Why Do We Obsess With Divisive Issues?
A party having a single obsession. Two candidates who radically differ on a single issue, but have similar views on all the others. Voters who, even though they have all the information, end up focusing only on what is divisive. It's not just an impression: according to a new theoretical model, our brains just work that way. And politics knows it very well.
In the article "A Model of Focusing in Political Choice" published in Journal of Politics, Salvatore Nunnari (Bocconi) and Jan Zapal (CERGE-EI) introduce a theory that explains why voters disproportionately focus on the issues where candidates have polar views. The consequence is a perverse dynamic: politicians end up accentuating those differences to attract attention. The result? Greater polarization, less attention to shared policies and, paradoxically, less rational choices even among informed voters. "Our model starts from a simple intuition: when two candidates are very different on one issue and similar on others, voters end up weighing the divisive issue quite heavily," explains Nunnari, Associate Professor of Economics. "But this has profound consequences for the political offer."
From recent theory to past news
In the 2016 US presidential election, Hillary Clinton and Donald Trump were opposed on Obamacare and the Paris Agreement, but similar on other issues such as infrastructure investment or the Trans-Pacific Partnership (TPP). Yet, public attention almost exclusively focused on the issues where the two candidates appeared most distant.
The same applies to the strategic use of the media. Trump, the authors note, used Twitter as a way to distract opinion: when the press increased coverage of the Mueller investigation into Russian interference in the 2016 election, the president would tweet about China, immigration or jobs. As expected, media attention shifted.
The military, the paper continues, also consciously uses these attention-grabbing mechanisms. In 2020, to influence Trump's decisions on how to respond to an Iranian attack, the Pentagon deliberately included the extreme option of killing General Soleimani, hoping it would appear so extreme that more moderate options would be sought. "Both politicians and institutions understand that public attention can be distorted, and they act accordingly," Nunnari comments. "What our study does is formally model this mechanism, showing its systemic implications."
Single-issue parties and stolen attention
The model also explains why parties with no chance of victory — such as single-issue parties on the environment, immigration or anti-Europeanism — still manage to influence the political agenda. Votes aren't needed; simply being on the radar of public attention is enough. This generates a domino effect: the major parties must react, polarize and differentiate themselves. "In our model, smaller parties act as levers of attention: they can shift the focus of voters toward specific issues," explains Nunnari. "And often, that's exactly what they are after."
The paradox of redistribution
The most counterintuitive part of the study concerns taxation. By analyzing voter behavior toward redistributive policy proposals, Nunnari and Zapal show that, as inequality increases, demand for redistribution can decrease. The reason? Wealthy voters, seeing their tax burden increase, tend to focus only on the cost to them, ignoring the collective benefits. Poorer voters, on the other hand, underestimate the benefits of higher taxes. The result is distortion: attention isn't directed where it should be. And redistributive policies struggle to emerge, despite macroeconomic data justifying their urgency.
A new lens for understanding politics
The study is part of a new current in behavioral political economy, which integrates voters' cognitive biases into rational choice models. The theory proposed by Nunnari and Zapal not only helps explain seemingly irrational electoral behavior, but also offers tools for interpreting political leaders' communication strategies. "It's not enough to ask voters what they are thinking. We must also ask them where they are looking and who is deciding what to look at for them," Nunnari concludes.
