Thursday, 2 July 2015

Elijah Armstrong replies to JayMan


1) Verbal abilities are probably more relevant to educational attainment than other specific abilities, but g is by far the most relevant. It would be odd if the error only affected verbal ability but not measured g.

Incidentally, the LBC study –– if memory serves –– gave the children two separate IQ tests, one of these the 1937 Stanford-Binet, and Ritchie et al. also controlled for SES in their study of educational effects. Two full-scale IQ tests (though with a strong verbal bias) plus an SES measure jointly compose an immensely reliable composite measure of IQ. Still confounded by differential rates of maturation, of course.

2) Of course those are valid criticisms! But, as Sandra Scarr said of twin studies, the holes don't go straight through. Logically invalid appeal to authority here –– I doubt that any decent intelligence researcher today believes in zero or zero-ish effects of schooling on IQ (you excepted), although they might consider those effects hollow.
I don't want to sound condescending, but you really should read Ceci's 1991 paper on education and IQ.

What a priori reason is there to believe that schooling does not affect IQ? I can think of a few: zero shared environment on adult IQ, but substantial shared environment on total educational attainment; the lack of effects of compensatory education; the lack of effect of school quality on achievement, as measured by Coleman. Good arguments, to be sure. But I do not think they outweigh those I've listed above.

With respect to shared environment, suppose that educational differences in affluent countries account for 10% of total variance in IQ scores (probably too high) and that total years of education exhibit shared environmentality of 20%. Then the total amount of IQ variance that could be explained by education-related shared environment is 2%. (Add to this quality of nutrition and other factors, and you could get more. So 2% is conservative, by my argument. Maybe 5%?) You would probably know better than I whether behavior genetic knowledge can, at the present time, reliably distinguish a 2%/5% from a 0% shared environmental effect. I suspect so, in which case the education-affecting-IQ theory faces a real problem. As you know, though, when behavior genetic studies include families living in genuine poverty, there are inconsistent effects –– sometimes, but not always, the shared environmentality goes up.

A final argument: IQ tests contain obviously scholastic information, vocabulary, arithmetic problems, and so on. How likely is it that education does NOT affect these? We have good evidence, if I am not mistaken, that there is some shared environment effect on educational achievement scores.

3) Kindly post the Danish study. If that replicates, it would suggest adult educational gains to be hollow, perhaps limited to crystallized intelligence or verbal ability (as found by Ritchie et al.).

Suppose that gains do end up generalizing across tests, as with the Flynn effect. Could they still be hollow? Yes, if there are some sources of variance common to all tests but not shared by real-world criteria.

Motivation is one. The relatively rigid and sequential format of "test reasoning", relative to the messier and ambiguous forms of real-world reasoning, are another. (This distinction was drawn by Ulric Neisser, and used by Sternberg in his triachic theory.)

More research! More research!


Wednesday, 1 July 2015

Back to school: Elijah Armstrong writes


You may remember a previous post on whether being at school boosts intelligence.

Re-reading it now I recollect that there are strong papers suggesting a boosting effect on intelligence, yet I had remained dubious about the strength of the effects, and I would still like to see a long data set to confirm the imputed effects. If staying longer at school really boosts intelligence then there should be a discernable and sustained jump in ability from previous levels. My scepticism may be simply because I had followed the previous orthodoxy that schools boost knowledge and skills, but not children’s underlying intellectual horse-power. Intelligence is the engine, education the gears.

You may also recall another one of my quips, cast as a tweet: Academic debates should be punctuated by long moments of silence, broken only by pages turning as the combatants do the necessary reading.

As testimony to the inherent wisdom of this pronouncement, it was a delight to receive a further comment on “School” a mere 162 days later. We do not rush things here. Elijah Armstrong has a “Psychological Comments” VIP card and Executive Lounge entrance key, so it is a pleasure to post up his comments immediately.

Elijah writes:

Sorry for the very late reply, but as the issue is quite important I think a response is warranted.

Ritchie et al. find, in their regression analysis, that school exerts a strong effect on crystallized intelligence but not on fluid intelligence or chronometric g –– as one would expect. If their findings were really the result of measurement error, why don't they find spurious effects across the entire intelligence domain?
Further, this analysis dovetails with other studies using similar designs––studies of uneducated, isolated communities; of regression discontinuity designs; of the effect of closed schools, during desegregation, on the IQs of communities; etc.

Yes, these studies have flaws. Maybe the measurement error that contaminates the Ritchie et al. study was actually confined to the verbal/crystallized domain, or maybe it's a product of the fact that they only used verbal tests to assess childhood IQs. Maybe isolated communities really have low IQs because they're inbred or malnourished, not because they're uneducated. Maybe the schooling effects found using regression discontinuity designs don't persist into adulthood. But these are ad hoc explanations: in essence, degenerative science. The total evidence that schooling influences IQ is quite strong.

JayMan: you implicitly admit that schooling influences IQ, above, but claim that its effects are likely g-hollow. This is an interesting question. However, it should be pointed out that even non-g increases in IQ may be valid. We know this because TBI, foetal alcohol syndrome, prenatal cocaine exposure, and malnutrition all lower IQ –– and are often causes of genuinely low "intelligence" –- but the method of correlated vectors suggests that none of them are on g. Thomas Coyle has also shown that SAT and ACT residuals (controlled for g) are good predictors of performance in allied college majors.

Furthermore, there are specific abilities or sources of variance for every cognitive task that has thus far been studied, including "real-world" ones like job performance: there are no really pure measures of g; so it is at least theoretically possible to increase or decrease a huge variety of specific abilities but leave biological g untouched, and thereby increase "real intelligence". I think this is what the Flynn effect has done, and very likely it's what educational effects do as well.
But this is an open question.

Three good studies on the issue would be:

a) a study of the effects of schooling on a massive array of cognitive abilities, including every Stratum II in Carroll's taxonomy, plus on a large set of information domains (including non-academic ones like sport, fashion, agriculture, etc.), plus on psychophysical variables like brain size and neural conduction velocity;

b) a regression-based mediation study to see if educational IQ gains affect occupational status, mortality, crime, financial distress, income and net worth, all that good stuff (this one suggested to me by Stuart Ritchie);

c) thorough interviews and impressionistic assessments of uneducated people. (I was in Dominica early this year, where most people are quite unlettered and the average Raven's IQ is ~70, and they didn't seem that dumb at all. But I only rarely saw them doing complex or abstract tasks.)


Monday, 29 June 2015

Cheating in sport

Among the many outrages in this troubled world, cheating in sport may not be considered a matter of the greatest importance. During an international football match a week ago a Chilean player patted the backside of Uruguayan player Edson Calvani, and then stuck a finger up his bottom. Calvani responded with a flick of the back of his hand, and which point the Chilean fell on the floor, writhing in agony, and the referee then sent off, not the offending Chilean but the provoked Calvani. Since I know my readers to be earnest seekers after the truth, they will be horrified by this outrageous provocation, and by the gullibility of the arbiter. On the other hand, if by chance any passing readers are of more Machiavellian personality, and eschew rules in sports, then they will approve of the adroitness of the anal molestation and subsequent play acting by the perpetrator, which led to the diminished Uruguayan team losing 0-1.

What are the characteristics of cheaters in sport, that athletic activity in which fair play should be paramount? A description of psychopathic personality includes general
poverty of affect (emotion), defective insight, absence of nervousness, lack of
remorse or shame, superficial charm, pathological lying, egocentricity, inability to
love, failure to establish close or intimate relationships, irresponsibility, impulsive
antisocial acts, failure to learn from experience, reckless behaviour under the
influence of alcohol, and a lack of long term goals. Is any of this relevant to sports cheats?

Edward Dutton and Richard Lynn. Cheating in Sport and Racial Differences in Psychopathic Personality. Mankind Quarterly 2015 55:4 325-334.

The authors have looked at American Football (National Football League: NFL) players; American Basketball (National Basketball Association: NBA); and English Premier League Football (Soccer) players. They have studied two kinds of cheating, namely the use of performance enhancing drugs and breaking the rules of the game. In a black/white comparison they have looked at the proportions of each group in each sport, using a visual and biographical analysis of each of the sportsmen in the games to identify their race. They then calculated the percentages of blacks and whites identified as cheaters compared with their percentages among the players.

In the NFL black players in 2010 were over-represented in suspensions for drug use, for suspensions for more than 4 matches, for indefinite or entire season suspensions, and for being suspended more than once. A similar pattern was found for 2013.

In the NBA black players in 2013-2014 3 were somewhat more likely to be fined or suspended but the differences were not statistically significant.

In the English Premier League Football (Soccer) the authors studied the number of  red cards handed out from 2006 to 2013. Interestingly, many players receive prior warning in the form of a a yellow card for a minor offence, and thus know that they must be on best behaviour.


However, these are not overwhelming differences. There is an over-representation of black players, but only in the 2006-7 season.

I will not pretend that I know anything about the first two sports, and have only a layman’s understanding of football, so I am absolutely open to correction on any of these matters. Nonetheless, I would not be persuaded by these findings that there is a significant effect overall. I turn to those who are more engaged in sports to
either point out other studies or to suggest other data sets which could be examined for patterns of cheating.

So there you have it. Now back to the important matter. One devious finger up an innocent bottom, and Uruguay is unfairly cast out of the Copa America. I hope you will join me in demanding a replay. I am aware that one notable Uruguayan player has bitten opponents (and been suspended for his crimes) but if one cannot kick a football about of a Wednesday afternoon without unwarranted fundamental intrusion, what is the world coming to?

Tuesday, 23 June 2015

Working link to Crime and Intelligence paper

Some readers have pointed out that the link in the previous article did not work, so here is the fixed version.

Dull minds and criminal acts

I have always had a warm spot for cold Finland. The people are much friendlier than their prices, which tend to be either high or higher. The Finns have a habit of singing about their landscape whilst drinking sahti, but no one is perfect. I spent some happy midsummer days in Vaasa, near the Artic circle, the guest of Per Fortelius and family, meeting his friends, photographing the local architecture and doing some artic temperature wind-surfing.

Finland is the sort of place where they do things thoroughly, things like testing the intelligence of a total population cohort of Finnish males born in 1987 and following up the results. Gold dust.

Joseph A. Schwartz, Jukka Savolainen, Mikko Aaltonen, Marko Merikukka, Reija Paananen, Mika Gisslerd. Intelligence and criminal behavior in a total birth cohort: An examination of functional form, dimensions of intelligence, and the nature of offending. Intelligence, Vol 51, July–August 2015, Pages 109–118.

They found that lower levels of intelligence are associated with greater levels of offending, that the IQ-offending association is mostly linear, with some curvilinear aspects at highest and lowest levels, and that the pattern is consistent across multiple measures of intelligence and offending. In some ways this is exactly as predicted and already observed, since the available literature shows that individuals with lower IQ are more likely to engage in criminal behaviour.  Criminal offending was measured with nine different indicators from official records and intelligence was measured using three subscales (verbal, mathematical, and spatial reasoning) as well as a composite measure. The results show consistent evidence of mostly linear patterns, with some indication of curvilinear associations at the very lowest and the very highest ranges of intellectual ability.

However, the advantage of these data is that they deal with an entire birth cohort, so there are no distorting effects caused by the loss of a few miscreants who might account for lots of crimes. The population is restricted to males n = 21,513 because only males in Finland do military service and sit the intelligence tests. Offending is judged from real documentary data, not from fallible self report, even more fallible when painful memories are involved. Lastly, they have verbal, mathematic and spatial IQ measures, so can investigate whether verbal intelligence has a particular effect, as some have argued.

Here are the results, for general intelligence, and all crime:


Note that violent crime is an order of magnitude higher in the bottom 20% of the population by ability than the top 20% of population by ability. The pattern is generally a linear one. The subscales of intelligence show the same pattern, though perhaps the spatial scores show a slightly less pronounced differential effect.



So, why do dull minds carry out criminal acts? The main effect is driven by general intelligence, so that raises a number of possibilities, in that highly g-loaded factors such as deficits in executive functions, including inhibition, processing speed, and attention are potentially linked to criminal behaviour. People with higher levels of intelligence are more dependable ( Deary et al., 2008b) and conscientious ( Luciano, Wainwright, Wright, & Martin, 2006), suggesting that they are more likely to think about the moral consequences of their actions compared to individuals with lower levels of intelligence. People with lower intelligence have been found to act more impulsively ( de Wit et al., 2007 and Funder and Block, 1989). People with lower levels of impulse control and related constructs, such as low self-control, have also been found to be significantly more likely to engage in various forms of criminal and antisocial behavior ( Gottfredson and Hirschi, 1990,Moffitt et al., 2011 and Pratt and Cullen, 2000). While only preliminary, current research suggests that lower levels of intelligence reduces the ability to weigh the costs and benefits of individual action, resulting in a greater propensity to make impulsive decisions, which in some cases involve illegal behaviour.

It is a minor finding, but the dullest are not quite the most criminal, an honour reserved for those in the 2nd decile of ability. It may be that those in the 1st decile are slightly restricted in their behaviours by their very low ability, and may be under supervision from care givers.

Equally minor, there is a slight uptick for criminality in the most intelligent, though hardly the torrent of criminal master-minds beloved of popular entertainments.

The authors say: “low intelligence is a strong and consistent correlate of criminal offending. For example, the risk of acquiring a felony conviction by age 21 is nearly four times (3.6) higher among those in the three lowest categories (1–3) of total intelligence as compared to those scoring in the top three categories (7–9). We observed differences of similar magnitude across each indicator of criminal offending and regardless of the measure of intelligence. We found no evidence for the hypothesis that deficits in verbal intelligence are more salient to criminal offending than deficits in other dimensions of cognitive ability.”

The authors mildly point out that, strictly speaking, these results may be confined to Finland. However, an easy test comes to mind: have a look at crime statistics in your country, and work out, for example, whether the crime rate for those below the 30th percentile rank is higher than those above the 70th percentile rank, and how much higher. Or, look at the crime rate in your country for those whose ability is equivalent to Finnish 30th percentile or below, which would be Greenwich IQ of 92 or below.

For group differences within nations use Emil’s calculator on tail effects for group distributions:

For example, if IQ 92 is the point below which criminality increases considerably, then 30% of the blue group are at risk, and 68% of the red group. In this way one can model what levels of crime would be expected if IQ were the main cause. A hypothesis worth testing.

Monday, 22 June 2015

The Cuckoo

On the day following the Solstice, which should have ushered in high summer, the English weather instead served up an imitation of winter, punctuated by uncertain rain, cold winds and brief glimpses of ironic sunshine. Probably the ancient spirits of Stonehenge have been disturbed by the presence of druidic revellers, and their clouds of stupefying substances have upset the very astronomical events they had gathered to celebrate. Cowering under this disordered weather I was searching for a distraction when an esteemed person of my acquaintance peremptorily instructed me from her nearby study that I had to watch the Royal Society Croonian Lecture 2015 given by Professor Nicholas Davies FRS on “Cuckoos and their victims: An evolutionary arms race”.

Prof Davies lectures well. He understands that a general audience responds best to clear and uncluttered language, and he strives to explain rather than to impress or confuse: a noble but dying tradition. His findings are displayed in simple formats which require no explanation, and there is only one mention of the word “correlation” which is then given as “good” and without a tedious number. Proper statistics. Even better, he works within a well-demonstrated evolutionary framework, so he has a good theory to rely on, and can use experimentation to weigh up different explanations, and map out the battle between host and parasite in exquisite detail.

Seen from the viewpoint of the hosts upon whom the cuckoo predates, they are horrible, lethal parasites. With arriviste insouciance the fledgling cuckoos begins life by expertly throwing out of the nest the host chicks and the clutch of un-hatched eggs. It is born to be genocidal, and having usurped the nest is then fed to massive proportions by the deluded parents, their devotion like that of concentration camp prisoners slavishly handing food to their guards. One wants to shout to the deceived birds: “Look right in front of you: your blood line is dying out”.

Prof Davies shows each stage in the evolutionary arms race: female cuckoos are able to remove a host egg from an unguarded host nest, and lay their own egg in its place in 10 seconds, then fly away without a backward glance. Talk about absent mothers farming out their brood. Their eggs look like those of the host bird eggs, and thus are often accepted. Host birds have in turn evolved techniques to spot the imposter eggs, and older host mothers learn to look for signs of foreignness: egg size and colour differences, and are thus better at rejecting the invader DNA. Better still, host mothers  have evolved to “sign” their eggs with individual signals of colouration in complicated designs, the better to recognise their very own eggs and thus detect the odd one out. Cuckoos in turn have evolved to fake those signatures, and lay their forgeries in all nests, accepting a high rate of loss in return for high rates of acceptance in the few nests where they happen to achieve a close match.

Davies shows that the optimal acceptance/rejection rate for host birds depends on the parasite infestation level, and can show that when birds are moved from cuckoo-infested West Africa to a cuckoo-free Caribbean island the need for egg “signing” diminishes over many generations, and dies out. In places where the move to cuckoo free areas is more recent, the drift towards more similar eggs is less advanced.

Of course, birds are very different from primates, so we should allow ourselves some monkey snootiness, but evolution applies to all species. Did you, like me, identify with the host birds, and hate the parasites? Davies, quite understandably, speaks of Cuckoos and their “victims” but these are very human interpretations. In the light of evolution the cuckoo is as opportunist as any organism should be, if they want to flourish. The cuckoo is the itinerant chancer, the picaresque swindler living off the stupidity of the locals, who deserve to die out for their misplaced altruism, ripe for the plucking. Cuckoos outwit the trusting locals, are better at deception, and keep ahead by recruiting them into acquiescing in their destruction, outbred to death. From an evolutionary point of view, they are fit, very fit, until the hosts learn how to retaliate.

Host birds mob intruding cuckoos, which can scare them off, and certainly raises a hue and cry which warns other local birds that there is an interloper on the genetic prowl.

At that point the cuckoos have evolved new strategies, making their plumage ape that of acceptable birds. And so it goes on, and endless battle in which, as Lucretius says (in De rarum natura):

Some nations increase, others diminish, and in a short space the generations of living creatures are changed and like runners pass on the torch of life.

Friday, 19 June 2015

Half a Million or simply 500,000?


The “metric shift” illusion is a common ploy, particularly when someone has an axe to grind. “If everyone were to switch off just one light bulb, we could close a power station”. (Marvellous, but how many power stations are there? A small reduction in power consumption will lead to a small reduction in power generation, and not a kilowatt more than that). “Just one penny of tax will raise X million of money for good causes”. (Bless, but removing an additional penny from each pound of income will take a large amount of earnings from every citizen, and they probably regard their own choices as better than bureaucrats’ choices). “An enormous number of citizens are diagnosed every year with Horrible Disorder X”. (My sincere commiserations, but either give me the total numbers for all other disorders, or just give me the rate per 100,000 so I can put all disorders in all nations onto a common metric. Also, “diagnosed” is not equivalent to “about to die from”).

So, seeking to impress readers and recruit more of them, should my boast be that Psychological Comments has achieved 500,000 readers or that it now stands at Half a Million readers? I assume that the word “million” has a dramatic impact, but “half” does not have quite the same ring to it. It clearly indicates incompleteness, with much left to be achieved. True. Sticking to the bare numbers gives the appearance of due modesty and, as everyone across the world knows, the English have much to be modest about. I will restrict myself to simply 500,000.

Even conceding that we are talking about the common metric of page views, not the more important and elusive metric of actual readers, there seems to be some quickening of pace

0                23 November 2012             -

100,000     12 January 2014           415 days

200,000     4 July 2014                   174 days

300,000      6 November 2014        126 days

400,000     17 March 2015              131 days

500,000     20 June 2015                  96 days





The notable performer in this last period was “Gone with the Wind” a meta-analysis of twin research, which took second place in blog history in a matter of a week or two, displacing some of my well-established popular posts. The other big performer was the post on income, brain and race, which was boosted by a mention from Steven Pinker. Poorer children have smaller brains, but very probably not because they are poorer.

A word about blogging’s noisy younger brother: Twitter. To my shame, when I had an early adopter’s first fling with blogging and tweeting in 2009, I abandoned both within two weeks. There seemed to be no audience, and I certainly did not see any reason to tweet about my blog, because all the academics I knew were on email, not on Twitter.

Now Twitter has become a familiar gateway to my blog and also a terse conversation in its own right. This is not because of the number of followers, which even by a psychologist’s standard is a lowly 1,100 but because of their loyalty and impact. They re-tweet quickly, comment, and direct me to new work. The standard Twitter Analytics records that in the last 28 days my 289 tweets have been seen 210,000 times, garnering 452 re-tweets and triggering 6,121 visits to have a look at my profile. My 3 tweets per day get 16 re-tweets and 23 favourites.

Twtrland rates my daily 3.1 tweets as just “average”, my getting 99 re-tweets per 100 tweets as “popular”, and my responsiveness as “chatty”.

Of more interest is tweets ranked by re-tweets. In pole position is a graph of effect sizes for early childhood interventions: 58 RTs. The last three (truncated at the bottom of this screen grab) are 21, 21 and 18 RTs respectively.


My blog readers are 77% of them below 35, which is gratifying.

According to more restrained observers, page views are an inflated measure, counting both robots and visitors who leave after 10 seconds, never to return. On the contrary, perhaps page views is a much better measure of what has been read than “number of readers” and certainly better than number of books on a shelf. Glancing even at my diminished store of books there are several I have not read, and others I have read only partially. Interesting if every book recorded and displayed exactly how many of its pages had been read. So many bookcases could be cleared of their surplus content, the virginal tomes discarded like spinsters, remaindered in ignominy.

I digress. The milestone is history, already surpassed after having been recorded. I really ought to go back to three papers which are half-read and awaiting comment. But the sun is shining, so I will consider the dilemma while having a coffee in the garden.

Thursday, 18 June 2015

The Dolezal ambiguity


The Rachel Dolezal story seemed too silly to comment on, but silliness thrives if left unchallenged.

A white woman in the US has pretended to be a black woman, lied on her application forms, and risen to represent a local chapter of the National Association for the Advancement of Colored People. She has mendaciously presented an unrelated older black man as her father and a younger black man as her son. She says she “self-identifies as black” and when asked precisely when she began to deceive people about her ancestry she replied:“I do take exception to that because it’s a little more complex than me identifying as black, or answering a question of  ‘Are you black or white?’  She also described herself as “transracial” and said: “Well, I definitely am not white. Nothing about being white describes who I am.”  She was in fact born to white parents, married a black man and had a child with him and later divorced, and had attended an almost all black college where, reportedly, she complained that as a white woman she was not treated fairly.

In her mitigation, her parents had adopted 4 black children, so she must have concluded that either her parents were very kind people in the public and general sense of that word, or very unkind parents in a very personal sense, and apparently she eventually came to the latter conclusion, and they are estranged. Her parents, Christian missionaries,  certainly kept making a point.  A purely psychological interpretation (I occasionally indulge in those, so please bear with me) is that she became convinced that her parents loved black children four times more than her, and thus wanted to become black to regain their love. A less convoluted interpretation is that after a racially perplexing childhood which favoured Black Americans she just exploited a particular set of historic circumstances in the US in which her assertion that she was black was accepted “at face value” though inspection of her face showed she was not. Whatever her confusions, she appears to have played the system, choosing whichever self-identification seemed convenient at the time, either as the aggrieved white person who had chosen a black college, only to be let down by perceived black racism; or as the noble black person championing black causes, and being subjected to perceived White racist threats, for which the Police could not find supportive evidence. Her parents, who shopped her to the Press for her deceit, might have have done well to have kept quiet, and to have thought more carefully about their own contribution to her confused reactions. (Please note: I have given you the environmentalist/cultural explanation, which comes easiest to me. The genetic explanation is that she is the biological daughter of missionaries, and is imbued with missionary zeal, and as she ages she is becoming more and more like them in rescuing fallen Africans and battling for social justice).

Enough about this poor lady. If there is any doubt about who her real parents are, one good quality DNA test will sort out her ancestry in exquisite detail, going back for as far as anyone is interested. No such test result has been provided so far, and she doubts her parents are her biological parents, birth certificate not withstanding.

Now for the real oceans of silliness: public figures and journalists in the UK have sought to excuse the deceit, not on the basis of the confusion very probably engendered by her parents’ adoption strategy, but on the basis of “race doesn’t exist because we are all confused about it, just as she is, and who can say what race they are anyway?”

In the Sunday Times a past leader of the Race Relations authorities followed this line, discussing discrepancies in census classifications but also using reference to past African slaves in London to explain the occurrence of sickle cell anaemia in white British populations and, by implication, their being somewhat African in racial terms. In fact, as regards racial self-classification, most people have no difficulty deciding from which genetic group the majority of their ancestors come. They look at themselves in the mirror, look at people round them or in books and films, and do a match. However, the “what is race anyway?” commentators have the megaphone, and broadcast their obfuscations as the new, fashionable position, thus: in certain situations race exists, as in race crimes (some people noticing the race of others, drawing unwarranted conclusions, and treating them badly) and in other situations race does not exist (some people pretending to be another race, and drawing unwarranted benefits). Race becomes a “now you see it, now you don’t” classification, a free pass to whichever charmed circle is desired.

Does one really need to spell out the difference between an emotional affiliation and the genetic code? People can support the cause of the Palestinians or the Israelis without claiming to share their DNA. A white person can be a supporter of black causes. Patently, this lady’s white parents did not pretend to be black when they adopted black children. Of course, individuals of mixed race can choose to favour one set of ancestry over another when they describe themselves socially, but they cannot change their genome. Accepting the occasional quirky racial self-description may be a courtesy socially, but it ceases to be credible when it is being used to deny ancestry and gain advantage.

The availability of genomic analysis will very probably lead to a much better classification of race. “Hispanic” needs revision, and perhaps just a scintilla of more specification should be applied to “Other”. The original classifications of race were a good match at a time when generation after generation had lived in relative geographic isolation. Now that about 1% of the global population are on the move, updating is required. Eventually the genetic code may substitute for census categories, even though self description usually matches the genetic facts pretty well. Race exists as a fact in the genome, whereas the classification of boundaries involves social choices, but so does the evaluation of poverty and inequality, and few of the social commentators want to abandon those latter concepts.

To me the main surprise is that we are truly living in a age in which a person can say “white is black and black is white” and be confident that no-one will have the courage to challenge them. 

The kindest thing one can say about the silly obfuscators is that they are mired in the past. The genome is our ultimate birth certificate. It traces the history of the pairings that gave rise to us, and gives the lie to fanciful stories and evasions. Look at your genetic code, find your individual dot among the branch of your close relatives in the scattered family tree of 7 billion, and learn to live with it.

Monday, 15 June 2015

Intelligence and social class in Peruvian children


Peru did not come off well after being visited by Spaniards. That painful confrontation is the stuff of legend.  W.H. Prescott’s A History of the Conquest of Peru (1847) and more recently John Hemming’s The Conquest of the Incas (1970) are the books to read, the latter the best.

Peru is 45% Amerindian, 37% mestizo (mixed Amerindian and white), 15% white (European background) and 3% other (e.g., black, Japanese, Chinese). Geographically, the country is divided in three regions: the Coast (53% of inhabitants), the Andean mountains (38%); and the jungle (9%). Although domes and arches, iron smelting and wheeled vehicles were unknown during the Inca Empire, the Incas were brilliant stonemasons and goldsmiths, and used Quipu, a base 10 coding system of knots on strings indicating that some sophisticated mental abilities were present in that ancient population. Subsequent history has not been happy and in a 1979 visit my conversations with farmers in the countryside were about hard times, political stalemate and their shame at national backwardness in economic development. Things are much better now: life expectancy of 75 years; 74% of population live with improved sanitation facilities; 78% are living in urban areas; mortality rate under-5 (per 1000 live births) is 18.2; and 77% are enrolled in a secondary school. However, Peru is bottom of the list on PISA exams, and has no universities rated among the top 500. The discrepancy between Peruvian low school performance and reasonable cognitive performance (mean IQ in Lima 96, Andean samples 78) requires explanation, which the authors seek to supply.

Denisse Manrique Millones, Carmen Flores-Mendoza, Rosa Millones Rivalles Intelligence in Peru: Students' results in Raven and its relationship to SES.  Intelligence 51 (2015) 71–78

Their sample was 1097 children (46.5% male), with mean age of 11.6 years (SD = 0.4; ) from 18 randomly selected schools in Lima (58.9% public, 41.1% private). They gave Raven's Standard Progressive Matrices and a local measure of socio-economic status and parental education based on a national housing quality assessment.

The first finding was that the results were skewed towards higher scores. SPM is tilted towards upper average performers, and the somewhat under-average are less well represented. (Good to see some data plotted: just the sort of statistics I can understand). Overall, the results are IQ 97 but the Flynn adjustment brings it down to IQ 91. From a philosophical point of view it is strange to apply the same adjustment to different cultures. I suppose one can argue that Peru has had 3 decades of improvement, but it is still far short of European living standards. Perhaps lifespan is the best measure, and the correction valid after all. The authors guestimate the Andean IQ at 66-78 and the Amazonian IQ in the same range. They say:

Weighing the distributions of inhabitants who live on the Coast (53%), in the Andean mountains (38%) and in the Amazonia region (9%), the mean IQ for the entire country could be 84 [(91 ∗ 53 + 78 ∗ 38 + 66 ∗ 9) / 100], almost the same IQ previously estimated by Lynn and Vanhanen (2012) for Peru.

The authors then look at the implied IQs of the 573 recent arrivals out of 1097 mothers, according to what region (coast, Andes, Amazon) they were born in before emigrating to Lima. This is a little difficult, because we do not know if these internal emigrants are brighter than the people they leave behind, which is usually the case. Also, although there was data on father’s education this is not utilized in this particular comparison, as far as I can see. (There is a supplementary file which may have it). The authors claim that there is an interaction effect which vitiates a biological interpretation of the basic differences between the three regional groups, but I am not sure about their argument. Here is what they say:

As expected, children whose mothers were born in the Coastal region had a higher mean IQ. The lowest mean IQ was obtained by children whose mothers were born in the Amazonian region. These results would favor the biological hypothesis (e.g. positive correlation between IQ mother and IQ offspring). However, the results indicated an interaction between genetics and environment. For instance, the mean IQ of children of Andean origin studying in Lima was higher than the estimated IQ of children who lived in the Andean zone (IQ between 78 and 66; Majluf, 1993; Raven et al., 2000). Effectively, our results indicated the following: a mean IQ of 84 (adjusted by the Flynn effect) for children whose mothers were born in the Amazonian region (N = 28; mean SPM score = 36); a mean IQ of 85 for children whose mothers were born in the Andean mountains (N = 147; mean SPM score = 37); and a mean IQ of 94 for children whose mothers were born in the Coastal region (N = 398; mean SPM score = 41). When weighing child distribution (in percentage) according to the place of birth of their mothers, the mean IQ for the partial sample (N = 573) was 91 [((5 ∗ 84) + (26 ∗ 85) + (69 ∗ 94)) / 100], the same IQ obtained when the total sample was used (N = 1121; IQ = 91).

If emigrating mothers marry coastal Lima fathers, a likely possibility, this would sufficient to explain the partial uplift in the intellects of the resultant children. Selective migration, as described above, might also be involved.

Fathers are included in the analysis of the education/SES effects with the apparent finding that educational differences have effect in lower classes but not in the highest class. The authors say: It should be noted that the size of relationship between parents' educational level and SES was not high (r = .387), due to the imperfect meritocratic social structure that exists in developing countries, such as Peru.

However, the very well developed United Kingdom shows exactly the same pattern, as described by Daniel Nettle (2003). Note that correlations are higher for lower social classes, consistent with higher intelligence being a way out of those occupations.




The authors say: countries like Peru need to improve and expand [ ] all the means relevant for educational and cognitive development. This begins [with] aggressive gains in health care and nutrition and concludes with university education that includes average students all the way to top ability levels. Finally, improvement in education will lead to significant advances in the cognitive condition for the next generation.

I do not argue with improving education anywhere, but one notable omission in the paper is any analysis of results by racial composition. On this purely biological hypothesis the authors are silent. Nonetheless, this is a very useful study, carefully done, and makes a good contribution to the literature on intelligence in Peru. A re-analysis looking at paternal and maternal educational and genetic backgrounds would strengthen the interpretation of the results.

Final disclosure: I am not a descendent of Inca Garcilaso de la Vega, the first high-born mestizo whose bones, sent back by Spain, I saw interred in Cuzco cathedral in 1979 (preceded by an excellent declamation by the Town Mayor that being mestizo was no cause for shame) but when I saw it his portrait it struck me as a stirring image of a chronicler, to which any scribbler could feel resemblance.

Prof Nick Fox on dementia, tomorrow in Edinburgh


Time and venue: 5pm, Tuesday 16th June. Room F21, Department of Psychology, 7 George Square, EH8 9JZ

CCACE are pleased to host Professor Nick Fox for our last seminar before the summer break.

Professor Nick Fox from University College London is the Director of the Dementia Resaerch Centre in London and is also a Consultant Neurologist in a cognitive disorders clinic. His research interests are in improving diagnosis in dementia and in using biomarkers to accelerate the research for effective therapies. Please find details of his talk below.

Talk title: "Imaging the onset and progression of neurodegeneration: Prospects for prevention?"

Abstract: There is now consistent evidence to suggest there is a long and detectable preclinical period to a number of neurodegenerative diseases including Alzheimer’s disease. Although the exact sequence and time course of biomarker and imaging changes in these diseases are unclear, in Alzheimer’s disease, cerebral amyloid deposition appears to predate neuro-degeneration and clinical decline by more than a decade. Hippocampal and brain atrophy rates become abnormal much closer to symptoms with pathological rates of loss evident around five years before clinical diagnosis.

As a result of this, and motivated by recent failures of Phase III trials in mild to moderate Alzheimer’s disease, there is increased interest in undertaking trials at a much earlier stage in the disease – when less irreversible neuronal loss has taken place and there is more to save – perhaps even before individuals have any cognitive symptoms. The first trials in presymptomatic familial and sporadic AD are underway and further studies are planned. Similarly there are now a number of initiatives in other neurodegenerative diseases such as frontotemporal dementia or Huntington’s disease where treatments will be trialed in presymptomatic or very early disease. Designing such “prevention” trials raises a number of challenges including how best to identify subjects for inclusion, how to assess how near to symptoms they are and how to assess progression. Imaging and biomarkers will have important roles to play in meeting these challenges.

This seminar is open to all and a wine reception will follow the talk.
Please do send this email across your own mailing lists as this talk has a wide appeal to those interested in both pathological and nonpathological ageing.
I look forward to seeing you there tomorrow.
Many thanks,

Dr Beverly Roberts
Scientific Administrator and Researcher
Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE)

Department of Psychology
University of Edinburgh
7 George Square

Mon/Tue/Wed AM: CCACE administration, room F2
Tel: 0131 650 3368
Wed PM/Thur/Fri: Personal research, room F8
Tel: 0131 650 4639

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