Psychology, Public Policy, and Law, Vol 32(2), May 2026, 144-152; doi:10.1037/law0000475
To broaden research on contextual information in forensic assessment, specifically credibility assessment, we designed an online vignette study that examined how motive-to-lie information impacts the judgment of a witness’s testimony. Three hundred twenty-five German professionals experienced in Statement Validity Assessment (SVA) were given information suggesting a motive to lie, information suggesting no motive to lie, or no information (control group). They then read one of three versions (with a low, medium, or high criteria-based content analysis [CBCA] score) of a statement from a woman who had accused her coworker of a sexual offense. Participants were asked for CBCA-based and veracity ratings. As predicted, two-way analyses of variance yielded a very large main effect of statement version on both CBCA-based ratings, ηp² = .60, 95% confidence interval (CI) [0.54, 0.65], and veracity ratings, ηp² = .33, 95% CI [0.25, 0.41]. Motive information had no effect on CBCA-based ratings, but a small effect on veracity ratings, with information suggesting a motive to lie slightly lowering veracity ratings, ηp² = .05, 95% CI [0.01, 0.11]. The predicted interaction effect of the statement version and motive information was not found. Overall, SVA professionals appeared to follow SVA guidelines when making veracity judgments by excluding motive information from their CBCA-based ratings and emphasizing differences in CBCA scores across statement versions. The small effect of motive information on veracity ratings may improve or bias veracity judgment in the field. This should be examined in future research, ideally involving SVA reports and SVA professionals. (PsycInfo Database Record (c) 2026 APA, all rights reserved)