1. The Expert Witness in Forensic Psychology
Chapter 3

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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