This month Nature Reviews:Neuroscience published an opinion piece “Gene-environment interactions in psychiatry: joining forces with neuroscience” by Avshalom Caspi and Terrie E. Moffitt who follow-up on their well-cited 2002 article in Science “Role of genotype in the cycle of violence in maltreated children.” In the opinion piece the authors present a broad overview of the opportunities and challenges present in studies that address the gene-environment interactions that exist within nature. In their earlier earlier paper they:
. . studied a large sample of male children from birth to adulthood to determine why some children who are maltreated grow up to develop antisocial behavior, whereas others do not. A functional polymorphism in the gene encoding the neurotransmitter-metabolizing enzyme monoamine oxidase A (MAOA) was found to moderate the effect of maltreatment. Maltreated children with a genotype conferring high levels of MAOA expression were less likely to develop antisocial problems. These findings may partly explain why not all victims of maltreatment grow up to victimize others, and they provide epidemiological evidence that genotypes can moderate children’s sensitivity to environmental insults.
It’s quite plausible that as this science develops it will enter into the social and legal arena where it will be useful in questions dealing with Indefinite Commitment Laws. David Rose tackles this subject, and provides a useful historical overview on “genetic determinism” scaremongering, in the latest issue of Prospect (UK). I want to add to the topic, but first a little background.
Indefinite Commitment Laws are designed to keep dangerous individuals from being released from prison after they’ve completed their terms of incarceration, have been passed in 16 U.S. States and have passed through Constitutional challenges by claiming that the commitment is a medical treatment, rather than a double-jeopardy penalty of continuing incarceration. The case law can be sampled here, here and here.
The impetus for these types of laws clearly centers on fears of high recidivism probabilities of the ex-convict. Because the legal proceedings are dealing with civil commitment rather than criminal commitment, the standard of evidence must only meet a clear and convincing threshold, rather than the higher bar of beyond a reasonable doubt. Due in large part to this lower evidenciary standard the adjudicating authority becomes a de facto actuary and much of the focus deals with probability of recidivism. To gauge the boundaries of the probability estimate there are prescribed protocols which must be followed by the State. More details in this Handbook for “Sexually Violent Predator Assessment Screening Instrument for Felons: Background and Instruction” and in this Memorandum on “Civil Commitment of Sexually Violent Predators” that was prepared for Virginia Circuit Court Judges. But what are the actual probabilities of recidivism that have spurred on this legislation? In their meta-analysis of recidivism studies, Predicting Relapse: A meta-Analysis of Sexual Offender Recidivism Studies, R. Karl Hanson and Monique T. Bussiere find:
On average, the sex offense recidivism rate was 13.4% (n = 23,393; 18.9% for 1,839 rapists and 12.7% for 9,603 child molesters). The average follow-up period was 4 to 5 years. The recidivism rate for nonsexual violence was 12.2% (n = 7,155), but there was a substantial difference in the nonsexual violent recidivism rates for the child molesters (9.9%; n = 1,774) and the rapists (22.1%; n = 782). When recidivism was defined as any reoffense, the rates were predictably higher: 36.3% overall (n = 19,347), 36.9% for the child molesters (n = 3,363), and 46.2% for rapists (n = 4,017).
Margaret A. Alexander performed a meta-analysis of 79 studies that looked at recidivism rates after the criminals participated in various treatments regimes in her study, Sexual Offender Treatment Efficacy Revisited and found the following recidivism rates: Rapists (treated 20.1%, untreated 23.7%); Child Molestors (treated 14.4%, untreated 25.8%); Exhibitionists (treated 19.7%, untreated 57.1%) and the by far largest group, Types not specified (treated 13.1%, untreated 12.0%). The last entry isn’t a typo, the untreated did in fact have lower recidivism rates.
I thought it would be useful to survey the probability universe that we’re dealing with when we deprive people of their freedom via Indefinite Commitment Laws for they do work on the basis of probabilities rather than certainties and it’s quite likely that genotypic information will significantly improve the accuracy of assessments, especially when such information is combined with data on the life history of the subject. Rose summarizes the 2002 Caspi and Moffitt paper:
The paper’s hypothesis was that one of the factors that differentiates individuals’ propensity for antisocial behaviour is a particular gene-the one responsible for generating the enzyme monoamine oxidase A (MAOA). This enzyme regulates neurotransmitter levels in the brain: one of its roles is to get rid of excess serotonin, dopamine and so on, in order to keep neurological circuits working smoothly.
In fact, there are five known variants-known as alleles or genotypes-of the MAOA gene, although three of them are rare. The authors of the 2002 paper examined the two main types. The low-activity allele, which programmes the body to produce low levels of the MAOA enzyme, is found in about one third of males. The more normal, high-activity allele is found in almost all of the rest. In order to test their hypothesis about the role of MAOA, the researchers went back to the Dunedin cohort. Its members’ history had already been examined and described, so that it was already known that between the ages of eight and 11, 8 per cent of the cohort’s children had suffered “severe” maltreatment, and 28 per cent had experienced “probable” maltreatment. As we have seen, the team already knew which members of the study had exhibited antisocial behaviour, and when. Now researchers also found which of the MAOA genotypes they had by examining their DNA.
As might have been expected, the Dunedin study found that maltreatment in childhood would, on its own, make someone more likely to commit crime and display antisocial behaviour. About 35 per cent of the maltreated men with the normal high-activity genotype had shown conduct disorder, and 20 per cent had a conviction for violence. But when the two risk factors were found together-the low-activity genotype and childhood maltreatment-the correlation with antisocial behaviour was far stronger. More than 80 per cent of the men in this category had exhibited conduct disorder, and more than 30 per cent had convictions for violence. As a group, they were all among the most violent third of men. No fewer than 85 per cent
of the cohort’s men with the low-activity genotype who had also been severely maltreated went on to develop antisocial behaviour.
Notice that the rate for conviction of violent crime was 50 percent greater in the low-activity genotype group than in the high-activity genotype group. In absolute terns the former group has a conviction rate that is 10 percent greater than the latter group. Compare these rates to the the recidivism rates for rapists (18.9%), child molestors (12.7%) and violent offenders (12.2%.) When we’re dealing with probabilities of recidivism it seems that genotypic information will only serve to improve the decision process underlying indefinite commitment proceedings.
An added benefit of developing this research will be the likely erosion effect on the Axiom of Discrimination as it pertains to the question of race and crime. We already have studies which have charted monoamine oxidase activity across demographic groups:
Reported here are variations for all three demographic variables such that significantly greater enzyme activity is seen in female, older, and white subjects relative to male, younger, and black subjects.
Note that the groups most prone to low enzyme activity are males, the young, and black subjects. Another study makes the implication more explicit:
Overall, low MAO activity appears to be associated with restless and uninhibited behavior patterns, and may reflect some of the mediating effects of serotonin and sex hormones (especially androgens) on criminal behavior. Lower MAO activity is more characteristic of males than females, and appears to be lower in Blacks than Whites, and lowest during the second and third decades of life.
Of course, a research design that broaches the sensitive topic of race, genetics, and criminality is certain to dissuade many scientists from getting involved, for as Stanford’s David Botstein remarks about genetic causes of violence:
“I think there’s more scientifically to that one, a greater likelihood of finding it, more than IQ. But it’s COMPLETELY unacceptable at the moment. You can’t even talk about it. Go to any university, research center, no one — NO ONE — will talk to you about this. Why? Simple. Because of the fear that there will be a racial correlation.
We need look no further than Rose’s essay for a sampling of what the future portends:
The academy can be a compartmentalised place, with surprisingly little dialogue between disciplines, and mainstream sociological criminology is only beginning to become aware of the work described here. It may not evoke a favourable response. A recent issue of the journal Criminal Justice Matters, published by the Centre for Crime and Justice Studies at King’s College London, contained a fierce attack on the work of Terrie Moffitt and others. The article accused researchers at the Institute of Psychiatry and elsewhere of “genetic fundamentalism-a belief in a mythic, not a real genetics,” and suggested that twin studies that found a genetic component in antisocial behaviour were without value. Moffitt and her colleagues have, in fact, stressed that genetic predispositions must be “switched on” by childhood maltreatment, and that the important thing was to concentrate on eliminating this and other types of adverse environment.
Asked to give an after-dinner speech to Liberal Democrat lawyers, I caught a different glimpse of the hostility that behavioural genetic research into the causes of crime can evoke. After I had presented an account of some of the work described here, the response was viscerally critical. Speakers claimed that it was “deterministic,” and would surely lead to a wanton attack on civil liberties. One distinguished legal practitioner went so far as to demand who had funded these investigations, claiming that they must have been cooked up according to some pre-ordered, authoritarian agenda.
For most of the regular readers of this blog these types of frothing-at-the-mouth attacks are old hat. Just a few weeks ago we saw Stanford’s Barres preparing the ground for classifying science he didn’t like as hate crimes:
. . . what is the difference between a faculty member calling their African-American students lazy and one pronouncing that women are innately inferior? Some have suggested that those who are angry at Larry Summers’ comments should simply fight words with more words (hence this essay). In my view, when faculty tell their students that they are innately inferior based on race, religion, gender or sexual orientation, they are crossing a line that should not be crossed – the line that divides free speech from verbal violence – and it should not be tolerated at Harvard or anywhere else.
The Leftist Creationists who believe that humans are immune to evolutionary processes will not go down without a fight. Unfortunately, these types of creationists are a monolithic bloc within Academia and they can indeed put up impediments to research or simply resurrect the tactics used during the Sociobiology Wars. However, even if they can groom an obscurantist of Gouldian proportions, they’re going to have a difficult time refuting the work of good scientists, work which been replicated many times over. In the end these new insights should aid society in furthering the cause of justice, just as DNA testing has been instrumental in setting unjustly incarcertated people free and helping to convict those who are guilty of crimes. The science and technology are neutral but they do aid in guiding the decisions made by our arbitors of justice.