A within-statement baseline comparison for detecting lies

To make veracity judgements in individual cases, practitioners may rely on baselining. That is, they may evaluate a statement relative to a baseline statement that is known to be truthful. We investigated whether a within-statement verbal baseline comparison could enhance discriminatory accuracy. Participants (n = 148) read an alibi statement of a mock suspect and provided a veracity judgement regarding a critical two-hour period within the alibi statement. This critical element was either deceptive or truthful and was embedded into an otherwise truthful story. Half of the participants received additional instructions to use the surrounding truthful elements of the statement as a baseline. Instructing participants to make a within-statement baseline comparison did not improve the accuracy of credibility assessments.