Political science research suggests that a great majority of people fall on a left-right spectrum of politics. Whether you fall on the left or the right seems to be dependent on the story we tell about ourselves. The progressive, left-wing story goes: “once upon a time things were bad, and now they’re good thanks to our party”. The right-wing conservative story goes the other direction: “once upon a time things were good, but now they’re bad thanks to the other party”.

The psychologist Jonathan Haidt argues that for people both on the left and right of the political spectrum, supporters of the opposite side of the spectrum are not just wrong; they are righteously wrong, morally suspect and even dangerous. He goes on to say that “Our righteous minds made it possible for human beings to produce large cooperative groups, tribes, and nations without the glue of kinship. But at the same time, our righteous minds guarantee that our cooperative groups will always be cursed by moralistic strife.”

But what has evolution to do with all this? Hundreds of thousands of years ago, the human species crossed an ‘evolutionary bridge’ that is the result of the moral hive mind in today’s politics and is called ‘shared intentionality’. This is the ability to share mental representations of tasks that two or more were pursuing together. When our ancestors began to share intentions, their abilities increased exponentially. They could now hunt together, raise children together and protect each other.

Shared intentionality caused everyone on the team to have the same intentions and when a teammate acted in a way that did not comply with the intention they reacted negatively. As a modern politicians it is not well accepted to change your mind often and it is expected that they comply with the shared intention of the party; when they deviate it will be received negatively.

Haidt concludes in his bookThe Righteous Mind: Why Good People Are Divided by Politics and Religionthat we need both left and right-wing parties to reach a livable middle ground. A philosopher once noted “A party of order or stability, and a party of progress or reform, are both necessary elements of a healthy state of political life.”