For over half of a century, social and behavioral scientists have been investigating the construct of psychopathy. Even so, psychopathy is still a highly misunderstood personality construct. Even though it has been estimated that psychopaths make up only about 1% of the general population, they are believed to consist of 15-25% of the prison population (Hare, 1996). However, not all psychopaths are in prison. Psychopaths can also be found in such fields as the legal profession, the business world and in politics (Babiak, 1995). In terms of criminal behaviors, psychopaths are arrested at earlier ages, have a higher rate of offending, commit a wider array of offenses, are more likely to have used weapons and threatened violence, and are more likely to have used violence (Hart and Hare, 1997; Hare and McPherson, 1984; Serin, 1991; Wong, 1985). Also, once released from an institution, rates of recidivism for psychopaths are found to be higher than those for other criminals regarding both violent and FTSnon-violent criminal acts (Hemphill, Hare & Wong, 1998). Therefore, the societal importance of the psychopathy construct demanded that more research be conducted to better understand its underlying etiology, potential variants in typology, clinical course and potential treatment. Prior theories have proposed subtypes of psychopathy based on cognitive variables (passive avoidance errors) and on physiological variables (BIS/BAS) and on environmental variables (supportive upbringing or not). This study utilized self-report measures to assess the presence of psychopathy and to test the validity of the cognitive and physiological explanations for subtypes of psychopathy. A cognitive dissonance task tested the validity of the physiological theory and an alteration of a punishment task which increases the degree and strength of punishment tested the cognitive theory. Further, for the first time the construct of optimism was tested to determine it's role in parsing out two types of psychopathy.