-Study-Gift...

by science writer Joel Shurkin, the first independent researcher to have access to the Terman longitudinal study files, explains the fanciful way in which those figures were arrived at. They were not validated by the member of Terman's team who made up those historical guesses at the IQ scores of people dead long before IQ tests were ever used.

Have any of you ever wondered how lists like this are compiled? It's laughable when you look at what was actually done to make these unvalidated guesses.

I wonder if the study controlled for the selection bias inherent in the decisions of males of various ages to reproduce and in their preferences for mates. Presumably, 50 year-old men are not procreating with women their age. Do older men choose younger, but dumber women to mate with? Do dumber men end up having children later in life? Are 50 year-old men worse parents?

Good point.

They good control it by looking at IQ relationships of brothers potentially.

Pick a list of successful people you believe are intelligent. Uncheck those who don't have brothers/sisters. Then look if they're an older/younger kid in the family. I've done the exercise out of curiosity and it appears the article is correct: most famous programmers were older brothers.

Also susceptible to other explanations. For instance, perhaps having a younger sibling to teach stuff to is good for your brain.

Yes, you'd really need siblings who came from the same parents, yet were separated at birth.

Then you run into problems of other parents since they will have their own parenting style which will affect the IQ.

I wonder if there's a big difference of the IQ in twins. If there is then the IQ difference of 3 in the article may not be all that significant.

The ideal case would be children from the same parents that lived in the same town, went to the same schools, participated in the same activities, had similar friends, and a whole list of other factors. It would also be convenient to have there be more than 2 kids to see the quantitative meaning of "older"

This may just be an indication of a first time parent spending a lot more effort on the first child or just having the resources to do so. During the early years the IQ of the first child is developed while there are fewer resources for the later children.

On the other hand, younger parents may just be starting out and have fewer resources/experience to help them raise the child.

You can also take a look at grandparents - younger parents will have a more active set of grandparents which may be contributing to this IQ boost as well.

Too may unknowns here but an interesting topic.

This is entirely anecdotal, but I'll jump in on this topic:

I have twin sisters (identical). Both of them are highly intelligent (go to Ivy league schools), but one has a slight "edge" on the other.

Growing up, they did everything together- the only difference between the two is that the slightly "dumber" one, I used to put down a lot more and make fun of (I got along with my other sister a little better).

It's funny how the little things you do when you're young (we have a great relationship now) can affect things when you're older.

How sad...I also have a sister I put down, and I can't help it.

Numerous studies have been done on siblings and twins who were raised separately. The IQ correlation between hereditary siblings is strong, that between twins is overwhelmingly strong and that between adopted siblings is almost non-existent past adolescence.

http://en.wikipedia.org/wiki/Inheritance_of_intelligence#Fam...

That risks conflating intelligence, IQ, fame, programming ability (and programming affinity), and general organizedness into one. You may be right -- but we have zero idea to what degree.

Two parts of your statement. 1. most famous programmers were older brothers: interesting statistic. But 2. it doesn't support the older-father-lower-IQ hypothesis.

You're absolutely right. While I don't hold a PhD in phycology or neurology or child development I don't believe in superior/inferior intelligence or natural talent: take this as a totally unscientific gut feeling that I'm sticking to, unless an undeniable evidence (something other than surveys or Einstein brain scans) emerges.

In my previous post I just stated an observation but I forgot to add that I don't hold it as an explanation nor proof. In this particular case I believe that older siblings enjoy more freedom and have an opportunity to grow up faster since parents become pre-occupied with younger brothers/sisters, thus older kids grow up being more independent.

Interesting. I happen to gut feel nurture >>>>>>>>>>>>> nature, but I think nature plays a part too. It seems unlikely to me that we all have slightly different bodies, and those bodies are heritable to some extent, but our brains are wired consistently the same and/or not heritable.

But I do over to the nurture side of the equation more - the interesting part on more freedom and growing up for older siblings is interesting. Also supporting your idea, older siblings often take on more responsibility in family affairs too.

I lean on the nature side. I also feel like this is the dogma in "formal" neuroscience; it is hard for nurture to maintain favor when all you look at is whether some gene turned on or some phenotype expressed.

But, there is an area where it may be impossible to show either way, and you have a battle of religion. To see why this is the case, consider inherited fear responses (I forgot the actual term for this). You can, for example, probably train a goose to not fear an eagle-shaped shadow. There would be a measurable change in neuronal wiring, because the fear response previously paired to the pattern recognizers of eagle-shaped shadows is now inhibited or diverted. If this works, it is "nurture."

But to turn it around, the fact that you could re-train the goose would imply that plasticity was part of the equation. This is "nature." Then, there are parts where plasticity is simply never going to be part of the equation (without some extreme bioengineering): you cannot teach a modern goose to read, period.

So, to rephrase: it is possible to interpret all "nurture" phenomenon under an all-nature framework: it's simply a distinction of whether you are born with plasticity for certain domains of learning. This difference, which you can validly call nature vs. nurture, is meaningful in many contexts, but in my opinion is not so much a dichotomy than different ways of looking at the same thing.

I'm not all about predeterminism though; the important task to figure out what, why, how, and when circuits are plastic.

While I was reading this article I felt almost the exact same thing - the whole article feels like bad science because they present the conclusion that "many scientists believe that genetic mutations that build up in the sperm of older men are to blame." Presumably, the only thing this study has shown is that lower intelligence is correlated with older fathers but the cause could be any number of factors like what you said or even, for example, that people with lower intelligences are predisposed to postpone having children.

Basically, thanks Freakonomics for bringing correlation/causation to my mind every time I read an article like this.

Correlation - xkcd

http://xkcd.com/552/

Good point. They also don't mention the standard error on their estimate. The difference of 3 points could easily be swallowed by the standard error.

As far as I know, a three point IQ difference doesn't have any practical effect. It may be statistically significant, but it's hardly a huge advantage to score three points higher than someone else.

I have always wondered - when reading articles like this - whether it would just be better to freeze one's sperm at age 20 and then save it for when you want to have a child. In fact, it might even be better to save sperm from age 14 or so to reduce even further the chance of generic mutation.

I don't know if this is easy or even possible to do (or whether using frozen sperm brings its own complications), but it's worth researching further.

I have wondered about this too, but I recall reading that sperm quality also varies with the current bodily state. Maybe the end of high school would be the best age. But it is a strange thought to have: you are essentially depositing unborn babies into a bank, and retrieving them when you decide you want them.

To take it further, you could freeze enough sperm for 100 conceptions, then get a vasectomy. Which probably yields an even more efficient outcome, with stranger connotations.

My stepfather has said a few times that he wishes he had taken the "further" option.

I'm not sure if I ever want kids, but something about freezing my sperm and getting a vasectomy worries me. A fire at the sperm bank, and my genetic legacy is lost forever.

(Of course I could go in for a reversal, but those don't always take, etc., etc.)

Heinlein's book "Podkayne of Mars" describes couples marrying and freezing entire babies to be thawed out later when they are older, wealthier, and presumably wiser.

You don't need to wonder. You can do it and then forget about it until you're interested in it again.

Can we draft a law preventing journalists from trying to interpret statistics?

First let's teach college teachers of statistics (who usually aren't statisticians) how to teach statistics. One of my favorite articles on that subject

http://statland.org/MAAFIXED.PDF

is so thoughtful that I reread it from time to time just to savor the language. Another good article about how to teach statistics

http://repositories.cdlib.org/cgi/viewcontent.cgi?article=10...

is helpful in guiding people who have studied statistics before to rethink what they think they have learned. It is by a very eminent statistician.

The same study found that children's IQ was marginally higher if they were born to older mothers, a finding scientists have put down to those women spending more time caring for and nurturing their infants.

Maybe younger fathers are more nurturing.

It looks like several journalists need to read the new book Intelligence and How to Get It by Richard E. Nisbett,

http://www.wwnorton.com/catalog/winter09/006505.htm

which I am reading just now. Nisbett reviews the best recent literature on IQ testing and what it means, and punches holes in the fallacious reasoning used by many advocates of a strong hereditarian view of influence on IQ.

A really good book for background reading on IQ testing and how it works is IQ and Human Intelligence by N. J. Mackintosh,

http://www.amazon.com/IQ-Human-Intelligence-N-Mackintosh/dp/...

which includes very clear explanations of how IQ tests have developed historically, how they are currently constructed and validated, and what we still don't know about human rationality despite a century of IQ testing.

This is purely anecdotal but my grandfather was 60 when my dad was born. By all accounts my dad was a highly intelligent man who achieved well in the Navy despite not finishing high school (needed money).

On the anecdotal side. A friend was born when her father was 75. Some people say she is a genius (clearly an exaggeration) but she s smart any way.

You are a product of your environment. --Clement Stone

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