Use of the model statement in determining the veracity of opinions

We examined the efficacy of a Model Statement to detect opinion lies. A total of 93 participants discussed their opinion about the recent strikes on two occasions, 1 week apart. In one interview they told the truth and in the other interview they lied. Each interview consisted of two phases. In Phase 1 they discussed their alleged opinion (truth or lie as appropriate). They then either listened to a Model Statement (a detailed account of someone discussing an opinion about a topic unrelated to strike actions) and expressed their opinion again in Phase 2 (Model Statement present condition) or they discussed their opinion again without listening to a Model Statement (Model Statement absent condition). The verbal cues examined were pro-opinion arguments, anti-opinion arguments, plausibility, immediacy, directness, clarity, and predictability. The truthful statements sounded more plausible in Phases 1 and 2 than the deceptive statements, providing further evidence that plausibility is a strong veracity indicator. The truthful statements included more pro-arguments and sounded more immediate and direct than the deceptive statements, but only in Phase 2. The Model Statement had no effect. Reasons for the Model Statement null-effect are discussed.