Crystal Smit

Social Network Intervention vs. Mass Media Intervention 4 87 in schools. The plastic soup also received a lot of (inter)national attention, for example, from the World Wildlife Fund, and even a famous national children’s choir released a song called “Plastic Soep” [Plastic Soup] in 2017, which became very popular (Alessi, Di Carlo, Campogianni, Tangerine, & Pietrobelli, 2018; Seleky, 2017). This (media) attention for water consumption has probably inspired some children and parents to drink more water in recent years. For this group, the content of the Share H 2 O intervention—which mainly focuses on the benefits of drinking water—could have been less or perhaps even not inspiring at all. It is therefore essential that future research focuses on updating the content in order to better respond to the current consumption behavior, norm and knowledge of the target children. This can be achieved, for example, by involving these children in the development of the content (i.e., co-design; Visser, Stappers, van der Lugt, & Sanders, 2005) and thus taking into account their vision, which can increase intrinsic motivation in health interventions (Gillison et al., 2019). Recent research has shown that intrinsic motivation is a crucial predictor of changing children’s water consumption (Smit et al., 2018). In line with our expectations, we indeed found that the prevailing social norms concerning water drinking moderated the effectiveness of the social network intervention on water consumption. First, the social network intervention was found to be more effective among children who already perceived that their classmates were drinking water before the intervention started (i.e., higher perceived descriptive norm). Probably, the higher prevalence of water drinking peers in their environment led these children to consider water drinking as a normal and socially acceptable behavior. When water drinking was promoted by peers they wanted to be like or went to for advice, this intervention ‘message’ was congruent with what these children were already perceiving in their environment. This may have resulted in it being perceived as a familiar message, making it easier to adjust their behavior accordingly. In contrast, for children with initially lower perceived descriptive norms, it may be that the discrepancy between the ‘message’ (i.e., drink more water) and what they perceived in their environment may have been too large to bridge, leading to lower behavioral change. This