Juror perceptions of witness credibility as a function of linguistic and nonverbal power

Abstract

While the effects of linguistic power on witness credibility in the courtroom as well as preliminary studies of the effects of nonverbal power on witness credibility have been studied, no research has focussed on manipulations of linguistic and nonverbal power together. For purposes of greater generalizability, the effect of different manipulations of linguistic power and nonverbal power in witness testimony is studied in this dissertation. Subjects viewed one of four videotaped versions of combined linguistic power/nonverbal power testimony and rated the witness's credibility. Through factor analysis and multivariate analysis of variance, the results showed that subjects rated the witness to be more credible in the following conditions: (1) when the witness used powerful linguistic/powerful nonverbal testimony versus powerless linguistic/powerless nonverbal testimony; (2) when the witness used powerful linguistic/powerful nonverbal testimony versus mixed testimonial styles; (3) when the witness used powerful nonverbal/powerless linguistic testimony versus powerless nonverbal/powerful linguistic testimony. Significant main effects were found for the powerful nonverbal condition. Preliminary gender findings suggest that the male witness was more credible overall. Interpretation of the findings, discussion of limitations of the study, and suggestions for further research are addressed.