The neurobiology of deception: evidence from neuroimaging and loss-of-function studies

Lying about the valence of affective pictures: an fMRI study

The neural correlates of lying about affective information were studied using a functional magnetic resonance imaging (fMRI) methodology. Specifically, 13 healthy right-handed Chinese men were instructed to lie about the valence, positive or negative, of pictures selected from the International Affective Picture System (IAPS) while their brain activity was scanned by a 3T Philip Achieva scanner. The key finding is that the neural activity associated with deception is valence-related. Comparing to telling the truth, deception about the valence of the affectively positive pictures was associated with activity in the inferior frontal, cingulate, inferior parietal, precuneus, and middle temporal regions. Lying about the valence of the affectively negative pictures, on the other hand, was associated with activity in the orbital and medial frontal regions. While a clear valence-related effect on deception was observed, common neural regions were also recruited for the process of deception about the valence of the affective pictures. These regions included the lateral prefrontal and inferior parietal regions. Activity in these regions has been widely reported in fMRI studies on deception using affectively-neutral stimuli. The findings of this study reveal the effect of valence on the neural activity associated with deception. Furthermore, the data also help to illustrate the complexity of the neural mechanisms underlying deception.

Neural correlates of forgiveness for moral transgressions involving deception

We used positron emission tomography (PET) to investigate the neural mechanisms underlying the willingness to forgive another person's moral transgression involving deception. During scanning, 12 subjects were asked to judge the forgivability of a perpetrator's moral transgression. These transgressions were described by four kinds of scenarios composed of a combination of two factors: the attitude of the perpetrator (dishonest or honest) and the severity of the moral transgression (serious or minor). Behavioral data showed that both the perpetrator's dishonesty and the seriousness of the scenario decreased the subjects' willingness to forgive the moral transgression. Neuroimaging data revealed that, relative to honest responses, a perpetrator's dishonest responses were associated with right ventromedial prefrontal activity, which possibly reflects the subjects' identification of the perpetrator's deception. The opposite comparison did not show significant activation. Moreover, a comparison of serious scenarios with minor scenarios did not reveal significant activation. Instead, minor scenarios, relative to serious scenarios, evoked activity in the right middle frontal gyrus and the right caudate nucleus, possibly reflecting increased demand on frontal control system function. Further analysis revealed that the left ventromedial prefrontal cortex showed a significant interaction between the two factors, indicating that this region functions as a mediator of the two factors, modulating judgments regarding the forgivability of moral transgressions. Taken together, these findings suggest that the ventromedial prefrontal cortex plays a key role in the forgiveness of moral transgressions involving deception.