UC Berkeley

We present the first field experiment on how organized interest groups' television ads affect issue opinions. We randomized 31,404 voters to three weeks of interest group ads about either immigration or transgender nondiscrimination. We then randomly assigned voters to receive ostensibly unrelated surveys either while the ads aired, one day after they stopped, or three days afterwards. Voters recalled the ads, but three ads had a minimal influence on public opinion, whereas a fourth's effects decayed within one day. However, voters remembered a fact from one ad. Our results suggest issue ads can affect public opinion but that not every ad persuades and that persuasive effects decay. Despite the vast sums spent on television ads, our results are the first field experiment on their persuasive power on issues, shedding light on the mechanisms underpinning-and limits on-both televised persuasion and interest group influence.