The influence of genetic, environmental and racial defendant characteristics on criminal trial outcomes

There is emerging evidence that aggression and antisocial behaviour may be influenced by the interplay between the low activity Monoamine Oxidase A (MAOA) genotype and history of childhood maltreatment exposure. Establishment of the genetic and environmental determinants of aggressive, antisocial behaviour has resulted in the court application of behavioural genetics evidence to achieve exculpation or leniency in the defendant's criminal sentence. However, this is yet to be explored in the context of racial differences. The present research aimed to build upon existing literature concerning the efficacy of the application of behavioural genetics evidence in court, by examining the cumulative influence of a defendant's genetics, environmental trauma and race on judiciary sentencing decisions. A total of 145 participants (118 female, 27 male), with ages ranging from 19-67 years, were randomly allocated to one of eight vignettes, where in which explanations concerning the defendant's genetics, childhood maltreatment and race were manipulated. Participants completed questions relating to their perceptions of defendant criminal culpability and appropriate sentence severity, and a self-report questionnaire to assess their attitudes towards modern genomics (PUGGS; Carver et al., 2017). Findings demonstrated no interaction between MAOA genetic, environmental trauma and Indigeneity status defendant characteristics on judicial culpability and sentence severity determinations. However, there was a modest effect on MAOA genetic evidence on judicial prison length decisions. This research is the first of its kind in an Australian population and contributes meaningful results to a growing field.