WASHINGTON -- One insistent question at the start of a new decade involves the lingering effects of the old: What scars will the Great Recession leave? We are already seeing some. Americans are moving less than at any time since World War II, reports demographer William Frey of the Brookings Institution. People are tied to existing homes, can't get loans for new ones and won't move to places without job commitments, says Frey. Only 1.6 percent of Americans are now moving across state lines, half the rate of a decade ago.

With a grim job market, the young also seem more cautious. A new survey by Fidelity Investments found that a quarter of workers from ages 22 and 33 want to stay with their present employer until retirement; in 2008, that was only 14 percent. John Irons of the liberal Economic Policy Institute worries that many young Americans, lacking tuition, will delay or abandon attending college, lowering their long-term earning power.

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So the Great Recession's nastiest scar could be an era of economic frustration, characterized by slower growth and contentious competition for scarce resources. Stunned by huge wealth losses in stocks and real estate, Americans save more and spend less. Businesses suffer from weak demand. Hiring remains sluggish. Worse, the slowdown coincides with an aging population, which could compound the effect. In 2020, the projected number of Americans 55 and older will reach almost 100 million, 29 percent of the total, up from 59 million, or 21 percent, in 2000.

"Younger people ... tend to be more innovative, more willing to take risks, more willing to do things differently," says Stanford University economist Paul Romer in an interview for the book "From Poverty to Prosperity" by Arnold Kling and Nick Schulz. As noted, today's turmoil could make even the young more risk-averse. Or older and middle-aged people could increasingly dominate corporate hierarchies and university research grants, as Romer worries. An aging society could become a stand-pat society, protective of the status quo and resistant to change.

Against this glum prospect, the standard rebuttal evokes history. The U.S. economy is amazingly resilient, the argument goes. It's been a consistent job creator: 21 million in the 1970s, 18 million in the 1980s, 17 million in the 1990s, 12 million in this decade through 2007. (Lower gains reflect slower labor-force growth, not less dynamism.)

A "can-do" culture -- combining intense ambition with a flexibility to adapt and an instinct for innovation -- ensures that the economy will ultimately rebound strongly. The harsh recession may have actually improved the long-term outlook by purging high-cost firms and forcing efficiencies. Productivity (output per hour worked) has risen 4 percent in the past year. Profits are already up 21 percent from their low; surviving firms will soon expand.

Which vision will prevail?

The answer may hinge on two things: trade and entrepreneurship. Most economists see stronger exports as a substitute for weaker consumer spending. Unfortunately, that depends heavily on economic growth and trade policies abroad. By contrast, entrepreneurship is a sleeper issue that depends on what Americans do.

If you doubt its importance, consider this: All net job creation from 1980 to 2005 came from firms that were five years old or less, according to a study by economists John Haltiwanger of the University of Maryland and Ron Jarmin and Javier Miranda of the Census Bureau. In any one year, that may not be true; but over time, mature firms lose more jobs than they create. "It's not small firms but young firms that count," says economist Robert Litan of the Kauffman Foundation, which sponsored the study.

If Americans don't continue to create new firms -- not just high-tech startups such as Facebook but construction companies, florists, restaurants, dry cleaners, engineering firms -- the economy may languish. Beginning a business is a risky, exhausting, chaotic process. Every year, there are roughly 500,000 to 600,000 new company "births" and almost as many "deaths." Half of new firms don't make it to year five, says Litan.

Some harbingers of growth look unpromising. In 2009, disbursements by "venture capital" firms -- investors in startups -- to first-time recipients hit an all-time low since statistics began in 1995. True, VCs support only a tiny fraction of new firms, mostly high-tech startups. But "angel investors" -- friends and family of entrepreneurs who support many more -- have also suffered huge losses in stocks and homes. They, too, have less to invest.

There's a warning here for the Obama administration: Complex regulations or high taxes may discourage startups and job creation. As for broader questions, the answers may remain murky for years. Has the mix of economic trauma and aging made us prudent -- or merely fearful? Has economic resilience survived -- or given way to a stand-pat society?