Amplifying deceivers’ flawed metacognition: encouraging disclosures after delays with a model statement

Truth tellers provide less detail in delayed than in immediate interviews (likely due to forgetting), whereas liars provide similar amounts of detail in immediate and delayed interviews (displaying a metacognitive stability bias effect). We examined whether liar’s flawed metacognition after delays could be exploited by encouraging interviewees to provide more detail via a Model Statement. Truthful and deceptive participants were interviewed immediately (n = 78) or after a three-week delay (n = 78). Half the participants in each condition listened to a Model Statement before questioning. In the Immediate condition, truth tellers provided more details than liars. This pattern was unaffected by the Model Statement. In the Delayed condition, truth tellers and liars provided a similar amount of detail in the Model Statement-absent condition, whereas in the Model Statement-present condition, liars provided more details than truth tellers.