1 Schur-Concavity, Social Value Orientation and Social Risk

2 Impact of Imaninary Future Generation on Time Preference and Risk Preference

1 It is not rare occation in a daily life to face a risk that affect not only one's own payoff but also the other's payoff, simultaneously. When we consider the risk attitude of an individual who chooses such social risk, we have to care about the stochastic nature of one's own payoff and the distributive issue between two persons' payoffs. The previous studies are not successful in separating these two issues. This paper proposes to measure the risk attitude of a social risk decision maker based on Schur-concavity. We report the laboratory experiments where a dictator makes a choice on social risks. We find that the subjects' risk attitude changes depending on whether they face a social risk or an individual risk. The difference between individual and social risks also depend on whether the risk involves negative paoff or not. Furthermore, the difference depends on whether the expost payoffs of the pair differ or not. This is ofcourse inconsistent with the expected utility preferences. Also it is not consistent with the expected utility replacing von Neumann Morgenstern utility with nequality averse type of social preferences. We investigate the ultimatum game and show the difference in risk attitude between individual and social risk differs dependent upon whether an individual is a proposer or a responder.

2 Conflict in interests between the current and future generations is the heart of issues on the sustainability problems. "Future Design (hereafter FD)" is a new method to cope with this hard issue in the pracitcal level. Specifically, let people play an imaginary future generation to consider such intergeneration dilemma problem. The recent case studies on various attempts of FD implemetation on public policy report some qualitative difference in the policy ecommendation generated from the public discourse between when the participants experience the imaginary future generation and when they do not. This research is an attempt to identify quantitatively such difference by measuring the participants' time preference and risk preference indices via context independent questionnaires. We use the field data from the actual participants in the public discourse held in Matsumoto and find their social orientation is

correlated with the degree of their time discount rate and the degree of risk aversion. Playing the role of future generation makes people more far-sighted and less risk averse. Such impact is more prominent on the pro-self participants than the pro-social.

本報告は、窃盗罪における占有概念に関する日台の学説動向を分析し、占有概念の具体化および具体化の限界について検討する。