Wednesday, 20 May 2015

Gone with the Wind


Every now and then a blockbuster paper comes along which, like the 1939 top grossing $1,640,602,400 movie “Gone with the Wind”, carries all before it. It may be that “Meta-analysis of the heritability of human traits based on fifty years of twin studies” by Tinca Polderman, Beben Benyamin, Christiaan de Leeuw, Patrick Sullivan, Arjen van Bochoven, Peter Visscher & Danielle Posthuma in Nature Genetics is such a paper. Although the title is not very snappy, it is a relief to read a paper on genetics where the author list is less than a thousand. This Magnificent Seven have ploughed through fifty years of twin studies to assemble 14,558,903 partly dependent twin pairs drawn from 2,748 publications. After all these monumental labours, perhaps their publication may yet get known as the “Gone with the Wind” paper, because it blows away much confusion, much prevarication and much obfuscation about twin studies.

Nature Genetics (2015) doi:10.1038/ng.3285

The authors find that estimates of heritability cluster strongly within functional domains, and across all traits the reported heritability is 49%. For a majority (69%) of traits, the observed twin correlations are consistent with a simple and parsimonious model where twin resemblance is solely due to additive genetic variation. The data are inconsistent with substantial influences from shared environment or non-additive genetic variation. (This finding has been under-reported).

All human traits contain a substantial heritable element. The blank slate is totally false. If you have colleagues who doubts the twin method or who have difficulty accepting the power of ancestry, shall I repeat for them Rhett Butler’s last words to Scarlett O'Hara right now, or is it better that I tell you a little more about the findings?

I expect you have an interest in the results on cognition, so rest easy, heritability is high, though not as strong as for skeletal, metabolic, ophthalmological, dermatological, respiratory, and neurological traits. Usually there is a big difference (top line of figures) between the high correlations for monozygotic and the lower correlations for dizygotic twins, showing a strong genetic effect. The exception is social values, in which the environment makes a bigger contribution than usual, though not quite as big as heredity.





Cognitive traits correlate 0.646 in identical twins, 0.371 in fraternal twins, with miniscule error terms of .01 in these enormous samples. An additive model seems appropriate for cognition.

They conclude: Our results provide compelling evidence that all human traits are heritable: not one trait had a weighted heritability estimate of zero. The relative influences of genes and environment are not randomly distributed across all traits but cluster in functional domains. In general, we showed that reported estimates of variance components from model-fitting can underestimate the true trait heritability, when compared with heritability based on twin correlations. Roughly two-thirds of traits show a pattern of monozygotic and dizygotic twin correlations that is consistent with a simple model whereby trait resemblance is solely due to additive genetic variation. This implies that, for the majority of complex traits, causal genetic variants can be detected using a simple additive genetic model.

Approximately one-third of traits did not follow the simple pattern of a twofold ratio of monozygotic to dizygotic correlations. For these traits, a simple additive genetic model does not sufficiently describe the population variance. An incorrect assumption about narrow-sense heritability (the proportion of total phenotypic variation due to additive genetic variation) can lead to a mismatch between the results from gene-finding studies and previous expectations. If the pattern of twin correlations is consistent with a substantial contribution from shared environmental factors, as we find for conduct disorders, religion and spirituality, and education, then gene-mapping studies may yield disappointing results. If the cause of departure from a simple additive genetic model is the existence of non-additive genetic variation, as is, for example, suggested by the average twin correlations for recurrent depressive disorder, hyperkinetic disorders and atopic dermatitis, then it may be tempting to fit non-additive models in gene-mapping studies (for example, GWAS or sequencing studies). However, the statistical power of such scans is extremely low owing to the many non-additive models that can be fitted (for example, within-locus dominance versus between-locus additive-by-additive effects) and the penalty incurred by multiple testing. Our current results signal traits for which an additive model cannot be assumed. For most of these traits, dizygotic twin correlations are higher than half the monozygotic twin correlations, suggesting that shared environmental effects are causing the deviation from a simple additive genetic model. Yet, data from twin pairs only do not provide sufficient information to resolve the actual causes of deviation from a simple additive genetic model. More detailed studies may identify the likely causes of such deviation and may as such uncover epidemiological or biological factors that drive family resemblance. To make stronger inferences about the causes underlying resemblance between relatives for traits that deviate from the additive genetic model, additional data are required, for example, from large population samples with extensive phenotypic and DNA sequence information, detailed measures of environmental exposures and larger pedigrees including non-twin relationships.

By all standards of academic debate, this is the mother of “F*** Off” samples, which should lay low five decades of quibbling about the twin method. Author Beben Benyamin has given reassuring interviews saying that it is not a case of “genetics versus environment” but genetics with environments (which was always understood by researchers). The genetic component is increasingly understood, the environmental component remains vague, with ad hoc speculations about shared variance which are usually not validated.  Despite this massive paper being reported in The Guardian (though without drawing attention to the findings on cognitive ability) I fear that many journalists, commentators and researchers, in the attributed words of a British Trade Union leader turning down a management offer he considered too low, will treat it “with a complete and utter ignoral”.

Where do the heredity sceptics go now?

"Frankly, my dear, I don't give a damn"

Monday, 18 May 2015

Are academics open to hypotheses?

I once attended a garden party and found myself next to Kate Adie, a notable BBC reporter who had covered the Iranian Embassy siege in London, and then subsequently a wide range of international affairs, mostly in war zones.

At this particular time the big domestic story was the surge of a group of 121 children in Cleveland, UK who had been diagnosed as having suffered sexual abuse at the hands of their parents or relatives.  This was based on a particular, non-standard, diagnostic procedure called the “anal dilation test”. Opinion was split between those who doubted that so many parents and care-givers would bugger their children, and those who felt that child abuse was widespread and unacknowledged. The local authority believed the test was sound and removed the children from their parents, and put them into social care. A purely scientific approach would have been to be open to the hypothesis that child abuse might be more prevalent than previously estimated and then looked at the supporting evidence in a critical light. What was particular about the case was the extremely elevated estimate of anal intercourse implied by the test administered by two paediatricians. Anyway, at the parents eventually obtained a court judgement that the children could come home.

The BBC, Kate Adie said, had just put this as the lead item on the news as “Children re-united with their parents”. I thought about this, and it seemed a perfectly fair description to me. “Although I am not on duty” Kate continued “I rang up the news desk to correct them”. I was still bewildered, but kept listening. “The News should have said ‘The children were returned to their parents”. Finally, the penny dropped. We would not have said “The children were reunited with the paedophiles who had been abusing them”. “Returned” was factual, “re-united” implied a happy family, and that it had been wrong to take the children from their families.

Leaving aside the later knowledge that the supposed diagnostic test was deficient, this revealed to me the power of unexamined assumptions. Bias is most powerful when it seems reasonable and universal. In social science most researchers and most of the student audience share particular assumptions about society, about causal variables and even about values. In American academia, the most influential in the world, about 80% are of Liberal persuasion.  From a high minded perspective this should not matter, because methods should be strong enough to counter all assumptions. If researchers are open to all hypotheses, then all explanatory possibilities will be examined with equal rigour and rectitude. However, that is not always the case.

Much of the literature on maternal deprivation made light of possible genetic confounders. Some of the developmental literature avoids genetic group comparisons. As far as I know, no one is repeating Dan Freedman’s observational work on neonate behaviour, showing profound differences in behavioural reactions in the first days of life.

Friday, 15 May 2015

The (diminishing) kindness of strangers?


Speaking of the moral sense and the social virtues of humans and other animals, and discussing social and moral faculties specifically in the context of the human social evolution, Darwin used a number of words to describe noble sentiments: aid, courage, duty, fidelity, heroism, kindness, obedience, patriotism, self-sacrifice and sympathy. Assuming that people retain their altruism, one would expect them to continue to use these words in their written texts: books, newspapers, articles and the like. The words are well established in the language, and not the fruits of recent and passing fashions, so if strangers still value kindness, then the word “kindness” should continue to be used in written language. Are these altruistic words still used?

AJ Figueredo and colleagues have dipped into Google Ngram to test the hypothesis that between 1850 and 2000 “eminence”, a relatively rare combination of genius and altruism, was selected for in the process of inter-group competition and selected against in the concurrent process of inter-individual competition. They propose a multilevel selection model in which they expect to find associations at the aggregate level between higher levels of cognitive intellectual abilities and natural behavioural dispositions that are costly to the self but beneficial to others, in other words “altruistic” as defined in evolutionary theory.

Henry Harpending observes that Figueredo and Woodley propose that selection on intelligence within and between human groups works in opposing directions. Between group competition, especially in the context of hard times, favours groups with high genotypic IQ, especially innovators with IQs beyond 140 or so. Easier times relax this selection within groups leading to genotype IQ decline.

The multi-level model distinguishes between words (or tasks) which are “Hard”  theoretically indicating heritable general mental ability (g.h)  and words (or tasks) which are “Easy” theoretically indicating environmentally-influenced specialized mental abilities (s.e).



The dysgenic hypothesis proposes that after the Great Exhibition in 1851 the age old rule of brighter and wealthier parents having more surviving children was reversed. Will this result in less altruism, less general intelligence, and the rise of environmentally driven specialised abilities? So it would seem:





Read the whole thing here:

Thursday, 14 May 2015

Marginal tribes, disparate outcomes

There are two genetic/cultural groups who constitute minorities in Europe. For various reasons they were kept at the margins of society, made liable to restrictions in terms of the trades they could follow, and often hounded and maltreated. In the 20th Century both were slaughtered by German National Socialists.

One of those tribes is well known and highly accomplished, the other less well studied, and with far fewer accomplishments. The contrast is striking. However, explaining that difference must wait for another day. At this point we need to get a better understanding of the abilities of the less well studied tribe, particularly since studies on their abilities are often not published in English, the de facto language of Google science.

I have covered the topic before,

but the London Conference paper brings things more up to date, and carries out a formal meta-analysis.



Dalibor Jurasek has found 38 usable datasets from 7 countries, resulting in a total N = 4468. He concludes that the best estimate of Roma intelligence is IQ 74. This is extremely low. There does not seem to be any verbal bias in the tests; there is weak or no Flynn effect; Spearman’s rule seems to hold.

Below you will find his Powerpoint presentation and, in a move which I hope many speakers will follow, his speaker notes, which give further particulars.

Now we can start working on why the Roma and the Ashkenazi differ in their accomplishments.

Wednesday, 13 May 2015

Hairs on your chest: Androgens and intellect




Continuing the series on selected papers from the 2015 London Conference on Intelligence I am testing the power of an arresting image, as used by Ed Dutton in his presentation: Population Differences in Androgen levels: A test of the Differential K theory.

I should point out that the fine figure of a man above was neither a speaker nor a guest at the conference, but hair is an indicator of hormones, so examine the hairiness of the back of your middle finger before reading any more.

All species face a dilemma: is it better to have very many offspring, and hope that some will survive; or have a few and work hard to ensure that they survive? The first strategy involves lots of sex and not much parental involvement; the second less sex and much more parental investment. The Reproductive strategy leads to fast, “live for the moment” lives, the Konservative strategy slower, “live for tomorrow” lives.

Dutton argues that most of the data fits well with the r-k continuum, but points out anomalies regarding body hair, which against prediction is higher in European groups, possibly as an adaptation to mildly colder climates.

Read it all here:

Monday, 11 May 2015

Bringing Intelligence to Life (Today 5 pm)



OK, Dancing Mice won’t be playing at the Darwin Lecture theatre tonight, but that is only because their lead singer, rockstar Ian Deary, will be giving the 2015 Jonckheere Lecture.

The 2015 A. R. Jonckheere Lecture entitled 'Bringing Intelligence to Life'
will be delivered by Professor Ian Deary (University of Edinburgh) on Monday
11th May at 5pm in the UCL Darwin Lecture Theatre, followed by a reception
in the South Cloisters.

Professor Deary is one of the foremost international experts on  cognitive ageing and is the Director of the University of Edinburgh's Centre  for Cognitive Ageing and Cognitive Epidemiology. His books include 'Looking Down on Human Intelligence: From Psychometrics to the Brain' (2000) which  won the British Psychological Society's Book Award in 2002, and (with Whalley and Starr) 'A Lifetime of Intelligence' (2009).  The Lecture is hosted by the UCL Division of Psychology and Language Sciences.

The Lecture is free of charge and open to all staff, students and alumni.

Strictly speaking, this is a UCL event, but the thirst for knowledge is the beginning of wisdom, so in the unlikely event that anyone in the audience wonders what department you were in, say you were invited by James Thompson, Honorary Senior Lecturer in the Dept of Psychology and Language Sciences. They will probably look at you totally blankly, so just lower your voice and mutter “Psychological Comments”. That should suffice.

Sunday, 10 May 2015

London Conference on Intelligence 2015 Keynote

Never let it be said that our conference lacked ambition. There were two keynote talks. Michael Woodley gave a detailed exposition of his recent paper “By their words ye shall know them” but I had already covered that a few days ago. Heiner Rindermann launched a Gesamtkunstwerk entitled “Evolution versus Culture in international intelligence differences”. This tour de force included a summary of the hereditarian hypotheses, where in Heiner’s view the evidence was only indirect,  and also a very good exposition of religion as a cultural force.

Wednesday, 6 May 2015

Intelligence conferences test intelligence

You will probably be aware that getting myself to a conference tests my intelligence to the limit. Calculating how to coordinate the flights with the hire car and the hotel booking creates great consternation. The reverse process is just as challenging, particularly estimating when I will be handing in the car (usually best done before the departing flight takes off). The complexities of passports, currencies, tickets all conspire to confuse me, more so when different time zones come into play.

In contrast, staying in one’s home city and organising a conference should be easy. Language, currency and time zone are all set to one’s advantage. However, new tasks arise as an organiser, such as coordinating later arrivals with speaker’s timetables, organising the program so it looks as if it has a structure, and finding suitable eating and drinking venues for hard working, hard thinking colleagues, without bankrupting less well paid young researchers.

Hence, I have not be able to multi-task and attend to the blog whilst also making conference arrangements, so I will be quiet until the event starts, and then I will send you a few comments on each paper, together with the abstracts. Mind you, I am likely to get distracted by the papers themselves, and multi-tasking by blogging could be too much for me, so perhaps my silence will be even more prolonged. 

Finally, given that the United Kingdom is having a general election tomorrow, I thought that I would use the opportunity to link that event to some aspect of intelligence. That has proved hard.

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.