CHICAGO >> They have a reputation for being environmentally minded do-gooders. But an academic analysis of surveys spanning more than 40 years has found that today’s young Americans are less interested in the environment and in conserving resources — and often less civic-minded overall — than their elders were when they were young.

The findings go against the widespread belief that environmental issues have hit home with today’s young adults, known as Millennials, who have grown up amid climate change discussion and the mantra "reduce, reuse, recycle." The environment is often listed among top concerns of young voters.

"I was shocked," said Jean Twenge, a psychology professor at San Diego State University who is one of the study’s authors. "We have the perception that we’re getting through to people. But at least compared to previous eras, we’re not."

Twenge, author of the book "Generation Me: Why Today’s Young Americans Are More Confident, Assertive, Entitled — and More Miserable Than Ever Before," has spent much of her career publishing work that challenges or attempts to explain commonly held beliefs about young people.

This study, published online this month in the Journal of Personality and Social Psychology, looked at the life goals, concern for others and civic orientation of three young generations — baby boomers, Gen Xers and Millennials.

Based on two longstanding national surveys of high school seniors and college freshmen, Twenge and her colleagues found a decline, over the last four decades, in young people’s trust in others, their interest in government and the time they said they spent thinking about social problems.

Steepest of all was a steady decline in concern about the environment, and taking personal action to save it.

Researchers found that, when surveyed decades ago, about a third of young baby boomers said it was important to become personally involved in programs to clean up the environment. In comparison, only about a quarter of young Gen Xers — and 21 percent of Millennials — said the same.

Meanwhile, 15 percent of Millennials said they had made no effort to help the environment, compared with 8 percent of young Gen Xers and 5 percent of young baby boomers.

Millennials also were the least likely to say they’d made an effort to conserve electricity and fuel used to heat their homes.

In the case of heating fuel, 78 percent of young baby boomers and 71 percent of young Gen Xers said they cut back, compared with 56 percent of Millennials.

It is important to note that most of the survey data available for Millennials was collected before the country’s most recent recession hit.

Even so, those working in the environmental field — including some Millennials themselves — aren’t that surprised by the findings.

Emily Stokes, a 20-year-old geography student at Western Washington University, grew up in the Pacific Northwest. She thinks people there are more likely to take environmental issues more seriously because of the natural beauty that surrounds them.

"But I still find myself pretty frustrated a lot of the time," said Stokes, who wants to go into marine resource management. "I just think our generation seems fairly narcissistic — and we seem to have the shortest attention span."

Kelly Benoit, a 20-year-old political science student at Northeastern University in Massachusetts, went as far as calling her peers "lazy."

"I think it can be due to our upbringing. We want what we want when we want it," said Benoit, who has worked with lawmakers in her state to try to ban the use of plastic bags in stores.

She thinks members of her generation, like a lot of people, simply don’t want to give up conveniences.

Or are they just overwhelmed?

Mark Potosnak, an environmental science professor at DePaul University in Chicago, has noticed an increase in skepticism — or confusion — about climate change among his students as the national debate has heightened. That leads to fatigue, he said.

"It’s not so much that they don’t think it’s important. They’re just worn out," Potosnak said. "It’s like poverty in a foreign country. You see the picture so many times, you become inured to it."

A lot of young people also simply don’t spend that much time exploring nature, said Beth Christensen, a professor who heads the environmental studies professor at Adelphi University on New York’s Long Island.

When she attended Rutgers University in the 1980s, she said it was unusual to find a fellow student who hadn’t hiked and spent time in the woods.

"Now a lot of these students have very little experience with the unpaved world," Christensen said.

So one of her goals is to get her students out into marshes and onto beaches — and even coral reefs in Australia — to help them connect with a natural world many have only seen on television.

Some of her students also volunteer with a group that cleans up trash in the bays that surround the island — one of many examples of young people who are taking environmental issues seriously.

At Babson College in Massachusetts, for instance, there is student housing called the "Green Tower," where residents focus on conserving resources. It is a growing housing trend on many college campuses.

At Muhlenberg College in Pennsylvania students are running a biodiesel plant on campus and building "permaculture," or indefinitely sustainable, gardens in their back yards.

They’re less likely to write a letter to their member of Congress or to try to change things on a global level, said Richard Niesenbaum, a biology professor at Muhlenberg. They also don’t like to label themselves as "environmentalists."

"In a lot of ways, they’re more pragmatic," he said, roughly dividing his student body this way:

— 5 to 10 percent "committed environmentalists"

— 5 percent "anti-environment" (These are the students who purposely avoid putting their trash in campus recycling bins, for instance.)

— 85 to 90 percent "open to protecting the environment and natural resources, but not leaders and not interested in being seriously inconvenienced or paying a cost to do so"

"The last group is obviously the environmental educators’ potential gold mine," said Niesenbaum, who directs the college’s sustainability studies program.

Twenge, the study’s lead author, is sometimes pegged as a critic of this generation because of her work about them. But the numbers speak for themselves, she said.

"I hope that young people see these findings as a challenge rather than a criticism," she said, adding that the lack of interest in environmental issues isn’t exclusive to young people.

"This is a change in overall culture," she said, "and young people reflect the changes in culture."

The analysis was based on two long-term surveys of the nation’s youth. The first, the University of Michigan’s Monitoring the Future project, is an annual survey of thousands of high school seniors, from which data from 1976 through 2008 was used.

Other data came from the American Freshman project, another large annual national survey, administered by the Higher Education Research Institute. Those responses came from thousands of first-year college students, from the years 1966 through 2009. Because of the large sample sizes, the margin of error was less than plus-or-minus half a percentage point.

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Online:

Babson’s Green Tower: http://www.babsongreentower.org/

Muhlenberg’s sustainability studies: http://www.muhlenberg.edu/main/academics/sustainability/courses.html

Adelphi’s environmental internships: http://academics.adelphi.edu/artsci/env/internship.php