of penalty phase instructions, the Supreme Court has stated that the trial court must
clarify for the jury which instructions apply to the penalty phase. (People v.
Babbitt, supra, 45 Cal.3d at p. 718, fn. 26; People v. Weaver (2001) 26 Cal.4th
876, 982 [111 Cal.Rptr.2d 2, 29 P.3d 103], cert. den. sub nom. Weaver v. California
(2002) 535 U.S. 1058 [122 S.Ct. 1920, 152 L.Ed.2d 828].) In order to avoid
confusion, the Supreme Court has indicated that the preferable practice is for the
court to provide the jury with a completely new set of instructions. (People v.
Weaver, supra, 26 Cal.4th at p. 982.) The committee recommends this approach in
the mental retardation phase as well.
When the defendant in a capital trial raises the issue of mental retardation, the jury
must decide the question unless the defendant has waived a jury on the issue. (Pen.
Code, § 1376(b)(1).) The hearing on mental retardation shall be conducted after the
guilt phase and prior to the penalty phase. (Ibid.) If the defendant has entered a
plea of not guilty by insanity, the hearing on mental retardation shall be conducted
after the sanity phase. (Pen. Code, § 1376(e).) The defense bears the burden of
proving mental retardation by a preponderance of the evidence. (Pen. Code,
The court must also give any necessary instructions on witnesses and evidence,
such as CALCRIM No. 222, Evidence, CALCRIM No. 226, Witnesses, and
CALCRIM No. 332, Expert Witness. The court must conclude with CALCRIM No.
3550, Pre-Deliberation Instructions.
• Hearing on Mental Retardation in Death Penalty Case. Pen. Code, § 1376.
•Execution of Mentally Retarded Unconstitutional. Atkins v. Virginia (2002)
536 U.S. 304, 319–321 [122 S.Ct. 2242, 153 L.Ed.2d 335].
• Mental Retardation Deﬁned. Pen. Code, § 1376(a); In re Hawthorne (2005) 35
Cal.4th 40, 47–49 [24 Cal.Rptr.3d 189, 105 P.3d 552]; American Association on
Mental Retardation, http://www.aamr.org/Policies/faq_mental_retardation.shtml
(accessed August 16, 2006 [case sensitive]).
• Should Give Jury New Set of Instructions (Penalty Phase). People v. Weaver
(2001) 26 Cal.4th 876, 982 [111 Cal.Rptr.2d 2, 29 P.3d 103], cert. den. sub
nom. Weaver v. California (2002) 535 U.S. 1058 [122 S.Ct. 1920, 152 L.Ed.2d
4 Millman, Sevilla & Tarlow, California Criminal Defense Practice, Ch. 87, Death
Penalty,§§ 87.16, 87.17, 87.18 (Matthew Bender).
Scope of Expert Testing
When the defendant places at issue the question of whether he or she is mentally
retarded, the defendant must submit to examination by a prosecution expert.
(Centeno v. Superior Court (2004) 117 Cal.App.4th 30, 40 [11 Cal.Rptr.3d 533].)
CALCRIM No. 775 HOMICIDE