Writing about the insanity defense over a quarter of a century ago, the author of this chapter stated: "Until we 'unpack' the empirical and social myths that underlie our misconceptions about the insane and the insanitydefense and hold us in a paralytic thrall, we cannot begin to move forward." Some five years later, he began a full-length book on the insanity defense by alleging, "Our insanity defense jurisprudence is incoherent." Five years after that, he concluded that "we as a society remain fixated on the insanity defense as a symbol of all that is wrong with the criminal justice system and as a source of social and political anger." Returning to this issue two years ago, he concluded that "nothing has happened in the intervening decade to lead me to change my mind." The myths have stayed with us, and we willfully blind ourselves to the empirical and behavioral realities.
At the roots of this incoherence and fixation is our nation's irrational belief system in a series of myths about the defense, each of which has been discredited, yet each of which continues to dominate political and social discourse. Multiple scholars have identified these "epic myths", but their power still controls the debate. Simply put, the valid and reliable research on the insanity defense contradicts most of the "commonly-held beliefs" about the defense's usage.
There are multiple reasons for this disconnect between myth and reality. We cannot understand the insanitydefense unless we look at it through the cognitive psychology construct of "heuristics," that is, the way that we seek to simplify information-processing tasks by privileging the vivid, negative, accessible anecdote, and by subordinating the factual, the logical, the statistical, the rational. One single vivid, memorable case overwhelms mountains of abstract, colorless data upon which rational choices should be made. Empirical studies reveal jurors' susceptibility to the use of these devices. Furthermore, we cannot understand theinsanity defense unless we come to grips with the meretricious allure of a false "ordinary common sense" (OCS) that has long pervaded, and poisoned, our jurisprudence in this area. OCS is self-referential and non-reflective: "I see it that way, therefore everyone sees it that way; I see it that way, therefore that's the way it is."
This chapter will consider the political/social myths that continue to dominate the insanity defense conversation, will present the empirical realities that refute each and every one of these myths, will briefly consider these issues through the lens of therapeutic jurisprudence, and will offer some conclusions as to why these myths continue to so hold us in thrall.
Perlin, Michael L., "The Insanity Defense: Nine Myths That Will Not Go Away" (2017). Articles & Chapters. 1128.