Tuesday, 22 April 2014

Nature and nurture: Rosalind Arden replies

 

Dr Rosalind Arden has investigated whether the concept of general intelligence, usually seen as exclusively human, can be found in apes and dogs, and finds positive results. This is interesting in its own right, and also useful in refuting the argument that “g” is just an artefact of the intelligence tests used in factor analytic studies. I will try to get her to report more about her work on dogs next week.

In the mean time, here is her note replying to the general question as to how researchers in the field see the topic of nature and nurture, and whether it is worth continuing to research it.

Nature and Nurture

The standard statistical methods in behavioural genetics (the field in which nature and nurture are empirically tested) quantify the proportion of differences among a measured population (at a specific point in time) on a given behaviour, characteristic or trait. This gives results such that differences among people are (for example) 60% genetic and 40% environmental.

What does the average reader make of this 40%? What do we mean by the ‘environment? Most people I work with seem to assume that: we don’t know exactly, but it is something to do with the world out there. That may be true, and there may be significant elements of the world out there that do contribute to such differences (such as acute infections in childhood). But we have done a woeful job of finding out just how much of this ‘environment’ could be random biological developmental noise, rather than the environment 'out there in the world'.  One place to start with this question is to measure the variability of specified traits within a population of organisms that share the same genes.  Work like this has been done - researchers have examined variability within such 'isogenic' populations, but their findings have not been much discussed in relation to the meaning of the 'unique environment' in human studies.

The potency of Nature is often misunderstood. Knowing that the differences in trait X between people are caused 60% by genes does not tell you that genes determine 60% of trait X in Jane or Jimmy. As others have said, a heritability estimate is not a ‘gene-o-meter’. Heritability is a population level statistic, not an individual metric. Nor is knowing the population-level estimate of genetic influence on psychological traits (such as intelligence) very informative about limits (such as Jane/Jimmy could never get A levels’ or ‘would be assured A levels’) because there are so many other determinants of getting A levels. These include aspects of the external environment – and other traits in Jane/Jimmy (such as propensity to be excited by work, having friends who encourage work, and so on).

It’s rarely useful to ‘know less’ (the alternative to knowing more); so learning more about nature and nurture is a good thing. There is great consensus among scientists who conduct empirical work in this area about the value of knowing more - which is encouraging. Pretty much everyone I know: shares the view that learning about ‘the causes of traits’ is a work in progress, has some humility about what we know, and is keen to learn more.

Rosalind Arden

Monday, 21 April 2014

A researcher replies

 

Why don’t Northeast Asians win Nobel prizes?;
Genius - being a highly original thinker - is predicted by a combination of high IQ (which the Northeast Asians have) but also by a certain personality trait profile which distinguishes the 'genius' from the normal academic. The Big 5 pesonality factors are Agreeableness (Altruism), Conscientiousness (impulse control), Extraversion (feeling positive feelings), Neuroticism (feeling negative feelings) and Openess-Intellect (a combination of creativity and intellectual curiosity). The normal academic has high Agreeableness and Conscientiousness (that is low psychopathology). The genius, in general, has high psychopathology (ie low Agreeableness and low Conscientiousness) and high Openness. So, it is the combination of intelligence and psychopathic personality which predicts genius. Northeast Asians have very low psychopathology. This would explain why they do not win as many Nobel prizes as their high IQ might predict. 

> The evolution of racial differences in intelligence, in psychopathic personality and sporting abilities

Cold Winters theory would predict two things: that those evolved to hotter climates would have lower intelligence (as there would be lower selection pressure for it) and, in general, lower Agreeableness (less pressure to co-operatate) and lower Conscientiousness (less pressure to control impulses). These predictions are correct. Sub-Saharan Africans have relatively low intelligence and relatively high psychopathology. Cheating is predicted by psychopathic personality (low Agreeableness, low Conscientiousness) and low intelligence. As such, we would expect West Africans (for example) to be over-represented amongst cheaters in sport and there is sound evidence - currently under review - that this is the case in many sports. Chess is often seen as a sport. However, it is very much a test of intelligence and we would therefore expect poor African representation and very high Jewish representation. This is indeed the case.

Sunday, 20 April 2014

Question time #LCI14

 

Would you like to ask some researchers questions about intelligence?

The sorts of topics could be: Spearman's Hypothesis examined for primate cognitive comparisons; Why don’t Northeast Asians win Nobel prizes?; The Roma: a Balkan underclass; Science and its discontents; The evolution of racial differences in intelligence, in psychopathic personality and sporting abilities; Sex differences in intelligence; Polygenic selection and human evolution; the intelligence of the Victorians; Understanding heritability estimates; the General Factor of Personality, Dysgenic trends in simple reaction times in Scotland and Sweden; Immigrant attainments in Denmark; cognitive ability in Mexico; g in dogs.

Leave your question as a comment on this blog, and I will try to get an individual researcher to reply to you, either directly or through me. If you favour brevity, then tweet me your question.

Friday, 11 April 2014

Agent Pistorius

 

I used to be in favour of televising trials, on the basis that justice needed to be seen to be done, and that the legal process should be known to all citizens as part of their education, in case they gave evidence or had evidence given against them, or wondered why someone had been set free or convicted, or failed to appreciate the power and majesty of common law.

Now I am not so sure. Why should I be watching a trial in another country, concerning people I do not know, in a case which is unrepresentative of South Africa, a country with very high rates of murder and rape perpetrated against the anonymous multitudes? Celebrity and beauty seem to be the answer. We can be enthralled, entertained and, perhaps, educated by someone famous and someone beautiful. More than that, we can be beguiled by the redemptive story of a man who, in the harsh parlance of the past ,would have been considered a cripple, rising on magic blades to take all the prizes including the prize girl.  The populace like nothing more than to see someone rise to the stars and then fall to the ground. Even better, they get to see the couple’s private text messages. Awesome.

Milady Judge Masipa, who looks like a bright cookie, was understandably severe with the hoi polloi who chattered at the dramatic bits, telling them acidly that this was not a public entertainment, but that’s what it is. It is both a very serious trial and an entertainment. I am in the audience, complicit in the drama, as are you, dear reader, if you know anything about this case.

Everyone has a cover story. The State wants to show that pretty, high status White Folk don’t get special treatment. The Judiciary want to parade their independence, and don’t mind their 15 minutes of fame, which will buttress their profiles and do their pensions no harm. The media and their lackeys, including psychologists it must be admitted, opine. The Police have been revealed to the world as flat-footed bunglers and watch thieves, which must bring some comfort to the long suffering public, though some embarrassment to the State. Best of all, South Africa puts on a riveting detective story which might even lead to a True Confession, and which might conceivably lead people to forget that the average victim of South African crime gets far less attention and the perpetrators far less flamboyant and expensive defence barristers.

What of the psychology? First things first. Mr Pistorius’s defence is that he made an honest mistake, understandable in the context of high crime South Africa, and even more understandable in terms of White fear of violent black men in the dark, but that doesn’t need spelling out, and is best left unsaid anyway. The State has a mammoth task, because they have to prove a malicious intention, yet all the material facts from which intention might be deduced have been admitted. So, the case hinges on some very psychological but intangible factors.

Rightly, the two barristers Roux and Nel have become stars in their own right. I think I have had about 8 cross examinations as an expert witness, and probably about 20 case conferences with barristers. In my experience they are bright, quick witted, adept at dissecting language and drawing out subtle implications from statements. They try to be several steps ahead, and usually succeed. They also have a large bag full of tricks. They love side alleys into which the unwary can be drawn, for no other purpose than to reveal them to be idiots or liars. They will pounce on an obscure and irrelevant distinction and worry it to death until the poor witness agrees to anything out of pure frustration and boredom, only to have this concession turned against them on contrived grounds.  They revel in double negatives, elaborate dependent clauses, arch suggestions and tendentious interpretations. Best trick of all is Nasty Surprise. The victim, known to them as Baby Seal, is fed a comforting diet of banal questions, each answer being met by flattering agreement “Absolutely right. So very helpful. I am most grateful to you for saying that” and then a new document is produced showing that the person you are championing has some fatal flaw they have not disclosed to you, or that you have ignored vital contrary evidence in a major publication. Too late, you look back at your former replies with painful regret. Another trick is to take a specific issue and to discuss it to death so that its importance rises to dominate the case. For example, a barrister of my acquaintance, later a notable Judge, was defending a driver who was so drunk that Police decided to skip the “walk a straight line” test, fearing he would fall on the station floor and injure himself. Roydon, for that was his name, spent a long time convincing the jury that the one single test which mattered, on which the entire case must hinge, was the straight line test, and that had not been carried out. Case dismissed. The prime aim of all barristers is to secure for their client a miscarriage of justice. For the barristers the Pistorius trial is business as usual, but this time with a global audience. In some South African township hovel a young child is muttering: That’s what I want to be when I grow up.

What do we make of Oscar Pistorius? As I said in another place (see below) psychologists should not comment on people they have not interviewed. A televised trial does not give you first hand observation of a person’s face, though one certainly picks up a lot from the tone of voice. Most important, the contingencies are that Pistorius will gain considerably if his account of what happened is accepted, so his statements and behaviour cannot be taken at face value. Perhaps viewers are learning first hand some of the expensive merits of adversarial justice.

The prosecution case has centred on a theme which is a staple of criminal justice: responsibility. Perpetrators tend to minimize their actions and wish to show them as reactions. The retired prison doctor Theodore Dalrymple described a young man’s account of stabbing someone thus: “Then the knife went it”. The knife did it. The guy just happened to be there, admittedly with a knife in his hand.

Agency has a dual meaning. It can signify that you understand that you are able to operate on the world, or it can mean that you are merely an agent, carrying out a role as required. In that sense perpetrators cast themselves as victims of circumstance, agents of some higher cause, in this case the respectable home owner defending himself and his guest from intruders. 

Prison psychologists once approached me to offer trauma services to perpetrators who were traumatised by what they had done. I questioned whether this was a wise course of action, since vivid regret at their actions might possibly guide these malefactors into questioning their behaviour for ever, to the benefit of society. I said I would concentrate my scarce resources on victims.

There is an interesting issue here: how does one tell that a person is lying? The answer is simple: you need a stopwatch. Lies take longer than truth, because liars are fabricators not reporters. Fiction takes time. Ask any novelist.

Live update: Now I have just seen the prosecutor Mr Nel ask the defendant the obvious question: if Pistorius believed he was shouting for his girlfriend to call the Police while pointing a gun at an intruder hiding in a toilet, why did not the innocent girlfriend answer from behind the toilet door with a simple “Its me, Oscar”. An implication which hangs there, with Milady Judge making a note, before the Court is adjourned till Monday.

What’s my cover story? CNN asked me to comment on the trial. Otherwise I would have continued leading the search for MH370. Honestly.

Thursday, 10 April 2014

IQ, Neuroticism, booze, and those damn vegetables again

 

A long suffering toiler in the groves of academe writes in to say that, rather than just bemoaning the lack of intelligence and personality measures in epidemiology, I should pay some attention to a study which has done precisely that, and help boost the visibility of such work in the health literature. In fact, I have a vague recollection of the paper, but now is the time to make amends for my forgetfulness.

Bryan Pesta apologizes for the “ghastly” link below, but it is free, folks, so just copy and paste into the search bar.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCoQFjAA&url=http%3A%2F%2Fwww.people.vcu.edu%2F~mamcdani%2FPublications%2FPesta%2520et%2520al.%2520(2012).pdf&ei=BvWtUoidBMqQqgGDrIC4Cw&usg=AFQjCNHPf-GLaItpBe3D5i95-YSflA2UkQ&sig2=RI5i4cm-xHyLWPB6Q07ojQ&bvm=bv.57967247,d.aWM&cad=rja

By way of background, to the external world the USA is a monolith with some minor regional variations. To its citizens is a union of sovereign states, and all the better for it when that union is not too close.  Pesta, Bertsch,McDaniel, Mahoney and Poznanski (Intelligence 40 (2012) 107–114) have gathered data on all 50 American states, have found a link between IQ and neuroticism measures and health variables, and have tried to tease out possible causal links.

They found that at the State level, drinking alcohol correlates positively with exercising and eating fruits and vegetables; and it correlates negatively with rates of smoking and many chronic diseases. These data are consistent with a growing but mixed literature showing that alcohol consumption correlates inversely with chronic disease rates. This may be nothing to do with ethanol as such, but we should follow the tradition of results first, explanations later.

The authors work through the key data using multiple regression.

At Step 1, the linear combination of IQ and N alone explained 57% and 61% of the variance in Chronic Disease and Metabolic Syndrome, respectively. Both IQ and N remained significant (but attenuated) predictors of disease, after entering Health Behaviors at Step 2. Not surprisingly, Health Behaviors itself explained large amounts of variance (over IQ and N) in both Chronic Disease and Metabolic Syndrome. Note that the variance explained at Step 2 is unusually large for social science research. Fully 80% of the variance in Chronic Disease (77% in Metabolic Syndrome) was explained by the combination of IQ, N and Health Behaviors.
The size of the effects here, though, could exemplify the "high resolution" that aggregate-level data offer, relative to studies that use individuals. At Step 3 they found that IQ (Beta=−.18), N (Beta=.35) and Health Behaviors (Beta=
−.53) all remained significant as predictors of chronic disease, even after controlling for state income (Beta=−.12, ns).

Here are the correlations between IQ and :

Neuroticism−.08

Health Behaviours .45

Chronic disease −.51

Metabolic syndrome −.53 C

Crime −.76

Education .41

Religiosity −.55

Income .57

So, here we have a nice clean study, admittedly at State level (aggregated data) which shows the importance of IQ and Neuroticism in influencing health outcomes. Why has this engaging study only been cited once? It may be that the intelligence literature is not read by epidemiologists. Another problem may be the title: “Differential epidemiology: IQ, neuroticism, and chronic disease by the 50 U.S. states”. It is accurate but dull, and hardly worth tweeting about in its current form. I think that the Pesta gang need to get with the spirit of the age, and re-issue it with a snappier, media friendly title:

Dull worriers die sooner: Avoid West Virginia.

 

Disclaimer: I am sure that the denizens of West Virginia are bright and stable people. It was just a suggestion.

Tuesday, 8 April 2014

Nature, the journal, and the Nature of Samples

 

As you will know by now, I lead a quiet life, avoiding trouble wherever possible. The natural calm of my afternoon was shattered by a Nature News piece with the startling and quite specific headline: “Stress alters children's genomes”. As if the drama of the finding was not enough, Jyoti Madhusoodanan’s article added further details: “Poverty and unstable family environments shorten chromosome-protecting telomeres in nine-year-olds”.

http://www.nature.com/news/stress-alters-children-s-genomes-1.14997

They shorten the genome. Not, they are associated with shorter genomes. They take a healthy long genome and shorten it. Imagine what the shock of the headline must have done to my genome. On your behalf, I read on, undaunted. Nature had posted up a nice picture of telomeres, which is usually enough to win over the unconvinced. Ever the sceptic, I read on, and came across these prize paragraphs:

When researchers examined the DNA of 40 boys from major US cities at age 9, they found that the telomeres of children from harsh home environments were 19% shorter than those of children from advantaged backgrounds. The length of telomeres is often considered to be a biomarker of chronic stress.

The telomeres of boys whose mothers had a high-school diploma were 32% longer compared with those of boys whose mothers had not finished high school. Children who came from stable families had telomeres that were 40% longer than those of children who had experienced many changes in family structure, such as a parent with multiple partners.

At this point I wondered who would be silly enough to imagine that n=40 was a suitable basis for concluding anything, and whether anyone would be even more silly to imagine that if there were observed differences between bright and dull mothers that it followed that those differences were caused by independently existing stressful environments, rather than being due to prior differences in the genetics and the behaviour of brighter mothers.

To spell it out: dull mothers are at risk of all sorts of things, from their genes upwards and outwards; brighter mothers might be spared those risks for reasons which range from their genes upwards and outwards.

However, I knew that I must have got it wrong, because such foolish errors would never be tolerated by Nature. So I had a look at the paper.

http://www.pnas.org/content/early/2014/04/02/1404293111.full.pdf+html

Here is the method statement:

Initially, we identified 40 families based on a three-step process. In the first step, the sample was constrained to boys meeting the following conditions: (i) boys provided saliva at age 9 (wave 5) in-home interview, (ii) whose mother self-identified her race as black or African American, (iii) for whom no data were missing on the criterion variables described below, and (iv) who were male.

Next, we arrayed the subsample on an index of advantage–disadvantage from birth to age 9 based on an equally weighted combination of (i) family economic conditions, (ii) parenting practices, and (iii) family structure/stability.

Finally, we took children with the 20 highest scores in the disadvantaged index whose mothers had experienced at least one depressive episode and the children with the 20 lowest scores on the index whose mothers had never experienced depression. Thus, boys who scored highest on this index (n = 20) lived in homes with high levels of poverty, high levels of family instability, harsh parenting, and maternal depression. Boys who scored lowest (n = 20) lived in affluent, stable families and were not exposed to either harsh parenting or maternal depression. We then assayed the children for Telomere Length.

So, from one perspective we can say they chose a bad genetic group and compared it with a good genetic group. From another perspective we can say they chose a bad luck group and compared it with a good luck group.

What steps did the authors take to compare these two perspectives? What steps did they take to distinguish, for example, between between bad luck on the one hand and bad decisions on the other; between the slings and arrows of blind fate on the one hand and the natural consequences of damn fool decisions on the other?

As far as I can tell, none. They assume that all this bad stuff rains down on one group and that the other group is spared, but that in genetic terms both groups are identical, or close enough to warrant a comparison of the effects of these extraneous life events.

I looked up the telomere lengths and did a t test. For the harsh environment 9.6 (4.2) and for the nurturing environment 10.3 (2.5). 20 boys in each sample. Non-significant. Nowhere close. So, I presume it is only significant if you put together a model of variables to be controlled for, but otherwise not.

To my primitive eyes the sample size seems far too small to conclude anything much, and far too small for comparisons of individual gene effects. In addition, there is a highly questionable assumption that all that these boys inherited from their parents was an “environment”. Incidentally, so many fathers were untraceable in the “unlucky” group that fathers had to be left out of the whole study. A look at the genetics of the mothers would be a start. Looking at the telomere length of the mother’s DNA might also be worth a look.

Have I got it entirely wrong, and is there some innocent explanation I have missed?

I would like some assistance from anyone who can help me understand why this paper, which I think flawed, is considered suitable for publication by the editors of Nature.

Is it healthier to eat 7 vegetables or 7 scientists?

 

I wish no harm to the authors of “Fruit and vegetable consumption and all-cause, cancer and CVD mortality: analysis of Health Survey for England data”

J Epidemiol Community Health doi:10.1136/jech-2013-203500

http://jech.bmj.com/content/early/2014/03/03/jech-2013-203500.full

whose recent publication has received approving coverage in the media. We are colleagues at the same godless institution, so they cannot be all bad. But (and you expect nothing less from me) I am not bowled over by their arguments about the benefits of vegetables. You will have caught the general tenor of my criticisms of this sort of work in “Diet is an IQ test” http://drjamesthompson.blogspot.co.uk/2013/11/diet-is-iq-test.html

Following Prof David Colquhoun, I joined him in quoting with approval a paper BMJ 2013;347:f6698 doi: 10.1136/bmj.f6698 (Published 14 November 2013) by John Ioannidis in whose train I ranted thus: “Samples of about 70,000 followed until death (with a proper link to death registers) will be required to identify even a few general patterns in diet which might account for a 5-10% increase in risk. If the studies are to mean anything, IQ, personality, sociological and occupational variables will have to enter the mix, and participants will probably have to be paid to stick to the course, and put up with random visits of inspectors looking in the fridge and the medicine cabinet.”

So imagine my pleasure, or alarm, when this paper turns out to have followed 65,226 persons drawn from a nationally representative sample for 7.7 years and visited them at home to find out what they had eaten yesterday (thus remarkably improving accuracy of their recall) and then linking the respondents to death registers. Rather disarming, isn’t it? The authors seem to have got good data without paying participants or raiding their refrigerators. The authors admit that the main limitation is that measurement of fruit and vegetable intake occurred at only one point in time and relies on self-report. There may be social desirability bias and random error (forgetting) in the recall of fruit and vegetable consumption. However, while short of perfect monitoring, this is a big step forwards. All this is very good, and shows epidemiology at its best.

Undaunted, I moved to the second half of my diatribe “IQ, personality, sociological and occupational variables will have to enter the mix”. Here I have found some things to complain about. Although they included sociological and occupational variables, they did not measure IQ or personality. Frankly, I don’t expect that of epidemiologists, because those measures are often neglected by psychologists anyway.

That aside, the authors carry on doing good things by offering us some old fashioned means and standard deviations, with participants categorized by the number of portions of fruit and vegetables they consume. These are the sorts of simple statistics I can understand. For example, the English eat slightly over 2 portions of fruit, and 1.5 portions of vegetables a day. The propaganda about vegetables has left them relatively unmoved.

Table 1 shows that those who do eat vegetables tend to have non-manual occupations, and the more vegetables they eat, the more likely they are to be in middle class occupations. Do vegetables make you rise in social class? Do bananas telephone? Do efficient compasses misdirect? (Can you spot the origin of the last two questions?)

Similarly, 7-vegetables-a-day types are much more likely to have a university degree than vegetable refusers, who tend to be less educated folk. Also, they are less likely to smoke and are more likely to be physically active. On the other hand, they are just as fat and almost as boozy as everyone else. Those who consumed more fruit and vegetables were generally older, less likely to smoke and more likely to be women, in a non-manual household, with degree level education. Veggie Mummies, yah?

Finally, when it comes to deaths during the study period, here’s the crunch: overall, 6.7% of the sample died during the study period of 7.7 years. The sad fact is that if you are 57 years old you have a 6.7% chance of being dead by the time you are 65 years old. (Or would have been 65, for pedants). Those who eat no vegetables have an 8.2% chance of death, the One to Three vegs a day 7.9%, the Three to Five vegs a day 6.4%, the Five to Seven 5.3% and the Seven Plus vegetables only 4.1%. So, although your chance of dying is relatively low, you can make it even lower by feasting on vegetables.

At first glance, the avid vegetable eaters have half the death rate of the no vegetable eaters. It suggests that vegetables are the cause of the difference. However, it could be that vegetables have nothing to do with it.

In table 2 they offer a “fully adjusted” Model 1: Adjusted for sex, age-group, cigarette smoking and social class; and the even more adjusted Model 2: Adjusted for sex, age-group, cigarette smoking, social class, BMI, education, physical activity and alcohol intake. Of course, as sharp eyed readers you will note that they do not offer a Model 0: adjusting for sex and age, the only things which are truly not controllable by individuals. That is a pity.

In table 2 they use hazard ratios, where eating no vegetables (the highest apparent risk category) is set to 1 and the other conditions lots of vegetables rates as 0.69. This certainly shows the differences with increasing consumption of vegetables, but no longer reveals absolute risk. I prefer table 1. In fact, I would have liked to have seen a correlation matrix. I can read those. I concede that such a matrix would not reveal covariance, but it would allow me to begin to think about the associations between the variables. One or two plots of data would also have helped. In my usual ferreting mode I had a look at the supplementary data.

clip_image002

At about 120 months the fruit effect dies out for some, probably artefactual, reason.

In both these adjusted models and in other variations the effect of vegetable consumption continues to be significant. They go into further detail about vegetables (good) and fruit (slightly less efficacious in keeping you alive) and note that canned fruit seems to slightly increase mortality, probably because of the sugary syrup in which they float.

The authors have bundled together factors that none of us can control like our age and sex, with factors we can control like how long we stay in education and the sort of work we do; with factors we can and probably ought to control like how much we eat and drink. All those different categories are “controlled for”. Some mistake, surely? I can understand the “control” for age. Older people are more likely to die in any time period than younger people. However, if I chose to become a university teacher, why “control” for that choice? I took up that occupation precisely because I thought it would be agreeable, if not well paid, and that I would be highly unlikely to suffer industrial accidents. My choice, plus my ability to get such undemanding light labour against, frankly, rather sparse competition, reveals something about me. It may explain my willingness to follow health advice, or it may simply be that I am a cautious man, minimising my risks in my personal and occupational life. A simple fearfulness of character could explain all the associations.

Consider the adjustments. These are based on the assumption that the cigarette smoking, social class, BMI, education, physical activity and alcohol intake are not related to something which itself has an influence on health. They are seen as imposed external factors which can influence health, rather than a series of behaviours related to an intrinsic factor: system integrity. System integrity is a hypothesized intrinsic characteristic which gives you a good body and a good mind, such that you are healthy and intelligent. This may be related to your genetics and/or a favourable beginning in utero. The one give-away sign of system integrity is fast reaction times to simple stimuli. See the Edinburgh group under Ian Deary for all these findings.

Seen this way, the intelligent live longer and healthier lives not because they are wise, but because they are lucky. They eat vegetables because it seems to be the clever thing to do from a health point of view, and perhaps because they can work out that the need for protein from meat is relatively small, so vegetables are more cost-effective. They may even like the taste of them. They also wear seatbelts, use condoms, brush their teeth, don’t smoke, go for walks, don’t eat or drink too much, study hard, strive to get good jobs and always save money.

The conclusion of this study is that we should eat our vegetables, and 7 portions rather than only 5. Perhaps so. It is still possible simply that bright people live longer, even when they are slightly plump and somewhat boozy. No, my gripe is about the way they have interpreted the findings, and the assumptions which underlie their calculations of hazard ratios. The authors make it clear that “This study has found a strong association, but not necessarily a causal relationship. There are additional unmeasured confounders not included in the analyses, including other aspects of diet.” However, they go on to mention other dietary factors, not the psychological ones.

Vegetables may be good for you. But I have been assured that scientists make a most delicious, nourishing, and wholesome food, whether stewed, roasted, baked, or boiled; and I make no doubt that it will equally serve in a fricassee or a ragout.

Monday, 31 March 2014

The mind’s construction in a face

Of course, this is only a bit of fun, but presumably you can tell how bright a person is just by looking at them? Such confident judgments are anathema to proper clinical psychologists, who would rather spend an hour giving a Wechsler intelligence test than stoop to such populist nonsense.

Now Karel Kleisner karel.kleisner@natur.cuni.cz  Veronika Chvátalová, and Jaroslav Flegr have decided to put this silly stereotype to the test in a PLOS One paper “Perceived Intelligence Is Associated with Measured Intelligence in Men but Not Women” and find it not so silly, at least as far as men’s faces are concerned. (As my readers already know, a stereotype is an insight waiting to be proved.) Perhaps the girls are so exclusively judged on prettiness  that their intellectual countenances are ignored, whilst boy’s faces can be judged for both intellectual and sexual purposes.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0081237

Let us get the criticisms in quickly. The sample size is small (n=160), and more importantly the faces are from university students and the raters are also university students (mean IQ 125 sd 17). This could be a case of bright people recognising other bright people. There is a restriction of range problem, and the authors should try a representative sample of faces and raters, and are likely to get better results.

I presume no-one was photographed with glasses on, though they “avoided cosmetics, jewellery and other decorations”. On the plus side, they have published their entire data set.

In general, I like the way the authors have presented this paper. They admit that their method of analysing the composition of faces shows no relation to measured IQ, yet that there must be something about the pictures of the men’s faces which allows the positive predictions of their intelligence to be generated. The authors say that this must be due to a cultural stereotype. Weak argument. Where on earth would such a “stereotype” come from? If cultural stereotypes mean anything they would be random, and have low predictive power. This reliance on the notion of “cultural stereotype” is a crucial misunderstanding on their part, because it does not explain how a correct stereotype comes about, other than by someone noticing something which is true.

Their line of best quadratic fit I found something of a disappointment. Above IQ 140 the strength of the prediction falls considerably, and these paragons of intellect are seen as pretty stupid. In statistical terms these outliers are freaks, so in evolutionary terms it might not be worth detecting them. Or they carry so much mutation load that they look awful.

In both sexes, a narrower face with a thinner chin and a larger prolonged nose characterizes the predicted stereotype of high-intelligence, while a rather oval and broader face with a massive chin and a smallish nose characterizes the prediction of low-intelligence.

Do you have a gracile face? For once in my life my larger nose seems to be a benefit in generating a positive stereotype about me.  Do you look like the clever person you actually are, deep inside? If you wish to comment, please append a photograph. If you are over IQ 140 you may omit the photo.

Rock and Roll

 

Lest it be thought I lead too quiet a life dwelling on the minutiae  of psychometry, I spent most of yesterday partying with rockers in a secret London location as the guest of Richard Thompson OBE (no relation) whose gig at the Half Moon on 4 April has sold out in 10 minutes. Since Fairport Convention he has achieved fame as a solo artist and has an extensive and extremely loyal fan base. His songs have been covered by everyone in the business, and I have witnessed adoring fans standing in the pouring rain at Fairport’s Cropredy Convention in Oxfordshire, hanging on every word and chord.

http://richardthompson-music.com/    http://en.wikipedia.org/wiki/Richard_Thompson_(musician)

In a respectful obeisance to rock tradition, he wore blue suede shoes (“Crepe, actually” the great man said).

 

2014-03-27 16.09.13

 

Also there was Jo “Nashville Rock with an English Accent” Burt who played with Black Sabbath, and whose wife and backing singer Antonia talked about their new album, suggesting “The Mess” as the track which would be of most psychological interest to my readers. The picture shows Antonia, with Richard Thompson in the background and Jo Burt, looking away to his left.

 

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https://www.youtube.com/watch?v=bw-5ilFaw20

http://www.joburt.co.uk/

Third up, a new duo launching their latest album next month, but once again for some reason my photograph shows the female part of the combination with somewhat greater emphasis than her truncated male partner.

 

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Following rock tradition, the rest of the party becomes a bit hazy, so the names have become somewhat jumbled, and I have run out of links. I am told that all of us danced to the classic tracks. There was a whole lot of shaking going on. You will have to help me recall the rest of it. Meet on the ledge.

Friday, 28 March 2014

#MH370 Reincarnation and sea junk

It would appear that, despite collecting data for several decades, we do not have baseline estimates for sea junk per area of ocean. Our watery world is crisscrossed by a conveyor belt of ships carrying container loads of materials, a portion of which fall into the water, joining the rubbish deliberately thrown overboard from ships and the rubbish which makes its way into the oceans from the stuff we throw into rivers and leave on beaches.

Baseline measures aren’t sexy. One unintended consequence of the search for flight MH370 is that we will have learnt that even the far reaches of the southern Indian Ocean, deep in the roaring forties, have generous scatterings of man made rubbish. Perhaps we will even be able to quantify this in terms of number of discriminable man made objects per thousand square miles.

Note that, if the number is very low (and the more appropriate measure turns out to be objects per ten thousand square miles, or even a hundred thousand square miles, which is a little over the size of the United Kingdom) this would strengthen the significance of finding any object floating in the ocean. Signal detection would become a little easier. We could argue, as the Malaysian government officials have done (they are not having a good time, are they?) that floating junk means floating plane junk. Find some junk and the plane will be on a sea bed somewhere upstream from the sea currents, if those can be calculated with any degree of precision.

On the other hand, if the number of floating objects is high, then the task becomes even more difficult, and pushes us towards the next problem: can crashed plane junk be discriminated by satellite or observer plane from all the other junk or do we have to rely on retrieval by ship of every likely floating object?

This question came into my mind a few minutes ago, when the revered BBC website displayed a picture taken by a journalist from a New Zealand plane showing a white floating rectangle. “I am no expert” as people say in the Twitter-sphere, (before launching into an elaborate speculation) but it is not immediately apparent to me how this object potentially relates to a crashed airliner. It is very probably nothing to do with the skin of the plane, nor does it look like any inner section, or any type of cargo. However, it is man-made, and floating.

So, how are our probability estimates looking at the moment? It seems that the range of the aircraft is fuzzier than previously disclosed. The plane was traveling faster than previously envisaged, thus burning more fuel, and therefore travelling less deeply into the southern wastes. If one plots out the error arc of the Inmarsat calculations, and the error range of the speed and fuel calculations, quite a chunk of ocean remains in contention. (I do not know how much, and wonder if anyone else does).

So, which way would you gamble, using Bayesian techniques? Three main components to be factored in are as follows: 1) area to be searched (ranging from the highly probable to the less probable) 2) the time left before the black box pinger battery gives up, and 3) search efficiency.

My rough calculations would be that: the search area remains too large; the pinger will fade to almost nothing in another 15 days (though cold water might extend that time) and search efficiency is extremely low. This latter point was well studied by the mathematician Bernard Osgood Koopman who wrote the first proper handbook for searches at sea in the 1940s. Looking at the sea is boring, you cannot scan the whole area so it is best to look a little down from the horizon, you should change places every 15 minutes to lift your alertness, you should start with probable places and move to slightly less probable place but ignore possible but improbable place (success is unlikely when probability of a target is low, and visual search is inefficient) and no plane can fly for ever.

My bet would be that, absent any more refinement in the calculation of impact location and subsequent drift, the searcher must gamble, and should maximise the area that can be searched. The area closer to Perth maximise the proportion of the target area that can be searched. Look where the light is brightest, particularly when the light is about to go out.

And finally, a word about reincarnation. About forty years ago I read somewhere, possibly in the Pali cannon of sayings of the Buddha or a commentary a line about the chance of someone being born without having been reincarnated. The chance was rated as being “as low the chance that a turtle that rises to the surface once in a thousand years will put its head through a life belt cast upon the Indian ocean”.

Can someone look it up for me? I am busy searching for a missing plane.