People who tend to splash their cash are unlikely to become more prudent after marriage, new research shows.

Hisaki Kono from Japan’s Kyoto University and Tomomi Tanaka of the World Bank in Washington DC, US, studied 134 married couples in a middle-class area in Vietnam to see if spendthrift behaviour before marriage was moderated after getting hitched.

The answer, published in the journal PLOS One, is a resounding “not really”.

The habit of splurging on impulse purchases is known in the jargon as “present bias”, defined by Kono and Tanaka as “the overvaluation of an immediate payoff”. It is a habit that often results in both short- and long-term problems, because it negatively impacts household budgets and savings bases. 

To test whether being married reduced present bias behaviour, the researchers interviewed all the husbands and wives individually, and asked them, as couples, to participate in a series of experiments that required them to make decisions about the allocation of imaginary funds. 

On the good news side of the ledger, the results showed that spendthrifty partners were less likely to be swayed by present bias when making joint financial decisions than when asked to make decisions on their own.

However, present biased spouses were also likely to contribute smaller sums from their income for combined household spending. 

In situations where the profligate partner was in charge of the financial planning – something that occurred unexpectedly often – the more prudent partner was likely to be asked to put a higher proportion of income into the common pot.

“Present-biased individuals also receive larger amounts of money from their spouses’ incomes, indicating that marriage not only fails to function as a savings commitment device but also exacerbates the problem,” the researchers write.

They also noted that when prudent partners were in charge of finances, they tended to allocate only small amounts of spending money to their spouses – but that the recipients also tended to “conceal money to counteract this strategy”.

The researchers tentatively suggest that in at least some partnerships unequal spending between partners was tolerated because of “the affection and acceptance that form the basis of marriage”, and because the union brought other, non-financial benefits, such as emotional support and protection.

It is perhaps not surprising, however, that Kono and Tanaka found that women were more likely than men to be disadvantaged by a present-biased partner – and that they were therefore more likely to use external money-management strategies such as talking to financial advisers and locking funds up in savings accounts.

Image credit: Getty Images

This article first appeared on cosmosmagazine.com and was written by Andrew Masterson.