Effects of Social Norms Information and Self-Affirmation on Sugar-Sweetened Beverage Consumption Intentions and Behaviors

Abstract

The separate and combined efficacy of a social norms and a self-affirmation intervention to motivate decreased sugar-sweetened beverage (SSB) consumption was examined in two experiments. College students were randomly assigned to receive information about SSB consumption risks, norms, both, or neither. In addition, participants performed either a self-affirmation or control task. Self-affirmation only weakly affected SSB consumption intentions and behaviors. However, participants in Experiment 2 who received risks information, norms information, or both reported greater SSB reduction intentions than did those who received no information. Two-weeks later, those who received both types of information reported more frequent behavior change preparations, and it appears this effect may have been partially mediated by the changes in intentions to reduce SSB consumption.

Effects of interventions based on the theory of planned behavior on sugar-sweetened beverage consumption intentions and behavior

“…"; 0 (not at all) to 4 (very frequently)). As in previous work (Rosas et al, 2017), the items displayed acceptable internal consistency (α = .75), and thus were combined into a preparations index for analyses (higher numbers indicating more frequent preparatory behaviors). Finally, the participants were asked the eight intentions items assessed at the initial session to assess their intentions to alter their future SSB consumption.…”

“…Intentions.-Eight items were used to assess intentions to minimize SSB consumption (Rosas et al, 2017). An example item is "I plan to avoid consuming sugar sweetened drinks entirely" (1 = Strongly Disagree; 7 = Strongly Agree).…”

“…Participants were 430 (72.9% female) undergraduate students, attending either the University of California, San Diego (UCSD; n = 224) or California State University San Marcos (CSUSM; n = 206). Sample size was based on power analyses utilizing effect sizes (Cohen's d;Cohen, 1969) obtained or calculated from previous research that compared risks information (Adams, Hart, Gilmer, Lloyd-Richardson, & Burton, 2014;Bleakley et al, 2015;Kothe & Mullan, 2014;Rosas et al, 2017;Sharps & Robinson, 2016), social norms information (Kothe & Mullan, 2014;Pliner & Mann, 2004;Rosas et al, 2017;Sharps & Robinson, 2016), or a planning task (Adriaanse et al, 2010;Ames et al, 2014;Conner, Sandberg, & Norman, 2010;Gholami et al, 2013;Kothe & Mullan, 2014) respectively, to a control condition. The average ds (.48 for risks information, .59 for social norms, and .41 for planning) suggested a need for 100 participants per condition to obtain a power of .80 (for the risks and planning manipulations).…”

“…In addition to the stereotypical SSBs (e.g., soda, fruit juices), the information and images in the booklet were designed to increase awareness of the heavy sugar content of beverages such as sports drinks and coffee drinks (e.g., Frappuccino's) that are ubiquitous on college (and high school) campuses. The information booklet was expanded from one used in a previous study (Rosas et al, 2017). In order to produce favorable SSB reduction attitudes, consistent with previous TPB interventions in other health contexts (See Fishbein & Ajzen, 2010;Hardeman et al, 2002), the risks information intervention was designed to both inform and convince participants that SSBs pose a significant health risk.…”

“…131). In previous work, we have demonstrated that such PNF was successful in convincing students that important people in their lives would want them to minimize their SSB consumption (Rosas et al, 2017). The PNF consisted of a direct comparison of participants' own perceptions (assessed at baseline; described below) of typical college students' approval of avoiding SSB consumption (injunctive norm) and efforts to minimize SSB consumption (descriptive norm) against the actual normative values.…”