Conviction Reversed where Expert Witness Bolstered Child Witness’s Credibility

The Supreme Court of Iowa has reversed a conviction for sexual abuse of a child after an expert witness vouched for the accusing child’s credibility, stating that the child’s demeanor was consistent with a child who had been abused.

In State v. Jaquez, the defendant was accused of sexually assaulting his girlfriend’s child. In its opening statement, the prosecution warned that the child might display emotional apathy when testifying about the alleged abuse. The prosecution then called an expert witness who had interviewed the child twice prior to trial.

The court permitted the expert to testify, but granted the defendant’s motion to exclude any expert testimony that would bolster the child’s credibility. However, when the expert witness testified about the interview she conducted with the child, she stated that “her demeanor was completely consistent with a child who has been traumatized, particularly multiple times.” Later, the child gave testimony that was inconsistent with her out of court statements. After the jury convicted, the defendant appealed, arguing that the expert witness improperly bolstered the child’s credibility.

On appeal, the supreme court analyzed a sole issue: whether the expert’s statement that “her demeanor was completely consistent with a child who has been traumatized” was admissible, as it found this issue dispositive.

In Iowa as in Washington state, expert testimony is not admissible to bolster the credibility of a witness. When this type of bolstering occurs, “the expert is giving his or her scientific certainty stamp of approval on the testimony even though an expert cannot accurately opine when a witness is telling the truth, the Iowa court said”

The court found that this one statement improperly bolstered the child’s credibility. It held the statement was ultimately prejudicial because the child gave conflicting statements: without the expert’s bolstering, the jury reasonably could have found the child’s testimony less credible. The court also reasoned it was prejudicial because the prosecutor emphasized the child’s emotional apathy in her opening statement, and then drew an answer from the expert witness which implied that the child’s lack of emotion during testimony proved she was abused. The court reversed the conviction and remanded for a new trial.