Sound source ambiguity augments illusory mislocalisation of computer presented stomach rumbles to self

Listening to a computer-presented stomach rumble can induce an illusion, whereby the sound seems to arise from one's own body - illusory mislocalisation. This represents one of the few examples of an interoceptive illusion and has been used to examine the nature of interoceptive hunger. The illusion's mechanism(s) is unknown as are the conditions necessary to maximise it. Here, we examine if illusory mislocalisation can be augmented by manipulating the ambiguity of the sound source. Participants were randomised to one of two conditions, either receiving sounds via headphones or from a hidden speaker. Test sounds - stomach rumbles, electrical noise, and silence - were presented in conjunction with food pictures, with participants judging desire to eat the depicted foods and the sound's source. Participants in both conditions experienced episodes of illusory mislocalisation (Cohen's d's > 1.3). However, significantly more people experienced it in the hidden speaker condition (Cohen's d = 0.4). Desire to eat ratings were higher in those reporting illusory mislocalisation, but this did not differ by sound presentation condition. The implications for putative models of illusory mislocalisation - notably associative and multisensory accounts - are discussed, with an adapted multisensory account best supported.