'The Witness Who Saw/He Left Little Doubt:' A Comparative Consideration of Expert Testimony in Mental Disability Law Cases

Journal of Investigative Psychology and Offender Profiling, Vol. 6, pp. 59-88, 2009

NYLS Legal Studies Research Paper No. 09/10 #9

31 Pages Posted: 26 Aug 2009

See all articles by Michael L. Perlin

Michael L. Perlin

New York Law School

Kris Gledhill

University of Auckland

Astrid Birgden

Deakin University

Abstract

The question of how courts assess expert evidence - especially when mental disability is an issue - raises the corollary question of whether courts adequately evaluate the content of the expert testimony or whether judicial decision making may be influenced by teleology (‘cherry picking’ evidence), pretextuality (accepting experts who distort evidence to achieve socially desirable aims), and/or sanism (allowing prejudicial and stereotyped evidence). Such threats occur despite professional standards in forensic psychology and other mental health disciplines that require ethical expert testimony. The result is expert testimony that, in many instances, is at best incompetent and at worst biased. The paper details threats to competent expert testimony in a comparative law context - in both the common law (involuntary civil commitment laws and risk assessment criminal laws) and, more briefly, civil law. We conclude that teleology, pretextuality, and sanism have an impact upon judicial decision making in both the common law and civil law. Finally, we speculate on whether the new United Nations Convention on the Rights of Persons with Disabilities is likely to have any impact on practices in this area.

Keywords: expert testimony, criminal law, civil law, psychologists, risk assesment, mental disability law, international human rights law

Suggested Citation

Perlin, Michael L. and Gledhill, Kris and Birgden, Astrid, 'The Witness Who Saw/He Left Little Doubt:' A Comparative Consideration of Expert Testimony in Mental Disability Law Cases. Journal of Investigative Psychology and Offender Profiling, Vol. 6, pp. 59-88, 2009, NYLS Legal Studies Research Paper No. 09/10 #9, Available at SSRN: https://ssrn.com/abstract=1462249

Michael L. Perlin (Contact Author)

New York Law School ( email )

185 West Broadway
New York, NY 10013
United States
212-431-2183 (Phone)

HOME PAGE: http://https://www.nyls.edu/faculty/faculty-profiles/emeriti_faculty/

Kris Gledhill

University of Auckland ( email )

Private Bag 92019
Auckland Mail Centre
Auckland, 1142
New Zealand

Astrid Birgden

Deakin University ( email )

Geelong, Victoria
Australia

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