SUMMARY

Immigrant Head is a head-mounted display (HMD) system that provides an unrealistic experience in which one’s head is clearly separated from the rest of his or her body. This bizarre experience is strongly related to the recent discussion on minimal phenomenal self (MPS). It questions whether one’s body image is a necessity to maintain one’s sense of self. It is of importance that this experience is expected to reveal various cognitive properties underlying the out-of-body experience (OBE).

In the HMD system, the physical head rotation of the HMD wearer is always associated with the avatar’s head rotation that the wearer sees in a HMD space. This correlation is essential to convey an illusion: it is as though the HMD wearer owns the avatar’s head as his or her body; this is referred to as full body illusion (Salmon et al., 2013). The unrealistic separation is exhibited in two ways. The first separation occurs by a physical blow to the head; a head-size gong is hung before the HMD and an experimenter beats the gong directly and intensely with a drum-stick. The timing of the crash is detected through a built-in micro-phone of the VIVE (HTC). Once the crash is detected, the perspective, which is located just behind the avatar’s head, is blown off backwards from the original body. The second separation occurs by intentionally leaning the physical head backwards; the consequence is in contrast with the first separation. The perspective is slowly separated from the original head according to the inclination of the angle of the head toward the backward direction.