Sixth Circuit Court of Appeals rules (Black v Carpenter, 2017) against norm obsolescence (Flynn effect) adjustment of IQ scores in Atkins death penalty cases

A newly published 6th Circuit opinion (Black v Carpenter, 2017) rules against norm obsolescence (the Flynn effect) in the evaluation of IQ test scores in Atkins ID death penalty cases.  I obviously disagree with this decision as outlined in my 2015 chapter in the AAIDD "The Death Penalty and Intellectual Disability" (Polloway, 2015).

I have no further comment at this time as my expert opinion is clearly articulated in the AAIDD publication and I will continue my efforts to educate the courts.  This decision is at variance with the official positions of American Association on Intellectual and Developmental Disabilities (AAIDD) and the American Psychiatric Association (DSM-5), the two professional associations with official  guidance regarding  the diagnosis of ID. 

This looks like another issue that might need the attention of SCOTUS.

The following section is extracted from the complete ruling.


E. Implications of the Flynn Effect

There is good reason to have pause before retroactively adjusting IQ scores downward to offset the Flynn Effect. As we noted above, see n.1, supra, the Flynn Effect describes the apparent rise in IQ scores generated by a given IQ test as time elapses from the date of that specific test’s standardization. The reported increase is an average of approximately three points per decade, meaning that for an IQ test normed in 1995, an individual who took that test in 1995 and scored 100 would be expected to score 103 on that same test if taken in 2005, and would be expected to score 106 on that same test in 2015. This does not imply that the individual is “gaining intelligence”: after all, if the same individual, in 2015, took an IQ test that was normed in 2015, we would expect him to score 100, and we would consider him to be of the same “average” intelligence that he demonstrated when he scored 100 on the 1995-normed test in 1995. Rather, the Flynn Effect implies that the longer a test has been on the market after initially being normed, the higher (on average) an individual should perform, as compared with how that individual would perform on a more recently normed IQ test.

At first glance, of course, the Flynn Effect is troubling: if scoring 70 on an IQ test in 1995 would have been sufficient to avoid execution, then why shouldn’t a score of 76 on that same test administered in 2015 (which would produce a “Flynn-adjusted” score of 70) likewise suffice to avoid execution? Further, even if IQ tests were routinely restandardized every year or two to reset the mean score to 100, and even if old IQ tests were taken off the market so as to avoid the Flynn Effect “inflation” of scores that is visible when an IQ test continues to be administered long after its initial standardization, that would only mask, but not change, the fact that IQ scores are said to be rising.

Indeed, perhaps the most puzzling aspect of the Flynn Effect is that it is true. As Dr. Tassé states in his declaration, “[t]he so-called ‘Flynn Effect’ is NOT a theory. It is a wellestablished scientific fact that the US population is gaining an average of 3 full-scale IQ points per decade.” The implications of the Flynn Effect over a longer period of time are jarring: consider a cohort of individuals who, in 1917, took an IQ test that was normed in 1917 and received “normal” scores (say, 100, on average). If we could transport that same cohort of individuals to the present day, we would expect their average score today on an IQ test normed in 2017—a century later—to be thirty points lower: 70, making them mentally retarded, on average.

Alternatively, consider a cohort of individuals who, in 2017, took an IQ test that was normed in 2017 and received “normal” scores (of 100, on average). If we could transport that same cohort of individuals to a century ago, we would expect that their average score on a test normed in 1917 would be thirty points higher: 130, making them geniuses, on average.

It thus makes little sense to use Flynn-adjusted IQ scores to determine whether a criminal is sufficiently intellectually disabled to be exempt from the death penalty. After all, if Atkins stands for the proposition that someone with an IQ score of 70 or lower in 2002 (when Atkins was decided) is exempt from the death penalty, then the use of Flynn-adjusted IQ scores would conceivably lead to the conclusion that, within the next few decades, almost no one with borderline or merely below-average IQ scores should be executed, because their scores when adjusted downward to 2002 levels would be below 70. Indeed, the Supreme Court did not amplify just what moral or medical theory led to the highly general language that it used in Atkins when it prohibited the imposition of a death sentence for criminals who are “so impaired as to fall within the range of mentally retarded offenders about whom there is a national consensus,” 536 U.S. at 317. If Atkins had been a 1917 case, the majority of the population now living—if we were to apply downward adjustments to their IQ scores to offset the Flynn Effect from 1917 until now—would be too mentally retarded to be executed; and until the Supreme Court tells us that it is committed to making such downward adjustments, we decline to do so.

* * *

COLE, Chief Judge, concurring in the opinion except for Section II.E. I concur with the majority opinion except as to the section discussing the implications of the Flynn Effect. In holding that Black did not prove that he had significantly subaverage general intellectual functioning, we concluded that Black’s childhood IQ scores would be above 70 even if we adjusted those scores to account for both the SEM and the Flynn Effect. Accordingly, I would not address the question of whether we should apply a Flynn Effect adjustment in cases generally because it is unnecessary to the resolution of Black’s appeal. Regardless, courts, including our own in Black I, have regarded the Flynn Effect as an important consideration in determining who qualifies as intellectually disabled. See, e.g., Black v. Bell, 664 F.3d 81, 95–96 (6th Cir. 2011); Walker v. True, 399 F.3d 315, 322–23 (4th Cir. 2005).