Deceptive behaviors enhance estrangement of the affected limb in people with Body Integrity Dysphoria

Although predicted by the notion of embodied morality, evidence for a link between bodily representations and (dis)honest choices remains inconclusive. In specific, it remains unknown whether a reduced Sense of body Ownership (SoO) is associated with increased dishonesty or vice versa. To cast light on this controversial issue, we tested patients with Body Integrity Dysphoria (BID), a unique clinical condition characterized by a chronic reduction of SoO towards one leg that they persistently desire to have amputated. Participants with BID played a card game in which they could voluntarily tell the truth or cheat an opponent, and thus either steal or give them money. Responses were communicated with the affected or the unaffected leg, facilitating an assessment of whether SoO towards the effector limb influences (im)moral decisions. We found that the SoO for the effector could not predict behavior during the card game. Crucially, however, a higher number of dishonest, self-gain choices was associated with increased reductions of SoO towards the affected leg. Our results support the idea that reductions of SoO represent a way to achieve separation from negative attributes, like immorality. Moreover, they represent a first step towards understanding the directional relation between body and morality.