Younger men’s working hours have declined more than those of older men over the last 15 years, according to a working paper by researchers at Princeton University, the University of Chicago and the University of Rochester and distributed by the National Bureau of Economic Research, a Cambridge, Mass.-based research group. The researchers analyzed how people spend their time when they are not working.

Older men are more likely to be employed than those who are younger. Some 66% of men looking for jobs aged 20 to 24 were employed in 2016, compared to 82% of those 25 to 29, 86.5% of those 30 to 34, 87% of those 35 to 39 and 87% of those 40 to 44, according to the Bureau of Labor Statistics.

Men ages 21 to 30 spent 203 fewer hours working in 2015 than they did in 2000, a decline of 12%, according to the researchers’ analysis of Bureau of Labor Statistics data. But men ages 31 to 55 saw less of a decline, 163 fewer hours in 2015 than 2000, down 8%. The researchers included schooling as a form of employment, so they concluded the decline among younger men did not happen because more of them were attending school rather than working.

There are obviously other, bigger forces at play too. Globalization and technological advancement have restrained growth in U.S.-based manufacturing jobs, many of which are dominated by men. At the same time, the technology sector has continued to surge. J.P. Morgan Chase JPM, -0.03%   CEO Jamie Dimon said last month the share of men ages 25 to 54 who are considered part of the labor force fell around 88% from 97% a half-century ago. More young men attending college and retraining after being burned by the 2008 downturn in the property market and the Great Recession amid a fall in demand for less-skilled workers.

To figure out why young men’s hours dropped so much, the researchers studied the Bureau of Labor Statistics annual time use survey, which reports how Americans spend their time through the years, between 2012 and 2015, compared to 2004 to 2007. Between those two periods, young men increased their leisure hours about the same amount they dropped their working hours, the researchers found.

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Working hours also dropped because there was less demand for work and, as the Pew Research Institute previously found, male workers fared worse during the Great Recession — accounting for 5.4 million of the 71%, of the 7.5 million jobs that disappeared from the U.S. economy from December 2007 through June 2009 But it’s historically unusual for younger men’s hours to decrease much more than older men’s. (The researchers did not analyze trends in women’s working hours in depth for this report.)

Gaming, meanwhile, is not exactly an inexpensive hobby. Americans collectively spent about $5.6 billion on video console games and $1.3 billion on computer games in 2002, which rose to about $9.3 billion on video console games and $2.7 billion on computer games in 2016, according to the market-research firm Euromonitor International. That does not even include the additional billions of dollars spent on online and mobile games.

The researchers in the latest study also compared young men’s leisure time across states, which saw different impacts of the recession; Nevada saw a higher increase in unemployment than Texas did, said Erik Hurst, a researcher from the University of Chicago who was one of the report’s authors. But even taking regional differences into account, young men have shown “a preference shift” for computer and video games, he said, spending about five times as much time on that activity as the researchers would have predicted.

One reason: Once young men purchase the console and game, they can spend many additional hours playing it at no extra cost, unlike visiting a restaurant or movie theater, which costs money each time, he said.

Young men also reported increased amounts of happiness during the 2000s, despite problems including stagnant wages, declining job opportunities and increased likelihood of living with parents and other relatives, the researchers said. They attributed that to men’s increased satisfaction with their leisure time, video and computer games included. “When you like leisure more, that has some effects on how much you’re willing to work,” Hurst said.

There’s been good news for Americans who have been struggling to find work in recent years: The unemployment in the U.S. has improved significantly since the peak of 10% in 2009. The unemployment rate dipped to 4.3% from 4.4% in May, the lowest level since 2001. Of course, some of the decline stemmed from people leaving the labor force, rather than an increase in the number of people finding work.