Graduation Year


Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Arts



Reader 1

Jennifer Groscup

Reader 2

Jennifer Ma

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Terms of Use for work posted in Scholarship@Claremont.

Rights Information

© 2014 Elaine Tsao


Past literature has indicated that jury instructions are not written in ways that result in optimal juror comprehension, and can be improved through various ways of simplification. Prototypes of the insanity defense have also been found to influence juror decision-making. Additionally, individual factors such as attitudes toward and myth endorsement of the insanity defense can influence verdict. The following study explored these effects of jury instruction format, insanity defense consistency, and participant factors on jury understanding and decision-making. Three hundred and eighty jury eligible community members were recruited online for this study. Participants were first asked questions pertaining to attitudes and myths about the insanity defense. Afterwards, each participant read one of two vignettes (an insanity defense consistent case and an insanity defense inconsistent case), and then read one of three jury instructions (traditional, simplified, or flow-chart versions). The participants then reached individual verdicts and answered factual questions about the insanity defense and their perceptions on the defendant. Results indicated that simplified instructions increased participant knowledge over the traditional and flow-chart instructions, but did not influence verdict selection overall. Consistency, myth endorsement, attitudes, and perceptions of the defendant were also all found to contribute to the verdict. These results contribute to the current research on comprehension of jury instructions, especially in the context of an insanity defense case, and may provide additional information for attorneys to consider during the voir dire process.