When Passive Feels Active--Delusion-Proneness Alters Self-Recognition in the Moving Rubber Hand Illusion

PLoS One. 2015 Jun 19;10(6):e0128549. doi: 10.1371/journal.pone.0128549. eCollection 2015.

Abstract

Psychotic patients have problems with bodily self-recognition such as the experience of self-produced actions (sense of agency) and the perception of the body as their own (sense of ownership). While it has been shown that such impairments in psychotic patients can be explained by hypersalient processing of external sensory input it has also been suggested that they lack normal efference copy in voluntary action. However, it is not known how problems with motor predictions like efference copy contribute to impaired sense of agency and ownership in psychosis or psychosis-related states. We used a rubber hand illusion based on finger movements and measured sense of agency and ownership to compute a bodily self-recognition score in delusion-proneness (indexed by Peters' Delusion Inventory - PDI). A group of healthy subjects (n=71) experienced active movements (involving motor predictions) or passive movements (lacking motor predictions). We observed a highly significant correlation between delusion-proneness and self-recognition in the passive conditions, while no such effect was observed in the active conditions. This was seen for both ownership and agency scores. The result suggests that delusion-proneness is associated with hypersalient external input in passive conditions, resulting in an abnormal experience of the illusion. We hypothesize that this effect is not present in the active condition because deficient motor predictions counteract hypersalience in psychosis proneness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Delusions*
  • Female
  • Healthy Volunteers
  • Humans
  • Illusions*
  • Male
  • Proprioception
  • Psychotic Disorders / psychology
  • Young Adult

Grant support

This study was funded by the James S. McDonnell Foundation, the Swedish Research Council and Söderberska Stiftelsen (A.K.) and by Vetenskapsrådet (DR:2013-7826) and Karolinska Institutet (A.L. and P.P.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.