Negativity Is Contagious, Study Finds

This is relevant to the role of persuasion and influence in the church community as an impediment to free-will.
This study supports other studies where people are influenced by the group to change their opinion.

In this study researches found that they could predictively influence the opinions of subjects by showing them information about the opinions of their peers. It is so effective that it could be used in marketing by competitors by going online and trash talking a product to influence consumers against it.
Sciencedaily.com

REFERENCE
Sciencdaily.com: Mind and Brain