Mistake Type:
Insularity
Assuming that the truths or norms accepted in one’s group are universally self-evident and applicable.

Examples:
“Everyone I know believes in strong border control; how could you possibly disagree?”
“All of my friends support universal healthcare; it’s common sense, really.”
“They’re crazy, how could they possibly believe that?”
About Insularity:
The insular mindset is often a byproduct of echo chambers, where individuals are only exposed to opinions that align with their own. This limited scope can lead to the false belief that one’s own group has a monopoly on truth or reason. In social media conversations being insular manifests as a dismissive attitude towards anyone outside one’s group, often treating their views as uninformed or even illegitimate.
Insularity hinders meaningful dialogue by precluding the possibility that other perspectives could have merit. It breeds an us-versus-them mentality, reinforcing group divisions and beliefs about individual superiority, and escalating partisan tensions. It also breeds an us-versus-them mentality, reinforcing tribal divisions and escalating partisan tensions.
The insular approach also tends to amplify confirmation bias, as it discourages engaging with information that might challenge one’s views. Over time, this can lead to an increasingly distorted perception of reality, further widening the gap between different social or political groups. Insular statements are particularly prevalent in discussions where complex issues are boiled down to binary choices: you’re either with us or you’re against us. The insular mindset reinforces this dichotomy, making it difficult to explore nuances or consider compromise.