Human Nature: Science, Technology, and Life.

Anti-Theft Drugs

Can a drug cure the urge to steal?

It looks that way. In the April 1 issue of Biological Psychiatry, scientists from the University of Minnesota School of Medicine report:

An 8-week, double-blind, placebo-controlled trial was conducted to evaluate the safety and efficacy of oral naltrexone for kleptomania. Twenty-five individuals with DSM-IV kleptomania were randomized to naltrexone (dosing ranging from 50 mg/day to 150 mg/day) or placebo. ... Subjects assigned to naltrexone had significantly greater reductions in ... stealing urges (p = .032), and stealing behavior (p < .001) compared with subjects on placebo. Subjects assigned to naltrexone also had greater improvement in overall kleptomania severity ... Naltrexone demonstrated statistically significant reductions in stealing urges and behavior in kleptomania.

It sounds like an April Fools' joke. But it isn't. In an interview with Reuters, the study's lead author explains that naltrexone "gets rid of that rush and desire" to steal.

Naltrexone is better known as a drug for alcohol or drug addiction. Many of us, while accepting these addictions as diseases, continue to regard theft as a matter of personal responsibility. Should we rethink that distinction? If the same drug relieves both conditions, should we take kleptomania more seriously as an illness?

The floor's open.

Race, Genes, and Criminal Justice

Is it OK to guess a perpetrator's race and appearance from DNA found at the crime scene?

A few weeks ago, Gautam Naik of the Wall Street Journal updated us on a fertility clinic's program to screen embryos for "eye color, hair color and complexion." The clinic hoped to use a method that could supposedly "identify [genes] that relate to northern European skin, hair and eye pigmentation in 80%" of IVF embryos.

Two weeks later, when the clinic suspended the program, I suspected its concession was more technical than moral. Predicting traits from genes is hard. That's one reason why so many threats and promises of genetic engineering haven't materialized.

But now it seems I may have underestimated the field. Naik has returned with further research on the genetics of appearance. Gene-trait correlations are becoming increasingly precise. And the practice to which they're being applied most aggressively isn't embryo screening. It's law enforcement.

Here's his latest report:

Murray Brilliant, a geneticist at the University of Arizona, is developing a predictive test for skin, eye and hair color. Supported by a grant from the U.S. Department of Justice, he and his colleagues recently analyzed DNA material provided by 1,000 university students from different ethnic backgrounds. They found a total of five genes that account for 76% of the variation for hair color, 75% for eye color and 46% for skin color. Similarly, scientists from Erasmus University published a paper in March in the journal Current Biology based on a DNA analysis of 6,000 people in the Netherlands. For that population group, they found that only six DNA markers are needed to predict brown eye color with 93% accuracy and blue eye color with 91% accuracy.

Some of those numbers are quite impressive. If they're packaged into an affordable embryo test, I guarantee you buyers will start lining up. But look where the money's coming from. Brilliant got his grant from DoJ. The Erasmus group got its funding from the Netherlands Forensic Institute, which "provides services to clients within the criminal justice chain, such as the Public Prosecution Service and the police." In fact, Naik points out, "[t]he push to predict physical features from genetic material," known as "DNA forensic phenotyping," has

already helped crack some difficult investigations. In 2004, police caught a Louisiana serial killer who eyewitnesses had suggested was white, but whose crime-scene DNA suggested—correctly—that he was black. Britain's forensic service uses a similar "ethnic inference" test to trace murderers and rapists. In 2007, a DNA test based on 34 genetic biomarkers ... indicated that one of the suspects associated with the Madrid bombings was of North African origin.

Whoa, there. Do we really want cops hunting for people of a particular race or ethnicity based on uncertain inferences from a DNA sample? Apparently several states don't. Nor does Germany. These jurisdictions, according to Naik, forbid "the forensic use of DNA to infer ethnicity or physical traits."

I understand the concern. But these prohibitions are a mistake. DNA forensic phenotyping doesn't need to be perfect. It just needs to be better than—or a substantial way of double-checking—the unscientific inferences we already make.

The Louisiana case sets off racism alarms because DNA phenotyping said the culprit was black, whereas witnesses said he was white. But that isn't the usual pattern. Decades of research suggest that a witness is more likely to misidentify a person as the perpetrator when the accused person is of a different race. And according to the Innocence Project,

Racism continues to be a significant cause of wrongful convictions. While 29% of people in prison for rape are black, 64% of the people who were wrongfully convicted of rape (and then exonerated through DNA) are black. Moreover, most sexual assaults nationwide are among perpetrators and victims of the same race (the federal government says just 12% of sexual assaults are cross racial), but two-thirds of all black men exonerated through DNA evidence were wrongfully convicted of raping white people.

DNA phenotyping didn't invent the problem of erroneous racial inferences in law enforcement. That problem is as old as racism and lives on through mug books, lineups, and eyewitness testimony. As the Innocence Project points out, DNA is beginning to clean up the problem. Granted, DNA phenotyping isn't nearly as reliable as DNA matching. But is it really worse than relying on witnesses alone? At the very least, wouldn't it be useful and wise to check witness recollections of the perpetrator's race or ethnicity against a DNA phenotype analysis?

The same goes for facial features. Naik reports:

Mark Shriver, an anthropologist and geneticist ... [is] trying to construct a "picture" of a person's face by analyzing DNA. He calls the technique "forensic molecular photo fitting," and it is supported by a $500,000 grant from the U.S. Department of Justice. ... His team collected DNA samples and photographs from 243 people ... and used computer techniques to correlate the genes with his subjects' facial features. They have found six genes that seem to influence such traits. One gene is associated with the height of the face; another is associated with its width. Yet another gene affects the shape of the lips and the nose. By piecing together these elements, Prof. Shriver hopes to create a modern-day version of the police artist sketch.

Initial results of this method will probably be pretty crude. But will it end up being worse than old-fashioned police sketches based on eyewitness accounts? Would we have caught the Son of Sam killer earlier, for instance, if his police sketch hadn't been wildly inaccurate, making him look Latino or Asian?

No, DNA phenotyping isn't perfect. But it's better than nothing. And it's better than trusting witnesses alone.

The DNA Defense

In Sunday's Washington Post, Rick Weiss detailed an important and underreported trend: the increasing role of genetics in legal disputes. His reporting illustrates how the march of science and the evolution of law are changing the way we think of ourselves. In South Carolina, the state's highest court overturned a murder conviction based on evidence that the killer acted out of genetically based depression. In Tennessee, a murder defendant blamed his conduct on inherited mental illness. In Georgia, lawyers in a murder case sought tests to determine whether their client had a gene associated with violence. In Arizona, a convicted killer argued on appeal that his attorney should have told the court about a similar gene-based propensity.

How did we get here? Weiss's research suggests a confluence of two trends. One is the habituation of courts to DNA. The growing familiarity of this kind of evidence masks the evolving purposes to which it has been put. First came DNA as identification, basic CSI stuff. Then came DNA as evidence of harm: Plaintiffs sued companies over toxic damage, but their DNA failed to show the toxin's expected effects. Then there's DNA as a cause of disease: In pollution and malpractice cases, courts have tested plaintiffs' DNA to check out the argument that genes, not products or procedures, sickened them. And if DNA explains the past, why not use it to predict the future? HIV tests have already been court-ordered to project victims' longevity and thereby calculate lifelong damages. Genetic longevity tests will be next. In a custody case, one parent successfully demanded that the other be tested for the deadly Huntington's gene. Apparently, the point was to challenge the second parent's fitness.

So, we're already in the business of testing for genes to predict fitness. That brings us to the second trend: the increasing use of biology to assess criminal responsibility. U.S. case law has traditionally discounted perpetrators' culpability in the event of sleepwalking, epileptic seizures, insanity, retardation, or "diminished capacity." Three years ago, the Supreme Court struck down death sentences for teenagers, citing evidence of their "underdeveloped sense of responsibility." Every month, scientists find new correlations between genes and traits such as aggression or mental illness. Just two weeks ago, the Human Nature News roundup flagged a study showing a genetic correlate of ruthlessness. As the cost of genetic testing declines, the temptation to test defendants increases. The persuasiveness of some genes increases as well: The allele cited in the Georgia murder case has subsequently been connected to violence in additional studies.

Put the two trends together, and you're looking at a gradual invasion of personal responsibility by genetic determinism. It's a conceptual shift from thinking of people as subjects to thinking of them as objects. The shift helps defense lawyers who need excuses for their clients' behavior. But it comes at a price: If your client is an object, why should we treat him like a subject?

As Weiss points out, courts already use unscientific evidence of "future dangerousness" to decide which killers should be executed. Genes could hardly do worse at predicting such risks. Weiss cites an Idaho case in which the defendant's genetic "propensity to commit murder" became a justification for executing him. A judge in the Arizona murder case drew the same conclusion about the appellant's "alleged genetic predisposition for violence." If your client's genes made him kill, they'll do it again. So don't expect us to let him live.

Nor should you expect us to protect his DNA from scrutiny under the Fourth or Fifth Amendment. If he's the product of his genes, as opposed to their manager, why should we treat them as his possession? He's their possession. Ditto for self-incrimination: If mental states are products of genes, we don't need his testimony; we just need his DNA. We can't make him open his mouth to testify, but we can make him open it for a swab, which could tell us plenty about his mind.

Are we more than our programming? Ladies and gentlemen of the jury, I leave that question in your hands.