Exploring jury decision-making in death penalty cases

This dissertation examines the importance of instruction comprehension injury decisionmaking at the sentencing phase of capital trials. Evidence manipulations were also tested for their impact on capital sentencing decisions, including emotionally abusive history, prior criminal record, heinousness of the crime, mental illness, and defendant age. Two studies explored jury decisionmaking, each within the context of a different state\u27s capital sentencing scheme. Study 1 utilized a sample of 230 jury-eligible community participants in a 4 x 4 experimental design to examine the importance of mental illness evidence and instruction comprehensibility under old (pre-1991), current, and revised versions of Texas\u27 unique “Special Issues” capital sentencing framework. The methodology for Study 1 involved written stimuli with non-deliberating mock juror participants. Instructions revised by the researchers failed to improve instruction comprehension, and comprehension was unrelated to decision outcome measures. Study 2 was a fully-crossed 2 x 2 x 2 x 2 x 2 experiment with four deliberating mock juries per cell. The sample of 735 jury-eligible participants included 130 individuals who identified themselves as students. Participants watched one of 32 stimulus videotapes based on a replication of a capital sentencing hearing. Evidence, based on the sentencing hearing from Buchanan v. Angelone (1998), varied in terms of defendant emotionally abusive history, bad prior record, and heinousness of the crime. Participants received either the original Virginia instructions used at the Buchanan trial, or instructions revised by the researchers that had been shown to improve comprehension in prior research. A list of case-relevant mitigating factors was either present or absent in the instructions. Instructions revised by the researchers were associated with higher levels of comprehension, as was presence of a list of case-specific mitigating factors. Instruction comprehension and presence of a list of mitigators in the instructions were associated with higher likelihood of life sentences. Heinousness of the crime and attitudes in opposition to capital punishment were influential factors in a social-cognitive path model of juror decisionmaking