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

Abstract

SummaryThe present study examined whether a defense rebuttal expert can effectively educate jurors on the risk that the prosecution's fingerprint expert made an error. Using a sample of 1716 jury‐eligible adults, we examined the impact of three types of rebuttal testimony in a mock trial: (a) a methodological rebuttal explaining the general risk of error in the fingerprint‐comparison process; (b) a new‐evidence rebuttal concluding the latent fingerprint recovered in this case was not suitable for use in a comparison; and (c) a new‐evidence rebuttal excluding the defendant as the source of the latent fingerprint. All three rebuttals significantly altered perceptions of the prosecution's fingerprint evidence, but new‐evidence rebuttals proved most effective. The effectiveness of the rebuttals depended, however, on whether jurors were more concerned about false acquittals or false convictions.