Thursday, 29 September 2016

Goodbye Sweden: Can I have a quick reaction?


Journalists, being fed news of some dreadful event, are prone to ask their studio guests: “Can I have a quick reaction?” Almost always the Talking Head comes up with an off-the-cuff reaction, also known as an opinion, as to whether the event is the end of: a dictator/a government/a country/low cost oil/Western civilization/the planet.

I would not dream of criticising this response, particularly because in former times on TV I sometimes ventured minor versions of such a response. I have not yet been asked to comment in a public arena as to whether the finding that contemporary reaction times are slower than in times of yore indicates the decline and fall of our civilization. You know the story full well: the much championed Flynn effect suggests that good food, free education and proper drains have boosted our intelligence, as well they might have; the Woodley effect suggests we are slowing up, losing our intellectual sparkle, becoming more specialised in our abilities but very probably sinking into the mire of soggy stupidity.

Now we have some even more solid findings to favour The Woodley Effect. (By the way, Charles Murray, responsible for coining The Flynn Effect,  suggested to me that the contemporary lowering of intellect should be named in this way).

Guy Madison, Michael A. Woodley of Menie and Justus Sänger

Secular Slowing of Auditory Simple Reaction Time in Sweden (1959–1985) Front. Hum. Neurosci., 18 August 2016 |

They say: There are indications that simple reaction time might have slowed in Western populations, based on both cohort- and multi-study comparisons. A possible limitation of the latter method in particular is measurement error stemming from methods variance, which results from the fact that instruments and experimental conditions change over time and between studies. We therefore set out to measure the simple auditory reaction time (SRT) of 7,081 individuals (2,997 males and 4,084 females) born in Sweden 1959–1985 (subjects were aged between 27 and 54 years at time of measurement). Depending on age cut-offs and adjustment for aging related slowing of SRT, the data indicate that SRT has increased by between 3 and 16 ms in the 27 birth years covered in the present sample. This slowing is unlikely to be explained by attrition, which was evaluated by comparing the general intelligence × birth-year interactions and standard deviations for both male participants and dropouts, utilizing military conscript cognitive ability data. The present result is consistent with previous studies employing alternative methods, and may indicate the operation of several synergistic factors, such as recent micro-evolutionary trends favoring lower g in Sweden and the effects of industrially produced neurotoxic substances on peripheral nerve conduction velocity.

The authors have collected new data on a large sample, with 7081 usable respondents on which there was much background material from previous testing. They pursued the respondents with reminders, and tested them online, using the best available software to ensure consistent exposure and recording of responses. This cannot be the same as bringing them in to a standard experimental set up of reaction time equipment, but on the other hand it generates much higher numbers of respondents. They have also considered the impact of these variations in methods which, if anything, would obscure rather than reveal underlying trends.

Reaction times seem to slow up after 1970. The authors say:

We found clear trends toward slowing auditory SRT when birth year was regressed against year-on-year SRT means for the years 1959–1985. It is notable that even without adjustment for aging, the SRT speed of the oldest participants is about the same as that of the subsequent generation, whom in the late twenties are supposed to have the shortest SRTs of all age groups (Der and Deary, 2006).

the secular slowing trend was present in all cohort comparisons (males, females, and both sexes combined), and was significant across the entire range of birth years for both the males and the whole sample, but not for the females, who nonetheless exhibited an overall negative trend in SRT performance consistent with potential secular slowing.

A potential cause of the apparent slowing may be exposure to neurotoxic industrial by-products such as heavy metals (Silverman, 2010) and dioxins (ten Tusscher et al., 2014), which may reduce SRT performance via their effects on peripheral nerve conduction velocity. However, as Silverman notes, known neurotoxins have come under tight governmental regulation, emissions have tended to decrease, and serum levels of lead, for example, have decreased since 1970 in the USA (Silverman, 2010, p. 46).

Another possible cause of this trend may be relatively recent micro-evolutionary trends favoring lower g in the population of Sweden. Several studies have revealed that g and fertility are inversely related in the US and the UK (as reviewed in Woodley of Menie, 2015) among cohorts born as far back as the 1890s (Lynn and Van Court, 2004; Lynn, 2011). However, the relationship between g and fertility in Scandinavian countries is less well characterized. Only one study has attempted to examine these trends across birth cohorts in Sweden (Vining et al., 1988). Utilizing aggregate data on fertility and IQ for a mixed-sex sample of Swedish cohorts resident in Stockholm county and born between 1909 and 1940 from Vining et al. (1988), it was possible to reconstruct predicted generational changes in genotypic IQ (I.e., the heritable variance component of IQ) due to the changing patterns of selection (I.e., the correlation between IQ and fertility established for each cohort) for four cohorts (see Appendix 2 for details of the method).

Main result here, but see the full paper:


In sum, this is strongly suggestive of a slowing of reaction times in Sweden, itself suggesting a possible drop in mental alertness and intelligence in that country. If the Flynn effect were a deep-seated real improvement in functioning then one would expect faster reaction times, not slower. An alarming result, worthy of further testing and attention.

Tuesday, 27 September 2016

Background slides to a short intelligence test

Here are the contact details for Julius
Twitter: @Julius_d_b
Here is the link to his lecture slides:
For the complete lecture, see the previous post.

Monday, 26 September 2016

A very short intelligence test


Here is an intelligence test which takes about 15 minutes, and is free. The link to the original project and 16 item test is given here.

This talk is about the testing of the 5 item instrument with Danish schoolchildren, and it contains many interesting findings, out of which I will select one: one of the best items in terms of discriminating students was a question which contained explanations as to how the question should be approached, help which usually makes items easier. Paradoxical, and interesting. Sometimes, explanations make the task a purer measure of ability.

You will need to contact the author for more details about his work in using the test in Denmark and reducing it from 16 to 5 items, so as to achieve time effective testing. His abstract is shown below.

ICAR5: a 5-item public domain cognitive test

Speaker: Julius Daugbjerg Bjerrekær

A 5-item abbreviation of the ICAR (International Cognitive Ability Resource) 16-item sample test was created thru exhaustive search. The 5-item version (ICAR5) was optimized for correlation with the 16-item version and for administration time. To validate the test, it was given to students in 6th to 10th grade in two Danish schools (N=236). Age was used as a criterion variable and showed the expected positive relationship (r=.43). Results furthermore showed that the abbreviated test was too difficult for the younger students (6th and 7th grades), but not for the older students. One item was found not to be very discriminative, so it should be replaced with a more suitable item.

Here is the full lecture:

Scientific Method Process picture



Scientific method process picture

I find this a useful picture. Can anyone let me know who put it together, so I can acknowledge it properly?

Sunday, 25 September 2016

Will Turks show Syrians the way in Germany?


Judgments about the wisdom of the German government giving effective citizenship to over a million Syrians (more correctly people from the Muslim world who say that they are Syrians) should be informed by looking at the achievements of Turks in Germany. They began immigrating to Germany in October 1961, by invitation, to join the labour force, providing workers for the German economic miracle. By now, 56 years after the first wave of immigration, they should have integrated into the fatherland.

Since Germany does not officially categorise people by ethnicity, population estimates are approximate only, but there are now roughly 4 million Turks in Germany. In 2012 the figure for Middle East/North Africa was given as 3.8 million, virtually all of them Arabic. Presumably that will now be over 5 million. Since Turks and Syrians are close genetic neighbours, one can look ahead in time to see how well the Syrians will do by seeing how second generation Turks are doing now.

In terms of their PISA scores, not very well. Turkish children are better than first generation immigrants, but not enormously so, and certainly not at ethnic German standards.

Here are some results from:



Turks second gen results

On the bottom of the Table, men and women together, immigrants from Turkey have the lowest rates of Highest Certification, and are by far the most likely to have no certification. Indeed, they are 16 times more likely to have no certification than an ethnic German. These are not good results.

Progress has not been good with immigrants as a whole.

Migrant competence in Germany

In general, Second generation immigrants are only fractionally better than their First generation parents, and very far below the mean for ethnic Germans. If a foreign born immigrant marries a German, then it would appear that the “gap” is immediately reduced, and the resulting children are closer to the German norm, as would be expected on a genetic basis.

Needful to say, the author makes no reference to intelligence, or racial differences in intelligence. There are several references to the need for increased “support”. This has always been given, but more is always demanded.

The median IQ estimate for Turkey from the Lynn database is 89.

Turkey      92      D 48       84        Kagitcibasi, 1972

Turkey 2,272     SPM        90        Sahin & Duzen, 1994

Turkey    180    DAM         96       Ucman, 1972

Turkey 2,397    SPM          87       Duzen et al, 2008

As usual, it would be good to have more intelligence test results, but these are rarely funded in less wealthy countries, hence the reliance on anything one can glean from scholastic attainment results.

Prof Heiner Rindermann is the “man to go to” on this educational issue. He says:

In PISA 2006 second generation immigrants show somewhat worse results compared to first generation immigrants of the order of  12.75 SAS points or 1.91 IQ points. This refers to all immigrants, not only those from Turkey. For all immigrants the first generation are more from Russia, the second generation more from Turkey.

I read in an interview with Petra Satanat, PISA Germany (, on PISA 2006 that, regarding only Turkish immigrants, the second  generation students are better than the first generation students. But there were no numbers.

(I have looked at this in a rough translation, and the main point is that Turkish immigrants are two school years behind ethnic Germans. That way of putting it always makes people think that if they could only be given an extra two years at school, all would be well. Not so. This is an intelligence difference, and lower ability means a slower rate of learning, and less ability to generalize from instruction.)

He adds a reference in German: Klieme, E., Artelt, C., Hartig, J., Jude, N., Köller, O., Prenzel, M.,  Schneider, W. & Stanat, P. (2010). PISA 2009. Bilanz nach einem 
Jahrzehnt. Münster: Waxmann. p. 222

Turkish results in Germany 2009

The PISA results show:

2000 No increases for second generation Turks, or worse.
2009 Second generation Turks are slightly better than first generation, but with very 
small increases compared to immigrants from Russia-USSR and Poland.

The usual response to these sorts of results is to say that even more education should be offered to immigrants, particularly language teaching. In fact, the latter does not appear to be strongly related to scholastic attainments. It also leaves aside the question as to why other immigrants who initially do not know German do better than Turks.

Would the German government have been so keen to let in a million Syrians had they read the PISA results of second generation Turks? I would like to think that better understanding of these results might have had an impact. However, these high level policy matters are rarely based on factual considerations.

Prediction: 30 years from now people will be demanding more educational support for Syrian children in Germany.

Friday, 23 September 2016

The science of the seasons


Recently I posted some findings about sex differences in the public understanding of science. I criticized the Pew quiz for having items which were far too easy, and proposed a few harder items, on vaccinations and the expanding universe.

Before I could refine questions on those two subjects,  a reader reminded me of a delightful program in which Harvard graduates in 1987 were asked “why do the seasons happen?”

I tried to put this particular question into the very simple and very restricted format of a Twitter poll. Of course my followers are not a random selection of the public (see below). I was reaching out to an elite. Of course I know I should look for samples which are representative and also sizeable. Of course, of course. 303 non-random respondents are not enough, though possibly more than in many social psychology papers.

However, my intention was to try to create one science item in a science quiz, which can later be improved. I know that an open-ended question is far better, because respondents are not prompted in any way. I made the Twitter question as simple as I could, but probably should have stuck to “why do seasons happen?”. However, physicist Roy Bishop asked his students in 1993 “What makes summer hotter than winter?” Yes, he was in Canada, so he had an geographic interest in the topic

Given 4 reply options, respondents know one of them must be correct, which makes their task easier. I found it hard to make the three other options equally plausible. You may be able to do better. As it is, the quiz may have taught people some science, which was not my intention. My very brief “correct” answer is insufficient as a full explanation, but will have to do for the time being.

why is it hotter in summer poll.

So, a majority got it right, and only a minority went for the traditional, but wrong, answer. Only 2% went for the silly answers.

Comments please. 

Disclaimer: my Twitter followers are 75% male. 57% are in the 18-35 years age range. 68% of followers are interested in science news. In brief, their scores ought to be high.


Thursday, 22 September 2016

Heads, I win: big brains lead to bright futures


Some people refer to intelligent persons as “big brains”. They imagine those with bigger brains are more intelligent, a simple idea which is very probably right. School children, who are able to observe how the entire class deal with the same problems they are set, soon work out which children are “brainy”. The general principle that larger brains have greater power holds for many species, not just within humans.

Buried in a recent paper in Molecular Psychiatry (2016), 1–9, which itself contains a full library of publishable findings, is a little gem,:

Infant head circumference

Yes, right at the bottom of this list (and the actual table is much longer) is an indication that infant head circumference is genetically related to later educational attainment.

Here are the results in heat map format:


Infant head circumference heat map


As you can see, the sample sizes are healthy, which gives us reassurance that the findings are very probably real. Infant head circumference shows a link not only to educational attainment but also to verbal-numerical reasoning.

The authors conclude:

For example, the genetic associations between infant head
circumference and intracranial volume with educational
attainment and verbal-numerical reasoning are important in
themselves, as are many other cognitive–mental health and
cognitive–physical health associations. Taken all together, these results provide a resource that advances the study of aetiology in cognitive epidemiology substantially.

For new readers, cognitive epidemiology is a developing field of health research, in which intelligence is measured and evaluated as an explanatory variable in health outcomes. Once included, it turns out to account for sizeable amounts of the variance. In my view, failure to account for intelligence renders much of ordinary epidemiology questionable.

From the point of view of chronology alone, it is likely that having a bigger brain leads to greater ability. For once, the Press paid attention to this finding, and gave it wide publicity. Slowly, genetic research is coming to public attention.

Here is a link to the full paper from which the above section from Table 2 is drawn.

In summary: cognitive epidemiology now has a new problem: it is generating so many interesting results that it is hard to keep up with them. A nice problem to have.

Sunday, 18 September 2016

Sex, lies, and videotaped lectures


In terms of information theory, communication is the reduction of uncertainty. Transmitter, channel and receiver are part of a system communicating Shannon bits: in-guessable knowledge. Equi-probable coin tosses are the most informative, because they are hard to guess. The more predictable dross is more easily guessable and therefore less informative. So communications to you should be in-guessable and informative, and all you have to decide is in what format you want your helping of Shannon bits per second.

Printed text is my preference. It is eminently skippable. Fast forward is my favourite button. I usually read the first few sentences of a paper to detect the obfuscation quotient, then scan the references to get a deeper estimation of quality. Then if all is well, I search for the figure or table that gives me what I want: the key finding, the author’s main story. After that it is plod, plod, plod to see if I believe that sparkling jewel of a result offered for my delectation. It means working through Supplementary Appendix 3, and all that. I read while battling boredom and confusion, to check that all is well, or as well as I can bear to find out about, before I lose the will to live. No wonder that scientific papers are more quoted than read. What a perverse art form! Published papers are a confection, everything tidy and shipshape because the Inspector General is calling. No vacillation, no confessions, and sufficient ritual humility about shortcomings to confuse the innocent. I never settled into the writing of papers. Writing a blog is a liberation: like talking to a friend, compared with preparing a tax return. Will the day dawn when a blog counts on an academic CV?

Why bother with lectures? The projector is often a problem. The text is usually too small, voices not always audible, and the pace variable. And yet, and yet, there is a delight to hearing the story unfold, the detective tale of curious events in the night, the skittles of accepted findings being set up so as to be knocked down, the swerves in the path to discovery, the researcher’s art of creation. There in front of us in the lecture room is the very person, showing every aspect of their intellectual endeavours, using their real everyday words, responding to the faces of the audience, making disparaging asides, cheerfully admitting problems and short cuts, cracking jokes, taking the occasional brief interruption and then answering questions at the end so that they become a fellow traveller on the way to find the treasure at the end of the rainbow.

Lectures can have way more impact than papers. They are the royal road to understanding the researcher’s subject: the task is make the story easy to understand, and to establish the speaker as a trusted guide. A good lecture motivates you to read further, on the basis of acquaintance, and even nascent friendship. So I think it is time to sit back and listen to a few lectures.

Let’s have a look at one speaker taking on the received opinion that there are no sex differences in intelligence. Prof Richard Lynn rises to the challenge, suggesting that the majority are wrong and dares to propose a radically different point of view.

His own review of published papers with Wechsler results show (visible at 9:50 on the tape) :

WISC (6-16 years) 32 studies, male advantage 2.85 IQ points

WAIS (adults)        32 studies, male advantage 3.60 IQ points

Intrigued by these differences, he managed to get some disclosures from the test publishers of the Wechsler test by the simple expedient of ringing them up to ask if they had any findings on sex differences in their standardisation samples. Their answer will raise a few eyebrows. Incidentally, Richard Lynn asked how many other callers had asked to see those results, and was told that he was the first to do so. Here are the results (visible at 10.24 on the tape. Ignore the red line, which is just the tape progress indicator):

WAIS standardisation sex differences

It very much looks like the publishers have been sitting on the sex differences which emerge from their standardisation samples. Indeed, though this was admitted in a telephone call and exchange of emails, permission to quote these findings in an upcoming publication was denied. This is disturbing, because the Wechsler is seen as the gold standard of intelligence testing, and if there are unreported sex differences even in the carefully constructed standardisation sample, that is a cause for considerable concern.

Having criticised the stilted format of scientific papers, and the poor quality of some lecturers, I would like to announce a new art form: the integrated slides-in-vision lecture. This sparkling product, produced by Mingrui Wang, gives you a front row seat, with the lecturer in full view, and the slides perfectly visible.








Thursday, 15 September 2016

Polygenic scores


Polygenic scores on Dunedin by Belsky


Stuart Ritchie (as in Intelligence: All that Matters) has done a guest post on the British Psychological Society Research Digest. This has wide readership among psychologists, so that it is very good news that they will be getting an update on contemporary research by an active researcher. I hope that they will consider the inheritance of characteristics in all their research.

This is intended to be a very brief post, just directing you to Stuart’s article, and adding a few links.

A few points to add: Stuart mentions the marvellous Dunedin study, so here is a link to those researchers, and the questions they set the ISIR conference in 2014:

Here is a post about recent work done on polygenic scores and human behaviours:

Here is a link to the Belsky paper Stuart mentioned, from which the above graph was drawn:

As Stuart says, only 1 or 2% of the variance in these behaviours is explained by the polygenic score. This sound little, and is, but the miracle is that any link can be shown between gene sequences and complex human outcomes.

The next paper by Selzam boosts the variance-accounted-for to 9.1%. Stuart says: The polygenic scores are already pretty good predictors: in Selzam’s study, they have just about half of the predictive value of asking about the parent’s socio-economic status, or testing the child’s IQ at age 7 (and the scores are based on DNA variants that are unchanged since birth and can be measured with a simple saliva or blood test).

Of course, parent’s socio-economic status is not random. Higher status is achieved by brighter persons. IQ at age 7 is usually a better predictor of adult success than class of origin, though the two are confounded, and quite properly so.

Stuart adds: Using an even newer polygenic education estimate from a more recent gene-finding study (published in Nature this year), Saskia Selzam and colleagues found that their polygenic score explained a remarkable 9.1 per cent of the variance in age-16 GCSE results in a sample of 4,300 British teenagers

It is worth noticing that the most easily available and most often used educational achievement measure is very crude: years of schooling. Once proper scholastic and intellectual assessment measures are used on much larger genetic samples the power of the predictive polygenetic scores can very probably be considerably refined.

Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact or the author

Here is the full paper:

It requires detailed reading, and links to other recent studies on educational attainment.

In summary, we now have an incredible advance. We can now understand a bit more about how DNA, the ultimate cause of how we are built, contributes causally to an important aspect of our behaviour.

Wednesday, 14 September 2016

Are science quizzes scientific?


Pew research science knowledge


Last year Pew Research announced the results of a science quiz they conducted in 2014 on a nationally representative US sample of adults. Here is their account of their findings, from which the above chart is drawn:

Please take the test yourself right now, even if you have done so before, just to remind yourself of the items.

Of the 12 questions, I find that two are particularly weak. For example, it is a good idea to ask how vaccinations work. For example, the correct answer could be given thus: Vaccines work by making us produce antibodies to fight disease without actually infecting us with the disease. (A shorter answer would be: make us produce antibodies).  Instead the quiz asks you which person developed a particular vaccine. This is general knowledge, not knowledge of the underlying science. (I admit that when I was introduced to Jonas Salk at a Institute of Science breakfast I was overcome and could only mumble pleasantries).

There are many questions which could be asked in astronomy, such as “What makes astronomers think that the universe is expanding” (I hope that “red shift” would still be considered a good answer). In fact the quiz asks a question about astrology, which is definitely not science. A wasted question.

I think that 2 out of the 12 questions are feeble. This makes an already easy test easier, and reduces real differences between persons and groups. I hope readers will take the test, and I imagine they will get 12 out of 12, as I did. Too easy. Only two questions (boiling point lower at high altitude; loudness of sound shown by amplitude) have any bite to them, and only one question (what a magnifying glass does to light waves) is psychometrically close to the optimum, in the sense of having roughly a 50% pass mark, which is the best level for distinguishing one person from another. The other pass rates are far too high. Yes, one should have a few easy questions at the start, just to encourage people, but this test is very weak.

Looking at the above summary table of results, the education level table is also a measure of intelligence, and shows large differences in scores according to intelligence, particularly for those with only high school attainments. To my eye, age differences are minor by comparison. The white/black is very large, putting black respondents 30% below the white score. This is a considerable difference in science understanding.

Out of interest, I have plotted out the individual answers according to sex differences, showing percentage pass rates for males first, females second, and then the sex difference.

Astrology            73     72    1

Core of earth     89     84     5

Altitude              39     30     9

Jonas Salk         79     70     9

Comet                84     73    11

Correlation       69     58    11

Tides                 83      71    12

Light year         78     66    12

Loudness         42     30    12

Radio waves     79     66    13

Lens                   55     37    18

Uranium           90     75    25

Women know as much about astrology as men! Women do almost as well as men on the easy “hot core of the earth” question. Women do more badly than men on the difficult “altitude lowers boiling point” question. Most people have heard of the Salk vaccine.

Thereafter the sex gap widens. The overall difference amounts to 15% less science knowledge for women, and because of some of the weak items chosen that may be an under-estimate. Of course it would be very silly to link this to male brains being 13% larger than women’s. (More of this later, when I post up a recent lecture on sex differences in ability by Prof Richard Lynn).

On a brighter note, 64% of the US population understand correlation as depicted in a scatterplot. 

Yes, more money should be spent on science education. Of course it should. Raise high the roof-beams, carpenters!







Tuesday, 13 September 2016

Loathing wealth


global wealth map


I watch the news go by like traffic on a motorway seen at a distance: speeding vehicles of uncertain purpose and unknown destination.  In the news this morning, a charity calls upon the Prime Minister to take action on wealth inequality, saying that the United Kingdom is very “unequal”. Their data are drawn from the annual Credit Suisse 2015 wealth report, an indispensable guide for those who fear they are not keeping up with the Joneses.  As you can see from the map above, Europe 1 and Europe 2 do well, as does Japan.

The supposition behind this complaint is that wealth should be equal, and that it is proper and fair that wealth should be equally distributed among all persons. Any deviations from equal shares is seen as a cause for concern and immediate reallocation of personal savings. However, people are not equal in ability or diligence, so if they are allowed to work as their intelligence and character permit, some will rightly be earning more than others, in proportion to their efforts and skills. From that perspective, it is grossly unfair to resent the different contributions that different people make, and to demand they support the less diligent. Those who rise early should not be hated by those who rise late.

Three features of accumulated savings need to be understood.

First, a person who has been working and saving for 40 years will have more wealth than someone who has been working for only 40 minutes. Wealth is age related, and would be so even if everyone was paid the same wages, so long as people were free to save some of their income. Compound interest compounds over time, so a contribution made in the first year of work has a great impact on an eventual pension. The contribution made in the last year has no time to compound. If people are willing to save, their deferred expenditure gives them protective capital to ride out life’s storms. It is grain in the larder to protect against bad harvests. The young world will probably be a lot poorer than the old world, and bright countries will do well, so long as their governments are not idiotic. Demographics and governance matter.

Second, wealth can compound over two or more generations, if families have the wit and the love to support their children. Given freedom, families can show restraint in their own expenditures so as to help their descendants. Unless they are prohibited from doing so, most parents help their children. Inheritance taxes force them to help other people’s children.

Third, if a nation has a long history of saving, and is attractive to global investors, then nationals of that country will be repaid for generations of restraint by enjoying higher valuations on their property, bonds and savings generally. So, a long history of respecting property rights, following the rule of law, and always repaying national bonds without ever defaulting gives England a five or six century advantage. This amounts to at least 24 generations, probably more, since in Saxon times they paid danegeld to Danish invaders, showing that there was already wealth to be taxed. Nowadays savers in other less well organised countries will use England or the US to store their wealth, thus boosting all local asset prices. It may be temporary, but Londoners are reaping the delayed benefits of the establishment of Copyhold just after the Black Death.

For me, the real question is whether wealth is proportionate. Calculating proportionality is slightly more tricky than the simple notion that the fruits of a person’s labour belong to everyone. The bright will have their labour valued more highly, at the rate of 60% higher wages for those one standard deviation above the mean. Paying more for more flexible and productive workers is a great engine of wealth, and also of proportionate differences in income. Being willing to forgo immediate gratification for a benefit which comes 40 years later is an intelligence and personality test. Saving is a personal decision, set in a social and national context. Despite incentives, not all citizens save of their free will. Many have no savings at all, and could not last more than a month or two without having others pay their bills. Whatever their income, savers will be wealthier than non-savers. Those with rare talents will earn most.

Now to the world as a whole. Almost everyone is getting richer, healthier, better educated and living longer. This is good news. We are “unequal” with the past, even the recent past of 1970. We are far richer.

Now to proportionate matters. We will use the US dollar as the unit of account, even though that currency is never seen or handled by billions of people.

Global wealth pyramid


Once you get to savings of $3,210 you are in the top 50% of savers. With $68,800 you are in the top 10%,  and with $759,900 you are in the top 1%. 

Here, an interesting psychological point arises: do you compare yourself upwards or downwards? Older readers with a house and the prospect of a pension will be richer than young researchers starting their careers, so sticking to age cohort comparisons makes more sense. Do you compare yourself with the highest earners, or more properly with those who made the same career choices, probably research, university life, teaching and the like? Most readers of this blog will have been motivated by interests other than money.

As you probably know, I can simultaneously regret not having joined the Rolling Stones and not being a famous author, so I am no role model for sensible comparisons. From my point of view, the worst comparison of all is when another psychologist takes a minor finding and writes a book which leads to a lecture tour which leads to millions, and all for an effect I had classified as marginally interesting and of little significance. I feel that I should say something to those of you whose books have sold millions.

Top of the wealth pyramid

Briefly, selling best sellers is not enough. Try selling psychological tests, or a cunning program which boosts intelligence in 7 easy steps. Do not rest on your laurels.

I suppose that loathing comes from comparing upwards. What have they done to deserve it, say people staring at richer people above them? I can think of lots of things. They may have worked long hours in offices, doing work for others that did not interest them. They may have taken career risks, and worked even longer hours to build up a business. A few may have had the gift to sing, or write, or a talent to amuse. Good luck to all of them.

Just don’t remind me I should have written a best seller on how to lose weight while boosting your sex drive. 

Monday, 12 September 2016

Genius twinkling in the dark


SMPY top achievers

Perhaps I should not be too sensitive, but I still get irritated by the “intelligence, whatever that is” brigade, who disparage any attempt to measure ability and strongly oppose any decisions being made on the basis of those assessments.

My irritation is compounded by the confidence with which they make their pronouncements, uncluttered by any knowledge of contemporary findings or any understanding of the debates in the literature.

So, when any work on intelligence gets some publicity, particularly concerning the benefits of high intelligence, I feel more optimistic that public knowledge about intelligence will be proceeding at the speed of publications, not the speed of funerals.

My imagined legions of devoted readers will not need to be reminded of the work of Benbow and Lubinski and the Study of Mathematically Precocious Youth.  I have mentioned this study 15 times, so I will restrict myself to linking to only the most recent of these posts.

Now David Lubinski writes to me in some haste with a confession. He and his wife have had great coverage of their work in a big spread in Nature, with much subsequent publicity. Ever concerned with accuracy, David wishes to correct an autobiographical misconception which crept into the final part of the article:

However, just so you know, I absolutely did NOT wrestle in college!  Had I done that my undergraduate GPA would have been 2.0 units below what it was and we would have never met.  I am pleased to report that my days of two 2-hour workouts per day -- followed by going home and eating a handful of grapes and (maybe) a carrot -- are over.

Personally, I did not think of David as a wrestler. Of a good muscular build, certainly. Mesomorphic, no doubt. But not the sort of chap you see in a leotard. So, is Prof Lubinski a wrestler? No, that is a myth. He was not a wrestler at college. Perhaps journalists rely too much on lackadaisical googling.

Am I a cage fighter?

Thompson cage fighter

I never talk about my evening work.

Anyway, here is a very good article about the power of intelligence, those bright people who are 1 in 10,000 minds.  Key points: to find them test for verbal, mathematical and spatial for best results. Terman was verbally focussed, and thus missed some very bright students. Don’t dream of creating a genius: just encourage and support children as they find their talents, and look after their intellectual and emotional needs. Allow the very bright to skip grades: they do better than those forced to follow the standard curriculum. Intelligence is key, but motivation, personality and effort make a contribution, though far from being as big as pure ability. There is no barrier at IQ 120 or anywhere else: every increase in measured ability leads to higher achievements. Predictably, some educationalists are lukewarm about selecting high ability students for accelerated opportunities. Darkness always has its advocates.

Please make sure that at least one clever silly of your acquaintance gets to read it.





Friday, 9 September 2016

The intelligence factory


Pupils in a classroom


For reasons of neighbourhood activism, I get lots of mail from nightclubs. They affect a keen interest in my well-being, and assure me that they are respectable operations, not the sorts of rowdy places from which drunkards disgorge in the small hours of the morning, vomiting, slamming car doors and occasionally knifing similarly inebriated revellers. No, they assure me, such things will never happen at their establishment, but just in case of any problems they have provided a telephone number for residents, which they ask me to circulate, where complaints will be carefully taken down, logged, recorded, considered and ignored.

So, it was with some excitement that I received what appeared to be a golden key to the VIP section of a nightclub, Room 70. In addition to the key there was a good quality brass lapel badge.  I was prepared to be suborned by these gifts, but it turned out to be the entrance to an even more entertaining locale: a Scottish intelligence factory.

The golden key was a USB with some good moody soundtracks and a 1950s lecture by Godfrey Thomson on the art of lecturing. Billed as “The man who tested Scotland’s IQ” the exhibition on Thomson is a look at the mind and the techniques of a very talented man, driven by a moral impulse: to do everything possible to improve methods of discovering intelligent children who might be overlooked, and guiding them into forms of higher education likely to both make them happier in their lot, and useful to a society and civilisation which needs them.

I write this today, Friday 9 September 2016 as Prime Minister Theresa May presents a policy of increasing the number of Grammar Schools, which in the English context are selective schools for brighter pupils. This policy is, as far as I can make out from this morning’s interview with Justine Greening, Secretary of State for Education, being proposed on the basis of increasing parental and pupil choice, but is being criticised and judged on its capacity to create social mobility, and mitigated, if that is the right word, by a requirement to take on a proportion of pupils who are poor. In sum, the policy does not propose selecting pupils solely by merit, but also by poverty, and the moral principles espoused by Thomson might cause some embarrassment in contemporary circles. The weight of informed educational opinion is that selective Grammar Schools are a bad thing. The Chief Inspector of Schools, Sir Michael Wilshaw has said: My fear is by moving to a grammar and secondary modern system - because, let's face it, that's what well have if you divide at 11 - we will put the clock back, and the progress we have made over the past 10 to 15 years will slow."

So, we are looking back at ancient educational history, because Sir Godfrey Thomson was intent upon discovering children who might be overlooked by the technique of testing their minds, not their parent’s wallets.

In the 1940s an 1950s Thomson was the largest-scale producer of IQ tests in Europe, distributed in their millions. A modest man, he did not seek personal acclaim, did not keep the money his tests raised but placed it in an educational trust, and did not call his tests after himself but after his place of employment, Moray House. A maths and physics graduate, and later pupil of C.S. Myers, he dominated his field, and was feted by E.L.Thorndike, Karl Pearson, and R.A.Fisher. He became famous and then faded. In a twist of fate, he was an early advocate of comprehensive (non-selective) education which, as it became the accepted wisdom, rendered his massive intelligence testing operation redundant, in social and political terms, if not in reality. He wanted equal amounts spent on each pupil, disregarding his needs and abilities.

Essentially a hard scientist, Thomson tackled intelligence testing from first principles, mostly drawn from maths. He was a statistical pioneer, leading to what is now called item response analysis, the detailed response characteristics drawn out by each individual test item. The centre of the operation was Room 70, crammed with psychologists and statisticians (using Facit calculators, of the sort I was still trained on in 1965) , in which tests were devised and then distributed. In 1949 alone that came to over one million tests. At around that time two in every three children in England sat a Moray House test.

Here is the justification for intelligence testing in one single sentence Thomson wrote in 1952: intelligence tests if properly constructed are less dependent upon educational opportunity and measure, to a larger extent than ordinary examination, the innate potential intelligence.

Thomson also knew that testing could not be reliable enough on a single occasion to come to a final judgement, and favoured repeated testing. Testing was fair because it could reveal the true potential of each child, and could be liberating, as it was for him.

Now we come to Thomson’s greatest legacy. On 1 June 1932 every child born in Scotland 1921 (87,498 in all) sat Thomson’s Moray House Test No. 12 of general intelligence.  On 1 June 1947 every child born in Scotland in 1936 (70,805 in all) sat the same test.

Within a short period Thomson could report that Scottish intelligence, far from falling because of lower class fecundity, had in fact risen somewhat. Having thus led the world in population intelligence testing, Scotland then put the results in a cellar, and forgot about them. Those who bothered to find them in 1997 turned copperplate records into research gold.

They launched the new field of cognitive epidemiology, showing that brighter children live longer, and not just because they make better choices in life. The 11+ results have provided a corrective to many fanciful cross-sectional health studies. You know the sort: too much/not enough sleep/sausages/bacon/vegetables/coffee/sugar/dental flossing/exercise/sitting at a desk/ is associated with: obesity/premature death/premature baldness/premature ejaculation. However, when you factor in intelligence at age 11 most of those disappear as causes of longevity, except for smoking. Don’t smoke, and don’t read too many health warnings, is my advice. Just hope you have been born with system integrity.

As to Grammar Schools, Faith Schools, Academy Schools, Comprehensive Schools, and good, bog-standard and bad schools, they account for 10% of the variance at the most. 90% is down to the student, at least in reasonably organized countries that can run reasonable quality subsidized schooling. My own view is that most head teachers know that, though most feel they cannot admit it in public, so they battle furiously to get the brightest students, which will make them look good. The angry debate is mostly about who gets first choice of the brightest.

Lest silence be taken to imply that Thomson was hell to work with, there are countless witnesses to his helpfulness to staff and students, his love of his family and of music and theatre. About leisure he said: with mastery, won in most cases before thirty, comes leisure which can be truly enjoyed, not leisure stolen from duty.

He had a formidable mind, but was gentle with it, he was world-renowned but maintained his humility, he turned down considerable personal wealth because he wanted above all to give every child the opportunity he got when he won a scholarship to a school, aged 13.

The exhibition in Edinburgh closes on 29 October, but the debate about the selection of students, and the best way to educate them, seems likely to last for ever.


Monday, 5 September 2016

Myths, mental illness and violence: Reply to Prof Lilienfeld

I am grateful to Prof Lilienfeld for responding to my blog post of 7th August.

Correct information about mental illness is an important matter, and worth debating, so it was good to be able post up his “Author replies”. Debate is the essence of empirical enquiry, so that arguments can be tested. I often let the reply stand without comment, but this time I am responding, albeit somewhat hesitantly and wanting to be sure of my interpretations, because the debate raises important issues about the public perception of mental illness.


To get an understanding of my arguments the following posts listed below would be helpful for new readers. For those in a hurry, the first post on “delusional numbers” would be sufficient.

Delusional numbers. 25 March 2013
This gives general background to the research, and discusses methods, and criticises some of the ways in which results have been presented. Summary: an increase in violence by schizophrenic patients over the population norm.

Bad Blood. 2 September 2013
This describes relative risk of getting a severe mental disorder depending on whether your parents have a severe mental disorder. Summary: 2.5 relative risk of getting a disorder. This is not directly related to violence, but relevant to the often-feared issue of hereditary madness.

Genetic story jumps ahead. 17 November 2015
Shows that schizophrenia and bipolar disorder exhibit a genetic correlation with cognition. Again, not directly about violence but about the genetic component.

Schizophrenia and violence. 30 December 2015
An early description of the just released A Sariaslan, H Larsson and S Fazel paper on violence in the mentally ill.

Myths dispelled, new myths propagated. 7 August 2016
Comment on Prof Lilienfeld chapter.

Detecting schizophrenia myths. 10 August 2016
Comment on the Large paper about detecting violent behaviour in schizophrenic patients; also includes more of the published A Sariaslan, H Larsson and S Fazel paper.

Postcodes and schizophrenia. 13 June 2016
Summary: Having psychotic experiences is very highly heritable; having the diagnosis of schizophrenia also highly heritable; and ending up in a deprived neighbourhood is also heritable.

Now, after that digression, back to the main story.

In his book Prof Lilienfeld disposes of the myth:

Myth 43 Most mentally ill are violent.

What I said in my post was: First, note the absolute nature of the myth: what is being dispelled is that a majority of mentally ill patients are violent. The myth is presented in exaggerated form, as a straw man, thus obscuring an important issue. What people fear is that mentally ill people are more violent than mentally well people, and on that basis it may be prudent to avoid them.

Prof Lilienfeld says this is not relevant to the myth he is describing, and that therefore my comments are a non sequitur. I felt that his putting up the “myth” in that strong form and then refuting it led to later misunderstandings, and that is why I worked through his supportive arguments and some of the references he gave in support. So, my apologies to Prof Lilienfeld. I should have made it far clearer that I agreed that Myth 43 was a myth. That was all he was claiming. On that basis Prof Lilienfeld is perfectly justified in reading no further.

Related matters

I do not know how many people actually think “Most mentally ill are violent”, which is the myth that Prof Lilienfeld and colleagues wished to refute in their book. As far as I can see, there is no confirmatory data from national surveys. I don’t think that most people go that far. They just assume or notice a link of some sort, enough to worry them somewhat. The Time Magazine article Prof Lilienfeld quotes in his reply does not confirm that the general public believe that most mentally ill people are violent, as Prof Lilienfeld himself readily concedes, but that they are more likely to be violent, particularly if they have schizophrenia. This is true. Media often exaggerate exceptional events. They are not always reliable sources of information about mental illness. The Time article links to a US government health website, which has this statement:
Myth: People with mental health problems are violent and unpredictable.
Fact: The vast majority of people with mental health problems are no more likely to be violent than anyone else. Most people with mental illness are not violent and only 3%-5% of violent acts can be attributed to individuals living with a serious mental illness. In fact, people with severe mental illnesses are over 10 times more likely to be victims of violent crime than the general population. You probably know someone with a mental health problem and don't even realize it, because many people with mental health problems are highly active and productive members of our communities.

The point of my original post was to question assertions of that kind. Namely, the 3-5% violence rate can only be interpreted if the rate of serious mental illness is also given. Being a victim of violence does not preclude also having been a more-frequent-than-usual perpetrator.

I was also somewhat critical about the “exposing myths” approach, while recognising that it is an engaging format, and that under that rubric some weak arguments have been exposed, and some popular beliefs revealed to have little research foundation. Some myths are myths. My concern is that once something has been called a “myth” then there is a risk it must be destroyed even if part of it is true.

I think that is happened in this case, because there is a middle ground where Prof Lilienfeld and I are in much closer agreement, namely about elevated levels of violence coming from some mentally ill persons, though we still differ in our emphasis as to how significant this is, and whether it explains a public perception of mentally ill persons being dangerous. We both reference work which shows elevated rates of violence among some mentally ill people. He sees those as modest. I see those as more significant, and the likely cause of some people’s over-generalised fear of mentally ill people.
For example, Prof Lilienfeld in his reply references the 2012 work of Van Dorn, Volavka and Johnson and quotes the authors’ conclusion: “..there is a statistically significant, yet modest relationship between SMI [serious mental illness] (within 12 months) and violence, and a stronger relationship between SMI with substance use disorder and violence.”
So, I looked up the figures which are shown in Table 1

The national household sample is a good one, though the period of reporting about violence is the past year only, which might produce lower overall estimates of a general tendency to offend. Violence rates are derived from reports during an interview, not an examination of convictions. The population base rate is 0.83, the Serious Mental Illness (schizophrenia, bipolar, major depressive) rate 2.88, or 3.5 times higher. Combined with substance abuse, the rate is much higher at 9.97, with a high relative risk of 11.45. Briefly, severely mentally ill persons who also take drugs are 12 times more violent than the mentally well. You may question why they take drugs, but those who do so are particularly more likely to be violent. Substance abuse is more common in people with mental disorders. (It is a bit like wayward youths getting into bad company: it is that sort of company many of them choose). Most people in the population are not violent. Those with severe mental illness are 3.5 more violent within one year, and those with severe mental illness abusing drugs, 12 times more violent within one year. As to whether these relative risk rates are modest is something the public can decide for themselves.

Personally, I disagree with the authors that these relative risks are modest (although the absolute risks are low). I judge them to be appreciable, and by the judicious avoidance of such persons the public can reduce their risks, if they wish to.
However, Prof Lilienfeld says that he and I are in agreement on this matter: “I (we) did and do not question Thompson’s conclusion that severe mental illness is tied to a heightened risk of violence, although at least some of this link appears to be mediated by substance abuse.”

(When researchers disagree only slightly, does this causes even more contention? Discuss!)

Prof Lilienfeld mentions that in his 1994 book he made comments on the Teplin (1985) paper, which chapter I did not know about. Ignorance on my part, pure ignorance, for which another apology. I have not been able to get the relevant book chapter yet. Prof Lilienfeld says: “There, I discussed some of the same sticky inferential issues regarding covariate control raised by Thompson.” So, any imputation that Prof Lilienfeld does not understand these issues is unwarranted. However, he did give Teplin (1985) as a support to establish that the rates of violence in severe mental illness were modest, and that was why I criticised that paper. It seems that both of us have reservations about the way that some covariates were controlled for.

Prof Lilienfeld has a further criticism: “Thompson seems to fall prey to the commonplace error of confusing relative with absolute risk ratios (see the following article for an excellent review of this and similar topics: Specifically, the fact that schizophrenia is associated with a several times higher risk of violence does not imply, or come remotely close to implying, that most people with schizophrenia are violent. To do imply thus would be to fall prey to the related error of base rate neglect, as the base rate of schizophrenia in the general population is probably a bit under 1 percent.”

For the avoidance of doubt, I was not suggesting that a higher relative risk meant that most people with schizophrenia are violent, merely that schizophrenia is associated with increased violence.

The link which Prof Lilienfeld has kindly given above is by the commendable Prof Gerd Gigerenzer. I have written 7 posts which reference Gigerenzer, including the one on Delusional Numbers above. Using the search bar on the blog will call them all up, including my commendation of him thus: “It can rarely be said of a psychologist that everything they write is worth reading. Gigerenzer is one such psychologist. He writes in plain English (presumably his second language) and understands his material so thoroughly that he can explain it simply, the sign of an intelligent and honest teacher. This straightforward approach means that you can follow this heuristic to make you smart: if you cannot understand him first time around, it is worth reading him several times until you do. With lesser writers, if you cannot understand them first time, turn elsewhere.”
Out of the 7 posts, here is one which particularly looks at absolute and relative risks.

So, it turns out that both Prof Lilienfeld and I are fans of Gerd Gigerenzer. That does not mean that I have got Gigerenzer right (please let me know if I have misunderstood relative risks or any other of his points, because I may need to read him several more times), but I suppose we could learn from him and move this debate away from percentages and relative risk figures to natural frequencies, which are better understood by the general public. A task for next time.

However, more recent work, not available when Prof Lilienfeld and colleagues were writing their book, suggests a more significant difference in violence rates for particular forms of mental illness. Let us use those findings as an up-to-date test case. How should we describe them in a way which is fair and balanced, and does not lead to misunderstanding and inadvertent myth making?

On 30 December 2015 I did a post on a recent population study about violence and schizophrenia in a full population sample of 1.8 million siblings drawn from 3.2 million men from Sariaslan, Larsson and Fazel (2016).

This massive study gets around most of the problems of representativeness encountered by convenience samples. Also, in typically Nordic fashion, the measure of violence is actual convictions drawn from the National Crime Register which includes custodial and non-custodial sentences and cautions, rather than report at interview, and not one year but lifetime since 1973, so a far more reliable indicator. The main findings are shown in Table 1 which I reproduce below, the findings of interest in the very bottom line:

Here is the link to the paper

Here are the results on violence in pictorial form:

A Sariaslan, H Larsson and S Fazel (2016)

The authors say: We observed that nearly one in four (23%) schizophrenia patients had ever been convicted of a violent crime, whereas the equivalent prevalence was 11% in patients diagnosed with bipolar disorder and 3% in controls.
This paper made me revise my earlier view that there is a fivefold increase in violence in schizophrenia. In this 3 million person population sample, schizophrenics are 7.5 times more violent, bipolars 3.5 times more violent. Some mental disorders lead to violence at rates which are higher than the general population norm. From the public’s point of view, the picture is clear enough.

In some ways this is all very simple: not every mentally ill person is violent, but the incidence of violence in mentally ill persons is raised in at least two conditions, schizophrenia and manic-psychosis (bipolar disorder) to above average levels. So the depiction of mental illness should be balanced, with most patients no more violent than anyone else, but in the case of those two conditions substantially higher, particularly when patients are in-medicated and using non-prescription drugs.
The risks should be given correctly so that people can come to their own conclusions. The link between mental illness and violence has some basis in reality. In some conditions such as schizophrenia the violence rate is raised appreciably. It would be an error to exaggerate the risk, and an error to over-generalize from one condition to all conditions, but in my view it would also be an error not to note that there is an elevated risk in the first place, which may account for some public alarm.

In summary, those who believe: “Most mentally ill are violent” are wrong. Not all the mentally ill are violent.

Those who believe: “A majority of the mentally ill are violent” are wrong. The majority of the mentally ill are not violent.

Those who believe: “Some of the mentally ill are more violent than mentally well people” are right. Some of the mentally ill are more violent than the general population.