The initial inspiration for the idea in the paper comes from (our visits to the National Zoo in Washington DC, and) the literature on evolutionary biology. In nature, male sea lions or walruses tend to be physically larger than corresponding females; in fact, this pattern holds for most species. A leading hypothesis is sexual dimorphism, which conjectures that because bigger and stronger males have an advantage in competing for and retaining females, this difference in size gets reinforced over time by natural selection (Weckerly 1998). It is likely that humans had to do the same a long time ago; that is why men, on average, are somewhat taller and larger than women. By now, the (sexual) returns to progressively larger males are much lower, if not negative. Men may discover that possessing a larger house, a bigger savings account, and more general wealth is a more effective mating strategy.
This of course is a much more serious exploration of the gender imbalance issue than the far-fetched and farcical "babe tax" solution that I commented on during my guest blogging week for Jim Fallows. The two economists explain their finding of significant correlation between gender imbalance and its contribution to China's high savings rate. Since Chinese high savings and low consumption rates figure as a key issue in global economic imbalances, the implicit implication, then, is that rebalancing the gender ratio in China may go some way toward rebalancing the global economy. Wei and Zhang argue thusly:
This paper proposes a new explanation for savings and tests it using data from China: a rising sex ratio imbalance, by increasing competition among men for potential wives, can stimulate households with a son to postpone consumption in favor of wealth accumulation....Across Chinese provinces, there is a strong positive association between the local sex ratios for the marriage-age cohort and the local household savings rate. The association is stronger for rural areas than for urban areas. The point estimates suggest that approximately 68% of the increase in rural savings rates, and 18% of the increase in urban savings rates in the recent years can be attributed in the rise in sex ratios...
Accumulating more wealth is not the only way for men to compete in the marriage market. Parents may also invest more in the human capital of their sons, and may also engage in more entrepreneurship, and other higher risk, higher returns activities.
The authors emphasize that this is simply a hypothesis with preliminary data. It is meant to offer an unconventional view to the Chinese savings conundrum that deviates from the rather dominant "precautionary savings" argument. That is, the dismantling of the socialist system in China has increased households' propensity to save for perceived financial burdens in the future--healthcare, pensions, retirement, and so on. I have little empirical evidence to contribute, except to say that the "highly competitive mating" environment in China seems to mesh with reality, and is particularly pronounced in urban China. I remember back in 2004 Shanghai, some of my Chinese friends quipped that the acronym "BMW" actually stood for "Be My Wife." If Bavarian Motor Works was the "dowry" in the mid-2000s, I can only imagine what it would be these days.