Forensic Psychology: History, Roles, and Expert Testimony – Comprehensive Study Notes

Objectives

• Identify major milestones in the history of forensic psychology

• Explain the roles and activities performed by forensic psychologists

• Describe the function of expert testimony and how it is assessed

History of Forensic Psychology

• Early research in forensic psychology

• Early court cases in Europe

• Forensic psychology in North America

• Landmark U.S. court cases

• Progress in Canada

• A legitimate field of psychology

Early Research in Forensic Psychology

• Cattell ($1895$) – The accuracy of everyday observations; relationship between confidence and accuracy

• Binet ($1900$) – Suggestibility in children; free recall vs. misleading questions

• Stern ($1939$) – The eyewitness ‘reality experiment’ conducted in 1901; emotional arousal and accuracy

Early Court Cases in Europe

• Von Schrenck-Notzing ($1896$) – Expert witness: Impact of pre-trial press; “Retroactive memory falsification” (observed vs. heard later)

• Varendonck ($1911$) – Expert witness: Children as eyewitnesses; children provide inaccurate testimony if suggestive questions used

Forensic Psychology in North America (1 of 2)

• Munsterberg – Provided input into police interrogations in several cases

• Published classic book On the Witness Stand ($1908$)

• Argued for the benefits of psychology within the legal system: eyewitness testimony, crime detection, false confessions, suggestibility, hypnotism, crime prevention, etc.

• Ideas largely rejected and ignored by the legal community

• Known as “the father of forensic psychology”

Forensic Psychology in North America (2 of 2)

• Psychology within criminal justice settings:

  • Clinic for juvenile delinquents ($1909$)

  • Laboratories for pretrial assessments ($1916$)

  • Psychological testing for law enforcement selection ($1917$)

Landmark U.S. Court Cases (1 of 2)

• State v. Driver ($1921$) – First time expert testimony is provided by a psychologist

• Partial victory as psychologist’s testimony rejected

• Use of psychological and medical tests in detecting lies questioned

Landmark U.S. Court Cases (2 of 2)

• Jenkins v. United States ($1962$) – Three psychologists claim defendant suffering from schizophrenia

• Jury instructed to disregard testimony during trial

• Reversed on appeal; court rules some psychologists are qualified to give expert testimony on mental disorders

• Psychologists now regularly contribute to legal proceedings

Progress in Canada

• Research on eyewitness testimony and jury decision making

• Leader in the field of corrections: risk assessment and treatment

• Canadian courts slower to allow testimony from psychologists – rely primarily on medical doctors (psychiatrists)

• Partially explained by different licensing standards vs. the U.S.

A Legitimate Field of Psychology

• Evidence of an established discipline: high quality textbooks, academic journals, professional associations, training opportunities

• Recognized as a specialty discipline by the American Psychological Association (APA) ($2001$)

Definition and Roles

• Definitions of forensic psychology

• Roles of forensic psychologists

• Forensic Psychologist as Clinician

• Forensic Psychologist as Researcher

• Forensic Psychologist as Legal Scholar

• Relationships between psychology and law

Definitions of Forensic Psychology

• Narrow definition

  • Focus on the clinical aspect of the field (assessment, treatment)

  • Excludes other aspects (e.g., forensic researchers)

• Broad definition

  • Human behaviour in relation to the legal system

  • Includes both research and practice aspects

• Textbook adopts a broad definition

Roles of a Forensic Psychologist

• Clinician

• Researcher

• Legal Scholar

Forensic Psychologist as Clinician

• Concerned with mental health issues in the legal system

• Tasks can include:

  • Assessment and treatment of offenders

  • Custody mediations

  • Providing expert testimony

  • Personnel selection

  • Critical incident debriefings

• Must be licensed clinical psychologist with forensic specialization

Forensic Psychologist as Researcher

• Conduct research on any issue related to the legal system

• Research interests can include:

  • Examining effectiveness of risk assessment strategies

  • Developing and testing ways eyewitness lineup procedures

  • Evaluating offender treatment programs

  • Factors that influence juror decision-making

• PhD-level training in a forensic program or forensic specialization

Forensic Psychologist as Legal Scholar

• The least common role for forensic psychologists

• Interests can include:

  • Scholarly analysis of mental health law and legal movements

  • Policy analysis and legislative consultation

• Programs at Simon Fraser University

Relationships Between Psychology and Law

• Psychology and the law – Using psychology to study the operation of the legal system – Testing assumptions, e.g., “Are eyewitnesses accurate”

• Psychology in the law – Using psychology within the legal system as it currently operates – e.g., Providing expert testimony in court

• Psychology of the law – The use of psychology to study the law itself – e.g., “Does a law reduce the occurrence of a crime?”

Psychological Experts in Court

• Functions of an expert witness

• Challenges of providing expert testimony

• Admissibility Criteria: Frye

• Admissibility Criteria: Daubert

• Admissibility Criteria in Canada: Mohan

Functions of an Expert Witness

• Regular witnesses: only testify about direct observations

• Expert witness: provide opinion based on relevant experience

• Primary function: Assist triers of fact (e.g., judges, jurors) – Impartial educator

Challenges of Providing Expert Testimony (1 of 2)

• Experts need to know:

  • Details of the case and their own testimony

  • Their role in the proceedings

  • How to communicate in persuasive and helpful manner

• Challenging because of differences between psychology and law

Challenges of Providing Expert Testimony (2 of 2)

• Many differences between Psychology and Law:

  • Epistemology (Objective vs. Subjective)

  • Nature (Descriptive vs. Prescriptive)

  • Knowledge (Nomothetic vs. Idiographic)

  • Methodology (Experimental vs Narrative)

  • Criterion (Cautious vs. Expedient)

  • Principles (Multiple Explanations vs. Single Explanation)

  • Latitude of Behaviour (Limited vs. Expansive)

  • Difficult to apply group level results to single case

Admissibility Criteria: Frye

• Frye v. United States ($1923$) – Resulted in the “general acceptance test” – Procedures used generally accepted in the scientific community

• Two major criticisms – Vagueness of terms “general acceptance” – Whether trial judges can make this determination

Admissibility Criteria: Daubert

• Daubert v Merrell Dow, Inc. ($1993$)

• Testimony is admissible if it is:

  • Provided by a qualified expert,

  • Relevant, and

  • Reliable.

• Daubert criteria for reliability means that the research must:

  • Be peer reviewed

  • Be testable (falsifiable through experimentation)

  • Have a recognized error rate

  • Adhere to professional standards

Admissibility Criteria: Mohan

• R v. Mohan ($1994$) – Canadian criteria for admissibility of expert testimony

• Mohan criteria states that, along with reliability, the testimony:

  • Must be relevant to the case

  • Must be necessary to assist the trier of fact

  • Must not violate any rules of exclusion

  • Must be provided by a qualified expert