In my experiments I’ve found that the most rigid thinkers have genetic dispositions related to how dopamine is distributed in their brains.
Rigid thinkers tend to have lower levels of dopamine in their prefrontal cortex and higher levels of dopamine in their striatum, a key midbrain structure in our reward system that controls our rapid instincts. So our psychological vulnerabilities to rigid ideologies may be grounded in biological differences.
In fact, we find that people with different ideologies have differences in the physical structure and function of their brains. This is especially pronounced in brain networks responsible for reward, emotion processing, and monitoring when we make errors.
For instance, the size of our amygdala — the almond-shaped structure that governs the processing of emotions, especially negatively tinged emotions such as fear, anger, disgust, danger and threat — is linked to whether we hold more conservative ideologies that justify traditions and the status quo.
I agree with almost all of your comment. However, say you have two children (to keep it simple) they have the same environment as they age (except, of course home life - important). Same school, same neighbourhood, similar friends etc. Their macro is so similar but their micro could be very different. This, in the developing brain will have larger effects down the line and could create vast differences in ideology - especially rigid ideology. So whilst I agree with you that it may not be inherent (although developing brain in utero, who knows), I think there is something to be said for the dopaminergic deficit in the cortex and the abundance in the striatum.