We believe this is because marriage provides an implicit social insurance since the spouses are able to share their income. However, if divorce rates are higher in a society, women have a higher incentive to obtain work experience in case they find themselves alone in the future. The reason the incentive is higher is because in our data, women happen to be the second earner in the household more often than men. European women anticipate not getting divorced as often and hence find less reason to insure themselves by working as much as American women.
Chakraborty and Holter use U.S data to run a model testing their theory; their findings are interesting:
We find that stable marriages lead to a reduction in labour supply. Both in the data and in the model the effect is on the extensive margin, i.e. whether women will choose to work or not. In our counterfactual economy, if just marriage stability in US were the same as in the European countries, it explains 24% of the cross-country variation in hours worked for females. When we also introduce European taxes, we are able to explain 43% of the variation in female work hours across the continents.
The authors also point out that Americans started working more in the 1970’s, right around the time the US started passing “no-fault” divorce laws and well before Europe started adopting such laws.