Romney adds his "job is not to worry about those people. I'll never convince them they should take personal responsibility and care for their lives.”

By contrast, voters actually had a positive impression of Obama's "you didn't build that" line during a rally in Roanoke, Va. Some 36 percent of respondents said they had a positive reaction to the comment, versus 32 percent who reported a negative reaction.

"If you were successful, somebody along the line gave you some help. There was a great teacher somewhere in your life. Somebody helped to create this unbelievable American system that we have that allowed you to thrive. Somebody invested in roads and bridges. If you've got a business — you didn't build that. Somebody else made that happen," the president said in July.

Republicans have repeatedly highlighted the remark, dedicating a full day of their national convention to a theme hitting the comment. Romney has said the remark betrays the president's belief that government, and not entrepreneurship, is the engine of the economy.

The divergent reactions to the perceived gaffes could be the result of a rocky month for the Republican nominee. According to the poll, 51 percent say what they've heard, seen and read about Romney in recent weeks leaves them with a less favorable impression. By contrast, just 36 percent say the same thing about the president. And more voters see Romney unfavorably than favorably, by a 3-point margin. Obama holds a 10-point net positive favorability rating.

But the poll did find a tightening national race, with the president leading Romney 49-46 percent among likely voters, down from a 50-45 percent lead two weeks ago.