The Truth about Lying: Inhibition of the Anterior Prefrontal Cortex Improves Deceptive Behavior

Institute of Medical Psychology and Behavioral Neurobiology, University of Tuebingen, Gartenstrasse 29, Tuebingen, Germany.
Cerebral Cortex (Impact Factor: 8.67). 06/2009; 20(1):205-13. DOI: 10.1093/cercor/bhp090
Source: PubMed


Recent neuroimaging studies have indicated a predominant role of the anterior prefrontal cortex (aPFC) in deception and moral cognition, yet the functional contribution of the aPFC to deceptive behavior remains unknown. We hypothesized that modulating the excitability of the aPFC by transcranial direct current stimulation (tDCS) could reveal its functional contribution in generating deceitful responses. Forty-four healthy volunteers participated in a thief role-play in which they were supposed to steal money and then to attend an interrogation with the Guilty Knowledge Test. During the interrogation, participants received cathodal, anodal, or sham tDCS. Remarkably, inhibition of the aPFC by cathodal tDCS did not lead to an impairment of deceptive behavior but rather to a significant improvement. This effect manifested in faster reaction times in telling lies, but not in telling the truth, a decrease in sympathetic skin-conductance response and feelings of guilt while deceiving the interrogator and a significantly higher lying quotient reflecting skillful lying. Increasing the excitability of the aPFC by anodal tDCS did not affect deceptive behavior, confirming the specificity of the stimulation polarity. These findings give causal support to recent correlative data obtained by functional magnetic resonance imaging studies indicating a pivotal role of the aPFC in deception.

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Available from: Ahmed A Karim, Oct 08, 2015
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    • "We did not choose a more posterior electrode as in previous studies (e.g. occipital cortex, Karim et al. (2010) and Bellaı¨che et al. (2013)), because of potential phosphene induction which could have interfered with stimulus processing in our experiment (Antal et al., 2003a, b). We used electrodes of two different sizes: 35 cm 2 for the active electrode, and 100 cm 2 for the return electrode. "
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    ABSTRACT: Orbitofrontal reality filtering denotes a memory control mechanism necessary to keep thought and behavior in phase with reality. Its failure induces reality confusion as evident in confabulation and disorientation. In the present study, we explored the influence of orbitofrontal transcranial direct current stimulation (tDCS) on reality filtering. Twenty healthy human subjects made a reality filtering task, while receiving cathodal, anodal, or sham stimulation over the frontal pole in three sessions separated by at least 1 week. Computational models predicted that this montage can produce polarity-specific current flow across the posterior medial orbitofrontal cortex (OFC). In agreement with our hypothesis, we found that cathodal tDCS over the frontal pole specifically impaired reality filtering in comparison to anodal and sham stimulation. This study shows that reality filtering, an orbitofrontal function, can be modulated with tDCS.
    Neuroscience 04/2014; 265:21–27. DOI:10.1016/j.neuroscience.2014.01.052 · 3.36 Impact Factor
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    • "It is somewhat plausible that an intervention of the kind described here would increase Andrew’s moral conformity, and it is not fantastic to suppose that such an intervention might be developed in the future. After all, transcranial electrical brain modulation can already be used to alter rather specific mental abilities such as numerical competence [15] and the ability to deceive others [16]. "
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    ABSTRACT: It is plausible that we have moral reasons to become better at conforming to our moral reasons. However, it is not always clear what means to greater moral conformity we should adopt. John Harris has recently argued that we have reason to adopt traditional, deliberative means in preference to means that alter our affective or conative states directly—that is, without engaging our deliberative faculties. One of Harris’ concerns about direct means is that they would produce only a superficial kind of moral improvement. Though they might increase our moral conformity, there is some deeper kind of moral improvement that they would fail to produce, or would produce to a lesser degree than more traditional means. I consider whether this concern might be justified by appeal to the concept of moral worth. I assess three attempts to show that, even where they were equally effective at increasing one’s moral conformity, direct interventions would be less conducive to moral worth than typical deliberative alternatives. Each of these attempts is inspired by Kant’s views on moral worth. Each, I argue, fails.
    Neuroethics 04/2014; 7(1). DOI:10.1007/s12152-013-9183-y · 1.31 Impact Factor
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    • "However, null effects of cathodal stimulation have also been reported on complex verbal associative thought [11], associative verbal learning [5], verbal fluency [19], picture naming [6], working memory [20], contrast sensitivity in the visual cortex [21], and probabilistic classification learning [22]. Moreover, some have reported cathodal stimulation to cause facilitation in picture naming in aphasic patients [23], in comprehension in subacute stroke patients [24], and in deception in an interrogation following a thief role-play [25]. Although the facilitatory effect of cathodal stimulation in individuals with brain damage is often ascribed to successful suppression of abnormal cortical activity [24], this interpretation, even if correct, does not explain the variety of results obtained with cathodal stimulation. "
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    ABSTRACT: Cathodal Transcranial Direct Current Stimulation (C-tDCS) has been reported, across different studies, to facilitate or hinder performance, or simply to have no tangible effect on behavior. This discrepancy is most prominent when C-tDCS is used to alter a cognitive function, questioning the assumption that cathodal stimulation always compromises performance. In this study, we aimed to study the effect of two variables on performance in a simple cognitive task (letter Flanker), when C-tDCS was applied to the left prefrontal cortex (PFC): (1) the time of testing relative to stimulation (during or after), and (2) the nature of the cognitive activity during stimulation in case of post-tDCS testing. In three experiments, we had participants either perform the Flanker task during C-tDCS (Experiment 1), or after C-tDCS. When the Flanker task was administered after C-tDCS, we varied whether during stimulation subjects were engaged in activities that posed low (Experiment 2) or high (Experiment 3) demands on the PFC. Our findings show that the nature of the task during C-tDCS has a systematic influence on the outcome, while timing per se does not.
    PLoS ONE 01/2014; 9(1):e84338. DOI:10.1371/journal.pone.0084338 · 3.23 Impact Factor
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