Crystal Smit

Social Network Intervention 2 29 agents in order to optimally motivate them to promote water consumption within their social networks. In the training, the influence agents were asked whether they actually would like to take on this role and, if so, providing them with the opportunity to determine for themselves how they would encourage their peers to drink more water. Research has shown that an autonomy supportive smoking cessation intervention focusing on choice increased adolescents’ autonomous motivation to not smoke (Williams, Cox, Kouides, & Deci, 1999). Similarly, self- persuasion is an effective manner to sustain behavior change because it increases people’s intrinsic motivation to change (Mussweiler & Neumann, 2000) by placing them in situations where they are motivated to persuade themselves in order to change their own attitudes or behavior (Aronson, 1999). In line with this, the training persuades the influence agents to consume more water themselves when asking them to argue in favor of water (“Write down arguments about how you could consume more water yourself”; Miller & Wozniak, 2001). The present pilot study was the first to test a social network-based intervention using peer influence on children’s self-reported water drinking behaviors. The aim of this study was to examine whether the Share H 2 O intervention could effectively promote water drinking among primary schoolchildren. We hypothesized that children who were exposed to the social network-based intervention would report an increase in their water consumption (H1), a decrease in their SSB consumption (H2) and have stronger intentions to drink water (H3) over time compared to those who were not exposed to the intervention. METHOD Design The study was a randomized control trial with schools as the unit of randomization. The schools were assigned randomly to either the Share H 2 O intervention (social network-based intervention) or the control condition (no intervention) by an independent researcher. The Share H 2 O intervention consisted of exposing the children to influence agents from their own classroom. Children in the control