Abstract

The United States first saw the introduction of a medicalized insanity test in its courtrooms in the mid-nineteenth century. From 1843 onwards, numerous sensational insanity trials entrenched the test in the common law of the country. Scholarly analyses of the defence primarily focus on the role of medical specialists and jurists in its construction. This thesis proposes that a cultural history of the insanity defence offers a fundamentally different vision of the defence as it emerged in the 1840s. My reading of media sources, such as trial transcripts, newspapers, and other public-oriented work, shows that the informal relationships the public drew between cases influenced perceptions of the plea which in turn shaped how jurists and doctors approached the plea in the courtroom. Consequently, as the defence upheld popular cultural perceptions regarding mental illness, criminality, race, and gender in its use, the insanity plea became constructed as a cultural defence in the law, one imbued with the subjectivity of those who used it in the courts. The cultural constructions of the defence during the nineteenth century illustrates the continuing dialectical relationship that has informed the use of the plea into contemporary times. Ultimately, these trials offer valuable insights for future research regarding public constructions of legal defences such as the insanity plea, and their impact on juror behaviour.