Court Opinion

ID: 9786097
Source: CourtListenerOpinion
Date Created: 2023-08-30 23:47:22.102586+00
Date Added: 2024-06-11T07:36:41.740187
License: Public Domain

CHIN, J.
I concur with the majority opinion, which I have signed. I write separately only to stress that although Penal Code section 1376 (section 1376) states no particular intelligence quotient (IQ) below which a person must score in order to be considered mentally retarded, standardized tests like IQ tests remain important. As the majority opinion explains (maj. opn., ante, at p. 47), section 1376’s standard is derived from Atkins v. Virginia (2002) 536 U.S. 304 [153 L.Ed.2d 335, 122 S.Ct. 2242] (Atkins). The Atkins court said that the 70-75 IQ range “is typically considered the cutoff IQ score for the intellectual function prong of the mental retardation definition.” (Atkins, supra, at p. 309, fn. 5.) Thus, a person whose IQ score is over 75 is very likely not mentally retarded, and in many, perhaps most, cases, a petitioner will not be entitled to relief absent a showing of an IQ at or below the 70-75 range.
Section 1376 defines mental retardation, in part, as including “significantly subaverage” intellectual functioning. (§ 1376, subd. (a).) The American Association on Mental Retardation (AAMR) states in its amicus curiae brief that “the term ‘significantly subaverage’ has been used by mental retardation professionals to describe the level of impairment found in individuals whose performance on standardized intelligence tests places them two standard deviations below the mean; that is, in the lowest two and a half or three percent of the population.” (Italics added.) This formulation is consistent with the Atkins court’s statement that between 1 and 3 percent of the population has an IQ between 70 and 75 or lower, the typical cutoff IQ for the intellectual function prong. (Atkins, supra, 536 U.S. at p. 309, fn. 5.)
*53Accordingly, to state a prima facie case regarding the intellectual function prong, petitioners must show that standardized intelligence tests, of which IQ tests are the most common, place them at least two standard deviations below the mean which, according to the AAMR, is roughly the lowest 2.5 to 3 percent of the population. They must also show that this intellectual deficiency manifested before the age of 18.
Kennard, J., concurred.
Petitioner’s petition for a rehearing was denied March 16, 2005. Brown, J., did not participate therein.