Assessing the psychological and mechanical impact of electoral rules: AÂ quasi-experiment

► Participants voted as if the Ontario elections took place under FPTP, AV and PR. ► The beneficiaries of PR are the third parties. ► Under PR, the psychological and mechanical effects converge. ► The main beneficiary of AV is the centrist party. ► Under AV, the psychological and mechanical effects run counter to each other.