The researchers rubbed roughly the same number of cowhage spicules ( the itch-inducing spiky bits of that plant , also known as velvet bean ) on three locations : the front of the ankle ; on the underside of the forearm ; and under the shoulder blade on the back .

研究人员用等量的刺毛黧豆毛刺（刺毛黧豆的毛刺能导致皮肤发痒，也叫绒毛豆（velvetbean））对身体三个部位摩擦：前脚踝、前臂下部以及后背肩胛处。