How we change what others think, feel, believe and do
Limits to Repetition
Repetition is a useful principle in persuasion, yet it has its limits in terms of when, where and how it is effective.
If you repeat something endlessly to someone, they may eventually be persuaded. They may also become bored or irritated and so react against you, effectively in revenge for being so annoying.
Research has shown that in general, three to five repetitions is enough (Briñol et al, 2008) and after that its effects either tail off or lead to reactance.
Reactance can also happen if the other person thinks you are trying to manipulate them. This does not take long with in-your-face obvious nagging. When a person is verbally repeating and another person is listening carefully, then repetition soon becomes noticeable.
If the argument being offered in the persuasion makes sense and is easier to agree with, then repetition should generally enhance and not weaken this power.
On the other hand, if a weak and invalid argument is being used, then repetition will not make it stronger, although it may be even more necessary if the goal is to wear the other person down and get acceptance rather than real agreement.
The credibility of the person making the argument is important. The more authority and trust they have, the more likely it is that the listener will be persuaded by them and will accept repetition as a sincere and important form of emphasis.
If only one person is saying something, especially if they have no particular credibility, then it is far less persuasive than if the same thing is heard from other people. In fact there is a huge leap in credibility when two people are making the same point, as opposed to just one. Credibility flattens off after a few people are supporting the argument and only takes a final hike when everybody (in a given group) agrees.
Briñol, P., DeMarree, K. G., & Petty, R. E. (2008). Processes by which Confidence (vs. Doubt) Influence the Self. In R. Arkin, K. Oleson, & P. Carroll (Eds), The uncertain self: A handbook of perspectives from social and personality psychology. Mahwah, NJ: Erlbaum
Moons, Wesley G.; Mackie, Diane M.; Garcia-Marques, Teresa (2009). The impact of repetition-induced familiarity on agreement with weak and strong arguments, Journal of Personality and Social Psychology, 96, 1, 2-44