Research gap at a glance
- Question: Are patients with focal posterior insula lesions more or less susceptible to the rubber hand illusion than patients with lesions elsewhere and healthy controls?
- Why it matters: The two literatures the wiki draws on make opposite predictions, so the result would decide between a lesion account in which the region is needed to generate the illusion and the precision-competition account in which weaker interoceptive input lets external signals capture the self-model.
- Theme: Emotion and self
- Status: open
What the wiki already knows
- Somatoparaphrenia, disowning one’s own limb, has been produced by a focal right posterior insular lesion, and the same region activates during the Rubber hand illusion (RHI) (Jones et al. (2010), Anosognosia and disorders of bodily unawareness).
- Jones et al. propose testing posterior-insula patients on the illusion and expect resistance to it (Experience of body ownership (EBO)).
- Lower interoceptive accuracy predicts greater illusion susceptibility (Tsakiris et al. 2011), read as exteroceptive input dominating when interoceptive representations are imprecise, which predicts that destroying interoceptive cortex should increase susceptibility (Experience of body ownership (EBO), Quigley et al. (2021)).
- Much of the supporting work for the precision-competition reading comes from the same laboratory as the original result (Experience of body ownership (EBO)).
What would answer it
- Test patients with focal posterior insula lesions, lesion controls matched for size and hemisphere, and healthy controls on the Rubber hand illusion (RHI) with questionnaire and proprioceptive-drift measures plus a cardiac accuracy task, and use Lesion-symptom mapping to relate damage extent within the insula to susceptibility.
Connections
- Raised on: Experience of body ownership (EBO), Anosognosia and disorders of bodily unawareness, Jones et al. (2010)
- Related concepts: Experience of body ownership (EBO), Embodied selfhood, Insular cortex, Multisensory integration, Anosognosia and disorders of bodily unawareness
- Related debates: Is more interoceptive awareness better?
Experience of body ownership (EBO) and Anosognosia and disorders of bodily unawareness both record this as the most tractable open item they hold: a cheap experiment with two clean, opposite predictions. The healthy-participant literature reads the rubber hand illusion as the result of weighting interoceptive against exteroceptive evidence, and finds that people with less precise interoception are more easily captured by the fake hand. The clinical literature shows that destroying right posterior insula can make a person disown a real limb.
On the precision account, a lesion that removes interoceptive cortex should leave external input unopposed and increase susceptibility. On Jones et al.’s reading the region participates in generating the illusion, so patients should resist it. Both cannot be right, and no study has asked.
The result would also inform Is more interoceptive awareness better?, where body ownership is one of the few cases in which more interoceptive precision has a clear consequence: a self-model less capturable by external input. Whether that is good is a separate question, but it depends first on whether the precision story holds when interoceptive cortex is damaged rather than merely less accurate.