© 2008 The Author Journal Compilation © 2008 Blackwell Publishing Ltd Social and Personality Psychology Compass 2/2 (2008): 765–784, 10.1111/j.1751-9004.2008.00081.x The Psychology of Tailoring-Ingredients in Computer-Tailored Persuasion Arie Dijkstra* University of Groningen Abstract Persuasive information can be tailored to individual characteristics using computer technology. Computer technology offers three ways to persuade people: adaptation, personalization, and feedback. Adaptation refers to the match between the type or the formulation of the persuasive arguments or recommendations and an individual’s psychological state. Personalization refers to the incorporation of one or more recognizable individual characteristics (e.g., one’s first name) in a persuasive text. Feedback refers to providing the individual with information about him or her that relates to important individual goals. These visible elements in a persuasive message are the tailoring-ingredients of computer-tailored persuasion. The present article focuses on explaining how these tailoring-ingredients influence persuasion, using existing social psychological insights in human functioning and persuasion. The persuasive effects of the tailoring-ingredients can be explained partly by different psychological processes. Computer technology has opened new perspectives in persuasive com- munication: persuasive information can now be tailored to individual characteristics (Brug, Oenema, & Campbell, 2003; De Vries & Brug, 1999; Kreuter, Strecher, & Glassman, 1999; Skinner, Siegfried, Kegler, & Strecher, 1993). During the last 15 years, many studies have been conducted to show the superiority of tailored materials over existing standard materials (Noar, Benac, & Harris, 2007). However, in only a few of these studies, tailored materials were compared with similar but non-tailored materials. The results of these well-controlled studies are mixed. Some found that tailoring was more effective (Brug, Steenhuis, Van Assema, & De Vries, 1996; Brug, Glanz, Van Assema, Kok, & Van Breukelen, 1998); others found no difference (Dijkstra, De Vries, Roijackers, & Van Breukelen, 1998; Owen, Ewins, & Lee, 1989); whereas other researchers found interaction effects (Skinner, Strecher, & Hospers, 1994; Strecher et al., 1994), whereby tailored information was only effective amongst specific subgroups of the examined samples. Thus, the state of the art is that computer-tailored persuasion (CTP) sometimes is more effective than non-tailored persuasion. To further increase the effectiveness of CTP, it is essential to deepen our