IQ Test Scores Are a Horrible Thing to Bet a Life On

There isn’t an exact definition of “intellectually disabled,” so when the Supreme Court ruled in 2002 that it was cruel and unusual and therefore unconstitutional to execute inmates with intellectual disabilities, it left the definition to the states. This week, Florida is having a difficult time proving that the standard it chose isn’t just an arbitrary one.

On Monday, the court heard oral arguments in a case challenging Florida’s law that says intellectual disability must be proved by an IQ score of 70 or less, and doesn’t allow those who score higher to escape the death penalty on the grounds of mental disability, despite the IQ test’s well-known limitations.

Freddie Lee Hall was sentenced to death in 1978 for murdering a pregnant woman, and according to The New York Times he has scored between 69 and 80 on IQ tests over the years. In 1991, a Florida court heard expert testimony and found that Hall has been “mentally retarded his entire life,” but upheld his sentence because capital punishment was not yet prohibited in such cases. Following the 2002 Supreme Court decision, Hall was kept on death row because of his IQ test scores, that Florida Solicitor General Allen Winsor told the court were “71, 72, 73, 74 and 80”—consistently above the 70 threshold, but not consistently outside of the 5 point margin of error. Hall's lawyers, then, were barred from presenting any other evidence of disability—for example, school records that consistently identified Hall as being mentally retarded, according to NPR.

On Monday, the majority of the Supreme Court seemed ready to find that Florida has made it too hard to prove that a death row inmate is intellectually disabled and thus ineligible for execution, according to Robert Barnes at the Washington Post. The justices, particularly Elena Kagan and Anthony M Kennedy took issue with Florida’s hard-and-fast rule that forbids further inquiry. “We have this whole line of cases that says when it comes to meting out the death penalty, we actually do individualized consideration, and we allow people to make their best case about why they’re not eligible for the death penalty,” Kagan said. “And essentially what your cutoff does is it stops that in its tracks.”

Not only that, Florida’s strict cutoff relies on a single, imperfect metric to determine a multi-pronged, multifaceted, life-or-death issue. There was not one single test or component that could accurately judge how well a person could perform mental and cognitive tasks.

According to the American Association on Intellectual and Developmental Disabilities, there are three major criteria for intellectual disability: significant limitations in intellectual functioning, significant limitations in adaptive behavior, and onset before the age of 18.

The IQ test is a major tool for measuring the first: intellectual functioning, which only one part of the definition. “A test score below or around 70—or as high as 75—indicates a limitation in intellectual functioning,” the AAIDD site says.

According to the well-publicized 2012 study, which called the intelligence quotient “a myth," “When you come to the most complex known object, the human brain, the idea that there is only one measure of intelligence had to be wrong.”

In the course of argument Monday, Justice Kennedy asked Winsor why the last 10 inmates Florida executed had been on death row for an average of nearly 25 years. Justice Anthony Scalia, who wrote a dissent on the 2002 ruling, piped up to say that it was mostly the Supreme Court’s fault for making executions exceedingly difficult and complex to do.

Florida’s attempt to streamline executions may have a hard time making it past the court. The decision in Hall v. Florida, due in early summer, will likely have to define mental disability on the federal level, or at least provide guidelines on how states should do so. It should simplify the process, but even if you can set aside ethical considerations, given that the human brain is the “the most complex known object,” the process can’t really ever be simple.