When deception becomes easy: the effects of task switching and goal neglect on the truth proportion effect

Abstract

Lying is typically more cognitively demanding than truth telling. Yet, recent cognitive models of lying propose that lying can be just as easy as truth telling, depending on contextual factors. In line with this idea, research has shown that the cognitive cost of deception decreases when people frequently respond deceptively, while it increases when people rarely respond deceptively (i.e., the truth proportion effect). In the present study, we investigated two possible underlying mechanisms of the truth proportion effect. In Experiment 1 (N = 121), we controlled for the impact of switch costs by keeping the number of switches between deceptive and truthful responses constant. We found that people who often responded deceptively made fewer errors when responding deceptively than people who only occasionally responded deceptively, replicating the truth proportion effect. Thus, while the truth proportion effect in earlier studies may be partially driven by the cost of switching between truthful and deceptive responses, we still found evidence for the truth proportion effect while controlling for switch costs. In Experiment 2 (N = 68), we assessed whether the truth proportion effect is influenced by goal neglect. According to this view, the truth proportion effect should be reduced if participants are cued to maintain the task goals, while it should be larger when participants are allowed to neglect the task goals. In line with this hypothesis, we found a smaller truth proportion effect when participants were cued with the task goals compared to when they were not cued. This study shows that the truth proportion effect is influenced by goal neglect, implying that frequent deceptive responding strengthens the goal of responding deceptively. Our findings imply that the accuracy of lie detection tests could be increased by using a majority of truth-items (i.e., induce the truth proportion effect), and that the truth proportion effect should be maximized by (1) increasing the number of truth-lie task switches and (2) inducing goal neglect.

Psychopathic Traits and Their Relationship with the Cognitive Costs and Compulsive Nature of Lying in Offenders

“…When instructed to lie versus tell the truth, we found that offenders made nearly twice as many errors and were substantially slower when lying compared to when telling the truth. This indicated that the behavioral costs of lying previously observed in undergraduate and community samples ([ 1 ], [ 3 ], [ 29 ]; [ 31 – 34 ]), generalizes to the forensic population (see [ 35 – 36 ]), and suggests that lying requires more mental effort than truth telling, also in offenders. According to the Activation-Decision-Construction-Action Theory (ADCAT; [ 37 ]), the cognitive cost of lying may be related to one or more of the following cognitive components: Automatic activation of the truth, the decision to lie, the construction of the lie, or acting sincere.…”

“…This implies that aggregating cued and choice trials, there was a higher proportion of truth trials than lie trials for most participants. A higher proportion of truth trials may facilitate truthful responding and hamper deceptive responding ([ 29 ], [ 33 – 34 ]). The observation in the present study that a higher lying frequency on the choice trials was related to reduced lying difficulty, supports this possibility.…”

Focused cognitive control in dishonesty: Evidence for predominantly transient conflict adaptation.

“…Answering a question with an honest response in half of the trials and with a dishonest response in the other half of trials precludes learning of a particular response to a question (see Foerster, Wirth, Herbort, Kunde, & Pfister, 2017). Indeed, increasing the frequency of dishonest responses to the inducer questions reduced the difference between honest and dishonest performance in probe questions (Van Bockstaele et al, 2012, 2015; Verschuere et al, 2011).…”

“…Such context effects have recently been reported in a range of studies that investigated how performance during lying and honest responding is affected by the recency and relative frequency of (dis)honest responding Foerster et al, 2016;Van Bockstaele et al, 2012;Van Bockstaele, Wilhelm, Meijer, Debey, & Verschuere, 2015;Verschuere, Spruyt, Meijer, & Otgaar, 2011). This broader perspective provides an elaborate approach to studying the role of cognitive control for dishonest responding by addressing dynamic changes in cognitive control (i.e., control adaptation).…”

“…That is, congruency effects should be smaller, both after a dishonest than after an honest response in the preceding trial, and when dishonest responses are frequent compared to frequent honest responses. However, preceding studies suggest that transient effects might play a larger role than sustained effects (Foerster et al, 2016;Van Bockstaele et al, 2015). Accordingly, transient adaptation effects should be stronger than sustained adaptation effects and both adaptation processes are expected to operate independently (e.g., Funes et al, 2010;Torres-Quesada et al, 2013;Wühr et al, 2015).…”