Is obesity un-American? Disease concerns bias implicit perceptions of national identity

The current research examined whether Americans incorporate obesity into their national identity, and further investigated the role an evolved behavioral immune system plays in shaping Americans' perceptions of obesity and national identity. Two studies revealed that obesity is not, on the whole, incorporated into the American identity at an implicit level. Moreover, when disease concerns were salient, either because of an experimental priming manipulation (Study 1) or due to recent illness (Study 2), thin individuals (for whom obesity may represent a particularly atypical morphology and thus a heuristic cue to disease) implicitly excluded obesity from the American identity to a greater degree. Thus, implicitly categorizing a subgroup of people as an outgroup pathogen threat may promote behavioral avoidance, exclusion, or stigmatization. This behavioral avoidance, could, in turn lead to less risk of fitness-reducing disease contraction. Further implications for evolutionary theories of disease avoidance, group identity, and discrimination are discussed.