The evolving

Since the Supreme Court’s Citizens United decision and the rise in social media, the ways in which politicians and campaign issues are advertised has exploded, with front groups and hidden funders reaching potential voters on their phones, targeted directly to somebody’s likes and dislikes. Correspondent David Pogue talks with media experts about why negative ads often win out over positive ones, even as people are down on negativity. He also talks with an independent voter in a battleground state – one of the most desirable targets of this election cycle.