Speaker：Alberto Simpser [ITAM]

Date：March 9, 2026／13:30-15:00

Location：Institute of Social Science, the University of Tokyo

Language：English

Target : Open to ISS members only

Abstract：Political polarization can weaken electoral accountability by shaping how citizens process information. We examine the impact of disseminating incumbent performance information on voting behavior in a polarized setting and assess the mitigating role of a debiasing nudge. We experimentally evaluate a local CSO's Facebook ad campaign that delivered COVID-19 case and death statistics to over 2 million unique users across 500 Mexican municipalities ahead of the 2021 elections. Polling-station-level results reveal that the information alone backfired: it increased (decreased) incumbent support in areas with high (low) COVID-19 impact. These effects are driven by areas with strong prior incumbent support, prevalent communal values, and higher stress indicators among citizens. However, a debiasing nudge provided before the information reversed this effect, resulting in voters rewarding (punishing) incumbents with low (high) COVID-19 impact. Our findings underscore how biases in information processing undermine electoral accountability in polarized contexts and demonstrate the potential for nudges to restore it.