Tuesday, 27 September 2016

Background slides to a short intelligence test


Here are the contact details for Julius

E-mail: julius.db@icloud.com

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 (www.spiegel.de/lebenundlernen/schule/pisa-studie-am-haertesten-trifft-es-die-migranten-a-521334.html), 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 help@nature.com or the author

Here is the full paper: http://www.nature.com/mp/journal/vaop/ncurrent/full/mp2016107a.html

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.