The Differential Importance of the Evidence and the Expert on Perceptions of Confessions

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Published in: The Journal of Forensic Psychology Practice, Volume 9, November 4, 2009.


In this study, we examined the effects of expert witness testimony and commonly used interrogation tactics on perceptions of confessions and equivocal forensic evidence. Results indicated perceptions of forensic evidence were influenced by expert testimony. Assessments of the value of forensic evidence were significantly lower for participants exposed to expert testimony, compared to those not exposed. This finding demonstrates the potential of expert testimony regarding interrogations to affect other types of testimony. In addition, perceptions of the interrogating detective were influenced by type of tactic. Participants' ratings of the detective were lowest in the maximization interrogation condition compared to minimization and length. Results are discussed in terms of the role of expert testimony and interrogation tactics as related to perceptions of forensic-type evidence.