Echoes of Influence: A Multi-Method Analysis of Political Microtargeting on Polarization in the Digital Age

Political microtargeting has become a defining feature of digital campaigning, yet its role in driving political polarisation remains contested. This paper conducts a secondary, multi-method systematic review of ten empirical, quantitative studies published between 2016 and 2025 that examine political microtargeting, psychological targeting, or online political polarisation. The review draws on field experiments, laboratory and online experiments, computational text modelling, and large-scale survey analysis. Findings show that personality- and issue-congruent microtargeting produces a measurable persuasive advantage at the individual level, sometimes substantial, yet this advantage is neither universal nor stable across contexts. Average persuasive effects of campaign contact approach zero in general elections, and microtargeted messages do not consistently outperform well-crafted generic appeals. At the collective level, evidence linking online exposure directly to rising polarisation is weaker and more conditional than popular narratives suggest; polarisation has grown fastest among demographic groups least exposed to digital media, while experimentally induced exposure to opposing views can increase rather than reduce polarisation. Detection research shows that psychological profiles are recoverable from ordinary online behaviour, yet transparency disclosures and persuasion warnings do not reliably neutralise targeting's persuasive advantage. This paper argues that microtargeting's democratic risk lies less in a uniform manipulative power over mass publics than in a persuasion–polarisation gap: real, conditional, individual-level effects that current safeguards are not yet equipped to govern. Implications for platform accountability and regulatory design are discussed.