Neurologically it has been found that the part of brain which is associated to feeling of guilt, remorse, empathy & love is nearly inactive in psychopaths & less reactive in sociopaths as compared to normal healthy brain. Further, the X-ray images show comparison between activity in psychopathic brain & healthy brain towards negative re-enforcement. Since psychopathic & sociopathic brain is non-reactive towards negative re-enforcement thus the psychopaths & sociopaths do not learn from mistakes & often commit repeated crimes.