Wednesday, 24 August 2016

More diversity illusions


Cover of the Race report 2016

It is unkind to mock the afflicted, but reasonable to ask them not to sneeze in our faces.

The Equality and Human Rights Commission in the UK has published a document entitled: Healing a divided Britain: the need for a comprehensive race equality strategy. Described by them as the biggest ever review into race inequality in Great Britain, providing a comprehensive analysis on whether our society lives up to its promise to be fair to all its citizens, the full report can be found here:

The Equality and Human Rights Commission does not regard itself as afflicted,  yet it is afflicted by significant bias: a tacit acceptance of a world view they believe to be inherently correct: that unless outcomes between ethnic groups are equal, that is prima face evidence of bias, also known as racial discrimination.

They state their objectives thus: The Equality and Human Rights Commission is calling on the UK, Scottish and Welsh Governments to address race inequality and discrimination experienced by people in Britain in a comprehensive and coordinated way.

They give details of inequality in education and learning; work, income and the economy; health and care; justice, security and the right to life; and the individual and society.

I started by looking at the references, and they mostly relate to government reports, trade union reports, a Guardian article and some books and working papers. There was nothing I could find from the peer-reviewed literature on scholastic attainment or intelligence, and nothing on genetics or the heritability of behavioural characteristics. This is a prime example of a confection which is lawyerly rather than scholarly. It is written by lawyers who ignore the world-as-it-is for the world-as-they-want-it-to-be; nay, the world as they command it to be.

At this point it might be wise just to turn away, because it is a weak publication, but to do so would make it seem that we have received the sneeze in our face without demur: that we had agreed that Britain is divided, and needs healing, and that new policies are required to make Britain more equal, and the underlying cause is racial discrimination by White British people.

The rejoinder is that Britain is doing its best to cope with large-scale unselective immigration, is paying the price with relative good grace, but cannot overcome genetic differences and deep-seated immigrant cultural norms. Furthermore, immigrants who are as bright or brighter than the locals do well, those who are less bright do worse, and the average intelligence of the country of origin is the best predictor of outcomes for immigrants to the UK.

Immigrant competences:

The suppression, or “ignoral” of these findings makes it possible to insult the White British majority with imputations of foul character, and to demand further taxation for race-based equality compensation schemes.

I will pick only a few areas for comment.

Here is a sample comment (page 5 bottom paragraph): It is indefensible that in 21st century Britain, Black workers with degrees earn over 23 per cent less on average than White workers with degrees; and if you are Black in England you are more than three times more likely to be a victim of murder and four times more likely to be stopped and searched by the police.

Degrees: University degrees in Britain are now obtainable from institutions of very different quality, ranging from the Russell Group who require very high exam results to institutions which require nothing more than good intentions. The latter weak institutions are numerous. Weaker students go to the weakest institutions, and gain less valuable qualifications. A good degree from a good university boosts income by about 60% over those without degrees. A bad university does not boost income to anything like that amount, if at all. The above percentages would be informative if the complication of heterogeneity of degree quality was acknowledged. Low scoring minorities are disproportionately represented in low achieving universities. Employers know all this, and many restrict recruitment to those universities who require high entry standards. A wise policy.

Victims of murder; and stop and search: What you will not find in this report is the descriptions victims give of their assailants. This would allow researchers to see whether Police are searching for suspects in line with the reported ethnicity of the assailant. Unless we know the race of the assailant the other statistics are misleading. If Black Britons are doing more of the crime, and offering more violence to those closest to them, other black males they compete with; they will be stopped and searched more often, and put in prison more often. This is a proportionate response, and would only be disproportionate if the data of the assailants were available. In the absence of UK data, here is some from the US. The overwhelming majority of black homicide victims (93 percent from 1980 to 2008) were killed by other black men.

Here is a study looking at criminal justice procedures, but controlling for IQ and previous criminality.

On education, the Commission report says (page 10, point 3): Ethnicity has been shown to impact a child’s educational attainment at GCSE level in England and Wales, and the GCSE equivalent (Standard Grade) in Scotland.6 Data in England shows that Gypsy/Roma, Irish Travellers and Black Caribbean pupils have the lowest attainment. In addition, ‘Is Britain Fairer?’ found that White boys receiving free school meals in England and Wales had the lowest educational attainment at the age of 16 in 2015.

“Ethnicity has been shown to impact…” is a curious construction. A more usual description would be “some ethnic groups get low examination scores”.

In criticism of Government initiatives they say (page 12, point 4, second paragraph): By addressing individual issues in a piecemeal way, without consideration of causes, drivers and levers for change, actions taken are unlikely to be effective in the long term or provide significant and sustainable change.

“Without consideration of causes” raises a wry smile, because they do not consider inherent behavioural differences at any stage. I think they would consider it morally wrong to do so. Blithely, they continue: For example, we will not make sustainable progress in reducing the ethnic minority employment gap unless we address the educational attainment gap.

Well, let us look at that. The US has tried to do that since the middle of the last century. Despite best and expensive efforts, the scholastic gaps at the end of schooling, though reduced, remain substantial, with commensurate impacts on later occupational achievements. Asians are ahead of Whites, who are ahead of Hispanics and Blacks. Using these data the proportions of the different racial groups who would be 2 sigma above the European white mean (and thus gain entrance to a highly selective university) are: Asians 4.78% , Whites 2.28%, Hispanics 0.82%, Blacks 0.47%.




For example, here is a bald statement which, in the Commission’s view, shows “inequality”:  Just 6% of Black school leavers attended a Russell Group university, compared with 12% of Mixed or Asian school leavers and 11% of White school leavers.

The predictions above would suggest that if entry were based on ability alone the rates of attendance would vary even more (this assume US results reasonable proxy for UK, which is close enough for illustrative purposes) . The main point is that differences in group level intelligence will have big impacts on participation at elite universities.

What they could have said is that since black school leavers have lower exam scores they go to less good universities. They could also have said that another genetic group, Asians, do better than Whites, so the big difference is between the scholastic levels of Blacks and Asians, not the fact of them being ethnic minorities in Britain. They could also have added “And this is in line with international scholastic ability, as shown in repeated PISA, TIMMS and other assessments.” The authors either intend to mislead, or have misled themselves so comprehensively that they cannot give a balanced account.

The Commission does not give tables or figures, perhaps because the greater scholastic abilities of the Chinese would be all too apparent. Instead there is a litany of percentages, from which it is difficult to draw any conclusions other than that minorities are hard done by. Often the use of percentages of percentages leads to confusion. Those seeking details are referred to other websites. It is the old “Supplementary Appendix 3” problem all over again.

Although the Commission is against racial stereotypes they cannot resist the temptation to use a new label “White boys FSM”. I wondered idly if this was white boys who, against the trend, were carrying out Female Sexual Mutilation, but it turns out to refer to Free School Meals: in other words, Poor Whites. It is now generally admitted that they are doing badly. Quite how this fits in with the narrative is unclear. The story seems to go like this:

White people are biased (hence the need for more anti-racial bias policies), and are prejudiced against other races. Formerly this bias was blatant, now it is subtle. Admittedly, they are not prejudiced against yellow skinned Chinese, and against brown-skinned Indians, but definitely against Black skinned Africans from the colonies, but not against Africans direct from Africa, who are doing well. But Whites are generally prejudiced anyway, so these exceptions need not concern us. Whites are even prejudiced against White people if they are poor because, I think, white people are racist and also class-ist, and hate foreigners and all poor people. Brexit has made them worse, because they now hate foreigners even more. Britain has had a spike of “hate crimes”. However, not given prominence in this report, Britain is still one of the world’s most favoured destinations for all immigrants. Nonetheless, more anti-racism policies are required.

You may need to help me here, because I have had to infer the argument from the tone of the report, and the contradictions are not discussed.

 One of their policy recommendations is interesting:

4. All governments improve the range and scope of the disaggregated ethnicity data available – including intersectional data – and ensure that ethnicity statistics and research findings inform their race equality strategies.

This is fine if they collect racial data on a broad range of issues, including the perceived race of assailants in reported crimes. It would be good if they could include data on racial differences in intelligence in their next report. None of this is likely to happen, but I am simply pointing out the obvious gaps in their arguments.

The Commission are entirely un-reflexive about immigration. It is presumed to be a good thing. They are secure in their opinions, and woe betide you if you do not share them. Criticising them may eventually get registered as a hate crime.

I know that I should track down every single thing they have left out, but it is August, the silly season, when people release silly stories to fill up the newspapers. Strangely, the sun is shining, so one should not get too agitated about biased, partial argumentation being used to strongly imply that racial differences must be the fault of one race, not the result of the different characteristics of all races. For example, the Olympic 100 metres final has been 100% West African for decades. This is not a black conspiracy, any more than East African dominance in long distance races is a conspiracy. It is a result of underlying genetics, plus some sponsorship.

Anyway, too much sunshine to push all this further.

I do not wish to speak ill of anyone, but I suspect this report was written by a lawyer.


Wednesday, 17 August 2016

Philosophical Printers: a study in complexity



I make a habit of confessing my cognitive errors, as a warning to others, an illustration of my inevitable limitations, and the better to understand them. You may remember the difficulties I have getting myself to conferences, because of having to coordinate travel times, country zone time changes, car rental and return times,  to say nothing of getting the dates of travel to correspond to the early commencement of welcoming lectures the following day.

Last week I had a struggle with a printer which would not print. Printers used to be insensate objects which merely printed. They knew their place: slaves to the computer master. Now they have developed philosophical doubts about their purpose in life, and will not print unless handled with extreme tact. They can hold your work hostage, and know how to exploit Luddite bargaining power. They demand registration, your personal details, and the right to tell you in subsequent communications how they are developing as a product. That is the unkind interpretation. A more gentle view is that they are suffering from identity anxiety and polymorphous existential doubt: they do not know if they are scanners, copiers, glossy photograph booths or even, in their atavistic past, fax machines. One gains the impression they have been reading Goethe’s “The Sorrows of Young Werther”.

Newly bought, my printer seemed benign: a harmless helper without sharp edges. It arrived without a full set of printing cartridges, so it sulked at being asked to work without the required complement of colours, particularly the missing magenta and cyan (it was quite peeved about those) and there was a delay till those were delivered the following week. The proffered installation disc was rendered obsolete by my new laptop no longer catering for this out-of-date medium, so I downloaded the software and then the problems began.

The printer had its own set of priorities. It was willing to connect by Wifi, but demanded that any device have a username and a password. My router had a username and a collection of passwords, though not labelled as passwords, on the underside of the router. I tried a variety of these, but the printer rejected them petulantly. Eventually I found a new potential password on the edge of the router, and that partially mollified it. It printed a test page, and then nothing else. Documents it rejected, keeping them in the Documents Printing queue for ever. This is the printer equivalent of the Passive-Aggressive ploy.

After many attempts, I decided to resolve the high level of complexity by going for a very simple solution: a cable between printer and computer. After a week the cable arrived, and when attached the printer still sulked, printing nothing, other than a page saying it was connected, but had elected to go Offline. It remained Offline thereafter, whilst still occasionally moving the print head in a suggestive and reassuring manner.

There were two problems: the connectivity problem, whatever it was; and my mental model of the problem, which was probably wrong in one or several of its parts. For example, should the computer and printer talk to each other through the router, or to each other? When the printer asks for a password, is it the password to the router or the computer? Why doesn’t the direct cable work,  and why does the obviously connected printer say that it is “offline” and remain sulking offline? Why do the many instructions distinguish between different types of cable, USB, Internet, etc. but not explain why? Why do the advice forums say that you should re-install the software? Why do so many advice forum questions get answered by people who have surface plausibility and zero knowledge?  Why are the simple installation manuals so simple, and yet so complicated in their ambiguity? Why does my iPhone have no problem connecting with the printer, even though it has never met it before, let alone never having been introduced properly?

You may say, quite rightly, that I should have solved this problem simply and quickly. True. I know it has not happened to you. I also confess that I do not know how I solved it, or if I have solved it permanently. It printed something, and I am grateful, as any supplicant should be. One of my many downloaded connectivity solutions may have done the trick, or they may yet interact to thwart me once again. It is a fraught relationship, ripe for psychoanalytic interpretations.

I simply illustrate that even trivial problems contain some complexity, and understanding some of the complexity does not necessarily help, because some complex understanding is itself imperfect, and because some things have become more simple as a new solution leapfrogs an old problem. That is the joy of competence, as Bryan and Harter found in 1897, in their psychological studies of the emerging technology of telegraphy. Once operators understand the overall meaning of a message, the details of the Morse codes of individual letters can almost be ignored. Key presses give way to a higher grammar, with a commensurate increase in speed and power of communication. Similarly, we will soon let computers connect to each other with their own handshakes, troubling us no more with their quaint requirements, local customs and digital shibboleths.

Till that day, there will be the odd confusion, born of imperfect understanding, a discrepancy between model and reality, in which the latter always triumphs, and the printer refuses to print. May it not happen to you.


Thursday, 11 August 2016

In a free state


The evening was English, overcast with a  brisk breeze, and the club garden seemed just warm enough for a drink, but not for a longer dinner. Then the wind abated, some blue sky appeared among the clouds, and we decided to risk it.

Almost at the end of our meal, with pink clouds glowing on a fine August evening, a new party came to dine, gathered round an older man with a face which seemed familiar from book covers. I was excited but also abashed, and wondered if it would be best just to leave him to his meal, uncertain that it was really him, and not wanting to intrude. I dawdled over a protracted coffee to consider what to do.

When it could no longer be delayed we rose to leave, saying goodbye to two separate tables of friends, and I gathered courage and approached his wife, saying: “Do you always get your meals interrupted by strangers paying their respects?” She was gracious and welcoming, saying it happened sometimes, asked my name, and told me hers, thus confirming I had recognized him correctly. His sons smiled in welcome. So I turned to him and all I could say was: “Thank you for writing”. He smiled warmly and thanked me, and I left, very emotional.

Authors have great power over us readers. We let them drive the car of our imagination, at speeds and on journeys of their choosing, and let them hold the keys for ever.

Thank you, Vidiadhar Surajprasad.

Wednesday, 10 August 2016

Detecting schizophrenia myths


The British Psychological Society publishes a Research Digest, and the latest one lists:

10 of The Most Widely Believed Myths in Psychology

Here is Myth No 3:

3. Violent offenders usually have a diagnosis of mental illness
When people with mental health problems commit violent crimes, the media takes a disproportionate interest. No wonder that surveys show that most of the public believe that people with mental illness are inherently violent. In fact, as Scott Lilienfeld and his colleagues explain in the 50 Great Myths of Popular Psychology, the evidence suggests that at least 90 per cent of people with mental illness do not commit violent acts, and the overwhelming majority of violent offenders are not mentally ill. Some patients with specific conditions (such as command-based hallucinations "telling them" to commit acts) are at increased risk, but actual acts of violence are rare.
A telling meta-analysis from 2011 concluded that 35,000 high-risk patients with a diagnosis of schizophrenia would need to be permanently watched or incarcerated to prevent one killing of a stranger by a patient.

In my last post I looked at the relevant item written by Scott Lilienfeld and colleagues in 50 Great Myths of Popular Psychology and found that the first few references, in my view, were not the endorsements that Lilienfeld and colleagues imagined they were, and that they had not dealt with the proper epidemiological papers in sufficient detail. (He disagrees, and will be writing a reply in due course). I thought that the rough estimate of male schizophrenic patients being five times more violent than members of the public was probably right.

Looking back at the BPS Research Digest I realized that I had not dealt with the last claim made in that publication, that “35,000 high risk patients with a diagnosis of schizophrenia would need to be permanently watched or incarcerated to prevent one killing of a stranger by a patient.” Here is the relevant paper:

The Predictive Value of Risk Categorization in Schizophrenia

Matthew M. Large, Christopher J. Ryan, Swaran P. Singh, Michael B. Paton, and Olav B. Nielssen,


DOI: 10.3109/10673229.2011.549770

You might imagine from the BPS Research Digest that this paper shows that you cannot detect which schizophrenic patients will be violent. Not really. The paper discusses whether a screening test applied to all schizophrenic patients would be able to detect a series of harms which vary considerably in frequency. The least frequent is the killing of a stranger in any one year, and that provides the astounding “35,000 patients to prevent one death” headline. Other harms are much more frequent, and more easy to detect. In defence of the above authors, their calculations are based on two assumptions: that the actuarial risks they use are the correct ones, and that the screening methods deployed are the best available. There are also new findings, available since they wrote their paper, to which I refer at the end of the post.

The base rates used by Large and colleagues are annual risk figures, not risks for longer periods. They derived them from from the published literature up till 2010.

As to screening instruments, Large et al mention Psychopathy Checklist–Revised (a semi-structured interview and questionnaire to elicit psychopathic personality); Historical Clinical Risk Management (specifically assessing violence risk from a historical, current and future perspective); Manchester Self-Harm Rule (assessing self harm and suicide risk), and the SAD PERSONS scale (suicide risk). So only the second scale is directly concerned with estimating the risk of violence to others. It is a well-validated scale with an extensive bibliography.

violence risk assessment

Is it any good at predicting violence? In a reassuring move, they answer this question using Receiver Operating Characteristics statistics, which show the overall accuracy of the measurement approach. I first came across this concept in the papers on attention written by John Morton, who thus taught me about ROCs and d prime long ago. Thanks, John.

A given area represents the probability that a randomly chosen person who scores positive on the dependent measure (in this study, is actually violent) will fall above any given cut-off on the predictor measure, and that an actually non-violent person will score below the cut-off (Mossman & Somoza, 1991). Thus, an area of .75 means that there is a 75% chance that an actually violent person would score above the cut-off for violence on the predictor, and an actually non-violent person would score below the cut-off. AUC values of 0.70 may be considered moderate to large, and .75 and above may be considered large.

The reported AUC values are in the .60s, .70s and some .80s according to which samples are being studied. In fact, the instrument is a good approach, and worthy of being improved further.

Rather than screening methods, I think that Operational Research is better. For example, evaluate those patients with prior problems of violence when they request re-admission for treatment (since not all those who apply can be admitted for treatment). That group will have a higher probability of offending than patients who comply with their medication. An illustration of the possibilities for a Bayesian approach can be derived from the very tables of frequencies given by the authors below.

The Large et al. paper is a careful piece of work, and I like their general approach. They know that actuarial methods are better than clinical judgment. They create a hypothetical screening instrument, but admit that the base rates for different harms are very different, and decide to use the same cut-offs for all harms, which may reduce the detection of violence to others. ROC curves would have been a welcome addition for comparative purposes. However, they say that they have set sensitivity and specificity to 80% each, exceeding what is reported in the general literature for future violence.

Here is the crucial table:

Positive predictive value in schizophrenia

As you can see, assaults are committed by 1 in 7 untreated schizophrenics and by 1 in 10 treated schizophrenic patients per year. Treatment is only moderately effective in this regard. These are very high rates compared to the general public. Even with a relatively weak predictor, you need to monitor only 2 or 3 patients to possibly prevent an assault. This would be a highly effective intervention, and should receive more publicity. Large et al. seem to be doubtful about the value of screening in general, but their own data show it has utility for assaults.

For violent crime, monitoring 26 patients is required for a possible prevention of a violent crime. Again, this is manageable given resources.

Homicide in untreated patients happens, according to this table, at the very high rate of 1 in 600 schizophrenics. That compares with homicide rates in the UK of 0.9 per 100,000 persons and in the US of 3.9 per 100,000 persons. (US 4 times as murderous as the UK). So, the rate of homicide in non-schizophrenics in the UK is 1 in 111,111 and in the US is 1 in 25,641 persons. Therefore, an untreated schizophrenic person, using the estimates given in this paper, is apparently about 42 times more likely to murder someone than a US citizen, and 185 times more likely to murder someone than a UK citizen. Can these figures be correct? If so, this is a very dangerous category of person. An instrument with a positive predictive value of 0.66%  (extremely low) requires that 151 persons be monitored. This would be onerous, but would prevent a murder. It is an indicator of the level of risk to the population when patients do not take their medication.

A homicide committed by a treated patient (1 in 10,000) means that treated schizophrenics are apparently 11 times more dangerous than UK citizens and almost 4 times more dangerous than US citizens. In the US it requires 2500 patients being monitored, a high number, and the best estimate of how difficult it would be to prevent one person being murdered, assuming most patients comply with treatment. Monitoring for most patients would probably involve no more than chasing up non-attenders at follow-ups, and doing some random checks on compliance with medication. This would be worth studying, particularly now that monitoring in diabetes is being trialled using mobile phone apps, with good results.

Here are a few reflections. Risk estimates vary considerably, but all are raised for schizophrenics, particularly in the early untreated phase. By implication, a schizophrenic patient who does not comply with medication falls into a high risk category. It seems very worth-while to screen for assaults, violent crime and homicide, particularly in untreated or medication-refusing schizophrenics.

Being alarmed about schizophrenia is understandable, and wishing them to have treatment and comply with treatment is also comprehensible. Screening schizophrenic patients in the UK is even more valuable than in the US, because of the massively increased risks compared to the lower UK norms.

Please check all these above figures for me. I have difficulty believing these risk estimates because they are so high. Clearly, detection rates are poor when the base rates are low, a familiar problem in signal detection of all sorts. The BPS Research Digest headline of the rarity of a schizophrenic committing a “stranger murder” is somewhat misleading, because we do not immediately have an accessible figure for “stranger murder” committed by the general public. One has to go through Bureaux of Justice Statistics 2008 to find that 25.5% of male murder victims and 11.9% of female murder victims are murdered by a stranger. Since 90% of offenders are male, I would guess that stranger murders are about 24% of the US total. Thus, in the US context, a US schizophrenic murders strangers at the rate of 1 in 140,000 and a normal US citizen murders strangers at the rate of (1 in 106,838) if I have done the sums correctly. Something wrong, I suspect. I looked up the original reference for this estimate, from Nielssen et al 2009, who is also co-author of the main paper being considered here.

Schizo stranger murder


Neilssen et al. say: A fixed effects model was used to calculate a pooled proportion of stranger homicides of 9.0% of all homicides by people with psychosis.

A fixed effects model was therefore used to calculate a pooled rate of stranger homicides committed by offenders with psychosis of 1 in 14.3 million people per year (95% CI=1 in 18.9 million per year to 1 in 11.5 million per year, Z=8.278,P<0.001). If it is assumed that 0.5% of the population have schizophrenia, the annual risk of a stranger homicide by a person with schizophrenia can be estimated to be about 1 in 70 000 patients per annum. If the prevalence of schizophrenia-related psychosis is assumed to be 1%, the estimated risk of stranger homicide is lower, about 1 in 140 000 patients per annum.

This explains the estimate used in the 2011 detection paper. However, if events have been under-recorded in the published literature, then the rates could be somewhat higher. I see the rates as quite variable, typical of rare events. However (see Sariaslan et al. paper below) the meth0ds do not give us certainty that all instances have been captured. At this stage I will need to do further work to understand the “stranger murder” calculations.

Here is a more recent finding about the general dangerousness of schizophrenia in a full population sample of 3,232,010 from Sariaslan, Larsson and Fazel (2015):

schizophrenia and violent crime in swedenA Sariaslan1, H Larsson2 and S Fazel1

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.

So, I revise my earlier view that there is a fivefold increase in violence in schizophrenia. In this 3 million person population sample, schizophrenics are 7.7 times more violent, bipolars 3.7 times more violent. Some mental disorders lead to violence. It would be good to get more details on the types of violent criminal event, but from the public’s point of view, the picture is clear enough.

Time to do some further work on detection, and arrange services on the understanding that some prevention of violence is possible, and worth doing.

Sunday, 7 August 2016

Myths dispelled, new myths propagated


It is a familiar journalistic trick to make a list of popular myths and then dispel them. One example is “50 Great Myths of Popular Psychology: Shattering widespread misconceptions about human behaviour” by Lilienfeld, Lynn, Ruscio and Beyerstein 2010. The authors are university psychologists of professorial rank, with active research careers, and their identification of myths and their attempted refutations are often entertaining. I am glad that some weak arguments have been exposed, and some popular beliefs revealed to have little research foundation, or to at least have foundations which can be questioned.

However, my view is that the “myths refuted” style of thinking is a prescription for poor science. In the late Earl “Buz” Hunt’s marvellous phrase, it leads to a type of argument which is “lawyerly” rather than “scholarly” because once you have identified something as a “myth” then you are honour-bound to destroy it, even if part of it is true.

So, I am going to look at one of Lilienfeld et al’s arguments from the point of view of argumentation and fact. Since the items are short, I will give their substantial arguments in full.

Myth 43 Most mentally ill are violent.

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.

Second, the relevant question is “are mentally ill people more violent than mentally well people, and if so by how much?”

A third relevant question is whether the most-focussed-upon disorder within mental illness, schizophrenia, makes people more violent, and if so by how much? 

Prospective studies of mentally ill people will give the answer. An associated question, though not strictly relevant to the main issue, is whether violence can be predicted by concentrating on a particular sub-set of the mentally ill, or particular behavioural indicators. Here are the key arguments from Lilienfeld et al.

Yet commonplace public beliefs about mental illness and violence don’t square with the bulk of the research evidence (Applebaum, 2004; Teplin, 1985). Admittedly, most studies point to a modestly heightened risk of violence among people with severe mental illnesses, such as schizophrenia and bipolar disorder, once called manic depression (Monahan, 1992). Yet even this elevated risk appears limited to only a relatively small subset of people with these illnesses. For example, in most studies, people with paranoid delusions (such as the false belief of being pursued by the Central Intelligence Agency) and substance abuse disorders (Harris & Lurigio, 2007; Steadman et al., 1998; Swanson et al., 1996), but not other mentally ill people, are at heightened risk for violence. Indeed, in some recent studies, severely mentally ill patients without substance abuse disorders showed no higher risk for violence than other individuals (Elbogen & Johnson, 2009). Nevertheless, psychiatric patients who take their medication regularly aren’t at elevated risk for violence compared with members of the general population (Steadman et al., 1998). There’s also some evidence that patients with “command hallucinations”— hearing voices instructing a person to commit an act like a murder— are at heightened risk for violence. (Junginger & McGuire, 2001; McNiel, Eisner, & Binder, 2000).

Still, the best estimates suggest that 90% of more of people with serious mental illnesses, including schizophrenia, never commit violent acts (Hodgins et al., 1996). Moreover, severe mental illness probably accounts for only about 3-5% of all violent crimes (Monahan, 1996; Walsh, Buchanan, & Fahy, 2001). In fact, people with schizophrenia and other severe mental disorders are far more likely to be victims than perpetrators of violence (Teplin, McClelland, Abram, & Weiner, 2005), probably because their weakened mental capacity renders them vulnerable to attacks by others. Furthermore, most major mental disorders, including major depression and anxiety disorders (such as phobias and obsessive-compulsive disorder), aren’t associated with a heightened risk of physical aggression.

Notice the form of the argument: a modestly heightened risk of violence among people with severe mental illnesses, such as schizophrenia and bipolar disorder. Fine, but it would have been better to state the risk compared to the normal population risk. This way the reader has to chase up the references. Start with Applebaum 2004. In fact this is a letter by J.S. Appelbaum. On examination it has no actual data to contribute. Quoting it as a reference is feeble, and immediately calls into question the notion that these authors are in a position to challenge “myths”.

Next, Teplin (1985). This is better, in that it contains data, and arguments about the link between mental illness and criminality. Teplin rejects the obvious approach, which is to take a set of people who have been given in-patient treatment for mental illness, and then see what their subsequent criminal records are, compared with the general population. I will call this the epidemiological paradigm: “study psychiatric patients and see whether they commit crimes later”. Instead she plumps for what is in my view a more complex and error-prone approach, which is to look at the behaviour of those who come into contact with the Police at criminal incidents, as part of a larger study on how the Police dealt with mentally ill people. Psychologists went with the police to disturbances, and rated citizen behaviour for signs of :

severe mental disorder, e.g., confusion/disorientation; withdrawal/unresponsiveness; paranoid, inappropriate, or bizarre speech and/or behavior; and self-destructive behaviors

As you can see, this is back to front. Instead of following a defined population, people known to have had mental illness, and then seeing how many of them commit criminal acts, this study looks at people who are interacting with the police (criminals, victims, bystanders) and tries to determine how many of them are in the midst of an episode of severe mental disturbance. The defined base population has been lost, and things have to be estimated from the population of “people of interest to the Police”, a far weaker method.

Here are the results, as presented in the paper:


Mental disorder and criminality

Describing this table, Teplin says this of those with severe mental disorder:

they were somewhat more likely, 35.3 versus 23.4% for non-mentally-disordered persons, to be suspects.

Somewhat more likely? 50% more likely. However, this is to misunderstand the table, which has nothing to say about how many psychiatric patients go on to commit crimes. It does not tell us whether the 85 severely disturbed persons are what you would expect among 2122 citizens. At 4% of the population this is quite a high rate of severe mental illness. For example, lifetime prevalence of  all psychotic disorders was judged to be 3.06% in 2007 in US populations. So, there may be a 33% over-representation of disturbed persons in this police sample. Frankly, the method is too weak for any firm conclusions, though even this weak method shows mentally ill persons to be over-represented as suspects of crimes, by 50%.

Teplin goes on to say:

mentally disordered citizens made up less than 5% of the persons who were involved with the police.

She gives the median rate of severe disorder as 1.7% so her observed rate is 3 times higher! She gets out of this by saying that the study area included some neighbourhoods with more mental patients, ignoring that that is what you would expect from psychotic downward social drift. Her task was to find out whether mentally ill people committed more crimes than average, not to find out where they lived.

Teplin keeps making the irrelevant point (irrelevant to the issue of whether mentally ill people commit more crimes) that most interactions of mentally ill people with the police are not about violent crimes. This obscures the finding of interest. Here is her second table, about the suspects themselves:



Mental disorder and type of crime

On her own figures, severely mentally disordered persons are 3 times more likely to have been the perpetrators of violent personal crime. However, since we do not have proper base rates on a defined population of mentally ill persons all we can say is that they appear to be higher, and it could be a chance finding. This study does not confirm that severely mentally disordered persons are no different from the normal population, though the sparse evidence points the other way.

In an attempt to make their case, Lilienfeld et al say:

Still, the best estimates suggest that 90% or more of people with serious mental illnesses, including schizophrenia, never commit violent acts (Hodgins et al., 1996).

That means that 10% do commit violent acts. What is the rate for those without serious mental illness? In the US in 2012 total violent crime was 387 per 100,000 which is a rate of 0.39%. On that reasoning the violence rate for the seriously mentally ill is 10/0.39 = 25 times higher. I think that this is probably an error, even though it is presented as a reassurance. A comment as silly as that was reportedly made by a former president of the Royal College of Psychiatry, though certainly not the present one.

A final comment from Teplin:

In an exhaustive review of the pertinent research literature, Monahan and Steadman concluded that if a number of socio-demographic factors known to be related to crime are taken into account e.g., race, age, and prior criminality, the relationship between mental disorder and criminality substantially diminishes.

I think that sums up the problem with these arguments: someone with mental disorder and a criminal record is given statistical “time off” for previous crimes, even though they may have been caused by mental disorder. “Taking into account” becomes a form of washing them away from the causal nexus. In my view, this is very silly, and Monahan, Steadman and Teplin must know that, or at least acknowledge that “taking into account” covariates can be a misleading procedure. Before “correcting” any finding, the assumptions behind the correction should be made explicit.

Lilienfeld et al continue: Moreover, severe mental illness probably accounts for only about 3-5% of all violent crimes (Monahan, 1996; Walsh, Buchanan, & Fahy, 2001). In fact, people with schizophrenia and other severe mental disorders are far more likely to be victims than perpetrators of violence (Teplin, McClelland, Abram, & Weiner, 2005), crimes (Monahan, 1996; Walsh, Buchanan, & Fahy, 2001). In fact, people with schizophrenia and other severe mental disorders are far more likely to be victims than perpetrators of violence (Teplin, McClelland, Abram, & Weiner, 2005),

So, do the other studies follow the epidemiological paradigm?The other papers mentioned by Lilienfeld et al. are interesting in that they identify the patients who are most likely to be violent: patients with command delusions who have not taken their medication. How violent are they? The rates are not given. 

Are there other relevant papers Lilienfeld et al. could have mentioned, particularly those done the right way round: identifying the mentally ill and then checking whether they are involved in violent acts?

For a fuller review see:

For more recent research, admittedly after the publication of the myths book, but making the same point:

So, the myth is not a myth: schizophrenic patients are roughly 5 times more violent than the general public. It is up to you whether you want to avoid them on that basis.

The rest of the Lilienfeld “myths” book has many myth-busting chapters with which I either agree or want to agree. However, I haven’t checked the references, so I cannot be sure whether these myths have been dispelled or propagated.

Monday, 1 August 2016

The g nexus: Detterman detail


It has been very hard getting intelligence research results out to the public. All researchers, whatever their subject, tend encounter the same problem: they get excited about findings which the general public don’t find interesting, or don’t understand. Researchers complain that their subject is ignored, misrepresented and on the odd occasion that it is noticed at all, the treatment is superficial, the selection of supposed experts absurd, the main points mangled

Intelligence research has experienced all of the above, and more. Researchers get thrown out of the university posts, harassed with legal challenges and cumbersome investigations, and systematically avoided by publishers and research funding bodies whenever the results are considered unwelcome.

One researcher who was given the full “ignoral” was Chris Brand. Before being consigned to the outer darkness he wrote a chapter in 1987 entitled “The importance of general intelligence” and Arthur Jensen quoted his summary in Table 9.3 (page 300) of his book “The g factor” in 1998. Brand had also written a book entitled “The g factor” in 1996, which was to have been published by Wiley, who then chose to “de-publish” it.

The list of positive and negative correlations with intelligence that Doug Detterman showed in his lecture is his updated version of Brand’s 1987 original, and as intelligence research flourishes it will continue to be updated. Any slide has to be a summary, but some of the entries were a bit too terse. Doug has provided some very brief explanations of the items readers found confusing.

“Abnormal is normal” means that the same genes that cause normal processes are the same ones involved in what we call "abnormal" conditions.  In other words, abnormality is simply the extremes of normality.

“World conservatism” refers to a score on a test of world conservatism and can be read as conservative in the common political sense of the word.

“Drop out rates” are, of course, negatively correlated with intelligence.  If  I said that, then what I should have said is that educational completion levels are positively correlated with intelligence.

For the background detail, Doug has provided a chapter he is working on.

Friday, 29 July 2016

Detterman’s 50 years of seeking satisfaction.





When I talk of people I admire, some readers assume that they are dead. Doug Detterman is alive and well, but I am going to say nice things about him anyway. Don’t talk ill of the dead, and don’t postpone speaking well of the living.

Doug is a quiet guy, who has entirely ignored the American habit of self-promotion, but has gently put modern intelligence research on the map. Almost unseen, in 1977 he founded and edited one publication Intelligence from precarious obscurity, to fragile partial visibility, to its present position as the leading journal on intelligence research.  He only got his freedom from the editorial coal mine last year. He also founded the International Society for Intelligence Research (ISIR) in 2000.

Now he looks back at 50 years of intelligence research, and avers that it is much more important than curing cancer, controlling global warming or ending poverty. He also regards teachers and schools as over-rated, since they only account for 10% of pupil achievement. Five decades dedicated to finding a satisfactory answer to a simple question: why are some people smarter than others?

His answer: a traffic jam. All the modules of the brain have to go through a central hub, and the poorer the connection the lower the intelligence.

His lecture is a treasure house: wise, instructive, and great fun to read.

Wednesday, 27 July 2016

Islam calling: Sacred and profane


Reading the news these days is like getting a personal email from the Islamic State. Another day, another horror, driving home the intended message “You are not safe and your government cannot protect you”.

A Catholic priest near Rouen made to kneel at his own altar to have his throat cut, with nuns and parishioners held as hostages. The desecration of a holy place, by common European consent a refuge from the hurly-burly of life’s troubles, converted for a bloody morning into a studio for an Islamic slaughter video. This act drives home the message that Islam is more determined than Christianity, or at the very least has adherents determined to kill Christians.

This is hardly a surprise, given the large number of Christians driven from the Middle East, after centuries of apparent co-existence. It is a common pattern, now coming to a church near you, or that is the propaganda message.

Then the usual cavalcade of important politicians giving serious press conferences, with assurances of toughness in the prosecution of a war, but no specific explanations as to what is intended.

I don’t do policy, but I can give the authorities a little lecture on base rates. If you want to find a needle in a haystack, first find a hay bale in which people have been hiding needles.

Start by considering the base rates. France regards everybody as a citizen regardless of origins or number of generations of residency, so estimates of the Muslim population vary somewhat. Let us take the lower band of estimates used by Pew Research and say 4.7 million. (Others say 6.13 million). Most of these are not terrorists, so any screening system will throw up a smokescreen of false positives.

Young men are the most likely to be involved in crime and violence, so let us guesstimate that 2.35 million men are Muslims. In 2010, the median age of Muslims throughout Europe was 32, eight years younger than the median for all Europeans (40). Perhaps 1 million of them are young men. Most are not terrorists, so not worth screening, because of too many false positives.

It depends on how they are asked about the issue, but some of these young Muslim men will have some “understanding” and sympathy for Jihadist actions. Pew Research estimates that young men are those Muslims most likely to understand (tacitly condone) suicide bombing. A figure of 42% has been claimed for 2006. Regarding British Muslims, on April 11 2016 The Times reported that “Only one in three British Muslims would tip off the police if they believed that somebody close to them had become involved with terrorist sympathisers, a poll has revealed.” I do not have the original questions, so cannot validate the estimate that 66%  of UK Muslims would keep quiet about Islamic terrorism. For the purposes of argument I will take the very low estimate of 25% turning a blind eye in France. That would give us 250,000 potential sympathisers. Too many to screen.

Criminals do criminal acts, and criminality is mostly a behaviour of young men. Being sent to prison is a double indicator: it indicates criminality, and a higher chance of being converted to Jihadist Islam while in prison.  Of the 67,500 people currently behind bars in France, it is estimated that 70 per cent are Muslim – when they comprise only 8 per cent of the French public. That gives us 47,250 prisoners to screen. This might be manageable, but given the rarity of jihadist perpetrators, it is probably too many.

Roughly 900 French Muslims have gone abroad to join Islamic State. Finally, this is a manageable number. These are the true believers. This is the hay bale in which the needles are hidden. These  volunteers cannot be watched full time, nor followed other than very occasionally, but some indicators could help narrow down the prime suspects: sudden changes of clothing towards more religious dress, or vice versa; more visits to Jihadist websites, purchases of weapons and other materiel, and other indicators like not using credit cards on Fridays.

(I digress, but my few contacts in the UK Prevent program regard returning Jihadis as an asset, because they generally come back very disillusioned with the Islamic cause, and do not like the reality of Islamic warrior life. The authorities would prefer to use them as counter-propagandists, rather than put them in jail. However, some come back disillusioned but even more dangerous and resentful.)

Adel Kermiche, 19, who murdered the priest, was twice arrested last year trying to reach Syria. He had been to jail, and was released with an electronic tag which, in a very French way, left him free to roam in the morning, but kept him under supposed surveillance in the afternoon and evening. I presume they thought he would sleep in till lunchtime.

This young man was a clear “person of interest”. Yes, there are 900 others to watch, so something has to be done to make the task manageable. Perhaps the task could be made easier by helping these wannabe Jihadis to move to a real Islamic state, and not stay in a France which is clearly not to their liking. Perhaps that is too obvious a suggestion, and it is much better to keep them in France.  It does not seem too big a step to say to a person who favours Islamic State over France: live in an Islamic State.

I do not make policy recommendations, but I hope someone in the French government considers making some.










(In England and Wales, Muslims account for 14 per cent of the prison population, and 5 per cent of the population nationwide.)


Tuesday, 26 July 2016

Genes and education


I have always thought it unseemly to spring psychological tests on my readers, but here is one of my standard annual test items: I manage to extract the slide presentation from a distinguished speaker, who with great aplomb has raced through a complex keynote presentation, and leave you to work out from the slides exactly what she said.

With Prof Yulia Kovas’s ISIR Keynote Address your task will be relatively simple, because after some comments on St Petersburg and Russian science she has listed the key points which come out of genetic research on educational outcomes, and also shows the front pages of many of the key references. If the pages seem familiar the whole talk will dance before your eyes. If some of them are new to you, you know exactly what you need to read next.

You can get the background on Yulia here:

Here is the Powerpoint presentation she kindly sent me, which contains lots of useful information:




Monday, 25 July 2016

Ansbach bomber pledged allegiance to ISIL


An hour is a long time in politics. The Ansbach bomber/failed asylum seeker has apparently been found, via his mobile phone, to have pledged alliance to Islamic State.

Bavarian Interior Minister Joachim Herrmann said the man, who has not been named, also "announced an act of revenge against Germans because they were standing in the way of Islam".

Herrmann said violent videos and bomb-making material were also found at the man's home in the Bavarian town of Ansbach.