When will a court grant a motion for a mistrial for abuse of an expert's testimony?

"A trial court should grant a motion for mistrial 'only when "'a party's chances of receiving a fair trial have been irreparably damaged'"' [citation], that is, if it is 'apprised of prejudice that it judges incurable by admonition or instruction' [citation]. 'Whether a particular incident is incurably prejudicial is by its nature a speculative matter, and the trial court is vested with considerable discretion in ruling on mistrial motions.' [Citation.] Accordingly, we review a trial court's ruling on a motion for mistrial for abuse of discretion." (People v. Avila (2006) 38 Cal.4th 491, 573.)

We agree the testimony was improper,⁴ but see no abuse in the court's decision to admonish the jury rather than grant a mistrial. "We presume the jury followed the court's instructions." (People v. Avila, supra, 38 Cal.4th at p. 574 [admonishment adequate; mistrial unnecessary].) Defendant asserts the testimony was prejudicial because the whole case turned on the natural and probable consequence doctrine. But that is not necessarily true. We just discussed how the jury reasonably could have found defendant aided and abetted the murder. Thus, the expert's testimony was not "'incurably prejudicial.'" (Id. at p. 573.)