I'm reading a very interesting book at the moment about how people's minds change.
It does cover social media - I am now on the chapter about "Arguing".
There's an interesting experiment.
They gave people a biography of a person to read and they all agreed he was an expert in the climate.
They were then told that this person believed in man made climate change, that the evidence was conclusive and that we must act. People who also believed in climate change agreed that he was an expert and must be correct. However, people who did not believe in climate change thought he was wrong.
However, in the alternate study, the other group were told he did not believe in climate change. Then - the people who believed in climate change thought that the scientist was wrong, whilst the people who did not believe in climate change agreed that he was an expert and he was right.
It's a fascinating book about human psychology, especially in the internet age.