Fading lies: applying the verifiability approach after a period of delay

We tested the utility of applying the Verifiability Approach (VA) to witness statements after a period of delay. The delay factor is important to consider because interviewees are often not interviewed directly after witnessing an event. A total of 64 liars partook in a mock crime and then lied about it during an interview, seven days later. Truth tellers (n = 78) partook in activities of their own choosing and told the truth about it during their interview, seven days later. All participants were split into three groups, which provided three different verbal instructions relating to the interviewer’s aim to assess the statements for the inclusion of verifiable information: no information protocol (IP) (n = 43), the standard-IP (n = 46) and an enhanced-IP (n = 53). In addition to the standard VA approach of analysing verifiable details, we further examined verifiable witness information and verifiable digital information and made a distinction between verifiable details and verifiable sources. We found that truth tellers reported more verifiable digital details and sources than liars.