We must insist on the further demand that the advertisement make a vivid impression, so that it may influence the memory through its vividness. Size is naturally the most frequent condition for the increase of vividness, but only the relative size is decisive. The experiment shows that the full-page advertisement in a folio magazine does not influence the memory more than the full page in a quarto magazine, if the reader is for the time adjusted to the particular size. No less important than the size is the originality and the unusual form, the vivid color, the skillful use of empty spaces, the associative elements, the appeal to humor or to curiosity, to sympathy or to antipathy. Every emotion can help to impress the content of the advertisement on the involuntary memory. Unusual announcements concerning the prices or similar factors move in the same direction. Together with the question of the apprehension and the vividness of the impression, we must acknowledge the frequency of repetition as an equally important factor. We know from daily life how an indifferent advertisement can force itself on our mind, if it appears daily in the same place in the newspaper or is visible on every street corner. But the psychologically decisive factor here is not the fact of the mere repetition of the impression, but rather the stimulation of the attention which results from the repetition. If we remained simply passive and received the impression the second and third and fourth time with the same indifference with which we noticed it the first time, the mere summation would not be sufficient for a strong effect. But the second impression makes the consciousness of recognition, thus exciting the attention, and through it we now turn actively to the repeated impression which forces itself on our memory with increased vividness on account of this active personal reaction.