Forensic psychology is the intersection between
psychology and the
justice system. It involves understanding fundamental legal principles, particularly with regard to
expert witness testimony and the specific content area of concern (e.g.,
competence to stand trial, child custody and visitation, or workplace discrimination), as well as relevant
jurisdictional considerations (e.g., in the United States, the definition of
insanity in criminal trials differs from state to state) in order to be able to interact appropriately with
judges,
attorneys and other
legal professionals. An important aspect of forensic psychology is the ability to
testify in court as an expert witness, reformulating psychological findings into the legal language of the courtroom, providing information to legal personnel in a way that can be understood. Further, in order to be a
credible witness the forensic psychologist must understand the philosophy, rules, and standards of the judicial system. Primary is an understanding of the
adversarial system. There are also rules about
hearsay evidence and most importantly, the
exclusionary rule. Lack of a firm grasp of these procedures will result in the forensic psychologist losing
credibility in the courtroom. A forensic psychologist can be trained in
clinical,
social,
organizational or any other branch of psychology.