Updated on April 27 at 11:00

Women earn a fraction of men’s average hourly wages in the United States, somewhere between 79 percent and 92 percent, depending on how one adjusts the data. Among the economy’s highest-paying jobs, this fissure looks more like a canyon. Four in five senior vice presidents and chief executive officers are men, and the women who do go into the highest-paying jobs have smaller paychecks. Female physicians and surgeons make 29 percent less than their male counterparts.

The wage gap at the top is the sum of many cultural forces, including discrimination at work and an expectation that new moms stay home while high-earning dads get back to work. But it is also the result of a subtler cultural force—a values gap. Among equally smart men and women, men, on average, gravitate toward making as much money as possible and working long hours to do it. Women, on average, do not.

Even before men and women enter the workforce, researchers see this values gap and its role in the pay gap. A new study of several hundred NYU undergrads (elite students, not average 20-year-olds) found that young men and women with similar SAT scores express starkly diverging visions of their ideal job. Young female students, on average, say they prefer jobs with more stability and flexibility—“lower risk of job loss, lower hours, and part-time option availability”—while male students, on average, say they prefer more earnings growth, according to researchers Matthew Wiswall, at Arizona State University, and Basit Zafar, of the Federal Reserve Bank of New York. The qualifier “on average” is important here. Genders are not uniform blocs. Some women are more interested in being millionaires than some men; some men are more interested in working part-time than their female friends.

Students’ values shape their majors and their jobs. Those who want to make a lot of money (on average, more men) are more likely to major in economics or business; men are more than 50 percent more likely than women to major in economics at every Ivy League university. Those who prize flexibility and accept lower pay (on average, more women) are more likely to be in the humanities. When Wiswall and Zafar followed up several years later, they discovered that college values predict first jobs: “Students with strong preferences for flexible hours and distaste for hours” were more likely to be in jobs with flexible hours and fewer hours.

Young American men’s preference for risk and reward has been established in other research. In a 2005 study from Stanford University, men and women solving math equations for money in a university lab were given the option to complete the problems in a tournament, where they had a smaller chance of winning but a higher potential reward. Men were twice as likely as women to enter the tournament—73 percent compared to 35 percent—and many who entered the tournament won less money. The study’s conclusion: Women sometimes shy away from competition, but also, “men compete too much.”

When Harvard Business School surveyed 25,000 of its male and female graduates, it found that high-achieving women failed to meet their career goals. At graduation, most women said they expected “egalitarian” marriages, where both spouses’ careers were taken equally seriously, but several years later, more women had deferred their husbands’ careers. This study, and others, suggest that while married couples often make work-and-home decisions as a unit, the cultural expectation that men be the top providers proves to be an insurmountable force, even (or especially) among the best educated households.

And yet there is evidence that women in the U.S. and in other rich countries are happier at the office, because they have sought out work that is more flexible. Female employees report being happier than men at work, according to a 2014 study by the Council on Contemporary Families. Researchers said the happiness gap might be explained by the fact that women work fewer hours and have more of the flexibility that they crave. This was not an isolated finding. Another 2014 study, from the University of Warwick, also concluded that women were more satisfied at work than men, partly because they spent less time at work. In an interview with The Daily Mail, one of the study’s authors noted that the survey found a link between choosing to work part-time and job satisfaction.

Rich American men, by comparison, are the workaholics of the world. They put in significantly longer hours than both fully employed middle-class Americans and rich men in other countries. Between 1985 and 2010, the weekly leisure time of college-educated men fell by 2.5 hours, more than any other demographic. "Building wealth to them is a creative process, and the closest thing they have to fun,” the economist Robert Frank wrote. Internationally, there is a positive relationship between income and happiness, but the behavioral economist Daniel Kahneman has found that the plutocratic dreams of young educated men, like the ones in the NYU study, are immiserating fantasies:

When someone reflects on how additional income would change [their sense of] well-being, they are probably tempted to think about spending more time in leisurely pursuits such as watching a large-screen plasma TV or playing golf … But in reality, they should think of spending a lot more time working and commuting and a lot less time engaged in passive leisure. ... By itself, this shift in time is unlikely to lead to much increase in experienced happiness.

Around the globe, the happiest countries seem to take an approach to work that’s more in line with the values of young women in the NYU study. Rich Europeans in general work significantly less than Americans, and yet seven of the 10 happiest countries of the world are in Europe. Northern Europeans’ unusually high satisfaction at work has been tied to the prevalence of flexible work hours.

Meanwhile, in the U.S. economy, women are twice as likely to work part-time than men—26 percent to 13 percent. This ratio holds for even high-paying jobs. A 2016 report from the health site Medscape found that female doctors were twice as likely to work part-time as their male peers.

It’s hard to identify the root causes of the values gap. Are women averse to high-risk, high-reward professions because they expect, from an early age, that these career paths are barricaded by discrimination? Maybe. Are women less interested in working more hours because pay disparities mean that the marginal hour worked earns them less money? Maybe. Are subtle and hard-to-measure cultural expectations nudging young women toward jobs that would offer flexibility (to care for kids they don’t yet have) while pushing men toward high-paying jobs (to provide for that family they don’t yet have)? Maybe. Are part-time female workers in the U.S. happier at work because their husbands are the primary breadwinners, and they don’t feel a similar burden at the office? Maybe. In addition to these cultural factors, are there biological factors that, for better and worse, make men more likely to seek out risks? Maybe.

But something else is clear: There is a workaholic mania among educated wealth-seeking American men, who seem uniquely devoted to working any number of hours to get rich. Remember the lesson of the Stanford study: Sometimes, the winners of a tournament are the ones who choose not to enter it.