The survey’s main question — “In America, how much conflict is there between poor people and rich people?” — was based on language used by Mr. Smith’s center at the University of Chicago, Mr. Morin said.

Mr. Smith said the question was often understood to mean, “Do the rich and the poor get along?” and “Do they have the same objectives?”

The issue has also become a prominent part of the political debate. President Obama has pressed the case that income inequality is rising as election season has gotten under way.

It has even crept into the Republican presidential primary race. At a debate in New Hampshire last Saturday, Rick Santorum criticized Mitt Romney for using the phrase “middle class,” dismissing the words as Democratic weapons to divide society. And conservatives have been wringing their hands over Newt Gingrich’s recent attacks on Mr. Romney’s past in private equity, saying they are a misguided assault on free-market capitalism.

Independents, whose votes will be fought over by both parties, showed the single largest increase in perceptions of conflicts between rich and poor, up 23 percentage points, to 68 percent, compared with an 18-point rise among Democrats and a 17-point rise for Republicans. Sixty-eight percent of independents believe there are strong class conflicts, just below the 73 percent of Democrats who do. (The survey’s margin of sampling error is plus or minus three percentage points for results based on the total sample.)

“The story for me was the consistency of the change,” Mr. Morin said. “Everyone sees more conflict.”

The demographics were surprising, experts said. While blacks were still more likely than whites to see serious conflicts between rich and poor, the share of whites who held that view increased by 22 percentage points, more than triple the increase among blacks. The share of blacks and Hispanics who held the view grew by single digits.