Plausibility: A Verbal Cue to Veracity worth Examining?

Truth tellers sound more plausible than lie tellers. Plausibility ratings do not require much time or cognitive resources, but a disadvantage is that it is measured subjectively on Likert scales. The aim of the current paper was to understand if plausibility can be predicted by three other verbal veracity cues that can be measured objectively by counting their frequency of occurrence: details, complications, and verifiable sources. If these objective cues could predict plausibility, observers could be instructed to pay attention to them when judging plausibility, which would make plausibility ratings somewhat more objective. We therefore re-analysed five existing datasets; all of them included plausibility, details and complications and two of them also verifiable sources as dependent variables. Plausibility was positively correlated with all three other tested cues, but mostly predicted by complications and verifiable sources, explaining on average almost 40p of the variance. Plausibility showed larger effect sizes in distinguishing truth tellers from lie tellers than the three other cues, perhaps because the plausibility cue consists of multiple components (complications and verifiable sources). Research has shown that the cues that showed the strongest relationship with veracity typically consisted of multiple components.