Image caption The new American Dream is embodied in America's under-30s, John Zogby says

Is the American Dream still achievable in 2011, amid lingering economic hard times, wars and political discord? Veteran US pollster John Zogby says fewer Americans think it is, but many have redefined what that dream means.

Steadily over the past decade, I have witnessed in my polling a fundamental redefinition of the American Dream, even for that matter, the American character.

While fewer Americans believe that the American Dream still exists for themselves or for the middle class than before (57% compared with 74% just prior to the Great Recession), more Americans say that the American Dream means something different to them than it did before.

Materialism rejected

In the late 1990s, I began probing how Americans define the dream. I discovered in 1999 that about one-third believed the American Dream meant some form of financial success: the acquisition of goods, a bigger house, a home with a piece of land around it and so on. I called them the Traditional Materialists.

But I found an equal-size group that eschewed both that label and that aspiration. I called this group the Secular Spiritualists, finding they had decided to reorder their priorities away from things and rejected the notion that he who dies with the most toys wins.

Instead, for Secular Spiritualists, life was about being genuine, about achieving a legacy larger than one's self, about leaving this earth a better place for family, community, and planet.

For the record, I found two other groups: The Deferred Dreamers (about 18%) who felt the dream of material acquisition could still be alive, but just not for themselves or their children.

And then there were the Dreamful Dead (15%), who felt the American Dream was simply dead. This last group included minorities, the poor and too many single mothers.

What I have witnessed over the past decade is the steady growth of the Secular Spiritualists to around 42%, while the Traditional Materialists now number about 31%.

There are four distinct sources of this growth in Secular Spiritualism.

Status anxiety

First, there is the growing number of Americans who work at a job that pays less than a previous job. When I first starting tracking this group in the early 1990s, that included about 14% of all adults.

Tweeting the Dream Can you define the American Dream in 140 characters or less? Send BBC_WNA a tweet and include #americandream - we'll publish the best at the end of the week. BBC World News America on Twitter

When I published my book The Way We'll Be: The Zogby Report on the Transformation of the American Dream in 2008, the number had grown to 27%.

Today, fully 35% work for less than in a previous job. This group is the most affected by status anxiety. They are often one or two pay cheques away from poverty and worry about health and healthcare, government costs, and being squeezed.

They are the new "haves" in the sense that are paying the costs for those below who need help and think they are paying disproportionately to cover those higher above who do not get socked as much by taxes.

They are afraid of losing ground, and most have changed their goals in life because the traditional materialist goals are simply unachievable.

The second source can be found on the polar end of the economic spectrum - the now approximately 10-11 million Americans who actually have succeeded quite well financially and now are concluding that they have too much, they do not need more, and that they actually can - and must - do with less.

Boomer self-indulgence

They are part of an active and engaged simplification movement in the US - people who have concluded that they do not need the next iteration of the iPhone because the last version did not make them a better person.

Image caption Some Americans are actively trying to simplify their lives and reduce material clutter

The third source is my age cohort, Baby Boomers - 78 million strong. I call us "Woodstockers", a paean to our self-indulgence.

We did such a great job creating adolescence that we still find it difficult to give it up. But give it up we must.

We are the first age cohort who will have one million of us reach the age of one hundred.

That means record numbers of us have 25 to 30 years of healthy living ahead of us. We will not (and most cannot) be retiring at 65, so we are entering a stage historian Robert Fogel argues will be one dominated by "vol-work" - as opposed to "earn-work" - in which we are ready to do something that really counts, that is fulfilling, that is on our own terms and leaves a legacy.

Lastly, the rise of Secular Spiritualism is born of a trait for which we Americans seldom credit ourselves: a spirit of sacrifice.

The continent was not settled by John Wayne and the Marlboro Man but by families who built communities and braved the elements together.

Young global citizens

In the 1970s, presidents from two different parties asked Americans to conserve energy and we did. In recent decades, despite the fact that we were very spoiled by creature comforts, we have begun to recycle massive amounts of waste, we have stopped littering our highways and towns, and we have largely given up smoking.

And this change away from materialism and toward this new American Dream is embodied by the under-30s among us - America's first global citizens.

They have passports and have travelled abroad. The world is in the palm of their hands, they are the least likely to say that American culture is superior to other cultures of the world, and they are by far the most likely of any age cohort to call themselves "citizens of the planet Earth".

They are multi-cultural (in 20 years America will look like Barack Obama, they say) and 40% say they expect (not hope or wish, but expect) to live and work in a foreign capital in their lives. They are revolutionizing the worlds of work, philanthropy, relationships, governing, and music.

The American Dream has changed. It has adjusted to the new world in which we live.

John Zogby is chairman of US polling company Zogby International.