Unloading the hired gun: Inoculation effects in expert witness testimony

Abstract

The current projects investigated the efficacy of inoculation as a trial strategy designed to counter mock jurors' perceptions that an expert is a hired gun. Additionally, the projects also examined whether the manner in which experts responded to these questions had a significant effect on their ratings as a hired gun and overall credibility. The project contained two independent studies with parallel manipulations. Study 1 examined the previously mentioned effects in a civil trial while study 2 examined them in a criminal trial. The effects of these variables on measures of case outcome were also examined.Results revealed that, in a civil setting, inoculation significantly affected mock jurors' views of psychology in general, but had no significant effect on ratings of the expert as a hired gun, expert credibility, or case outcome. However, experts who responded to questions about bias in a narrative versus a fragmented manner were viewed as less of a hired gun. These results were not replicated in the criminal context. In that setting, not using inoculation led to higher ratings of expert knowledge. No other significant effects of inoculation or response style were found in the criminal setting.Implications of these results regarding current theory about hired gun expert witnesses are discussed. Additionally, suggestions for the fields of trial strategy and expert witness testimony are made. Finally, due to the context dependent nature of the results that were obtained, these findings suggest that future research in this area should be wary to generalize findings from a civil context to a criminal context and vice versa.

Battling to a draw: Defense expert rebuttal can neutralize prosecution fingerprint evidence

“…It is important to note, however, that we observed no backfire effect from the prosecution's inoculation effort, suggesting that prosecution attorneys may suffer no harm from seeking to develop a more effective inoculation statement. Our inoculation testimony acknowledged the risk of error but explained why that risk was not present here; one alternative approach would be to seek to undercut the credibility of the anticipated rebuttal expert, perhaps by characterizing that expert as a ‘hired gun’ (Ziemke & Brodsky, 2015) or with evidence of that expert's own prior mistakes. Given the potential impact of rebuttal testimony on juror perceptions of forensic evidence, the parties have a strong interest in developing effective counter‐measures.…”

Evaluating the Reliability of Expert Evidence in Compensation Procedures: Are Diagnosticians Influenced by the Narrative Fallacy when Assessing the Psychological Injuries of Trauma Victims?

“…It cannot be ruled out that legal decision makers already more critically evaluate information from psychological experts who also treat the litigating victim than information from independent experts. The former may be seen as hired guns —experts who simply take the position of their client in return for payment (Ziemke & Brodsky, 2015 ). Several studies suggest that the opinion of such experts is often considered with suspicion by legal decision makers (see Edens, Smith, Magyar, Mullen, Pitta, & Petrila, 2012 ; Mossman, 1999 ).…”

Juror appraisals of forensic evidence: Effects of blind proficiency and cross-examination

“…Similarly, Lieberman et al [26] found DNA evidence strongly influenced guilty decisions, even after a cross-examination. Ziemke and Brodsky [27] examined an "inoculation tactic," whether having an expert acknowledge during direct examination he was being paid and often testified for defendants would neutralize a prosecution effort to portray the expert as a "hired gun;" they found no effects of doing so. Thompson and Scurich [28] found mock jurors rated a forensic odontologist as less credible and were less likely to convict when the examiner admitted on cross examination that the bitemark examination rested on his subjective judgment, and that he was exposed to potentially biasing task-irrelevant contextual information, relative to when these issues were not raised.…”