Modelling Perjury: Between Trust and Blame

Abstract

I investigate: (1) to what extent do folk ascriptions of lying differ between casual and courtroom contexts? (2) to what extent does motive (reason) to lie influence ascriptions of trust, mental states, and lying judgments? (3) to what extent are lying judgments consistent with previous ascriptions of communicated content? Following the Supreme Court’s Bronston judgment, I expect: (1) averaged lying judgments to be similar in casual and courtroom contexts; (2) motive to lie to influence levels of trust, mental states ascriptions, and patterns of lying judgments; (3) retrospective judgments of lying, after being presented with the state of the world, to be inconsistent with previous judgments of communicated content: participants hold the protagonist responsible for content she did not communicate. I performed a survey experiment on the Qualtrics platform. Participants were recruited through Amazon Mechanical Turk (N = 630). I employed standard Likert scales and forced-choice questions. I found that: (1) average lying judgments are similar in casual and courtroom contexts; (2) motive to lie decreases trust ascription and increases lying judgment; (3) judgments of lying are inconsistent with previous judgments of communicated content: participants hold the protagonist responsible for content they did not communicate (effect size of the difference d = .69). Perjury ascriptions are inconsistent. The Supreme Court’s worries expressed in the Bronston judgment are well founded. This article helps reforming jury instructions in perjury cases.