The Effect of In Utero Androgen Exposure on Juror Decision-Making

Factors affecting juror decision-making have been studied extensively to determine what drives juror's decisions (Skorinko, Laurent, Bountress, Nyein, and Kuckuck, 2014). In utero androgen exposure measured using the 4D:2D ratio has been studied to understand how the amount of in utero androgen individuals are exposed to affects their personality and emotional development (Manning et. al., 2010; Kempe and Heffernan, 2011; Hampson, Ellis and Tenk, 2008; Fink, Manning and Neave, 2004; Knickmeyer, Baron-Cohen, Raggatt, Taylor and Hackett, 2006; Knickmeyer and Baron-Cohen, 2006; Wakabayashi and Nakazawa, 2010). Using 106 undergraduate students, the current study sought to understand how the 4D:2D ratio affects juror decision-making in civil cases by having participants assign a proportion of liability to a defendant. Participants reviewed jury instructions, as well as three case vignettes. One of these case vignettes was removed due to a description error that led almost all of the participants to find the plaintiff at fault. This study had three different experimental groups where age of the plaintiff was counterbalanced to control age as a factor in the amount of liability assigned. It was hypothesized that a higher 4D:2D ratio would result in lower defendant liability. Here we show that there was a significantly lower proportion of defendant liability assigned by the high 4D:2D ratio group as compared to the low 4D:2D ratio group; t(210) = 2.89, p < 0.01, d = 0.36. Interestingly, despite the difference between the group means, variability was such that the 4D:2D ratio was not predictive of the proportion of defendant liability assigned for experimental conditions.