The Expert Witness in Forensic Psychology Chapter 3

History of Expert Witness Many instances occurred prior to the development of clinical psychology 1846 trial for the murder of Betsy Bolt On the Witness Stand (1908) Jenkins v. United States (1962) Allowed clinical psychologists to testify in court Created a demand for forensic psychologists

Admissibility of Expert Testimony Frye test - Frye v. United States (1923) allowed to testify if the theory or procedure was generally accepted Compare probative value against the prejudicial consequences Probative proves a particular point or is useful in deciding an issue Prejudicial potential bias evidence or testimony could cause

Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) Relevant Reliable (scientific validity): Is the theory or technique testable and has it been? Has it been subjected to peer review or publication? What is the known or potential error rate? Is it generally accepted in the scientific community? General Electric v. Joiner (1997) judge is the “gatekeeper” and evaluates methodology Kumho Tire Company v. Carmichael (1999) Daubert inquiry was applicable to nonscientific testimony

Challenges to Expert Testimony Cross-examination “battle for power and control” Opposing Expert Modest impact Judicial Instructions Juror comprehension is low Many factors impact comprehension Impact is questionable

Factors that Influence Credibility Host of theoretical factors Dressing professionally, good eye contact, projecting, court familiarity, keeping composure Empirically supported factors Hired gun effect Experts from local community, actively practice, testify for both prosecution and defense, pro bono

Criticisms of Expert Testimony Taking over the courtroom Ultimate Issue or Ultimate Opinion Testimony Corruption of Science Financial Incentives Extra-forensic relationship Attorney Pressure Politics and Moral Beliefs Notoriety Competition Lack of Recognition of Bias

Ethics of the Expert Witness Face pressure from the courtroom Public opinion is largely formed from media images APA Ethical Principles (2002) Competence Staying with one’s scope of practice Informed Consent and Confidentiality Financial Arrangements Avoid contingency fee relationships Multiple Relationships

Syndrome Evidence: Controversial Aspect of Expert Testimony Set of symptoms that occur together in a meaningful way and normally have a triggering event Dozens of different psychological syndromes Battered woman syndrome, rape trauma syndrome, child sexual abuse syndrome, etc. Typically based on clinical experience, not on research

Syndrome Evidence Generally lack empirical support High number of false positives Has been used to describe as well as to prove a substantive claim in a case Substantive evidence Character evidence Continue to be admitted Anti-therapeutic consequences