2017 年 15 巻 1 号 p. 73-80
Existing research have investigated the effects of free will belief on aggressive behaviours. So far, studies have shown that when people's free will belief is denied, their motivation of self-control decreases, thereby increasing aggressive behaviours. An alternative and inconsistent account is that people who have strong belief in free will attributes the other party's attack to the actor's intention, which lead them to take revenge. Given that aggressions practically occur within a social interaction, the present study examined the relationship between free will belief and aggression in a social interactive situation. We hypothesized that people who have high free will belief will behave more aggressively when they are attacked by another individual. Based on a sample of 45 undergraduates, we measured free will beliefs and trait aggression as an individual-difference variable. We employed a modification of the Point Subtraction Aggression Paradigm in order to measure participants' aggressive behaviours. As a result, the effects of fatal determinism - a subscale of free will - were found significant. Specifically, when participants were unattacked by their interactive partner, those with low fatal determinism belief behaved less aggressively. Incurring no attack from the partner, participants may have experienced higher responsibility for taking aggressive actions themselves. Under such circumstance, having a low fatal determinism belief, and thus regarding their behaviour as undetermined by nature, may have further increased their sense of responsibility, consequently decreasing aggression. In contrast, when participants were attacked by their partner, aggressive behaviours increased on the whole relative to the non-attacked condition; receiving an attack may have simply provoked participants' motivation to revenge. This study highly suggests the relationship between fatal determinism belief and aggression in social interaction situations, offering a ground for future investigations including parameters to further explain the relationship.