How Identity Shapes Our Health: The Social Psychology Behind Polarized Behavior

Our new paper explains how group identification—not just misinformation—drives the deep divides in Americans’ health behaviors.

and

Dec 03, 2025

In 2020 and 2021, the COVID-19 pandemic took the lives of 76% more Republicans than Democrats. Why does politics so strongly impact their health and well-being?

In a new pre-print, we review how and why politics can shape health outcomes, especially in a highly polarized environment. We argue that people’s political identities ultimately shape the health decisions they make.

To explain why this happens, we answer two questions: What shapes peoples’ health decisions? And how does social identity affect these decisions?

What shapes people’s health decisions?

When we are deciding whether to get vaccinated, start a new workout routine, or quit smoking, what determines whether we take the plunge or hold back? Psychologists argue that these decisions are based on our beliefs about the behavior. In particular, we can distinguish three kinds of relevant beliefs.

First, we can have behavioral beliefs about different properties of the behavior itself. This includes beliefs like “vaccinations will reduce my risk of getting sick” and “this workout routine will help me reach my fitness goals.” But it also includes beliefs like “vaccines can hurt a bit” and “this workout routine requires an expensive gym membership.” Overall, these beliefs shape how desirable or undesirable the behavior is to us personally.

But our individual beliefs aren’t the only thing that matters. After all, we don’t just make decisions as individuals. As social creatures, our behaviors are also shaped by normative beliefs about what others around us are doing. This can include beliefs like “nobody I know is getting vaccinated” and “everybody on my college campus is binge drinking.” So, the same exact behavior can be more or less compelling to us based on what we see other people doing or what they expect us to do.

Finally, we also have beliefs about our ability to do the behavior. If you’ve never stepped foot in a gym, you may have no idea where to start, and it may strike you as an overwhelming feat. If you live in a food desert, far from supermarkets or grocery stores, you may accurately believe that access to affordable vegetables are difficult to get. These sorts of beliefs also play an important role in determining whether our planned behaviors become a reality.

With all these different beliefs buzzing around in our heads, how do we use them to take (or avoid) action? Each of our beliefs has a weight—our sense of how important that belief is relative to others. These weights help determine whether the behavior is good enough, on average, to move us to take an action.

The amount of weight we give each belief varies from person to person and from belief to belief. For one person, the social stigma of being the only family member to wear a mask at a gathering might outweigh their desire to minimize risk of catching COVID or the flu. For another person, the importance of these different beliefs might be flipped.

Of course, people aren’t always explicitly tallying up the pros and cons of every decision to themselves in their head. These processes can go on in the back of our minds, without us having to consciously think about them. The key takeaway is that in order to understand the health decisions a person makes, we should know what beliefs may make them want or not want to take the behavior, and how important each of these beliefs are to that person.

How does social identity affect health decisions?

Now that we know a bit about how people make health decisions, we can ask how social identities—ranging from membership in a political party, to a run club, to being a university student—affect these decisions. We suggest that there are two main ways this can happen.

First, our social identities can affect the beliefs we hold about a behavior. This can be seen most strikingly in the way political identities affect beliefs. During the COVID-19 pandemic, Republicans and Democrats developed starkly different beliefs about the health complications arising from COVID and the risks of the vaccine. One explanation for this is that Republicans and Democrats inhabited different information environments, looking to different partisan news sources and following different influencers on social media. Because they saw different information, they developed different views.

Another explanation is that members of different parties have different motivations. It can be a discomforting experience to disagree with members of a social group you are a part of. As a result, partisans may have been motivated to “toe the party line” and view COVID-19 and its vaccine the same way other members of their party did.

Second, social identities can affect how important different beliefs are to us. If you are a college student feeling strongly attached to your peers, you may be more likely to value fitting in and binge drinking when they do. If you join and stay in an anti-vaccine community online, you may adopt the values of your community and start to take the demonstrated health benefits of vaccinations less seriously.

Each of these two processes—changing beliefs and changing their weight, or importance—can happen independently. Together, they make for powerful, mutually reinforcing effects of our social identities on the kinds of health behaviors we do and do not choose to do.

Encouraging people to take the right actions to improve their health will require attention to beliefs, social norms, and feelings of self-efficacy. If all of these things are aligned—people have accurate beliefs about an effective action, their group members are already taking this action, and they feel capable of doing it—then it is far more likely they will act in a way that impacts their well being.

The kinds of health behaviors we choose are consequential—not just for ourselves, but also for those around us. In order to understand how people make these decisions, it is important to consider the social context they are in. We need to understand the kinds of social groups people identify with, and how these groups shape their beliefs and values.

By understanding this aspect of group psychology, we hope that medical experts, public health professionals, and policymakers will help provide better solutions to keeping us all healthy.

This newsletter was written by Raunak Pillai and edited by Hannah and Jay. It summarizes a recent paper from our lab which you can read here. We welcome any suggestions.

News and Updates

Jay is giving a public talk at NYU on “The Power of Us: How Shared Identities Shape Conflict and Cooperation” at NYU on December 4th at 5pm. RSVP here if you want to attend. Here is the abstract:

”What does it mean to belong — and how does our sense of identity unite or divide us? Group cooperation is one of the most remarkable features of human nature, enabling people to build teams, communities, and nations. Yet the same psychological forces that bind us together can also drive conflict and polarization. In this talk, I explain how our social identities — the groups we feel part of — shape our thoughts, emotions, and actions. Drawing on insights from social psychology and cognitive science, this talk reveals how understanding identity can help us understand and address some of today’s greatest challenges, including political division, misinformation, climate change, and threats to democracy. Ultimately, The Power of Us shows how we can harness our shared identities to foster cooperation, strengthen communities, and build a more connected world.”

Check out our last Ask Me Anything session for the fall! Paid Subscribers can join us for our monthly live Q&A with Jay or Dom where you can ask us anything from workshopping research questions, career advice to opinions and recommendations on pop culture happenings—for paid subscribers only. Upgrade your subscription using the button below. We will be posting more sessions in the new year.

December 11th @ 4:00 EST with Dom
January 21st @ 2:00 EST with Jay
March 4th @ 2:00 EST with Jay
May 6th @ 2:00 EST with Jay