Addition 12/29: Thank you to an astute reader of this site who sent us the following link: “a study in the Nov 24 New Scientist seems to bolster the conclusion in ‘Does our Effort Make Any Difference?’ The study was done by by Andre Martins of the Univ. of Sao Paulo, and while its results are simple and preliminary, they show that when people holding centrist or ‘middle’ opinions were exposed to people espousing views that were considered to be more extreme or uncommon, the subjects’ views tended to shift away from the center toward the more extreme, less accepted viewpoints.”

“Extremist views explained by aligning atoms” summary:
24 November 2007, by Michael Brooks, Magazine issue 2631
“In certain societies, people’s views naturally migrate over time towards extreme ends of a political spectrum, where they will become entrenched. This, at least, is what a mathematical analysis of human behaviour by Andr