It’s known as the ‘Brazil nut effect’, technically apparently Granular Convection: https://en.m.wikipedia.org/wiki/Granular_convection It’s apparently not fully explained, but theories suggest things like buoyancy, or that larger particles are blocked from sinking by smaller particles, which on the other hand can slip below the larger ones.
It’s a small step to correlate locations and thoughts with minimal processing.
You’re at home when your network starts connecting to 4chan? - You’re a deviant.
You frequent a bar that is a known gay meet up? - You’re a deviant
You visited a location where a(n opposing) political rally was held? - You’re a deviant and now you’re also on the watch list.