This chapter reviews the existing empirical literature that examines the social psychological aspects of the trial court processes in American capital cases. It also reviews the existing empirical research that addresses the trial court processes in capital cases in an effort to delineate some of the fundamental challenges that the death penalty poses to the legal system. Perhaps the biggest black box in the capital case process has to do with the prosecutorial decision to seek death. The death qualification process has been more extensively studied, and the existing research suggests that the process itself contributes to some notable biases in shaping the capital jury as a decision-making body. Mock and actual capital jurors also appear to evaluate the evidence presented in the penalty phase in a manner that disadvantages the defendant. There is mixed research about the role of expert testimony, especially psychiatric and psychological testimony about the defendant's mental state in capital jury sentencing decisions.