Unloading the hired gun - inoculation effects in expert witness testimony
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.