Attack ads aimed at GOP front-runner Donald Trump don't work on men, a new study shows.Republican data and analytics firm Evolving Strategies tested the effectiveness of four anti-Trump ads ahead of Indiana's primary Tuesday, and three of the four spots convinced 8 percent of women tested to abandon Trump, though men's support didn't waiver, Roll Call reports."When you're looking at these ads, they're not game changers," the firm's co-founder Adam Schaeffer tells Roll Call. "This is shifting margins only slightly overall."The ads include one questioning Trump's conservativism , one repeating his past negative remarks of women, one featuring attacks from 2012 GOP nominee Mitt Romney and one highlighting the failed history of Trump University All four ads were sponsored by the Our Principles PAC, an anti-Trump super PAC that, according to Roll Call, has spent about $16 million on attack ads.Of the four ads, the one highlighting Trump's break with the conservative agenda failed to move any voters, including women; 54 percent of men and 51 percent of women in Indiana still supported Trump after viewing the ad.The other three that questioned Trump's character resonated with women, however, whose support for Trump dropped from 52 percent to 44 percent, the analysis finds."There are still women on the fence who are really ambivalent, and this seems to suggest that you can push them off the fence and back away from him fairly easily by raising concerns about his honesty and temperament," Schaeffer tells Roll Call.Katie Packer, who heads the Our Principles PAC, responded to the study with a short statement and a windy emoji, Roll Call reports."I always thought that women were smarter than men," she tells Roll Call.