Date of Award

Spring 5-19-2014

Degree Type


Degree Name

MS Experimental Psychology




Paige H. Fisher, Ph.D

Committee Member

Susan Teague, Ph.D

Committee Member

Marianne Lloyd, Ph.D

Committee Member

Kelly Goedert, Ph.D


kleptomania, juror bias, defendant mental illness, juror decision-making


Jurors are instructed to only consider legal factors when making verdict and sentencing recommendations, but research has shown that biases can still affect these decisions. For instance, research has found that jurors can be influenced by both the type of defendant mental illness (Higgins, Heath, & Grannemann, 2007) and causal attributions regarding the mental illness (Rendell, Huss, & Jensen, 2010), even if jurors have not explicitly been told to consider this information. Although individuals with kleptomania often experience legal troubles (Grant, Odlaug, Davis, & Kim, 2009), this mental illness has not received attention in the mock juror literature. The current study employed a mock jury paradigm to investigate both the impact of a kleptomania diagnosis and related causal attributions (biological vs. psychological) on the legal outcome for a defendant arrested for shoplifting. Results suggest that a defendant with kleptomania was more likely to receive a not-guilty verdict and less likely to receive a criminal justice intervention than a defendant without mental illness. Causal attribution did not affect verdict choice, but a defendant whose situation was explained with the biological causal attribution was more likely to receive a mental health intervention than a defendant with the psychological causal attribution. The interaction between diagnosis and defense did not affect verdict or sentencing recommendations. These findings suggest that similar to other defendants with mental illness, jurors either view defendants with kleptomania as less guilty for their crimes or as less deserving of punishment from the criminal justice system than defendants without mental illness.