Sensory pathways in the brain must reinforce engrams more effectively than thought patterns. In other words, if you read or hear a message through your senses,

Sensory pathways in the brain must reinforce engrams more effectively than thought patterns. In other words, if you read or hear a message through your senses, that fixes the neural pathways triggered by this stimulus more firmly than had you just been ruminating on the topic. At least, that's my theory as to why the internet has increased polarization. People have always been able to think in odd ways, but the negative reinforcement from a conforming outside culture suppressed these thought patterns. The internet gives your brain external stimuli that validate your thoughts, and this causes your brain structure to change moreso than had your thoughts not been reinforced. The inability to communicate between those on opposite sides of society's divisions is not just a failure of imagination. In some cases the brain circuitry of the interlocutors is so different that being subjected to the same stimulus leads to wildly different responses and consensus is impossible without one or both parties altering their brain structure through sensory counter programming.