The Intersection of Psychology and Law

By: Victoria Tumilty

What is Forensic Psychology?

Forensic psychology is the field where psychology and the law intersect. This field of study explores how psychological approaches are applied to the criminal justice and legal systems. Forensic psychologists make use of their knowledge of psychology and research methods to advise, evaluate, and reform the legal system.

Forensic Psychologists as Advisors

One way a psychologist can serve as an advisor to the legal system is through testifying as an expert in court. A lawyer may hire a psychologist to testify about a particular aspect of a case. This is most notably done by clinical psychologists. These psychologists are often asked to testify about a defendant’s competency to stand trial or

about the likelihood of future risk and dangerousness of a defendant to society.

Another way psychologists can serve as legal advisors is through serving as a trial consultant. These psychologists are hired by attorneys to help with jury selection, witness prep, and trial strategy. Psychologists serving as trial consultants use psychological knowledge in an attempt to shape the trial process in favor of the side that hired them.

Lastly, psychologists can serve as legal advisors by writing arguments, or briefs, to submit to the court. This is done when a case is appealed to a higher court like the U.S. Supreme Court. These briefs often summarize empirical findings and conclusions of research conducted by social scientists on areas that pertain to a particular case.

Forensic Psychologists as Evaluators

There are numerous programs put in place within both the criminal justice and legal systems. Some of these social programs are used to deter offenders, treat offenders, punish offenders, and rehabilitate offenders. While it is important to have programs like these in place, it is also important to look at whether these programs really work to accomplish their goals. To do this, psychologists conduct evaluation research. This research can take on a multi-disciplinary approach by combining multiple areas of social science like psychology, criminology, sociology, and anthropology. Evaluators can also approach research questions through a clinical, social, cognitive, or developmental psychology lens to determine if a social, legal program is working. Many psychologists who serve as evaluators work in academia where they can conduct research in labs, or they work in other research-oriented positions.

Forensic Psychologists as Reformers

The role of psychologists serving as reformers to the legal system goes hand in hand with the role of psychologists as evaluators. As an evaluator, psychologists are researching areas within the criminal justice and legal systems to see if they meet the desired goals or if the programs need to be improved. Those that find areas needing improvement can step outside of their role as an objective social scientist and advocate for change. This can be done by educating police and legal practitioners about psychological phenomena to improve practices within the criminal justice or legal systems. Reform can also occur by psychologists making direct attempts to influence legislation through the process of lobbying. One professional organization that uses psychology to lobby for reform is the American Psychological Association (APA).


The science of psychology can interact with the law in a vary of ways. Psychologists from many different subfields of the science can use their knowledge and skills to serve as either advisors, evaluators, or reformers. In doing so, these psychologists strive to educate others in how the two disciplines intersect as well as how to improve the efficiency and accuracy of the criminal justice and legal systems.


Costanzo, M., & Krauss, D. A. (2018). Chapter 1: Psychology and Law: A Cautious Alliance: In Forensic and legal psychology: Psychological science applied to law (pp. 36-62). essay, Worth Publishers. (picture link)