Exploring the Malleability of the Body Schema Using the Anne Boleyn Illusion

Researcher(s)

  • Isabel Folger, Psychology, Carleton College
  • Sarah Scotti, Health Behavior Science, University of Delaware

Faculty Mentor(s)

  • Jared Medina, Psychological & Brain Sciences, University of Delaware

Abstract

The Anne Boleyn illusion uses a mirror box and concurrent, synchronous stroking on both hands to facilitate multisensory integration and prompt illusory embodiment of a sixth finger. Research has shown that the illusion is continuous and robust, but several aspects of its nature and underlying cognitive mechanisms remain unclear. First, it was originally thought to require stroking in two discrete places on the fifth finger of the hand hidden behind the mirror, so that touch would be remapped onto the fifth and “sixth” finger on the somatotopic map of the hidden hand. However, the necessity of this component has not been empirically tested. Second, we have yet to discover how the strength and nature of the embodiment would change if the starting or departing locations of the strokes were varied. Third, it is not evident why this illusion withstands manipulations that break other visuotactile body illusions, and whether proximity to the perceiver’s visible real hand (or “anchoring”) facilitates the resilience of the illusion. We developed novel conditions to test these three research questions. We found that stroking in only one location not only does not abolish the illusion, but does not significantly reduce embodiment. Starting location had a significant main effect on embodiment, but anchoring did not significantly affect embodiment.