Option-Splitting Effects in Poll Regarding Japan’s Right to Exercise Collective Self-Defense

Against the backdrop of heated debates within and outside Japan regarding Japan’s push for the right to exercise collective self-defense (CSD), the Japanese mass media have reported a series of polls on Japan’s exercise of its right to CSD, with significantly disparate results. In this article, we present one natural experiment and one controlled experiment that show that the disparate outcomes are due to the different ways the options are segmented. We conducted a comparative analysis of two questionnaires, one presenting two options of ‘approve’ and ‘disapprove’ and the other with three options, splitting the option of ‘approve’ into two answers presenting different means of approving the use of the right to CSD. As a result, more respondents chose ‘approve’ when the option was split into two. The result shows that option-splitting expands the respondents’ range of perception and psychological availability, which in turn raises the selection rate. This research implies that inducing the poll results through option-splitting is possible, which might eventually affect the policy-making process in democratic societies where public opinion polls affect policy.