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Expert testimony in capital sentencing: juror responses
John H Montgomery1, J Richard Ciccone, Stephen P Garvey
1Department of Psychiatry and Human Behavior, Univeristy of Mississippi Medical Center, Jackson, USA. jmontgo651@yahoo.com
The Journal of the American Academy of Psychiatry and the Law
|January 6, 2006
Summary
Capital jurors were swayed by mental illness testimony but not by future dangerousness predictions from psychiatric experts. This impacts understanding of expert witness influence in death penalty sentencing.
Area of Science:
- Forensic Psychology
- Legal Psychology
- Capital Punishment Research
Background:
- The U.S. Supreme Court mandates individualized sentencing in capital cases (Furman v. Georgia, 1972).
- This led to increased use of psychiatric and psychological experts in death penalty sentencing phases.
- Experts testify on mitigating mental state and future dangerousness.
Purpose of the Study:
- To explore capital jurors' responses to psychiatric and psychological expert testimony.
- To investigate the impact of expert testimony on perceptions of mental illness and future dangerousness.
Main Methods:
- Utilized data from the Capital Jury Project in South Carolina (n=214).
- Employed ordered logit regression analyses to assess correlations.
- Examined the influence of defense and state-introduced psychiatric testimony.
Main Results:
- Defense psychiatric/psychological experts significantly correlated with jurors' impression of mental disturbance (p < .005).
- State-introduced psychiatric testimony showed no significant relationship with jurors' impressions of future dangerousness.
- Jurors were significantly influenced by testimony on mitigating mental abnormality.
Conclusions:
- Psychiatric testimony on future dangerousness may not powerfully impact capital jurors as commonly believed.
- Expert testimony regarding a defendant's mental state as a mitigating factor significantly influences juror perception.
- Findings highlight the differential impact of expert testimony in capital sentencing.
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