3The thin ideal is the western concept of an ideally slim or underweight female body 1 , 4 and its omnipresence in the mass media has a negative impact on women's health [2][3][4][5] .
5Media consumption is associated with a drive for thinness, body dissatisfaction, low 6 self-esteem, and disordered eating in women of western and/or industrialised 7 societies 4 . Furthermore, cross-cultural research suggests that the media have similar 8 effects when they are introduced into non-western or non-industrialised societies 2,6,7 . 9No study, however, has attempted to induce a change in female body size ideals in a 10 population that is not exposed to the thin ideal and that has currently no access to the 11 media. Here we show experimentally that a short exposure to the thin ideal can 12 change body size ideals in a media-naïve population. 80 rural Nicaraguan men and 13 women with very low to non-existent media access created their ideal female body 14 before and after seeing photographs of either thin or plus size fashion models.
15Analyses revealed a significant interaction between time and group, meaning that 16 exposure to media images shifted the subjects' ideal female body size. We discuss 17 problems posed by the pervasiveness of the thin body ideal in the context of the 18 global obesity pandemic. 19Up to 30-50% of girls and women from western or industrialised countries have 20 negative body image 8,9 , which contributes to widespread psychopathologies such as low 21 self-esteem, depression, and disordered eating 10,11 . One key sociocultural contributor to 22 body dissatisfaction is the thin body ideal and its omnipresence in the mass media 1,3,5,[12][13][14] .
23For example, across 77 correlational and experimental studies, media exposure was 24 associated with a stronger internalisation of the thin body ideal, higher body dissatisfaction, 25 and higher eating disorder symptomatology 4 . Furthermore, cross-cultural research has 26shown that populations with limited access to the media have a higher female body size 27 ideal 7,[15][16][17] , and that the introduction of television in previously media-naïve populations is 28 accompanied by an increase in body dissatisfaction and pathological eating attitudes 2,6,7,14 . 29Although past research suggests that the media impact female body size ideals and 30 so have a negative effect on women's health, it suffers from two important limitations. First, 31 experimental research has never shown that the thin ideal and the media can induce a 32 change in body size ideals in a non-WEIRD (western, educated, industrialised, rich, and 33 democratic)
18, media-naïve population. Instead researchers have used western, 34 industrialised subjects in countries where the thin body ideal is already omnipresent in the 35 media and where poor body image is already widespread [19][20][21] . Second, all cross-cultural 36 research using non-western or non-industrialised subjects has been correlational, cross-37 sectional, or pseudo-longitudinal, and has therefore failed to es...