The rubber hand illusion modulates pseudoneglect

The rubber hand illusion (RHI) refers to the illusory perception of ownership of a rubber hand that may occur when covert tactile stimulation of a participant's hand co-occurs with overt corresponding stimulation of a rubber hand. It is proposed that integrating the rubber hand into one's body image may shift the subjective body midline away from the rubber hand. The present study investigated the influence of the RHI on pseudoneglect on the line bisection task, i.e. the leftward bias when marking the centre of horizontal lines, in 79 neurologically healthy adults. Overall, pseudoneglect was reduced after RHI application. Importantly, this effect was specific for individuals who reported having vividly experienced the illusion (high responders) as opposed to individuals who did not (low responders). Moreover, pseudoneglect was eliminated only after RHI application to the left hand. This pattern of results is consistent with functional hemispheric asymmetry for spatial processing and suggests that integrating the left sided rubber hand into one's body image shifts the subjective body midline to the right, thus counteracting pseudoneglect.