Hanger Reflex of the Head and Waist with Translational and Rotational Force Perception

The hanger reflex is a phenomenon in which the head involuntarily rotates when force is applied via a wire hanger placed on the head. The application of pressure to particular points of the head is necessary to induce this phenomenon, which occurs when shear deformation of the skin induces illusory force perception. Because the hanger reflex represents the induction of force and motion using a simple device, and has been found in other body parts such as the wrist, waist, and ankle, it is expected to be useful as an application in haptic interface technology. In this paper, we describe new directions of force associated with the hanger reflex; four translation, and two rotational directions of the head, and four translation and one rotational direction of the waist.