In 1885 the first skyscraper penetrated the skies above Chicago…all nine stories. This was also the year that Hermann Ebbinghause published studies about memory. The Ebbinghause Curve of Forgetting has since been the foundation of advertising’s most effective strategy: frequency. The Ebbinghause studies showed that two-thirds of us forget specific messages one day after exposure. After one week, only a quarter of us can remember those messages.
Just as we finish reading an ad our recall is 100%, but for the vast majority of us, that recall quickly fades (as indicated by the blue-green parabolas). Ebbinghause's research showed that each repetition of a particular message builds on previous exposures to significantly improve recall. Imagine throwing mud at a wall. The first handful mostly falls away, leaving just a mark. Keep throwing, however, and more and more of the mud sticks. In fact, the amount that sticks with each throw increases as the mud finds a grip. Your ads are the mud. Keep throwing them to see them stick better and better!