Happiness and Sex Difference in Life Expectancy

The aim of this study is to test the explanatory power of happiness on survival at the aggregate level. Based on previous findings that psychological stress adversely affects survival and that its effect on survival is more severe for men, this study uses the sex difference in, rather than the level of, life expectancy as the dependent variable. As long as psychological stress and happiness are negatively correlated, happiness is expected to have a greater impact on men’s life expectancy and negatively influence the life expectancy gap between women and men. However, at the same time, the causality is expected to run in both directions. In the reverse direction from the life expectancy gap to national happiness, the intermediary is the women’s widowhood ratio. Since the widowed are, on average, less happy, an increase in the life expectancy gap, which raises the women’s widowhood ratio, is expected to lower women’s average happiness. For this reason, this study first investigates the reverse causality and demonstrates that the life expectancy gap negatively affects national happiness. Then, taking this reverse causality into account, it shows that happiness is significant in explaining the cross-country differences in the life expectancy gap. As national average happiness decreases, the sex difference in life expectancy increases. This result suggests that happiness has a significant impact on survival even at the aggregate level.