How we change what others think, feel, believe and do
Displaying certainty about an attitude when talking with another person will act to increase and harden that attitude. When the attitude displayed is more uncertain, then it will act to soften the attitude.
Using an emotional attack on a cognitive attitude will increase resistance, whilst a cognitive attack will be more effective. The same effect happens in reverse, where a logical argument has little impact on a person who is emotional whilst an emotional argument is more powerful.
Clarkson, Tbormala and Rucker found that increasing attitude certainty strengthened attitudes and increased resistance to persuasion when the attitudes was univalent but weakened them when they were ambivalent.
A cleric wants to persuade another towards a religion. When the target person states opposing beliefs, the cleric shows vague agreement. When the person states better beliefs, the cleric becomes more confirmatory.
To persuade another person, align your projected attitude with theirs. If you are non-aligned you will only act to create resistance.
To put off a persuader, mis-match their attitudes. When they are logical, be emotional, and vice versa.
Clarkson, J.J., Tormala, Z.L., & Rucker, D.D. (2008). A new look at the consequences of attitude certainty: The amplification hypothesis. Journal of Personality and Social Psychology, 95, 810-825.