Today’s youngest workers are, on average, lazier and less selfless than previous generations. Many companies have been appealing to the Millennial Generation’s altruistic values as a tool to recruit young employees, “but that strategy’s not going to work any better now than it did 15 or 30 years ago,” says Jean Twenge, a professor of psychology at San Diego State University. “It might even work a little less well.”

According to Twenge’s latest research, what has changed most about work values through the generations is that “millennials place a much higher value on leisure—things like a job that has at least two weeks vacation, a job that has an easy pace, and a job that allows time for other things in your life,” says Twenge. “They’re also more likely to say work is just for making a living, less likely to say work is a central part of their life, and less likely to say they are willing to work overtime to do a good job.” At the same time, extrinsic rewards—money, respect, and status—are more important to them than they were to boomers.

Twenge’s study draws on a large database called “Monitoring the Future,” a national survey of high school seniors that has been conducted every year since 1976. Twenge and colleagues used three time points representative of three generations. Boomers (born 1946-1964) experienced the civil rights and women’s movements, the assassinations of JFK and Martin Luther King, the Vietnam War, and Watergate. Gen X (born 1965-1981) went through the AIDS epidemic and the fall of the Soviet Union. The Millennial Generation, also known as Generation Me (born 1982-1999), grew up wired and watched the fall of Enron. GenMe’s answers to the survey questions, from making friends on the job to making a difference in the world, seem to show “less interest in work in general,” says Twenge.

Are nonprofits suffering from the rise in selfishness this study found? According to Tim Wolfred, a senior project director at CompassPoint Nonprofit Services, applications to nonprofit jobs are up again. Wolfred adds, “I experience [the younger generation] as working as hard as any of their predecessors—certainly very dedicated to their work, and working much smarter.” Of course, trends are just averages, and in the nonprofit sector, “You’re going after the segment of the generation that does want to make a difference and be worthwhile to society,” says Twenge.

The way to recruit the best of them is to appeal to their desire for a balanced life. “This generation wants work-life balance right out of the gate, even when they don’t have children,” says Twenge. Give them “more vacation, some flexibility in schedules, the ability to work at home,” she says, so “they can spend time with a friend who comes to town or take off for a few days and go skiing. The phrase ‘mental health day’ is a rather recent invention.”

Jean M. Twenge, Stacy M. Campbell, Brian J. Hoffman, et al., “Generational Differences in Work Values: Leisure and Extrinsic Values Increasing, Social and Intrinsic Values Decreasing,” Journal of Management, 36, 2010.

Read more stories by Jessica Ruvinsky.