Politics: Our emotions control our choices

Imagine you’re taking part in a political discussion. Suddenly you notice – your heart’s beating faster, you’re turning red, your voice is getting louder.

Why do we react so strongly?

According to professor of political psychology Lene Aarøe, recipient of the 2025 Holst-Knudsen Research Talent Award, our political convictions are not only based on our opinions and reason; they’re also on our emotions and psychological dispositions.

“Psychology research indicates that we humans are strongly disposed to join groups and to defend the groups we feel part of. If we view party identification as a social group identity, we understand why people react with strong emotions when their party is attacked. This research helps us to understand phenomena like the deep polarisation in American politics, where the Democrats and the Republicans have misconceptions about how extreme the opposite wing is,” Lene Aarøe said.

This strong political party group identity can become a lens through which we interpret new information. It can help us explain, for example, why Democrats and Republicans disagreed about whether there were more spectators at Obama’s inauguration in 2009 or at Trump’s inauguration at 2017, even though photos from the square in front of Capitol Hill should have provided all the information they required.

“Both wings become so coloured by their political party affiliation that they interpret all new information in a certain light, and sometimes a distorted light.  Politics is about disagreement, and we cannot and should not take disagreement out of politics. The problem arises when the debate becomes so polarised that we cannot conduct a democratic discussion,” Lene Aarøe said.

Hunger affects our attitudes towards the welfare state
Political scientists have usually investigated political opinion formation using conventional techniques like interviews or surveys. But in 2012, Lene Aarøe and her colleagues conducted a laboratory experiment that used physiology to answer a political science question. The resulting study helped push the boundaries of how we study political science.

“Political opinions arise in the mind, in the body. So we gain a better understanding of political opinion formation if we also include insights from biology. We wanted to investigate how experiences of scarcity shape our attitudes towards how we share resources in the modern welfare society. We hypothesised that hungry people are are more likely to think that resources should be shared and thus support the redistribution of resources through the welfare state,”Lene Aarøe said.

Although slightly surprised by the request, the administrative head of the political science department helped her research teram transform one of the department’s reading rooms into a temporary laboratory. The fasting participants answered questions about their attitude towards the welfare state after drinking either a sugar-free or regular soft drink, while their blood sugar levels were measured by medically trained personnel.

“Participants who had low blood sugar because they drank the sugar-free soft drink were more supportive of a generous welfare state than those who drank a sugary soft drink. This suggests that people are more supportive of a generous welfare state when they are hungry,”Lene Aarøe said.

Food scarcity has been a recurring challenge in human history, and the experiment indicates that we have deeply ingrained strategies to obtain resources when facing scarcity. This suggests a lin between our evolution as a species and contemporary attitudes towards the organisation of the welfare state.

The experiment at the political science department was part of a wave that has grown over time: at Aarhus University, the Cognition and Behaviour Lab at BSS conducts a wide range of experiments that monitoring physiological responses.

Scepticism towards immigration may be due to fear of infection
Our emotions also play a major role in our political opinions on hot-button issues like immigration. Lene Aarøe’s research illuminates how unconscious bias towards immigrants may derive from fallacies caused by what she calls our ‘behavioural immune system’. There is a strong correlation between people’s fear of infection and their opposition to immigration. 

Disease and infections have been a constant challenge throughout our evolution. On a biological level, our body’s immune system fights external infections, and on a psychological level, we have also developed a behavioural immune system to avoid potential risks of infection. Lene Aarøe said:

“Research shows that this psychological mechanism can cause us to distance ourselves from people who look different than us. In some people, the behavioural immune system is so hyperactive that they unconsciously categorise harmless differences - for example, in skin colour - as a potential risk of infection. This leads them to react on an unconscious level, displaying distrust and distancing themselves from immigrants.”

A classic approach to promoting tolerance is telling stories about immigrants who demonstrate good intentions, learn the language and embrace democratic ideals. But people with a hyperactive behavioural immune system aren’t convinced by any of these arguments, because their concerns are based on something else entirely, Lene Aarøe said:

“Our political opinions come from deeper places than we initially assume, and they can create misinterpretations in modern society. This helps explain why the debate about immigration can become so emotional, why the divides are so deep, and why integration is difficult. Political opinions are shaped by a psychology and biology that we weren’t even aware of until a few years ago.

“The link between immigration and the risk of infection is not meaningful, so increased awareness of the issues in our psychological immune system could increase mutual understanding between different groups, thus strengthening integration and democratic dialogue.”

Lene Aarøe is currently still engaged in interdisciplinary research into political opinion formation, with her latest work involving the use of AI, such as ChatGPT, to analyse social media texts.