In an apparent rejection of the basic principles of the U.S. economy, a new poll shows that most young people do not support capitalism.

The Harvard University survey, which polled young adults between ages 18 and 29, found that 51 percent of respondents do not support capitalism. Just 42 percent said they support it.

It isn’t clear that the young people in the poll would prefer some alternative system, though. Just 33 percent said they supported socialism. The survey had a margin of error of 2.4 percentage points.

The results of the survey are difficult to interpret, pollsters noted. Capitalism can mean different things to different people, and the newest generation of voters is frustrated with the status quo, broadly speaking.

All the same, that a majority of respondents in Harvard University’s survey of young adults said they do not support capitalism suggests that today’s youngest voters are more focused on the flaws of free markets.

“The word ‘capitalism’ doesn’t mean what it used to,” said Zach Lustbader, a senior at Harvard involved in conducting the poll, which was published Monday. For those who grew up during the Cold War, capitalism meant freedom from the Soviet Union and other totalitarian regimes. For those who grew up more recently, capitalism has meant a financial crisis from which the global economy still hasn’t completely recovered.

A subsequent survey that included people of all ages found that somewhat older Americans also are skeptical of capitalism. Only among respondents at least 50 years old was the majority in support of capitalism.

Although the results are startling, Harvard’s questions accord with other recent research on how Americans think about capitalism and socialism. In 2011, for example, the Pew Research Center found that people ages 18 to 29 were frustrated with the free-market system.

In that survey, 46 percent had positive views of capitalism, and 47 percent had negative views — a broader question than what Harvard’s pollsters asked, which was whether the respondent supported the system. With regard to socialism, by contrast, 49 percent of the young people in Pew’s poll had positive views, and just 43 percent had negative views.

Lustbader, 22, said the darkening mood on capitalism is evident in the way politicians talk about the economy. When Republicans — long the champions of free enterprise — use the word “capitalism” these days, it’s often to complain about “crony capitalism,” he said.

“You don’t hear people on the right defending their economic policies using that word anymore,” Lustbader added.

It is an open question whether young people’s attitudes on socialism and capitalism show that they are rejecting free markets as a matter of principle or whether those views are simply an expression of broader frustrations with an economy in which household incomes have been declining for 15 years.

On specific questions about how best to organize the economy, for example, young people’s views seem conflicted. Just 27 percent believe government should play a large role in regulating the economy, the Harvard poll found, and just 30 percent think the government should play a large role in reducing income inequality. Only 26 percent said government spending is an effective way to increase economic growth

Yet 48 percent agreed that “basic health insurance is a right for all people.” And 47 percent agreed with the statement that “Basic necessities, such as food and shelter, are a right that the government should provide to those unable to afford them.”

“Young people could be saying that there are problems with capitalism, contradictions,” Frank Newport, the editor in chief of Gallup, said when asked about the new data. “I certainly don’t know what’s going through their heads.”

John Della Volpe, the polling director at Harvard, went on to personally interview a small group of young people about their attitudes toward capitalism to try to learn more. They told him that capitalism was unfair and left people out despite their hard work.

“They’re not rejecting the concept,” Della Volpe said. “The way in which capitalism is practiced today, in the minds of young people — that’s what they’re rejecting.”