• Journal of the Chungcheong Mathematical Society
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• v.34 no.2
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• pp.169-180
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• 2021

This paper investigates the time-inconsistent agent's optimal consumption and investment problem under inflation risk. The agents' discount factor is governed by hyperbolic discounting, which has a random time to change. We impose the inflation risk which plays a crucial role in long-term financial planning. We derive the semi-analytic solution to the problem of sophisticated agents when the time horizon is finite.

• Journal of the Chungcheong Mathematical Society
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• v.32 no.2
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• pp.215-224
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• 2019

We investigate the optimal consumption and investment decision problem of an agent whose time preference is time-inconsistent. Specifically, for a time-separable utility function, the agent's subjective discount factor is supposed to be changed randomly in the future. We provide closed-form solutions in the presence of income process. The method can be extended into the case with a stochastic income process.

• Korean Journal of Cognitive Science
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• v.24 no.4
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• pp.323-338
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• 2013

There are multiple process mechanism in causal reasoning, which is estimation of the causal strength between cause and result. Further, because these mechanisms operate on different time phase during causal reasoning, it is highly possible that different individual difference factors are related to individual mechanisms of causal reasoning. Especially, the phenomena of conditionalization and discounting reflect attention to multiple potential causes when people infer the relationship between cause and effect. In this study, we manipulated self-construal which is an individual difference factor that reflects context sensitivity in cognition. As results, no difference was observed in conditionalization between individuals with an independent self-construal and those with an interdependent self-construal. However, independent self-construal group was observed to be lower in discounting than the interdependent self-construal group. The results indicate that conditionalization and discounting are independent cognitive process in human causal reasoning.

• East Asian Economic Review
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• v.27 no.3
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• pp.179-211
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• 2023

This paper investigates the relationship between the spread of COVID-19 and time preference. In contrast to previous studies that compared time preferences before and during the pandemic, this study estimates time preferences during the COVID-19 period using eight surveys conducted over two years. Additionally, a regression analysis was conducted on the number of new COVID-19 cases and the time elapsed since the outbreak, with estimated time preference as the dependent variable. Despite a small sample size, statistically significant results were obtained, showing that as the number of new cases increased, time preference also increased. However, this effect diminished over time and disappeared by the end of 2021 in Japan. This may be due to the public's growing familiarity with the risks of COVID-19 and the availability of vaccines and treatments. Despite a significant increase in new cases in 2022, time preference was lower than immediately after the outbreak, and this was reflected in private investments. Immediately after the outbreak of COVID-19, private investments decreased by 12% compared to the previous year, but the investments are returning in 2022 despite the surge in the number of cases. The trend of time preference explains the trend of Japanese private investments very well.