Women are outliving men in every country in the world, despite facing higher levels of poverty than men, greater odds of encountering sexual violence and many additional, diverse forms of discrimination.

But while women are living longer, it’s unclear whether their wellbeing is showing comparable strides. As women gain political, economic and social freedoms, one would expect that they should feel even more contented relative to men. But this isn’t so.

The “paradox of declining female happiness” was pointed out by economists Betsey Stevenson and Justin Wolfers, who also happen to share a house and kids. They analyzed the happiness trends of US citizens between 1970 and 2005 and found a surprising result.

Stevenson and Wolfers discovered that American women rated their overall life satisfaction higher than men in the 1970s. Thereafter, women’s happiness scores decreased while men’s scores stayed roughly stable. By the 1990s, women were less happy than men. This relative unhappiness softened after the turn of the century, but men continue to enjoy a higher sense of subjective wellbeing that is at least as high — if not higher — than women’s.

Those 35 years saw advances in American women’s rights and financial power. For example, in 1974, Congress outlawed credit discrimination based on sex; in 1975, states were prevented from excluding women from juries. Until 1976, marital rape was legal in every US state. Over the 35-year period, women working full time went from earning less than 60% of a man’s median salary to earning about 76% of it — still an embarrassment for a country that aspires to be a meritocracy but an improvement nonetheless.

Of course, things happened during the period in question that probably made American women less happy. Take, for example, the massive rise in incarceration rates among their actual and potential male partners. (This rise wouldn’t have left traces in the male happiness data because prisoners were not included in life satisfaction surveys.)

The 20 years between 1980 and 2000 saw a five-fold increase in the number of African American men in jail, leading to more black men behind bars in the US than were enrolled in colleges and universities. Those kinds of statistics imply big changes to the marriage market.

Household chores make men statistically less likely to become depressed but contribute to depression in women

Although increased incarceration has affected African Americans more than others, even when all Americans are considered together, the rise in male incarceration between 1970 and 2000 has been held responsible for a 13% drop in US marriage rates. The reduced pool of free men has also encouraged many women to accept marriage proposals from men they would have otherwise rejected, an effect that has been shown to be sufficient to shift the economic advantage of marriage away from women and toward men.

But putting more men in prison cannot fully explain the lessening happiness of American women, because women in other industrialized countries – which do not lock up nearly as many of their men – have also become less happy in recent decades. Stevenson and Wolfers found the gap between male and female happiness in Europe, over approximately the same period, had a strikingly similar trend and magnitude to the US gender happiness gap.

So why is this? Evidence supports the idea that women’s rights and roles in the home in the US and Europe have not moved in step with changes in the workplace. Therefore, because women with jobs often do most of the chores and childcare, they shoulder a dual burden that cuts into their sleep and fun. Long commutes are thought to make British women more miserable than British men because of the greater pressure on women to meet responsibilities at home as well as work.

When the dual burden is carefully measured – as it has been across European countries – the results illustrate the influence that expectations have on how happy we feel. Experiencing the dual burden leads working women in Sweden, for example, to feel more miserable than their counterparts in Greece, probably because Swedes’ expectations around gender equality are more ambitious. (Fewer than 35% of Swedish women do three-quarters of the housework, compared to 81% of Greek women.)

Expectations also lie behind the curious finding that performing household chores makes men statistically less likely to become depressed but contributes to depression in women. Taking on housework seems to encourage men to judge themselves as generally likeable, fair-minded dudes, kindly reducing their wives’ load. On the other hand, taking on housework seems to make women feel exploited.

The social history of Switzerland, where women weren’t allowed to vote until 1971, reveals the subtleties of employment expectations on happiness. A decade after Swiss women gained suffrage, the country’s citizens voted in a referendum on whether the constitution should be amended to state that women deserve equal pay for equal work.

Different parts of Switzerland voted very differently. Unsurprisingly, cantons (Swiss states) with a high proportion of votes in favor of the amendment were recorded as having a small gender wage gap some years later. But strangely, working women in areas with strong traditional values – where most people had voted against equal pay – were happier than working women in liberal cantons.

Even though their salaries were further below those of the men around them, the women in more traditional communities were less likely to report discrimination than their countrywomen in more liberal areas.

This inside-out result probably arises from different cognitive comparisons. Women in liberal communities are less happy and notice discrimination because they automatically compare their opportunities and salary to everyone else around them, men included. Traditionally minded women perhaps base their identities more firmly on their gender roles, and think only of other women when they evaluate their privilege and opportunities.

This kind of difference might explain the lessening happiness of American women. As women’s rights and opportunities have increased, it seems reasonable that women in industrialized countries have internalized ever more complex and optimistic expectations, and judged reality against these. Asked how satisfied she is with her lot in life, the housewife of the early 1970s probably just reflected on whether things were going well at home. The same question today evokes evaluations across many areas of life.

Declining happiness among women may seem depressing. But who ever claimed an expanded consciousness brings satisfaction?