An analysis of the effects of subjective and objective instruction forms on mock-juries' murder/manslaughter distinctions.

Defendants' emotions at the time of their crimes may potentially serve as mitigating circumstances in murder/manslaughter cases. The present study examined whether differences between two forms of instructions given juries in such cases affected mockjuries' murder/manslaughter distinctions. Jurors' reasons for their verdicts and definitions of murder and manslaughter were also compared. In addition, three factors found to be predictive of murder/manslaughter distinctions in previous research were evaluated. It was found that, though instruction forms affected jurors' stated reasons for their verdicts and their definitions of murder and manslaughter, they did not significantly affect murder/manslaughter distinctions. Defendants were most likely to be convicted of murder if they had a history of violence with the victim and dwelt upon their emotions. We suggest jurors likely construe instructions given them to fit their a priori understandings of murder, manslaughter, and the potentially mitigating role of defendants' emotions.