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Arbitrary Execution: Why the Law Needs Help from Neuroscience, Psychology and Philosophy


On February 29th, 2012, Robert Henry Moormann was executed in Arizona for murder. Back in 1984, he was in prison for kidnapping and molesting an eight year old girl, when the state gave him three days of compassionate leave. His elderly adoptive mother took a long bus trip to go and meet him. After an argument in a motel room where she was staying, he beat, stabbed and suffocated her, then dismembered her body. He asked a number of local businesses if he could dispose of “spoiled meat and animal guts” in their refuse containers, before disposing of most of her remains in bins and sewers around town. He also asked a prisoner officer to dispose of a box of what he described as “dog bones”. This behaviour raised suspicion. Moormann claimed not to remember the details of the crime, and at the original trial, Moormann’s lawyers mounted a defence of insanity. The jury rejected it. Since 1985, he had been living on death row while his appeals process was gradually exhausted.

In light of the gruesomeness of his crime, it is easy to think that if anyone ever deserved the death penalty, Moormann did. But the contention of Moormann’s defence lawyers that he was intellectually disabled casts a new light on the case.

MoormannThe US Supreme Court ruled in Atkins v. Virginia (2002) that executing the intellectually disabled (then known as “mentally retarded”) is constitutionally prohibited. They classed it as a needless imposition of pain and suffering that amounts to “cruel and unusual punishment” because it fails to serve the reasonable penal goals of retribution or deterrence. The intellectually disabled are less culpable than others, and less capable of taking into consideration any potential punishment for their crimes. Arizona statutes require that for a person to be defined as intellectually disabled for these purposes, they must score 70 or lower on an IQ test, taking into account its margin for error (this score is two standard deviations below the mean, comprising about 2% of the population). This is in line with the criteria for intellectual disability outlined in the “Psychologist’s Bible”, the fourth edition of the Diagnostic and Statistical Manual (DSM-IV). Prosecutors in Moormann’s case argued successfully that his IQ had earlier been measured as above 70, so he could not provide clear and convincing evidence that he met Arizona’s definition of intellectual disability.

Legally, Moormann’s case may have been relatively clear cut. Ethically, things are murkier. As Julian Savulescu has previously argued on this blog, the law’s dividing line at an IQ of 70, two standard deviations below the mean intelligence level, is entirely arbitrary. Whether someone is a bit less or a bit more than two standard deviations below the mean is not what we care about in assessing whether they are properly blameworthy for their actions. All it gives us is, at best, an inaccurate proxy measure for other things that we care about. Whether the accused had an IQ of 69 or 73 is as arbitrary as whether the crime was committed on a Tuesday.  The law must draw bright lines, by necessity. But it would be better if there were a rational justification for the lines that it draws.

For medical purposes, setting the threshold of intellectual disability at 70 is still arbitrary, but much less so than when that threshold is used for the purpose of assigning or withholding the death penalty. We make use of our definitions of medical disorders primarily to determine who among us has special claims to medical attention, or to social assistance, in order to help them deal with the consequences of their diseases or disabilities. We cannot give everyone a special claim, so it fits our purposes to draw an arbitrary line that delimits some small percentage of the population most disadvantaged by low intelligence. The law might be similarly less arbitrary if it accurately delimited some small percentage of the population who are the least blameworthy for their actions, or if it diminished punishment gradually in line with blameworthiness. Unfortunately, it does neither, because it does not offer diminishing punishments, and because IQ is at best a very imperfect measure of blameworthiness.

Why then, has anyone been willing to live with a law that draws an arbitrary threshold at an IQ of 70? People generally agree that full blameworthiness requires full control over one’s actions, or that a person is fully blameworthy only if what he does fully expresses his agency, in the form of his calculated moral (or immoral) attitudes towards others. Failure to meet these thresholds is presumably, therefore, supposed to be evidence of sufficiently diminished control, or sufficiently diminished expression of agency. But because we should recognize that the law draws an arbitrary dividing line using an inaccurate proxy measure, we should see that the conditions of full blameworthiness may not yet be met, even in cases like Moormann’s where the legal thresholds are exceeded. Given Moormann’s obvious intellectual shortcomings, what reason do we have to accept that his moral understanding, or his degree of control over his actions and emotions, was any more sophisticated than that of a small child?

The execution of Moormann may have been unjust, because medical criteria were profoundly misapplied in determining his degree of culpability. In cases like Moormann’s, we should be willing to either assess degree of blameworthiness on the individual merits, or else develop a better legal measure for assessing it. Lawyers, neuroscientists, psychologists and philosophers need to collaborate to develop more sophisticated ways of measuring blameworthiness and allotting punishments that will be less arbitrary, and considerably more just.

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