Wednesday 29 April 2015

Have you a Jewish personality?


At the stage in my life when I sometimes went to Speaker’s Corner on Sunday afternoons to listen to random opinions I got into conversation with other bystanders on some important matter of the day. Despite my lack of a soapbox, a small crowd gathered round me, and as the discussion became more intense one of my interlocutors suddenly demanded: “Are you a Jew?” I said I was not. “Well” came the reply “you argue like a Jew”.

You will understand, I am sure, that people who gather on a Sunday afternoon, avoiding the obvious attractions of sitting with an ice cream on a deckchair in Hyde Park in order to squabble about politics, are not a representative sample of humanity, me included,  but the intended insult was instructive. I was mildly affronted that the accuser had made this mistake. Surely he could detect I was an expatriate, free thinking, non-practicing Protestant? What had I done wrong to generate these accusations of semitic tendencies?

Now, of course, with the calm wisdom of advancing years, I would have asked him: “How do Jews argue, in your opinion?” In point of fact, there may be Jewish, Protestant, Jesuit, and Anabaptist ways of having a Sunday afternoon argument. I little doubt that there are Wahhabi ways of arguing. Whether any of these presumptions are true is worth investigation, even if only to preserve life and limb in public places.

Whilst I cannot, just at the moment, provide direct evidence on the effects of religion on argumentation, I can pass on some findings about personality, from which types of arguing could be inferred.

Curtis S. Dunkel, Charlie L. Reeve, Michael A. Woodley of Menie, Dimitri van der Linden (2015) A comparative study of the general factor of personality in Jewish and non-Jewish populations.  Personality and Individual Differences 78 (2015) 63–67

Dunkel and colleagues speculate that Jews will have high scores on the general factor of personality: Individuals high on the General Factor of Personality are altruistic, agreeable, relaxed, conscientious, sociable, and open-minded, with high levels of well-being and self-esteem. Those with poorer personalities are at the other end of the descriptive spectrum. They would tend to be selfish, disagreeable, anxious, not dependable, unsociable, closed-minded or rigid thinkers, with high levels of distress and low self-esteem.

The authors say that the personality traits of Jews are partly constituted by a group-level orientation towards slow life history strategy, characterized by a continuum of physiological and psychological variables.  While a ‘fast’ life history strategy is characterized by high mating effort such as early maturation, weak pair bonds, and a focus on short-term mating, ‘slow’ life history is characterized by lower mating effort and the production of relatively fewer highly invested-in offspring. A key behavioural manifestation of life history is the general factor of personality, which is the common factor variance amongst various diverse personality measures – somewhat akin to the g factor of intelligence. On the basis of life history theory we therefore propose that Jews may have a higher GFP than non-Jews, and in conjunction with this hypotheses, it was predicted that differences in personality would be largest on the most GFP-loaded personality traits (e.g., there will be Jensen Effects associated with the group differences). Given that Jewish/non-Jewish difference in intelligence is well established and that there may be a substantial association between the GFP and intelligence (Dunkel, 2013), intelligence could drive any Jewish/non-Jewish differences in the GFP. Note that response bias is an alternative interpretation of the GFP (e.g., Bäckström, 2007) and, therefore, it could also simply be a matter of more intelligent individuals being more adept in presenting themselves in a positive light in their responses on personality questionnaires (Major, Johnson, & Deary, 2014). For this reason, along with the demographic variables of age and sex, intelligence was also controlled in the present analysis into this putative source of group differences.

The Big Five personality traits of Agreeableness, Conscientiousness, Extraversion, Neuroticism, and Openness were measured using a five-point Likert-type scale to rate 20 items from the Mini-International Personality Item Pool. The first unrotated factor using Principal Axis Factoring (PAF) was used to extract a GFP. This factor had an Eigenvalue of .89 and explained 17.96% of the variance among the trait scales.

Here are the results for the 3 separate study samples: ADD Health, MIDUS II and Project Talent.







Get the whole paper here:

So perhaps my Speaker’s Corner antagonist was paying me a compliment in suggesting my arguments were Jewish: mature, socially sensitive, cultured, altruistic, agreeable, self-confident, relaxed, conscientious, sociable, and open-minded. I am willing to believe the best about human nature whenever possible, but that particular interpretation might be pushing things too far.

Sunday 26 April 2015

London Conference on Intelligence Website


University finance departments have their own set of rules, and one of them is that before any of you slope off to a conference you must provide the relevant website link, so that all the people in accounts can check up on you. This makes sense: public finances must be protected, and if it turns out that there is only one lecture a day and that all other activities are on the beach, in the delightful presence of very helpful representatives of pharmaceutical companies, then it may not be a conference that the university wishes you to attend.

In a welcome improvement on our procedures last year, a Conference Website has been kindly created and hosted by Emil Kirkegaard

It would be great if you were to circulate it to your colleagues, because even though they may not be able to come, they can be forewarned that I will be posting up the abstracts and author contact details.

Nyborg un-Watsoned?


One of the perils of contemporary academia is that your freedom to think is challenged by a pack of wolves telling you what not to think, and savaging you if you do not submit to them.

You may have heard of old sea captain Helmut Nyborg who, after a stint in his youth as a merchant seaman, turned from those honest labours to take up psychology, a nefarious practice full of foul vapours, wild imaginings and internecine warfare.  A falling out occurred between him and colleagues at Aarhus University(world ranking 116) in Denmark, of the sort which happens in academia world wide, in which professors debate over coffee and then return to their departments in a bad temper, and sometimes even write angry letters to each other. This time it was different. Angry that Prof Nyborg had written a paper they did not like, some of his colleagues had him hauled before the Danish Committee on Scientific Dishonesty.

It is not crucial, but you can get some of the historical background here:

Initially I thought this Government Committee was yet another department handing out subsidies in the usual manner: “Here is the money, dear boy, so long as you say that everything is due to the environment”. Grant Giving Bodies is the usual name for these dubious conspirators. However, the Danes do things differently, and there has been a protracted, time wasting, energy sapping Governmental enquiry, which may now, finally, be resolved. The Government capitulated a year ago, and is reconsidering whether they really ought to be interfering in any academic matters. Last to comment this month was the journal that had published his paper, who had set up their own committee of enquiry. Jelte Wicherts, one of the assessors, has circulated the resultant editor’s note.

Think for a moment what this entire process has achieved. Many of you are researchers, already under pressure to publish, but battling with teaching loads and administration. Research time is precious. Imagine what your careers would look like if you were accused of scientific dishonesty by your enemies in academia, and had to stop your work to try to defend yourself, not just against the usual criticisms which are part of scholarly debate, but as part of a process that had been raised to Governmental level, and made students doubt that they should read your work, or have anything to do with you. To my certain personal knowledge a student in the field of intelligence felt that he should not read Nyborg’s paper because he was up before the Committee accused of dishonesty.

Anyway, at the risk of spinning out this drama in the way that his accusers intended, I am simply letting you know that the journal of Personality and Individual Differences has just published an editorial note on his paper, to which I link below.

Finally, what of the paper itself? Nyborg argued that European intelligence will be lowered by two developments: the higher fertility of the less intelligent Europeans, and the increased immigration to Europe of migrants who have higher fertility and lower intelligence. If you can show that this is wrong, then you are bound to get your paper published. Try Personality and Individual Differences for a start.

It is an open question whether a similarly resentful legal process could be started against papers asserting strongly environmentalist hypotheses, for example that smaller brains were due to poverty. Dragging in lawyers and government departments is a silly idea. Why not just have an exchange of letters with the authors, identifying points of agreement and disagreement, and suggesting further lines of research?

Of course, even at what is probably the end of the process, damage has been done to Nyborg. Searches on his name may link to the accusation for some time, and not everyone will read through to the very end of the process. His name will be known, and those of his accusers forgotten, which I suppose may turn out to be no bad thing, but it remains a nuisance.  Nyborg is still doing research, most recently on group differences in intelligence and occupational success. If you want to hear about his research and even buy him a drink when he visits London, let me know.

Friday 24 April 2015

London Conference on Intelligence 8-10 May


Readers of this blog are offered specially reduced terms if they wish to attend the London Conference on Intelligence. The Conference begins on Friday 8th May at 2 pm and ends on Sunday 10th May at 1pm and takes place in central London.

A selection of the papers to be presented:

Evolution vs. culture as background factors for international intelligence differences

Spearman’s hypothesis: Hypothesis or Law?

By their words ye shall know them: Evidence of genetic selection against general intelligence and concurrent environmental enrichment in vocabulary usage since the mid 19th century

National-Level Indicators of Male Hormones (Androgen) Relate to the Global Distribution of number of Scientific Publications and Nobel Prizes

In chimpanzees, more g-loaded cognitive abilities are more heritable, evolvable, and exhibit more inter-individual variability

General and domain-related effects of prenatal methyl-mercury exposure

Admixture in the Americas

Intelligence and occupational achievement in the US

Does intelligence explain the overrepresentation of liberals and leftists in American academia?

Population Differences in Androgen levels: A test of the Differential K theory

A Meta-analysis of Roma Intelligence: an update

Intelligence is correlated more with higher non-verbal ability than with verbal ability

Using frequencies of GWAS hits to estimate selection pressure and to increase the statistical power of GWA studies;

Spearman’s hypothesis tested on group differences in personality



For readers, the Registration Fee is set at £15 to cover tea, coffee and biscuits and room hire. We don’t have facilities to take credit cards.

If you would like to attend, (this is written so as to confuse a robot) write to me at my electronic address, using my first and second names separated by a dot, then the at sign, and then         I will then send you further details.

Thursday 23 April 2015

Der Tag

For many years a favourite toast in the German Army and Navy was “Der Tag”-the day when war would come. Despite my having read with fascination histories of the Battle of Jutland, the inconclusive but deadly clash of great fleets on 31 May/1 June 1916 where both navies used the same German description for their confrontation, I have no wish to sink beneath the waters of the North Sea. However, as I have already confessed, in my case the wished-for Der Tag is the mythical occasion when I address a  stadium full of readers chanting “Avoid confounding variables”.

Something like that happened today, 22 April 2015. Last March had slow days when only 450 readers graced my portals, and then as April dawned I had some days with super-totals as high as 1,690. Tracking back, these usually could be attributed to a kind mention by Steve Sailer.

Today readership spiked to 4,729. I have already sent my own thanks to the person responsible. A cup of internet coffee to the first reader with the explanation.


Sunday 19 April 2015

Howitzer or Katyusha: Reply to Prof Noble


Dear Kim,

Thanks very much for coming back to me with your comments. Despite my friendly entreaty to all authors to respond to my postings, many choose silence, so it is great to be able to debate with you. I do not have a “Psychological Comments” T-shirt or coffee mug to offer you (and doubt they would be considered highly motivating) but I appreciate your response.

We agree that it is worth looking at data sets which have interesting or unique aspects (in this case brain scans) despite them not being fully representative of the general population. Wherever the characteristic in question is rare we are justified in digging up every possible data set, and making Bayesian approximations to obtain the best available estimate of the variable in question.

However, where very big issues like social class, social mobility, income, wealth, health, and scholastic achievement are concerned, representativeness is crucial. Epidemiological samples rule. For example, the Dunedin sample shows that most social problems, and subsequent costs of remediation, are due to a small number of children. As I mentioned in my post on your paper, Moffitt and Caspi show how one might misunderstand child development in general just by missing a small number of difficult children, who are of course those least likely to volunteer for a health checkups, let alone brain scans.

I think we agree on that anyway, but we may differ on the implications, particularly when it comes to your intervention study, which I will discuss later.

Now to our main points of disagreement, which is that the results you report could be due to genetic factors, whether or not those have been measured in the study.

Correcting for race differences in your sample does not correct for the overall heritability of intelligence and the heritability of other characteristics like brain size in your study children. You corrected for race differences and showed that the income and education correlations with brain surface were not driven purely by racial group differences. (There seems to be a big difference due to African ancestry, but that does not explain all the SES effect). However, that still leaves wide open the obvious explanation, that what you are recording with your scanners are inherited differences that run through the entire sample. I said in my note: SES and brain size can have the same relationship in all racial groups, and yet still be driven by inherited intelligence.


Do you agree that point, or not? My objection was that you appeared to think you had covered the overall heritability confounder with your racial group correction, and you haven’t. To illustrate the point, imagine you restrict your analysis to the European children and find that income and education are correlated with brain surface. That association could be due to the common factor of genetics. Bright parents have brighter children (on average) and also command higher salaries (though their resultant wealth probably doesn’t give much of a boost to the school attainments of their children). Even if you don’t have genetic data in your particular study, the many publications on the heritability of intelligence mean that it is very likely that your results are driven by inherited characteristics, and these can’t be ignored simply because genetic effects have not been measured in your particular study. For example, this recent study finds “Genetic influence on family socioeconomic status and children's intelligence” from purely genetic analyses.

It was for that reason that I argued it would have been better to have collected more data on the parents. (This could include scans of parental brains, but testing ability would be more cost effective). Having parental intelligence scores would have allowed you to compare the predictive power of three variables: income, education and parental intelligence. (Or if that hadn’t been done by the PING study, at least it would have allowed you to explain how such data would have helped you identify possible causes). Those three variables of income, education and intelligence are enough to begin to sketch out putative causes, particularly when considered over generations. For example, the Pew Trust has looked at social mobility in the US and finds that IQ is a much stronger predictor than race for escaping the bottom quintile of income (Pew Trust report; NLSY again, AFQT=IQ scores). If you are bright you rise.


Now we come to what I consider the crunch. Here are your comments: One thing in your commentary I find unclear. You state that we “could have given the parents the psychometric test battery for good comparability.” However, parent cognitive ability is, of course, itself influenced by both genetic and environmental factors, so it is not clear to me how this would have disambiguated this question of causality. Both cognitive ability and socioeconomic status have significant heritable and environmental components, and our study was not designed to address the question of their relative balance. Parent-child genes are correlated, but so are parent-child environments. Incidentally, scanning the parents would not solve the problem either, as parental brain morphometry would be both genetically and environmentally influenced, as well.

I think is worth expanding upon this point. Your study may not have been designed to address the question of the relative balance and power of parental cognitive ability and socioeconomic status, but I was suggesting a quick way beginning to repair that omission. By measuring parental status and parental intelligence we can compare the power of these two predictor variables. I mentioned the Nettle (2003) paper in my original posting. Regarding my suggestion that the parents be given the adult version of the test battery taken by the children you said (above) “parent cognitive ability is, of course, itself influenced by both genetic and environmental factors, so it is not clear to me how this would have disambiguated this question of causality.”

What Nettle did was to show, on an excellent epidemiological sample and a long follow up, that childhood intelligence at age 11 was a better predictor of social mobility than social class of origin. For the class-based sociological hypothesis regarding life outcomes that is an awkward finding. It suggests that something which is not under direct social control (intelligence) is having a bigger effect than something which, in sociological theory, is almost entirely under social control (allocation to class). That is why I say you need to test the abilities of parents, not just their incomes or years of education. There is a quick summary of why heritability applies to cognitive neuroscience by Deary and Plomin (2014)

Davies et al. (2015) is a good example of current work on the genetics of intelligence.

As opposed to the genetics plus environment position, the dominant position in much of contemporary psychology seems to be the sociological argument, which gives precedence to social class, income, wealth and power. The argument goes thus: class strongly influences living circumstances; those living circumstances determine most social outcomes; class casts some people into poverty, poverty stunts intellectual development, lower intelligence is a downstream effect of class-based poverty, so the best way of dealing with low ability is to increase income.

If this sociological hypothesis were correct, social class of origin would be the best predictor of later achievement, and other measures influenced by class would be somewhat weaker predictors. They would trail in the wake of social status.



To use a ballistic analogy: if the higher status, income and wealth of parents are like a big Howitzer which fires their children much longer distances so that they land further up the social hierarchy, then the intelligence of those children is mainly a downstream effect of wealth, and is of lesser significance predictive significance. If poverty per se is so impactful on the developing brain, class of origin will strongly influence everything about the child, including their intelligence.

As far as I can see, that isn’t so. Even within the same family, brighter children end up earning more than their less bright siblings. This cannot be explained by family wealth and status. Additionally, genetic studies tend to find zero effect for the “shared variance” of family and school, but a big effect by the creation of personal niches, the so-called “non-shared” environmental effect.

It seems that families are more like Katyusha multiple rocket launchers, firing salvoes of rockets less accurately than a Howitzer, with different ranges due to the lack of a gun barrel and variations in the propellant in each rocket, the propellant being, by analogy, individual differences in intelligence.

Anyway, by looking at sociological variables through the generations, and looking at intelligence as well, one can identify their relative power in determining which children will be in each class in the next generation. The composition of classes varies from one generation to the next. Your objection (above) is that every measure is a mixture of genetics and environment, and thus uninformative. Not really. If parental intelligence turns out to be more predictive than social status, that is highly informative. No genetic testing is necessary, though it would be a welcome addition. The possibility that genetics is driving intelligence and consequently social class remains open as a major confounder of your observed income/brain link, even if the particular study design makes it hard to reveal its influence. I doubt you intend to commit the “sociologists’ fallacy” of assuming that by selecting people by income and finding differences it can be suggested that income has been established as a cause of those differences. Reader “Galtonian” in the comments section on your post gives an interesting link to a paper showing high heritabilities for brain surface, which has obvious relevance to your study. Twin studies are informative, and their results have wide application.

I think that all these genetic studies should be part of your thinking about your findings. I said that you had “missed a trick”. Just one test result on the parents would have strengthened whatever conclusions you later came to in your paper. You say your study could not disambiguate the question of causality, but in fact your interpretive framework clearly and explicitly favours the environmental over the genetic. I am asking you to consider both, and to make that more apparent in your interpretations of your findings.

In parenthesis I should say that although I can find examples of good studies showing that intelligence measures outperform social class measures, I don’t think there is a meta-analysis of all the published studies. Together with Tim Bates I would like to collect a database of studies which include both social variables and intellectual measures so that we can check whether this finding (of IQ being a better predictor than social circumstances) holds true in all the relevant literature.

My reference to the other studies listed here is not meant to bludgeon you, but to reveal the findings which I rely upon for my arguments. (I do not pretend it is an exhaustive list, merely some exemplars I can recall). Richard Feynman once remarked that psychology differed from physics in that psychologists weren’t particularly bothered with confounders even when publications showed they were present (he gave an example from animal learning which revealed an experimenter artefact). Physicists, on the other hand, stopped what they were researching until they had ironed out the measurement and interpretative imperfections. I know that psychology is different from physics, but his insight made me smile ruefully.

Now a few comments on your upcoming intervention study. Showing any effect experimentally would be great. I expect you will find some effects. However, virtually all intervention studies with developing children throw up positive results in the early stages. By age 17 the effects tend to be smaller or disappear. The follow up will be the test, and you might have to wait 10 years for that, which is the peril of these studies, before saying the intervention was “definitive”. Few interventions achieve that status. The Abecedarian project had to wait 23 years for a full evaluation, and Ramey told us in 2013 that he would be repeating the experiment, and that every child would have brain scans and a full genomic analysis. (I don’t know the state of progress at the moment). I assume, given funding, you will collect genetic samples from both children and parents. If at some stage you can send me the protocol, or just an outline of the experimental set-up, that would be good. I point out that though you say: “Both cognitive ability and socioeconomic status have significant heritable and environmental components, and our study was not designed to address the question of their relative balance” the hypothesis you are about to test in your intervention study is entirely about the environmental component of cash payments to families. I have a suggestion below.

In sum, it seems we are still wide apart on the central issue, which is that the heritability of behaviour and abilities should be a standard part of the interpretation of children’s development, and that more data needs to be collected on the abilities of parents. Even now, in your intervention study pilot, why not give parents and children the WORDSUM test or something like that? It is very quick and pretty crude, but much, much better than nothing. You could see if this measure of parental intelligence helped predict the outcome of your interventions, and whether it did so more powerfully than the usual demographic variables. You would also be able to compare your sample with US SES norms on vocabulary. Given a bit more time, your assessment of parental intelligence could be more detailed, allowing you to compare the predictive power of class and intelligence on a common format.

It is not too late. Don’t hesitate: test the ability of the parents!

Best wishes


Friday 17 April 2015

Income, brain, race: Prof Kimberly Noble replies


Dear James,

Thank you again for sparking a thoughtful discussion on the paper. Below I will try to address some of the points you raise.

You are of course correct that the PING study is not – and was not designed to be – an epidemiologic or representative sample. Like much university-based research in the behavioral and neurosciences, we miss out on those who choose not to participate in research or who were who were never recruited in the first place. This is mitigated slightly by the relative socioeconomic, geographic and racial diversity in our sample, relative to most other similar studies. A true representative sample in brain research is challenging as it requires neuroscientific expertise to be available wherever participants are recruited. In practice, studies have to take place where the scanners are. But I agree in principal that an epidemiologic sample of brain development would be informative indeed, and well worth funding.

The original PING study ( was not designed with questions of SES in mind per se. As such, family income and parent education data were collected, as you point out, not as actual figures but in categories. While this is not how my lab chooses to assess socioeconomic factors in our studies employing primary data collection methods, this paper was a secondary data analysis, using the best dataset in existence to address the question of SES disparities in brain structure. It is, unfortunately, the sample we have, and comes with these inherent limitations.
I believe your larger concern, however, is the treatment of environmental and genetic mediators the observed effects. You write, “It seems to have escaped notice that the apparent SES/brain link might both be driven by a common factor of inherited intelligence.”

From the results of this study, we were unable to make any conclusions as to whether the observed effects were driven by genes, experience, or their interaction. We state this in our discussion: “Furthermore, in our correlational, non-experimental results, it is unclear what is driving the links between SES and brain structure.”

Paragraph 3 of the discussion then goes on to discuss possible environmental links (of which we measured none), and paragraph 4 discusses possible genetic links (of which we measured one).

From paragraph 4: “Notably, our results can only speak to the effects of GAF [genetic ancestry factor], a proxy for race. Thus, although the inclusion of genetic ancestry does not preclude the possibility that these findings may reflect, in part, an unmeasured heritable component, it reduces as far as possible the likelihood that apparent SES effects were mediated by genetic ancestry factors associated with SES in the population. Furthermore, associations between SES factors and brain morphometry were invariant across ancestry groups.”

You write: “There is a mention of ‘an unmeasured heritable component’ but it is then dismissed because the SES and brain measure relationships were invariant across racial groups. That is a different matter.”

Of course that is a different matter! The first sentence you refer to was a recapitulation of the finding that there was no main effect of genetic ancestry, and the second was meant to stress that neither were there any SES x genetic ancestry interactions. We simply cannot comment on other heritable factors because we did not measure them.

One thing in your commentary I find unclear. You state that we “could have given the parents the psychometric test battery for good comparability.” However, parent cognitive ability is, of course, itself influenced by both genetic and environmental factors, so it is not clear to me how this would have disambiguated this question of causality. Both cognitive ability and socioeconomic status have significant heritable and environmental components, and our study was not designed to address the question of their relative balance. Parent-child genes are correlated, but so are parent-child environments. Incidentally, scanning the parents would not solve the problem either, as parental brain morphometry would be both genetically and environmentally influenced, as well.

The bottom line is that, to truly establish the direction of causality, we need a random experiment. I am pleased to be part of a team of social scientists and neuroscientists in the US who are planning just that. We are currently piloting and fundraising for a large study in which a sample of low-income mothers will be randomized upon the birth of their child to receive a large or small monthly income supplement. We then plan to follow the families longitudinally to estimate the causal impact of an unconditional cash transfer on children’s cognitive, emotional and brain development. While this won’t answer all questions, it will provide definitive evidence on the extent to which young children’s cognitive and brain development is affected by poverty reduction.

Best wishes, Kim

Kimberly G. Noble, MD PhD
Associate Professor of Neuroscience and Education, Teachers College, Columbia University
Assistant Professor of Pediatrics, College of Physicians & Surgeons, Columbia University

Thursday 16 April 2015

Credit, where credit is due, to Lyndsey Layton

After the “poverty shrinks children’s brains” paper in Nature Neuroscience, I thought that once again in my blog I was setting the record straight, but only to my esteemed, select and highly refined readers, and to no one else. Naturally, I cherish my audience, but I cannot help but hanker for a stadium full of cheering fans, chanting “Avoid confounding variables”. Ian Deary, an actual rock-star psychologist, could probably suggest something more anthemic.

As per usual, I offered the authors the right of reply (which I normally post up without further comment) and had a friendly exchange with the lead author, to whom the blog is of course still open, without rush or deadlines.

Then a strange thing happened. I was contacted by Lyndsey Layton (@lyndseylayton)  of the Washington Post who had covered the original paper. She said she wanted to write a follow on story in greater depth. As far as I recall, this is only the second or third time that a main stream publication has contacted me on an intelligence related story. Lyndsey conducted a good interview over the phone, noting my points and correctly recording what I had said.

It has appeared in the Washington Post today.

A small step for a blogger, a giant leap for education.

Wednesday 15 April 2015

In the beginning was the Word


Words can be repeated easily, but are understood with more difficulty. The sense must be determined partly by context, and then the specific function of the word refined by closer examination of how it is used, and how it differs in meaning from other similarly functioning words. Listen, repeat, guess, venture a usage, test, refine, test, utilise. Search for meaning, not noise; reduce uncertainty rather than increase it. Concepts, not tropes.

Thus the word stores of individuals vary: not all people will be able to use precision instruments, or even see the need for them. 40,000 tools is a lot to carry in a brain. A passable job, rough and ready, can be achieved with 9,000. Vocabulary stores are good predictors of general ability, and their high storage cost must be worth it.

Looking across generations is harder. My brothers and I laughed at my grandmother for referring to a drinking glass as “a tumbler” and mocked her for insisting such vessels always be placed on a lace doily, so as to leave no ring marks on the dining table. Testing contemporaries on dated usages is unfair. Does that mean we cannot determine anything about the vocabularies of today compared with those of our grandparents?

I was pondering these weighty matters when once again the familiar urchin messenger boy arrived with yet another missive from the grand house of Woodley of Menie. I cannot be sure, but I think the miscreant boy calls on the under kitchen maid first, and only afterwards comes round to knock on the front door, which may account for his flushed countenance.

What Woodley and his dining companions Fernandes, Figueredo and Meisenberg have done is to tie together four disparate but crucially related aspects of vocabulary: the extent to which a word can be defined (intelligence loaded vocabulary test), the historical birth of the word (when it first shows up in dictionaries, which they call “word age”); levels of national literacy and the extent to which it is now used in written texts (Ngram usage measures 1850-2005). Crafty, this gang. Here are a few highlights before you look at the final corrections on the not yet finished proofs.

Michael A. Woodley of Menie, Heitor B. F. Fernandes, Aurelio José Figueredo and
Gerhard Meisenberg “By their words ye shall know them: Evidence of genetic selection against general intelligence and concurrent environmental enrichment in
vocabulary usage since the mid 19th century.” Frontiers in Psychology published: xx April 2015 doi: 10.3389/fpsyg.2015.00361

It has been theorized that declines in general intelligence (g) due to genetic selection
stemming from the inverse association between completed fertility and IQ and the Flynn effect co-occur, with the effects of the latter being concentrated on less heritable non-g sources of intelligence variance. Evidence for this comes from the observation that 19th century populations were more intellectually productive, and also exhibited faster simple reaction times than modern ones, suggesting greater information-processing ability and therefore higher g. This co-occurrence model is tested via examination of historical changes in the utilization frequencies of words from the highly g-loaded WORDSUM test across 5.9 million texts spanning the period 1850–2005. Consistent with predictions, words with higher difficulties (δ parameters from Item Response Theory) and stronger negative correlations between pass rates and completed fertility declined in use over time whereas less difficult and less strongly selected words, increased in use over time, consistent with a Flynn effect stemming in part from the vocabulary enriching effects of increases in population literacy. These findings persisted when explicitly controlled for word age, changing literacy rates and temporal autocorrelation. These trends constitute compelling evidence for the co-occurrence model.

The co-occurence model is the decidedly unsexy name given to the theory that Flynn effects and dysgenic effects co-occur. I call it “the leaky boats hypothesis” (Loehlin, 1997) : Flynn effect is the rising tide; Woodley effect the leaky boats.

In the West, up until the early to mid 19th century, those with high levels of socioeconomic status, wealth, and education (all of which are proxies for intelligence; Herrnstein and Murray, 1994) had higher numbers of surviving offspring relative to those with comparatively lower levels (Clark, 2007; Skirbekk, 2008), suggesting that higher intelligence may have conferred fitness advantages
on individuals having to cope with extremes of cold, disease outbreaks, and conflict (Woodley and Figueredo, 2013). Subsequent increases in global temperature, coinciding with the end of the Little Ice Age in the mid-19th century, reduced environmental harshness, boosting agricultural yields thus reducing ecological
stress and conflict (see: Zhang et al., 2007, 2011 for a demonstration of the inverse historical relationship between temperature and conflict). This would have substantially relaxed selection against those with lower intelligence (Woodley and Figueredo, 2013). This was coupled with advances in medicine (which would have included better means of fertility control, hygiene, nutrition, and medication; Lynn, 2011), and also social innovations such as welfare, mass schooling, and universal healthcare. The combined effect of these was a demographic transition characterized
by general reductions in fertility, which were most pronounced among those with higher intelligence (Lynn, 2011). This was mediated primarily by fertility control coupled with the increasing prevalence of opportunities to delay fertility (i.e., higher
education, increasing status competition, etc., which disproportionately attenuated the fertility of high-IQ.



As the authors say: More difficult words presented sharper historical declines in usage
over the 1850–2005 period, []words for which pass rates are more negatively
associated with fertility are decreasing in usage over time, which is consistent with those being the more difficult words []words that are both more difficult and for which pass rates are more negatively associated with fertility are decreasing over time.

It may be a minor matter, but I did my own little analysis, and find that word A is an outlier. It is very easy, and much more frequent than the other items: all the other words are rare by comparison. Every test needs to start with an easy item, but I wonder how much work this particular word does. However, even this very common word shows exactly the same trend as the other easy, but far less frequent words.

In sum, have Woodley et al. put another crucial piece into the dysgenic jigsaw? At the moment, it looks like it.

I sent the messenger boy off with his usual shilling, and noticed a certain impudence as he accepted it. Perhaps the under kitchen maid has been spreading false rumours about me, in her contumely way.

Sunday 12 April 2015

Antibiotics: a tragedy of the commons?


In his famous 1968 essay “The tragedy of the commons” Garrett Hardin argued that “freedom in a commons brings ruin to all”. In a nutshell, he proposed that there is an initial benefit to increasing one’s own herd, because even though the pasture is eaten down even further, each herd still increases in total yield, but there is a crushing delayed cost in that eventually the common land becomes a desert. Something has to give: individual needs or common resources.

Currently, the needs of individuals lead them to take antibiotics. Those who, in the rush to take something for a cold, or those living in laxer countries across the world take antibiotics as a matter of course as an over the counter drug, are the front runners of egotism. Despite my lay knowledge of antibiotic resistance, I have taken them, for a number of apparently legitimate reasons i.e. prescribed for conditions in which antibiotics were clearly indicated, and have followed the full course of the prescription. Nonetheless, there remains the possibility that I carry antibiotic-resistant organisms that I can pass on to someone else. Other persons, including persons more altruistic than me who have avoided antibiotics, may succumb to those organisms. So, our individual gains in fighting the bugs within us may lead to all bugs winning the war against us.

The sting in the tail is that, in our society, when a person is in dire need of an antibiotic they are probably in a hospital surrounded by other carriers of dire-need resistant bugs, and these are provided with an ideal breeding ground among immune compromised humans. Hospitals are in an arms race: strong and stronger antibiotics being deployed against stronger and stronger bacteria. “We can still always find something that works” said Hannah, the cheerful lady doctor in the casualty department in the small hours of the morning, faced with my fast-fading elderly relative with a pneumonia acquired at that same hospital earlier that week. Others in the casualty station who had come off motorbikes or had been involved in disagreements which had ended in bleeding eye sockets gathered round in companionable communality, exchanging jokes and accepting offers of mugs of tea. No green clad nurse required any of us to wash our hands, nor would it have made much difference. Call all hospitals the grand International Congress of Bugs that Bugger up Humans. I know that these bugs hold the original title deeds to the entire biome, but there is no real need to give them such strategic advantages.

In other writings Garrett Hardin made clear that, in his view, the tragedy of the commons had corollaries:

1 The commons must be protected: A community that renounces war as a means of settling international disputes still cannot survive without that discriminating form of altruism we call patriotism. It must defend the integrity of its borders or succumb into chaos.

2 The commons must be managed: A managed commons, though it may have other defects, is not automatically subject to the tragic fate of the unmanaged commons.

3 Ultimately the commons can only be protected and managed by force: All persuasion takes place through coercion, mutually agreed upon by the majority of the people affected.

4 Managing the commons requires managing fertility in the long term: Remember the competitive exclusion principle: if fertility varies in a population that is offered options in fertility, then as generations succeed one another, the pro-natalist elements in the population will, in time, displace the ones who conscientiously limit their fertility. If the world is one great commons, in which all food is shared equally, then we are lost. Those who breed faster will replace the rest. Sharing the food from national territories is operationally equivalent to sharing territory; in both cases a commons is established, and tragedy is the ultimate result.

5 Managing the commons requires the management of immigration: Controlled immigration becomes the default position of population policy. A heavy burden of proof falls on anyone who proposes doing away with border control.  In a less than perfect world, the allocation of rights based on territory must be defended if a ruinous breeding race is to be avoided. Overpopulation can be avoided only if borders are secure; otherwise poor and overpopulated nations will export their excess to richer and less populated nations.

As you will expect of me by now, I can put forward a strong counter-argument. First of all, medieval man was not stupid: commoners usually had well defined, circumscribed rights, and it was the breaches of those rights which caused particular commons to be stinted. The few remaining commons in contemporary Britain are covered by the Commons Act 2006 which protects against abuses. In current times global problems arise when the oceans are treated as unregulated commons. If fish are freely available, then the very biggest factory ships should hoover them up from the depths.

Although although our planet is finite, there is still scope to increase its productivity. Private land owners can use better land management, irrigate, use artificial fertilizer, and improve the genetics of the plants and the animals. As regards the more general issue of global public health, infections might be controlled by other techniques to attack bacteria, even if new antibiotics prove difficult to develop. The problem of the remaining commons might be ameliorated by requiring that prospectors pay for defined licences before they can draw on common resources like the oceans. It is the fact of these global resources being held “in common” which makes them liable to exploitation. Title deeds (private property) are the best protection against resource mismanagement (common ownership), because owners have strong incentives to preserve their capital, commoners less so. 

Even under current circumstances with still-rising populations and all the problems of warfare and local conflicts, food is winning out over hunger. It may seem that resources will always run out, but so far human ingenuity has provided for our needs. The stone age did not end because of a shortage of stone. Bronze replaced it. Malthus may be right in the end, but if humankind has sufficient wit, that end may be a very long time coming. In short, the brain might win out over the stomach and the genitals. My money is on intelligence, but it may be a close run thing.

Thursday 9 April 2015

Original paper (part 1) Emil Kirkegaard on brain size and poverty


When Ezra Pound was planning to write the primer which eventually became The ABC of Reading he intended to give no more than a collection of key readings without any further comment. Pound thought that his readers would get the drift of what good literature was about, and that explanation was superfluous. In that spirit, why not read Emil Kirkegaard’s publication just out out today:

The general brain factor, working memory, parental income and education, and racial admixture



Famously, Ezra Pound resiled from his minimalist position, and consented to make a comment or two about the exhibited texts, thus writing a classic of literary tutelage.

What I like about Emil’s paper is that despite being a very bright young guy he goes through data sets in the ancient and systematic way that AE Maxwell always championed: he looks at the data in detail, and gets to know what is there: the good, the bad, and the ugly. If, as in any real data set, there are lapses, quirks, anomalies and blank spaces it is well to know about them in advance, not jump to the towering castles of fancy statistics before surveying the whole terrain, and seeking secure foundations. I can follow his thought processes, even though I am not running as fast as he is.

Emil gives an erudite introduction, and draws out the relationships between the variables. He then deals with missing variables; the problems of adjusting for sex differences in brain size; the benefits of adding in cubed age to deal with residuals; the problem of there being no size measures for the children with which brain/body comparisons could be computed (Encephalization Quotient); the reasons for factor analyzing the many brain surface measures; lists the known association between brain measures and cognitive ability; notes that 11 regions were studied in the left hemisphere versus 8 in the right (which might unbalance the analysis of results); finds that brain size appears to increase till age 10 and then falls (?); then slogs through many factor solutions; showing that 4 factors offer by far the best, congruent solution; looks at the results for the Flanker distraction task (I would not have given this measure priority, because it is of less significance than mainstream intelligence), and that some children simply don’t understand it; looks at the working memory test; shows the memory test is more correlated with brain size; then looks at the core measures of education and income and finds slightly higher correlations for boys than girls; works through the racial admixture data; finds difference between different scanners…….. and then it is night in Denmark, and also night in England.

More is on its way, but this an argosy of treasures. I await his next findings.

Before I leave you, I would normally have said: “This paper should be published in Nature”, but we can’t really say now, can we?

I hope you will be impressed, as I am, by the company I keep. 

The wages of intellect

In an ideal world what one person pays another would be determined freely by both parties, and unless both were satisfied there would be no deal. In practice that freedom may be constrained by law. Indeed, those legal constraints may extend to what type of person you can employ and what wages you can pay. For those reasons, wages are a imperfect indication of earning capacity, but they are by far the best available.

Wages are only one part of income, since the latter may include tips, payments in kind and a whole host of benefits. These social transfers and outright payments tend to inflate the incomes of those who otherwise command only low wages in the open market. People like university teachers, who need all the help they can get from the public.  These provisos need to be borne in mind when we look at contemporary data linking IQ, income and wealth.

Steve Hsu posted up interesting data from the Bureau of Labor Statistics on the NLSY79 sample, a group brought to wider prominence by Charles Murray. Steve points out that the income figures at low ability levels appear to include benefit payments, so are probably not pure earnings.

Indeed, the NLSY79 website shows that Child Support, Alimony, AFDC Payments, Food Stamps, Other Welfare and SSI, Education Benefit/Grant, Disability, and VA Benefits are included. Since respondents often refused to answer financial questions, later surveys encouraged them by asking for a range of figures, and accepted estimates to the nearest $10,000. This will probably inflate lower wage levels and wealth estimates. There are larger problems due to stating household income without revealing whether the figures include the wife’s earnings, or those of other working household members. Per capita incomes can be low if the household has many children.

Nonetheless, accepting the imperfections which are part of any survey, we can at least put forward a rough estimate of the link between IQ and income and in the US in 2008.

Clearly, even at the 1st decile, US men in middle age are getting a good return on their abilities, better than the returns obtained by most citizens in most countries of the world. No wonder people want to make a life in A m e r i c a. To my eye the pattern looks like a straight line function, with perhaps an upturn for the 10th decile, which will include some very bright and men. As the Lubinski and Benbow data show, the very bright are very productive, and often very rich. Even among billionaires the brighter ones have more billions, so the benefits play through into the highest levels of ability.


Wealth by IQ has very different shape to it. Since these are middle aged men the estimates reflect about 27 years of accumulated spending and saving decisions. It is the real life acid test of deferred gratification. At first glance the brightest have become the richest, thus showing that the “IQ leads to wealth” argument has considerable support. That silly little pencil and paper test has revealed its full power three decades later. A “school far” test (at a distance from any particular school curriculum) has been shown to have very high “reality near” predictive value. Continuing that first glance, even the 2nd and 3rd deciles have little to their name, the next 5 deciles far more, and only the 9th and 10th have riches.

Now consider the picture from the point of view of relative accumulation, proportional to income. I am sure that the US tax system will have an impact on how much of the income remains for actual use, but I will skip that. Despite compensatory benefits, 1st decile men have only about 2 and bit years of income saved up. Average intellects in the 4th to 8th deciles are stuck on a plateau of about 4 years of income. To my surprise, 9th decile men are also at about 4 years worth of their somewhat higher incomes, and 10th decile men also at about 4 years of their even higher incomes.

So, here is a little factoid: by middle age most American men have no more than four years of income in assets. Post retirement lifespans may be 20 years. This is a poor show, unless the estimates have ignored personal and state pensions. However, you may think that 4 years of savings is enough. That is up to you.

Life is an IQ and Personality test.

Tuesday 7 April 2015

Digit span boosters?

It takes heroic amounts of practice to boost digit span, mostly by using chunking procedures (which themselves have to be learned) so as to improve the encoding of random number strings. There are better things to do in life. Digit span forwards is a measure of the length of acoustic memory trace that can be reported on before it fades. If you have the misfortune to number your digits in Welsh, then because the names of digits in that language are long, you will be able to fit in slightly fewer digits into the quickly fading memory trace. Digits backwards, of course, can be affected by the same variables, yet it is the additional  difficulty of that task which is particularly interesting, and not strictly relevant to these discussions about the increase in digits forwards since 1923.

However, it remains plausible that practising numbers in real life, like remembering telephone numbers, might have an impact on digit span forwards. Reader Richard Harper kindly sent me the Ngram for “combination locks”. Two can play at that game. Undaunted, I have immediately retaliated by adding in “telephone number” and “password” as comparable phrases, with the results shown below:



This shows that “combination lock” is, relatively speaking, nowhere. “Telephone number” became frequent in 1940 but after a steep rise began to fall by the millennium. Mobile phones allow names to be substituted for numbers, reducing memory load. The surprise is that “password” had been popular from the 1900s onwards, but the demanding, demeaning, insolent, insistent word booms after 1980, and becomes virally toxic just after 2000. Will no-one spare us from this pest? Mercifully, the agony is somewhat abating. Perhaps “iris” or that old standby “fingerprint” is responsible for saving us from the need to remember which unbreakable code we used to protect our bank accounts, payment systems, gas bills, electricity bills, mobile phone bills, google accounts, airline memberships, newspaper subscriptions, publisher’s login details, online supermarket accounts, amazon accounts, pension payment accounts, department store accounts, linkedin accounts, ISP accounts, anti-virus accounts, paypal, researchgate, ucl library accounts, science direct accounts, ebay accounts, squirrelmail, consumer organisations, and even places where you have once bought one random item, before sitting down to have a coffee near a wifi that will not let you in without a password, but will reject you once you give your email, because it is already taken by your former self, a slightly younger version who generated a password with insouciance, and never thought to write it down.

Personally, I doubt the demands of modernity have done much for digit span forwards. It is rarely a matter of life or death so the six or so generations since the rise of telephony will not confer any selective advantage. Gains may be due to general improvements in health and living standards. As regards passwords, I suppose it might be worth testing if alphanumeric recall had improved considerably between 1980 and 2000. However, I can think of a reason why recalling passwords will not have boosted any memory ability. A large section of the population, when asked to generate a password, obligingly choose “password”. Folk who resemble them in wisdom increase complexity by listing single digits in order of magnitude, no mean feat. Perhaps all these good people are very trusting, or cannot calculate probabilities, or simply have nothing to lose. A final word: digits forwards is only predictive when scores are low: high scores are less indicative of intellect. Rest easy.

Sunday 5 April 2015

Adolf Hitler responsible for Germanwings crash

The great advantage of fighting a world war is that, if you win, you quickly find out a great deal about the deposed tyrant. We knew more, and more quickly, about the deposed tyrant Hitler than his erstwhile confederate tyrant Stalin, whose secrets were opened up a decade later, and only partially, by his successor Krushchev, in a speech which remained secret for some years after.

When a tyrant falls it is perfectly natural to make a “never again” list, and if that list is too inclusive then it seems a small price to pay to avoid the rise of another beguiling tyranny. A wide list of “never again” resolutions in Germany included the steps taken to deal with the actions of Nazi doctors, who participated in what were originally presented as mercy killings, and then went on to become a model for for widespread killings as a matter of covert state policy. Robert Lifton chronicled these chilling matters in “The Nazi doctors” in 1986. id=bv8IAqVh8EAC&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

I reviewed it for the British Medical Journal in 1987, up against a very tight word limit despite the size of the book. Digging up that review from the BMJ archives 28 years later (in itself a mildly emotional event, because I had forgotten it)  I see that I concluded: “Lifton's book represents a considerable achievement. I believe that it should be in every medical school the world over, and that it would be fruitless to teach medical ethics without it.”

What conclusions did post-war German government draw about medical matters? Medical confidentiality was given an understandably highly protected status. The ministrations of the Gestapo in Nazi Germany and later the Stazi in East Germany were vivid reminders of the dangers of giving the authorities carte blanche to poke about in citizens’ private matters. Medical records can be very intimate. Doctors already have the authority to break the confidentiality vows if they feel their patient puts others at risk, said Frank Ulrich Montgomery, head of the Federal Chamber of Physicians recently. However, having the authority is different from having the habit of doing so when the public interest seems to demand it. As this debate gets started in Germany there have been the usual calls for the need to avoid hasty moves, with less discussion of the dangers of slow immobility.

One case, however terrible, should not overturn a general principle. Esteemed psychiatrists of my acquaintance assure me that the suicidal co-pilot would most probably have been picked up in the UK, and would not be anywhere near a cockpit, meaning that UK psychiatrists would have at least threatened to break confidentiality in similar cases, at least to the extent of saying to employers, if the person was unwilling to disclose his problems himself: “This person must not pilot an aircraft in his current state of health”. There are regulations and guidelines on these matters. However, these same UK psychiatrists think that, for entirely understandable reasons, Germany has taken medical confidentiality too far.

Here is a quick snapshot of some of the problems in monitoring pilots for mental health problems:

1) Detecting low frequency/high impact events is notoriously difficult. The false positive rate is very high, and it is difficult to maintain vigilance throughout the system because most of the time nothing happens.

2) Pilots are motivated to make light of their problems, or they will lose flying hours, income, and promotion. That puts the screening physician in the position of having to detect mental state and also to detect lying. This is not impossible, but rarely part of medical training. Clinical Assessment of Malingering and Deception Third Edition Edited by Richard Rogers is an essential reference.

3) Humans are mutative. If they are closely monitored they may become even more devious. As a consequence, airlines would have to ensure that there were very high payments for honesty, to encourage disclosure of all personal problems.

4) Crew members should inform management when a colleague seems mentally unwell, but that will put them under equal scrutiny, and is not conducive to crew teamwork, apart from the difficulties of spotting it anyway.

5) More intrusive monitoring might lead to more stress related errors.

James Reason of “Human Errors” used to say that error reduction was like a bathtub: errors fall right down and then, just as you feel safe, they start rising at the other end. Call it The Godel Limit: not every risk can be specified, and at some point the safety cost of protecting against a small risk becomes bigger than the benefit obtained. For example, having two persons in the cockpit at the same time will reduce single agent risks but may increase social distraction risks.

Juvenal was there first: Quis custodiet ipsos custodes?

Nonetheless, even if mental illness is assessed as occurring in 25% of the population, there is a strong case for recruiting pilots from the more stable 75% without a history of such disorders. Passenger safety is more important than pilot careers.

Another approach is to get rid of the pilots altogether. Planes can take off and land automatically at most airports, and level flight is pretty boring and routine anyway. Once we can get automatic systems to cope with frozen Pitot tubes, volcanic ash clouds, engine flame out, major storms and other such rare events, it could be autopilot all the way. Pity about the uniforms. The software would need to be good, and every programmer entrusted with upgrading the system would have to be subject to psychological screening………. It’s Juvenal all over again.

Finally, if you have read this far, please acknowledge the power of a headline.

Friday 3 April 2015

Digit Span bombshell

You may recall that I wrote with great enthusiasm about the wonders of digit span, describing it as a modest bombshell. It is a true measure: every additional digit you can remember is of equal unit size to the next, a scaled score with a true zero. Few psychometric measures have that property (a ratio scale level of measurement in SS Steven’s terms), so the results are particularly informative about real abilities, not just abilities in relation to the rubber ruler of normative samples. If there are any differences, including group differences, on such a basic test, then it is likely they are real.

Then last November Gilles Gignac dropped another bombshell. He found that if you looked at total digit span scores since 1923 there was not a glimmer of improvement in this very basic ability. This cast enormous doubt on the Flynn effect being a real effect, rather than an artefact of re-standardisation procedures. Gignac noted that digits forwards and backwards were in opposite directions, but not significantly so.

Later, I darkly suggested that another paper was in the offing, taking a different view of these data. Picture my pleasure when a barefoot messenger boy arrived at my humble cottage bringing a parchment missive with the unmistakeable seal of Woodley of Menie, the young inheritor of the great estate further North.

Young Woodley tells me that Gignac’s “substantial and impressive body of normative data on historical means of various measures of digit span covering the period from 1923 to 2008” reveals a hidden finding: the not-very-g-loaded digits forwards scores have gone up and the g-loaded digits backwards scores have gone down. This suggests that the fluffy forwards repetition task has benefitted from secular environmental gains, while the harder reversal task reveals the inner rotting core of a dysgenic society. Perturbed at these findings, I made sure that the messenger boy was kept outside, away from the under-maid, while I penned my reply.

Michael A.Woodley of Menie  and Heitor B.F. Fernandes (2015) Do opposing secular trends on backwards and forwards digit span evidence the co-occurrence model? A comment on Gignac (2015). Intelligence 50 (2015) 125–130

Woodley and Fernandes opine:  Gignac's (2015) observations are important as they add to the list of rarely considered cognitive measures the secular trends for which seem to defy the Flynn effect. These include inspection time, which, like digit span, seems to show no secular trends (Nettelbeck & Wilson, 2004), simple visual reaction time, which seems to show quite pronounced secular declines (Silverman, 2010; Woodley, Madison, & Charlton, 2014a; Woodley of Menie, te Nijenhuis, & Murphy, 2015; Woodley, te Nijenhuis, & Murphy, 2013b, 2014b) and also society-level indicators of cognitive capacity, such as per capita rates of macro-innovation and genius, which also indicate pronounced declines starting in the 19th century (Huebner, 2005; Murray, 2003; Simonton, 2013; Woodley, 2012; Woodley & Figueredo, 2013).

Woodley has proposed a co-occurrence model: losses in national IQ brought about by the higher fertility of the less intelligent exist at the same time as IQ gains brought about by more favourable social environments. “A rising tide raises all boats, but some are leaky”. More specifically, the dysgenic loss should be concentrated on g as dysgenic fertility and mutation load are biggest on more g-loaded subtests (Peach, Lyerly, & Reeve, 2014; Prokosch, Yeo & Miller, 2005; Woodley & Meisenberg, 2013a). Secular environmental IQ gains (i.e. Flynn effects) are concentrated on ability specific sources of performance variance (te Nijenhuis & van der Flier, 2013; Woodley, te Nijenhuis, Must, & Must, 2014c), thus narrow abilities should be increasing in parallel. Key to this is the observation that heritabilities rise with increasing g loading (Kan,Wicherts,Dolan,& van derMaas, 2013; Rushton & Jensen, 2010; te Nijenhuis, Kura, & Hur, 2014). Heritability may therefore mediate the effect of both dysgenic selection and related factors, such as mutation accumulation, and environmental improvements on IQ scores, concentrating the effects of the former on g and the latter on the specific variances of cognitive abilities.

Woodley and Fernandes have done a re-analysis of the forwards and backwards digit scores, using sample-size-weighted least squares regression. As befits his aristocratic origins, Woodley does not deign to make it clear what A and B stand for. In my role as interlocutor I can tell you that, for no particular reason, A = Backwards digits and B = Forwards digits. If only I had been consulted! Airliners have crashed due to such poor labelling, and operating table errors due to these baffling descriptions don’t bear thinking about.



In summary, digits forwards have increased somewhat, digits backwards have decreased. Woodley appears to have got another indicator of mild dysgenic trends.

Selecting the best scrap of paper I could find in the oaken desk, I acknowledged the kind communication of this intriguing finding, and bade Woodley of Menie a Happy Easter. I bestowed the same valediction on the messenger boy, plus the customary shilling, and sadly without the shilling, wish you the same.

Thursday 2 April 2015

Income, brain, race: more questions

I have been looking again at the Supplementary tables of the Nature Neuroscience paper “Family income, parental education and brain structure in children and adolescents”. The authors have used data collected as part of the multi-site Pediatric Imaging, Neurocognition and Genetics (PING) study (

The great problem is that this is not an epidemiological sample, so it is almost impossible to draw any solid conclusions from it. By recruiting “a coalition of the willing” you miss out the unwilling who, unless approached with care and some incentives, tend to avoid surveys, and are disproportionately more likely to have problems and get into trouble. The Dunedin birth sample has made all this very clear. Tracking a birth sample is a strong method: roping in bystanders a poor one. In particular, when recruiting minority groups you may end up with “the brightest and the best” who are better integrated, rather than the most needy, isolated and less able.  All of this is such a pity, because brain scans are expensive, and would have been a great addition to a properly constructed sample.

The education variable in this paper is a somewhat cruder composite than I had realised. As I had already said, this is not a fatal error, but it certainly means that a fine detail analysis of the lower and higher bounds of any education effect should probably be taken with a pinch of salt. Indeed, the coding system might under-represent educational effects at both ends of the spectrum. For example, knowing the actual years of schooling rather than “fewer than 7 years in school” might be particularly relevant for some recent immigrants. Equally, a little more power might have been achieved for all those at the higher educational level by trying to enquire how many of the qualifications were in the hard sciences, or from hard-to-enter colleges. None of this is a big issue of itself, but in my view the problem does not disappear in the later statistical treatment: it influences the results in ways which might somewhat underplay the effects of education.




The income classification is also too lumpy at the lower level. This is even more important to the thesis being examined by the authors. At low incomes every extra dollar counts. As far as I can see the authors simply had to take over these classifications, but it underplays the possible effects of very low incomes. As a general rule, income effects show strongly diminishing returns, and it would be good to know what the precise shape of the function looks like at lower incomes if more fine grain detail was available. Again, not a fatal error, but it makes life harder for what the authors are trying to show.


They continue: we investigated associations between socioeconomic factors (parent education, family income) and surface area, adjusting for age, scanner site, sex and genetic ancestry factor (GAF; Table 1). In all of the analyses, we took care to examine the unique and overlapping variance in brain structure attributable to distinct socioeconomic factors.

That is to say, genetic group differences are adjusted out, so an actual source of difference in brain size is removed from the regression equations, though it still exists in reality. The authors use genetic analyses to get rid of racial variance so as to obtain what they see as being a purer measure of socio-economic status.

With an average income of $ 97,640 these families are very wealthy in global terms. The authors do not mention it, but U.S. real (inflation adjusted) median household income was $51,939 in 2013. The distribution is skewed so the figures are not comparable, but it seems this sample was richer than the US average, which often happens with volunteer samples (they can afford to contribute to something they value). They are at the 80th percentile in the US. Rich, in anyone’s language. So, if there are effects due to absolute poverty per se, they would be shrinking the brains of most of the global population.

Table 2 reveals a highly significant finding for brain surface and the African group:

GAF African       Beta −0.213   t   −7.731    p  <0.001

That holds true for Model 1 (depicted) and Models 2 and 3. No other racial group stands out to this extent in their set of analyses, as far as I can see.

After trying various adjustments, the authors say:

Specifically, when adjusting for age, age2, scanner, sex and the 20 PCs, parental education was significantly associated with surface area (β = 0.152, P = 0.021, F(37, 1060) = 20.34, P < 0.001, R2Adjusted = 0.395; Supplementary Table 1). Similarly, when adjusting for age, age2, scanner, sex and the 20 PCs, family income was also significantly associated with total surface area (β = 0.183, P = 0.005,
F(37, 1060) = 20.94, P < 0.001, R2Adjusted = 0.402; Supplementary Table 2).

Comment: If you see parental education as a rough proxy for parent’s intelligence, and parental income as another, probably weaker, proxy, then this makes sense. Brighter parents have brighter children, and this study shows us that brighter children have bigger brains.

As you will be aware, I am blessed with a sharp-minded readership. One reader Franklin D Madoff spotted far more material than I did in all the supplementary spread sheets, and another  reader Emil OW Kirkegaard has very quickly crunched that data and will work on it further before posting it up himself early next week.

Emil says: The sample appears to be heavily selected for cognitive ability; participants may have been selected from university neighbourhoods, which would explain why performance scores and incomes are high; the actual results may reveal a general factor of brain size, and there are some interesting other findings on the sub-groups.

I would demand more of him, but Emil tells me that despite the obvious pleasures of data analysis he has a social engagement tonight, and I would not dream of standing in the way of Danish conviviality, which I so recently experienced first hand a few days ago in Copenhagen. Happiest country in the world, according to global surveys. It is a pity this important finding was not made known to Emil’s distant ancestor, Soren, who cheerfully observed:

Since boredom advances and boredom is the root of all evil, no wonder, then, that the world goes backwards, that evil spreads. This can be traced back to the very beginning of the world. The gods were bored; therefore they created human beings.