The use of neuroscientific evidence in Canadian criminal proceedings.

This article addresses the question of how neuroscientific evidence is currently used in the Canadian criminal justice system, with a view to identifying the main contexts in which this evidence is raised, as well as to discern the impact of this evidence on judgements of responsibility, dangerousness, and treatability. The most general Canadian legal database was searched for cases in the five-year period between 2008 and 2012 in which neuroscientific evidence related to the responsibility and recidivism risk of criminal offenders was considered. Canadian courts consider neuroscientific evidence of many types, particularly evidence of prenatal alcohol exposure, traumatic brain injury, and neuropsychological testing. The majority of the cases are sentencing decisions, which is useful given that it offers an opportunity to observe how judges wrestle with the tension that evidence of diminished capacity due to brain damage tends to reduce moral blameworthiness, while it also tends to increase perceptions of risk and dangerousness. This so-called double-edged sword of the biological explanation of criminal behavior was reflected in this study, and raises questions about whether and when the pursuit of such evidence is advisable from the defense perspective.