The cold pressure tank allows researchers to monitor the pain threshold ( the point at which volunteers first notice the pain ) and pain tolerance ( the point at which volunteers can no longer stand the pain ) 这个冰冷的压力槽让研究人员能监控疼痛门槛(志愿者最先注意到疼痛的时间点)以及疼痛容忍度(志愿者无法再忍受疼痛的时间点) 。