Kasian, M., Spanos, N. P., Terrance, C. A., & Peebles, S. (1993). Battered women who kill: Jury simulation and legal defenses. Law and Human Behavior, 17, 289-312.
This study assesses acquital rates using mock jurors in cases involving a battered woman charged with killing her husband. The simulated trial format was based on actual courtroom proceedings including witness cross-examination and jury deliberation proceedings. The type of plea entered was varied and reflected either self-defense, automatism, or a hypothetical plea of psychological self-defense. The severity of abuse incurred by the defendant was also varied along with expert testimony. Jurors more frequently found the defendant not guilty when a plea of automatism was entered compared to a plea of self-defense. The frequency of acquittals following a plea of psychological self-defense resulted in more acquittals than the self-defense plea but significantly fewer than the automatism plea. The likelihood of acquittal increased under conditions of severe abuse as opposed to moderate abuse. Expert witness testimony was observed to influence verdicts during juror deliberations.
<1>No impact of expert testimony or defendant plea on jury verdicts, but expert testimony coincided with men becoming more lenient and women more severe after deliberation. <2>Verdicts influenced by defendant injury caused by victim and defendant plea; acquittal more likely with severe abuse and when defendant pleaded automatism rather than self-defense.