I have a confession: I’m a political junkie who HATES primary season. I’ve been involved in political activism since before I could vote. I have a productivity blocker set to keep me off Politico during work. I have political convictions and opinions, and I love to talk about them, but something about primary season makes my skin crawl.

This year we have only a Democratic primary (because there is a Republican incumbent), so the divisions we are seeing are among the Democrats. But both sides get this way during primary season.  Most striking right now is seeing people who are all part of the progressive Left suddenly become fierce opponents. Sanders’ supporters vs. Warren supports vs…. well, I suppose it makes sense given that the candidates themselves are opponents.

But why do so many of us go along for this ride and start to trash members of our own party? Once we’re committed to a particular candidate, why do the negative attributes of other candidates suddenly come into sharp relief? Why do we become so much more willing to believe negative press about the other candidates and so dismissive of negative press about our own preferred  option? Why do we see supporters of other candidates as uninformed, blind fools, or disingenuous actors?

It reminds me of a type of experiment that’s been conducted many times in the past 50 years.  If you were a participant in one of those experiments, you and other participants in the study would be divided into two groups based on some arbitrary criterion—say, whether you overestimated or underestimated the number of dots in a picture, or whether you preferred an abstract painting by Klee vs. Kandisnky. You’d then be asked to distribute money between someone in your group and someone in the other group. The money isn’t going to you personally, and you won’t be interacting with these people further, and there’s no opportunity for them to pay you back. So, there’s no good reason to divide the money unequally between people in your group and people in the other group. In fact, you don’t even know who any of these people are! But if you’re like most people in these studies, you’ll probably give more money to people in your group than people in the other group.

Unfairly distributing money is just the tip of the iceberg. You might also be asked to evaluate members of the two groups.  Knowing nothing about your group other than that you’re a member of it, you still might find yourself rating the members of your group in more positive terms than members of the other group.  Similarly, if you’re asked to evaluate something created by members of the other group, all the flaws stand out to you, whereas you’re willing to overlook the weaknesses in work created by members of your own group. And if a member of your group  does something unethical or a little unfair? Well, that’s just to be expected, but when someone from the OTHER group does the same thing, it just goes to show how awful people from that other group can be, doesn’t it?

This research procedure in which people are assigned to arbitrary groups is known as the Minimal Groups Paradigm, and for half a century, social psychologists have used it to study intergroup conflict. The idea is to strip away all the history, ideology, excess baggage, and real differences that we see between real social groups so that we can see whether similar conflicts arise when the groups are essentially meaningless. And, results have consistently showed that even these bare bones groups are sufficient to create bias and conflict. By being assigned membership in these meaningless groups, we favor the group we belong to over the group we don’t belong to.

So I’ve been wondering whether the supporters of different candidates from the same party do the same thing? Perhaps identifying with a candidate is similar to being placed in a minimal group. This identification might lead a Warren supporter to view Sanders’ followers as more sexist, might cause a Sanders supporter to see Warren as too Capitalist, and might lead a Buttigieg supporter to view the others as unrealistic. It might lead all of them to see the policies of the other camps as more poorly argued and to focus on the bad behavior of another candidate’s campaign staff, while justifying similar behavior from people on their side.  Add to this the fact that the effects of the Minimal Groups Paradigm increase when groups are in competition with each other. If we’re focusing on the primary horse race, then all of these sources of bias should be in overdrive!

Let me clarify that I don’t think the differences between supporters of Sanders, Buttigieg, Biden, Gabbard, or the other Democratic  candidates are as trivial as the differences between people who overestimate versus underestimate dots in the Minimal Groups Paradigm. Political groups differ in important ways in terms of policy preferences and priorities, demographics, life experiences, and so on. But it’s worth noting that behavior not unlike what we see between supporters of different political camps can arise without any basis in true, reasoned differences of opinion.

So, what can we do to do unify warring tribes and promote cooperation within a party before the general election? How can we make sure that people’s actions in the political space are determined by their values and not by the quirks of their tribalistic minds?  The answer may come from another classic study in social psychology.  Muzafer Sherif orchestrated conflict between two groups of boys at a summer camp. By dividing the boys into two groups and having the groups compete with one another in baseball games, tug-of-war, and other contests, Sherif led the boys to become so hostile toward one another that the two groups were unable even to watch a movie together without taunting one another and fighting. But the researchers were able to completely eliminate this conflict over the course of only a few days.

The key to unifying the two groups wasn’t having them merely interact or talk with one another about their differences. Instead, the two groups were united by having them work together to solve problems set up by the researchers. For example, the two groups had to work together to tow a bus that had “broken down” and fix a water supply that had been blocked by the researchers. Pursuing these common goals completely eliminated hostility between the two groups, and subsequent research has found that the same thing happens when adults from opposing groups work together toward common goals. When we see ourselves facing a common enemy or needing to work together for our shared interest, we start to see ourselves has being part of a bigger, unifying group, and old divisions recede.

This is, I think, where attempts to unify the Democratic party around Hillary Clinton in 2016 failed. Some (though certainly not all) supporters of Bernie Sanders did not feel that they were pursuing the same goal as Clinton supporters and the Democratic party at large. Their goal was not “stopping Trump” but instead, “stopping neoliberalism,” a goal that did not unite them with the broader Democratic party, thus maintaining divisions and conflict between factions of the party. If the Democratic Party hopes to win in this fall’s election, Democrats will need to agree on some common goals and perhaps pack their love for their own candidate (and their animosity toward other candidates) during the primary process.  In that way, they can retain a shared identity and a sense of common cause after the nominee is chosen, just like the boys in Sherif’s summer camp study.  

Or perhaps I’ll just take a nap now and wake up when it’s time to vote on Super Tuesday.

For Further Reading

Stafford, T. (2013). What does it take to spark prejudice in humans? BBS Future. https://www.bbc.com/future/article/20130409-what-sparks-prejudice-in-humans

Brewer, M.B. (1979). In-group bias in the minimal intergroup situation: A cognitive-motivational analysis. Psychological Bulletin, 86, 307-324.

Brewer, M.B. (1996). When contact is not enough: Social identity and intergroup cooperation. International Journal of Intercultural Relations, 20, 291-303.

Greenaway, K.H., Wright, R.G., Willingham, J., Reynolds, K.J., & Haslam, S.A. (2015). Shared identity is key to effective communication. Personality and Social Psychology Bulletin, 41, 171-182.

Sherif, M. (1958) Superordinate goals in the reduction of intergroup conflict. American Journal of Sociology, 63, 349-356.

Xiao, Y.J. & Van Bavel, J.J. (2019). Sudden shifts in social identity swiftly shape implicit evaluation. Journal of Experimental Social Psychology, 83, 55-69.


Alysson E. Light is an Assistant Professor of Social Psychology at University of the Sciences in Philadelphia. Outside of work, she volunteers as a community organizer, working on local and state elections.