The splitting into camps (in the US) based on particular topics started much earlier than social media:
* https://en.wikipedia.org/wiki/Southern_strategy
> Not quite, but one of the most effective temptations one can offer is giving people a moral excuse to hate others.
The psychology studies referenced in the book show us-versus-them / in/out-group mentality without getting in moral questions or political topics.
The splitting into camps (in the US) based on particular topics started much earlier than social media:
* https://en.wikipedia.org/wiki/Southern_strategy
> Not quite, but one of the most effective temptations one can offer is giving people a moral excuse to hate others.
The psychology studies referenced in the book show us-versus-them / in/out-group mentality without getting in moral questions or political topics.