Bringing Social Identity Theory Back In: A New Measure of Issue-based Affective Polarization
This paper introduces and validates the APSIT index, a new two-dimensional measure of issue-based affective polarization grounded in social identity theory, which reveals that while outgroup hostility drives democratic costs across all issue camps, ingroup love among supporters can partially offset these negative effects.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
In the landscape of modern democracy, a quiet but powerful force is reshaping how people relate to one another. It is not merely a disagreement over tax rates or environmental regulations; it is a deep emotional divide where political opponents are viewed not just as wrong, but as threats to the moral fabric of society. This phenomenon, known as affective polarization, has long been studied through the lens of party lines, particularly in the United States, where the gap between Democrats and Republicans has widened into a chasm of mutual distrust. However, the roots of this emotional conflict run deeper than party labels. Social identity theory, a well-established framework in psychology, suggests that humans have a fundamental need to belong to groups. When we identify with a group, we naturally feel a sense of closeness and pride toward our own members, a feeling often described as "ingroup love." Simultaneously, to feel good about our own group, we often compare ourselves to others, sometimes viewing those outside our circle with suspicion, disdain, or hostility, a dynamic known as "outgroup hate." While these two feelings often travel together, they are distinct psychological processes. Understanding whether the love for one's own side or the hatred for the other side is the true driver of democratic erosion is crucial, because the solution to a problem depends entirely on correctly identifying its cause.
A team of researchers set out to untangle these complex emotions by looking beyond traditional party politics to the specific, heated issues that divide societies today. Focusing on Switzerland, a country often seen as a model of consensus, they examined four contentious topics: migration, climate policy, vaccination, and the use of gender-inclusive language. The researchers wanted to know if the same emotional patterns found in party politics also existed around these specific issues, and if so, whether the love for one's own camp or the hostility toward the opposing camp was more damaging to the health of democracy. To find out, they surveyed over 4,000 people, asking them to place themselves on a spectrum for each issue and then measuring their feelings toward those who agreed with them and those who disagreed. They designed a new, precise tool to measure these feelings separately, capturing the warmth of belonging to one's own group and the coldness of rejecting the other group.
The study confirmed that emotional polarization around these issues is indeed a two-sided coin. People who feel a strong connection to their own side also tend to feel a strong aversion to the other side, but the researchers found that these are not the same thing. They validated a new measurement index that successfully separates the feeling of belonging from the feeling of hostility. When they tested this new tool against older methods, which often just asked people how much they liked or disliked a group, the new measure proved to be more accurate. It revealed that while the two feelings often rise and fall together, they are distinct forces that can be measured independently. This distinction allowed the researchers to ask a critical question: which of these two forces is actually hurting our faith in democracy?
The answer they found was striking and clear. The study revealed that the damage to democratic values—such as trust in institutions, the willingness to compromise, and the belief that democracy is working well—comes almost entirely from the hostility toward the opposing group. The feeling of "outgroup hate," the belief that the other side is dangerous, immoral, or a threat to freedom, is what erodes support for democratic principles. In contrast, the "ingroup love," the feeling of pride and connection with one's own side, does not seem to harm democracy. In fact, for those who support a particular issue, this sense of belonging can actually strengthen their commitment to democratic values, acting as a buffer against the negative effects of polarization. The researchers discovered that this dynamic holds true regardless of which side of the issue a person is on; whether one is a supporter or an opponent of migration, climate action, or vaccination, it is the hostility toward the other side that undermines democratic stability.
This finding challenges the common assumption that simply loving one's own group is the problem. The study suggests that the real danger lies in the act of comparing one's group to another in a negative way. When people view their political opponents as a threat to their way of life or their personal safety, they become less willing to accept the legitimacy of those opponents and less supportive of the democratic system that allows for such disagreement. The research indicates that the emotional cost of polarization is not paid by the act of identifying with a group, but by the act of demonizing the other. This distinction offers a nuanced view of political conflict: it is possible to feel a strong sense of belonging and solidarity with one's own camp without necessarily damaging the democratic fabric, provided that this solidarity does not turn into a rejection of the humanity and legitimacy of those who disagree. The study concludes that to heal the divides in modern democracies, the focus must shift from trying to reduce group identity to curbing the specific hostility that arises when groups view each other as enemies.
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