How "Folk Psychology" Has Contaminated Forensic Mental Health Law: The Powers of Heuristics and the Fraudulence of “Ordinary Common Sense"

• In Event: Data in Indigent Defense: The International Society for Therapeutic Jurisprudence

Abstract

“Folk psychology” is a “ prescientific, commonsense conceptual framework” used to explain behavior, employed extensively by judges and jurors in all aspects of forensic mental health law. Importantly, empirical studies have disproved a number of legal folk psychology theories of human behavior and mental processes. Yet, it continues to hold sway in courtrooms.

This misuse is contaminated further by our reliance on heuristic devices (e.g,, the vividness heuristic, a cognitive-simplifying device through which a “single vivid, memorable case overwhelms mountains of abstract, colorless data upon which rational choices should be made”) and false “ordinary common sense” (a self-referential and non-reflective” way of constructing the world). These devices affect every aspect of testimony in forensic cases, and are regularly misused by fact-finders in criminal cases.

We believe that the use of therapeutic jurisprudence – a legal school of thought that seeks to determine whether legal rules, procedures, and lawyer roles can or should be modified to increase their therapeutic potential while not subordinating due process principles – is the best way to correct the harms done by the misreliance on folk psychology.

Author

• Michael Perlin, New York Law School