Their short-term assessment of personal progress, according to the study, is the worst it's been in nearly half a century.
The survey by the Pew Research Center, a Washington-based organization, paints a mixed picture for the 53 percent of adults in the country who define themselves as "middle class," with household incomes ranging from below $40,000 to more than $100,000.
It found that a majority of Americans said they haven't progressed in the last five years. One in four, or 25 percent, said their economic situation had not improved, while 31 percent said they had fallen backward. Those numbers together are the highest since the survey question was first asked in 1964. Among the middle class, 54 percent said they had made no progress (26 percent) or fallen back (28 percent).
Asked about their financial experiences in the past year, 53 percent of middle-class people said they had to cut spending because money was tight. About one in five said they had trouble getting or paying for medical care, while 10 percent reported they had been laid off or otherwise lost their jobs.
Looking ahead to the coming year, half of the middle class surveyed said they expected to have to cut more spending. Among those employed, one in four, or 25 percent, expressed worries that they would be laid off, that their job would be outsourced or that their employer would relocate in the coming year, while 26 percent were concerned that they would see cuts in salary or health benefits.
Middle-class prosperity overall also lagged compared with richer Americans. From 1983 to 2004, the median net worth of upper-income families - defined as households with annual incomes above 150 percent of the median - grew by 123 percent, while the median net worth of middle-income families rose by just 29 percent.
At the same time, most middle-class people remained upbeat when asked to measure their progress over a longer timeframe, although their level of optimism lagged behind their richer counterparts. Two-thirds, or 67 percent, of middle-class Americans say their standard of living is better than the one their parents enjoyed at the age they are now.
In contrast, 80 percent of richer people said they exceeded their parents' standard of living. Among the lower class, only 49 percent reported better conditions.
"It's been a lousy run for the American economy and people feel it," said Paul Taylor, director of Pew's Social & Demographic Trends project and lead author of the study. He noted that people's pessimism largely tracks annual median household income, which has seen little gain in recent years. Middle-class people also may be disproportionately feeling the pinch because they tend to borrow more heavily against their homes to support their lifestyles, Taylor said.
"Still, over a span of a generation, it's been a pretty good run, even as there are some recent pressures that I think people are feeling," he said.
The Pew poll involved telephone interviews with 2,413 adults, conducted from Jan. 24 to Feb. 19. The margin of sampling error was 2.5 percentage points.
Among the other findings: