Adding Dynamic Norm to Environmental Information in Messages Promoting the Reduction of Meat Consumption

ABSTRACT

Research has shown that dynamic norm information can promote pro-environmental actions (i.e. information indicating that a growing number of people are behaving pro-environmentally). Yet, the question remains whether adding dynamic norm information would increase the effectiveness of information on the environmental consequences of behavior. We compared the effects of environmental information with versus without dynamic norm information on encouraging reductions in meat consumption, and whether effects would depend on receivers’ intrinsic motivation. We also explored whether message effectiveness would vary according to receivers’ intrinsic motivation to reduce meat consumption. In total 197 volunteers participated in a one-month messaging intervention through a chatbot. Results showed that both environmental and environmental + dynamic norm messages increased positive attitude towards reducing meat consumption, and decreased meat consumption. These effects were still present at follow-up (i.e. one month after the intervention stopped). Interestingly, both messages particularly persuaded receivers with a relatively weak intrinsic motivation to reduce meat consumption, while environmental only messages were even counterproductive in receivers with a relatively strong intrinsic motivation. These results advance our comprehension of the effects of messages aimed at reducing meat consumption.

KEYWORDS:

• Meat reduction
• environment message
• intrinsic motivation
• dynamic norm
• attitude change

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 To control the levels of attrition across conditions, we also ran a mixed model analysis including partial data from those who dropped out from the survey, finding essentially the same results (see Supplement - Results).

2 As we did not include a control condition, we examined whether the changes in attitudes and meat consumption across time differed from other studies that can serve as a reference point (see Supplement - Results). Comparing partial eta square (Lakens, 2013), we found that the levels of change over time detected in our study were higher than those of other studies that measured attitude and meat consumption over time either without exposing participants to any kind of intervention or comparing an environmental message condition to reduce meat consumption with a control condition. This suggests that the observed effects were likely due to the exposure to the messages, and not to other factors that could have caused a shift in diet. Although the studies used as a comparison had roughly the same study period and methods, this comparison must be interpreted with caution, because the demographics of the studies differed (for details, see Supplement – Results).

3 A mixed model analysis including partial data from those who dropped out from the survey shows essentially the same results (see Supplement - Results). These findings suggested that both interventions resulted in more positive attitude towards reducing meat consumption and decreased meat consumption at T3 compared to T1, and that there was no difference across condition.

4 A mixed model analysis including partial data from those who dropped out from the survey finds instead that at Time 2 participants in the ENV condition had a marginally more positive attitude towards reducing meat consumption than participants in the ENV+DYN condition, Estimate: 0.49; Std Error = 0.25; df = 346; t  = 1.92; p = 0.055; 95&CI: -0.01, 0.99, suggesting that the different values of attitude at Time 2 in the two conditions disappeared over time (see Supplement - Results)