Adaptive persuasive systems : a study of tailored persuasive text messages to reduce snacking

This article describes the use of personalized short text messages (SMS) to reduce snacking. First, we describe the development and validation (N = 215) of a questionnaire to measure individual susceptibility to different social in¿uence strategies. To evaluate the external validity of this Susceptibility to Persuasion Scale (STPS) we set up a two week text-messaging intervention that used text messages implementing social in¿uence strategies as prompts to reduce snacking behavior. In this experiment (N = 73) we show that messages that are personalized (tailored) to the individual based on their scores on the STPS, lead to a higher decrease in snacking consumption than randomized messages or messages that are not tailored (contra-tailored) to the individual. We discuss the importance of this ¿nding for the design of persuasive systems and detail how designers can use tailoring at the level of social in¿uence strategies to increase the effects of their persuasive technologies. Keywords: Persuasion, social in¿uence, personalization, tailoring, persuasion pro¿ling