Crystal Smit

Chapter 3 54 Descriptive Norms Participants’ perception of others’ behavior was assessed with the following item separately for parents and friends: “How often do your parents/friends eat fruits and vegetables as a snack?” (Pedersen et al., 2015). The same items were also used for water consumption. Response options ranged from 1 = ‘never’ to 6 = ‘always’. Injunctive Norms Participants’ perception of what others consider appropriate was assessed with the following item separately for parents and friends: “Do you experience that your parents/friends think you should eat fruits and vegetables as a snack?” (Pedersen et al., 2015). The same items were also used for water consumption. Response options ranged from 1 = ‘no, certainly do not’ to 6 = ‘yes, certainly do’. Intrinsic Motivation Intrinsic Motivation to eat fruits and vegetables was assessed with four items, based on the Health Care self-determination theory package (Williams, Ryan, & Deci, 2017). Participants were asked: “Do you eat fruits and vegetables as a snack because you . . . (1) like it?, (2) enjoy it?, (3) want this yourself? and (4) think it is pleasant?” The same items were also used to assess participants’ intrinsic motivation to drink water. Response options ranged from 1 = ‘no, certainly do not’ to 6 = ‘yes, certainly do’. Several studies have used similar measures to access participants’ intrinsic motivation (Ryan & Connell, 1989; Vansteenkiste, Claes, Soenens, & Verstuyf, 2013). Principal axis factoring analyses showed that one factor could be extracted from the scale items, with an eigenvalue higher than 1 explaining 71.4% of the variance for fruit and vegetable consumption and 69.1% for water consumption. Also, the inspection of the scree plots revealed a clear break after the first factor, indicating that the four items reflected one construct. A total score for intrinsic motivation to eat fruits and vegetables or drink water was constructed by averaging the four items, which demonstrated good internal consistency (Cronbach’s α s = .87 and .85, respectively).