Message factors and the Truth Effect; refers to the finding that simply repeating a statement causes it to be perceived as more valid regardless of whether the statement is true, false, or just an opinion. If you repeat something often enough, some people will come to believe it (Dechene et al., 2010). This works for other weak and strong arguments, but is most effective when people are not motivated to pay close attention.
Dissonance Theory also sheds light how and why people sometimes believe their own lies.
Groupthink; when members of a group place more importance on concurrence than critical thinking.
Amazing how an image like that can say so much. Thanks for prompting me to review the Social Behaviour chapter of my Psych text this morning!
Not forgetting the “Halo Effect”