Transparency is not enough: Warning people that they are being microtargeted fails to eliminate persuasive advantage

The practice of microtargeting in politics, involving tailoring persuasive messages to individuals based on personal vulnerabilities, has raised manipulation concerns. As microtargeting's persuasive benefits are well-established and its use facilitated by AI tools and personality-inference models, ethical and regulatory concerns arise.Here, we explore countering microtargeting effects by creating a warning signal deployed when users encounter personality-tailored political ads. Two studies evaluated the effectiveness of warning "popups'' against potential microtargeting by comparing persuasiveness of targeted vs. non-targeted messages with and without popups.Using within subject-designs, Studies 1 (N = 666) and 2 (N = 432) reveal a targeting effect, with targeted ads deemed more persuasive than non-targeted ones. More importantly, the presence of a warning popup did not significantly impact persuasiveness. Overall, across the two studies, personality-targeted ads were significantly more persuasive than non-targeted ones, and this advantage persisted despite warnings. Given the focus on transparency in initiatives like the EU's AI Act, the lack of a significant transparency measure effect is potentially concerning.