Forensic psychology is a sub-discipline of psychology that is the intersection of psychology and the legal system. It has its own research journals, professional organizations, and educational and training programs; and professionals who work within the field must obtain highly specialized training and skills.
Forensic psychologists work with and represent a variety of people within the legal system (people working for the legal system and people using the legal system). One of their primary jobs is to provide psychological counsel to various people, groups, and entities and to then translate their diagnoses into information that can be used in a court of law. Therefore, forensic psychologists must be knowledgeable, skilled, and practiced in both psychology and law.
According to writer and educator Kendra Cherry, the field of forensic psychology started with the study of testimony. James McKeen Cattell, a researcher at Columbia University, proved through a study of students that eye-witness testimony lacked consistency and reliability[i]. Other researchers confirmed his findings, and their collective studies led to the systematic study of forensic psychology and the effects of mental processes and human behavior on legal processes and outcomes. The view that expert testimony from qualified psychologists was critical to the fair assessment of legal proceedings became more and more prevalent throughout the 1940s, 50s, and 60s. Forensic psychologists soon started conducting personality tests on police officers and criminals and used the results to train and classify them. Since its inception, the field of forensic psychology has grown and expanded to the extent that our modern-day legal system would not be the same without it.
When considering the field of forensic psychology, it is important to keep in mind that it is may be incredibly competitive. Many practitioners have earned a PhD in clinical, counseling, or forensic psychology, and most have extensive training in both psychology and law. Some forensic psychologists even pursue dual degrees in the subjects. Also, forensic psychologists, just like other psychologists, must acquire state-level licensure or certification before they can practice.
If you are interested in how to become a forensic psychologist, consider doing the following:
According to the site, Everything Forensic Psychology, there are numerous famous psychologists in history who helped the field become what it is today[ii]:
Sources: [i] psychology.about.com/od/psychologycareerprofiles/a/forensicpsych.htm | [ii] everythingforensicpsychology.weebly.com/famous-forensic-psychologists.html