Crystal Smit

Social Network Intervention 2 33 Based on self-persuasion theory (Aronson, 1999), the influence agents were then asked to generate arguments on how to consume more water themselves (Miller & Wozniak, 2001; Mussweiler & Neumann, 2000). After that, their role as influence agent was explained and they were asked whether they were willing to take on this role. All children accepted this role. The influence agents were then asked to think about possible ways through which they could promote water consumption among their peers. From these options, drinking more water themselves and spreading the health and environmental benefits of water were discussed explicitly. Based on the insights of self-determination theory (Deci & Ryan, 1985; Soenens & Vansteenkiste, 2010) it was emphasized that the influence agents should decide for themselves how they wished to encourage their peers to drink more water. In addition, they received a reusable water bottle to stimulate water consumption among their peers. Two follow-up sessions (one and four weeks after the training) provided researchers the opportunity to offer visible support, resolve any problems that the influence agents experienced in their role, and refresh the information that was discussed in the initial training. Measures Sociometric Questions Five peer nomination items were used to identify the most influential children in each classroom. The children were asked to nominate up to five classmates whom they “respected”, “wanted to be like”, “looked up to”, “went to for advice”, and “regarded as good leaders” (Campbell et al., 2008; Starkey et al., 2009). In the intervention schools, children who received the most nominations were trained as influence agents to promote water consumption within their social networks for eight weeks. To ensure gender balance in proportion to the composition of the class, 15% of boys and 15% of girls with the most nominations over all questions were selected (Campbell et al., 2008; Starkey et al., 2009).