2016 年 14 巻 1 号 p. 41-47
Psychopathy is constructed with two factors, interpersonal/affective features including callousness, manipulation and lack of remorse or empathy (Primary Psychopathy), and behavioral problems including impulsivity and lack of long-term goal (Secondary Psychopathy). While it is hypothesized that psychopathic traits are related to both dysfunction of frontal lobe and risky decision-making, there are few empirical studies. To test this hypothesis, we conducted two studies employing questionnaires and laboratory experiment. In the first study, we used Primary and Secondary Psychopathy Scale and Frontal Behavioral Inventory to examine the relationship between psychopathic traits and the function of the frontal lobe. In the second study, we used a gambling task to clarify the relationship between psychopathic traits and risky decision-making. In this task, participants decided whether or not to bet their own money or another participant's money in order to increase their own gain or the partner's gain. Results of these studies showed that psychopathic traits were associated with frontal lobe function, and high psychopathic individuals chose risky options more frequently than low psychopathic individuals. In particular, primary psychopathy prompted risky choices when participants could use partner's money, but not use their own money. Taken together, psychopathic individuals seem to be inclined to make selfish decisions, and this tendency might be caused by the dysfunction of frontal lobe.