Our brains are excellent pattern-matchers and reward us for using this very helpful skill. Repetition creates a pattern, which consequently and naturally grabs our attention at first and then creates the comfort of familiarity.

If something happens often enough, I will eventually be persuaded.

Repetition creates familiarity, but does familiarity breed contempt? Although it can happen, the reality is that familiarity leads to liking in far more case than it does to contempt.

Repetition can also lead to understanding, as it gives time for the penny to drop. What at first may be strange, after repeated exposure becomes clear and understandable. We have to repeat things more than once for them to finally sink into our memories. Our short-term memories are notoriously short-term. Repetition is one of getting things into longer-term memory and hence is a key method for learning.

With repetition you can connect a cue or trigger with a selected action. This can be a color, a shape, a tune or a host of other things. The ideal that advertisers search for is that when you see the product in the shop, the pleasant or funny feelings that the advert evoked are re-awoken, making you somehow want to buy the product.

A core principle of music is repetition. It appears in runs, trills and stanzas, as well as in pounding rock rhythms and dance music. Music, rhythm and repetition have a hypnotic effect that can lull people into following a pattern in unthinking ways.

Summing-up: Use friendly repetition to create familiarity and hence liking. Use it to help the other person remember the things you want them to remember. And whilst you are at it, associate the repetition with a trigger that can re-stimulate good feelings.