Evolution of Pain Professor Donald M. Broom - Pain is an aversive feeling associated with actual or potential tissue damage - Two types of pain: - Acute pain or physiological pain (useful for behavior avoidance or learning to avoid behaviors) - Chronic pain or pathological pain (evolved for suppression of activity that leads to pain) - Mechanism for switching off pain (opiod pathway in humans) is useful because behavior avoidance can be detrimental / dangerous if it persists. E.g. after a pin prick, pain never goes away and we keep avoiding the use of hands, it is detrimental