Lee Carter, of the firm Maslansky + Partners, showed how Republicans, independents, and Democrats reacted to a single ad supporting five of the major GOP contenders for the White House.
Carter said "the most surprising" of the focus-group reactions was in response to a new Sen. Ted Cruz (R-Texas) spot, in which the hard-line conservative took a much more soft-spoken tone than he is known for.
"Barack Obama sticks by his principles. It's time for Republicans to stand by ours. That's how we win. And that's how I'll lead," Cruz said in his ad, speaking directly to the camera in what could be his living room.
The focus-group dials showed that Republicans and independents gave rave reviews to Cruz's campaign commercial.
"It showed a softer side of Cruz," Carter said. "I think a lot of people are concerned that he's bombastic and a little over the top. This was a really, really good ad for Cruz. And I think it was the best thing we saw this week out of the political ads."
Both independents and Republicans also responded very favorably to an ad from a super PAC supporting New Jersey Gov. Chris Christie (R). That campaign commercial featured Christie's vow to keep terrorists in the Guantanamo Bay detention camp.
Meanwhile, real-estate mogul Donald Trump's first and only television commercial thus far performed quite well among Republicans in Carter's focus group. The Republican front-runner's provocative ad repeated his proposal to bar Muslim tourists and immigrants from entering the US.
The two other ads featured in the Fox News segment - from Sen. Marco Rubio (R-Florida) and former Florida Gov. Jeb Bush (R) - did OK with Republicans and independents, but not as well as the other candidates' ads shown.