Figure 5. Schematic diagram of the pressure and pain stimuli and experimental conditions.

(A) Pressure ring with spherical beads. (B) Pain ring with polyhedral beads. (C) Self-induced movement, in which the subject squeezes his own left hand with his right hand; the pain ring is pictured. (D) Externally induced movement, in which the experimenter squeezes the subject's left hand; the pain ring is pictured. Within the rubber ring was the cross holder, consisted of the yellow short arms and the grey long arms.