Cal. Pen. Code § 1127g
In any criminal trial or proceeding in which a person with a developmental disability, or cognitive, mental, or communication impairment testifies as a witness, upon the request of a party, the court shall instruct the jury, as follows:
In evaluating the testimony of a person with a developmental disability, or cognitive, mental, or communication impairment, you should consider all of the factors surrounding the person's testimony, including their level of cognitive development. Although, because of his or her level of cognitive development, a person with a developmental disability, or cognitive, mental, or communication impairment may perform differently as a witness, that does not mean that a person with a developmental disability, or cognitive, mental, or communication impairment is any more or less credible a witness than another witness. You should not discount or distrust the testimony of a person with a developmental disability, or cognitive, mental, or communication impairment solely because he or she is a person with a developmental disability, or cognitive, mental, or communication impairment.
Ca. Pen. Code § 1127g