Sexual Crimes and Morality




Professor of Psychology

Project Summary

Along with my co-investigator Christina Uria, I participated in a yearlong research project under the mentorship of Professor Robert Kurzban and PhD student Kristopher Smith. Our project focused on people’s moral judgements of sexual crimes, specifically why moral judgments of violent crimes with a sexual intent are harsher than judgments of violent crimes without a sexual intent, even when physical harm to the victim is the same in both scenarios.

We hypothesized that crimes with an added sexual intent would be perceived as causing more harm to the victim because of the potential cost to an organism’s fitness. We defined fitness as a measure of one’s ability to survive and reproduce in a given environment, and any cost to fitness would cause a disadvantage in an organism’s ability to do so. Thus, we predicted in our first study that people would assign greater punishment to perpetrators that commit a violent crime with a sexual intent against a victim with high reproductive value, such as a female victim of reproductive age, compared to a victim with lower reproductive value, such as children or seniors. We tested this prediction using hypothetical vignettes to measure the amount of punishment in terms of length of jail time that participants assigned to perpetrators that committed a violent crime either with or without a sexual intent. We did not observe a significant effect of victim age, and therefore could not support our hypothesis that punishment judgment of sexual crimes track fitness costs. We did, however, find that crimes with a sexual intent committed across all ages were punished more harshly than that same crime without a sexual intent even when physical harm to the victim remained constant.  

Although we did not find strong evidence of our first hypothesis, in our second study we continued to investigate what exactly about sexual crimes elicits such a harsh judgment for perpetrators compared to that of violent crimes. In our second study, we tested whether the clarity of evidence of the perpetrator’s intent would impact punishment judgments. We manipulated this by presenting participants with scenarios that included a crime of commission in which the perpetrator’s intentions were made clear, as opposed to a crime of omission where there was less clear evidence of the perpetrator’s intended outcome. Again, we manipulated whether the perpetrator had sexual intent behind the crime. However, in this study we did not find an increase in punishment from the violent crime with an added sexual intent compared to the same violent crime without a sexual intent. In addition, the clarity of the perpetrator’s intent in the condition also did not significantly impact participants’ punishment judgments.

Thank you to the Millstein Family Undergraduate Research Grant for funding a Amazon Mechanical Turk that enabled us to gather data from large groups of participants for both of our studies. My research experience was incredibly rewarding and both Tina and I were grateful for the opportunity to design and run two complete experiments in order to investigate our hypotheses. I also valued my experience working with my co-investigator on our project.

Sexual Crimes and Morality