The relationship between social identity, descriptive social norms and eating intentions and behaviors

Social factors, particularly social norms, have been reported to influence eating behaviors. From the perspective of Social Identity Theory, a strong association between a person and the norm referent group is key to the effectiveness of descriptive social norms on behavior. The general aim of the studies presented in this paper was to examine the effects of descriptive social norm based messages on eating intentions and behaviors, and whether social identity moderates these effects. Study 1 and Study 2 examined whether the effect of a descriptive social norm message promoting vegetable intake (or limiting junk food intake) was moderated by the extent to which participants identified with the norm referent group. We found that centrality of social identification with the norm referent group moderated the effect of descriptive social norm messages on intentions to eat vegetables and intentions to limit junk food intake. Study 3 built on those findings by examining whether priming social identity enhanced the effects of a descriptive social norm message on actual food intake in a laboratory setting. We found that intake of fruit and vegetables was enhanced after exposure to a descriptive social norm message (versus a health message) but this effect was only significant for participants whose identification with the norm referent group had been primed. Taken together, these data add to the suggestion that acting in line with group norms is more likely when individuals regard their membership of the group as being important to their identity.