This study examined the role of waist-to-hip ratio (WHR) and shoulder-to-hip ratio (SHR) of the rival in evoking jealousy in an adult sample of 70 men and 69 women. Women paid more attention to the rivals’ waist, hips, and hair, and men paid more attention to the rivals’ shoulders. Potential rivals with a low as opposed to a high waist-to-hip ratio (WHR) evoked more jealousy in women than in men, particularly among women with a low WHR. Among women, the low WHR-high SHR rival the V-type body build evoked the highest level of jealousy and was perceived as most attractive and the most socially and physically dominant. In contrast, among men the low WHR-low SHR rival, that is, a rival with a linear and slender body build, evoked the highest level of jealousy and was perceived as the most attractive and socially dominant, but not as the most physically dominant. As men were older, the SHR of the rival was a less important factor in evoking jealousy, whereas among women jealousy in response to the rival’s WHR was not affected by age.
When individuals are confronted with the situation that one’s partner and a rival are romantically interested in each other, especially a rival who is attractive to the opposite sex will be perceived as a threat to one’s relationship (e.g., Dijkstra and Buunk, 1998 and Dijkstra and Buunk, 2002). A number of studies by Singh and his colleagues have shown that men and women alike find a low WHR of women an important determinant of her attractiveness as a partner (e.g., Singh, 1993; Singh & Young, 1995). An evolutionary explanation of this phenomenon is that a low WHR (around .7) signals health and fertility as it is the result of high levels of oestrogen that cause more fat to be deposited on the buttocks and hips than on the waist. Women with a high WHR have indeed been found to be less fertile and to suffer more from hypertension, hyperlipidemia, coronary heart disease, stroke, diabetes, and depression (e.g., Epel et al., 2000). Because higher testosterone levels in men stimulate fat deposits in the abdominal region while inhibiting fat deposits on the hips and thighs, healthy adult men generally have a much higher WHR than healthy adult women, typically around .9 (e.g., Singh, 1995). Among men as well as women, however, WHR’s higher than the optimal ratio are perceived as increasingly unattractive. A number of studies have confirmed Singh’s original findings, employing different methods such as altered color photographs (Henss, 2000) and a large variety in WHR’s (Streeter & McBurney, 2003), and examing various populations, including preadolescent, Mexican-American, British and Greek participants (Furnham, Moutafi, & Baguma, 2002; Markey, Tinsley, Ericksen, Ozer, & Markey, 2002). Moreover, Streeter and McBurney (2003) demonstrated that, unlike what was suggested by for example Tovée and Cornelissen (1999), a preference for a low WHR ratio is independent of weight. Nevertheless, there is evidence that in many non-Westernized societies the attractiveness of a woman may be mainly determined by her weight (e.g., Wetsman & Marlowe, 1999; Yu & Shepard, 1998), supposedly because in cultures where few resources are available to provide adequate nutrition, being overweight and having a high WHR may be viewed as signs of high status, wealth and prosperity.
Nevertheless, because at least in contemporary Western cultures WHR is an important determinant of particularly women’s attractiveness, especially among women a rival with a low WHR will evoke more jealousy than a rival with a high WHR. However, as the waist narrows, not only the WHR decreases, but also the body taper seems to increase. Therefore, showing that the degree of WHR affects jealousy does not provide unequivocal evidence that a rival’s WHR rather than a rival’s body taper induces differences in jealousy ratings. This is the more relevant as there is considerable evidence that the attractiveness of men, much more than that of women, is determined particularly by relatively broad shoulders in relationship to the waist, thus by a high shoulder-to-hip ratio (SHR) signalling a high level of physical dominance (e.g., Franzoi & Herzog, 1987; Horvath, 1979). There is indeed medical evidence that the shoulder-pelvic ratio correlates positively with beta-lipoproteins, hormones that are related to testosterone levels and muscle development in men (e.g., Evans, 1972). In line with these notions, a study by Dijkstra and Buunk (2001) among undergraduate students showed that while rivals with a low as opposed to a high waist-to-hip ratio (WHR) evoked more jealousy in women than in men, rivals with a high as opposed to a low shoulder-to-hip ratio (SHR) evoked more jealousy in men than in women, particularly when the rival had a high WHR.
The present study examined the role of WHR and SHR of rivals in evoking jealousy in a sample of adults in various age groups from the general population. There were two reasons to conduct this study. First, students form a very restricted sample with regard to age and educational level, severely limiting the generizability of the findings of Dijkstra and Buunk (2001). Second, and more importantly, according to life history theory, men may follow two important strategies to achieve reproductive success (e.g., Hill & Hurtado, 1996): a strategy of physical dominance or a strategy of eminence (Kemper, 1990). Physical dominance refers to the elevated social rank that is achieved by physical competition, and contributes especially to the mate value of young men who at their peak with regard to health and fitness (Kemper, 1990). In contrast, eminence refers to the elevated rank that is achieved through socially approved accomplishments, which will peak as men get older, whereas their physical dominance will decline. Because men most often will be confronted with rivals of approximately the same age (due to women’s preference for males who are only slightly older than themselves; Kenrick & Keefe, 1992), it was expected that as men get older, a rival’s SHR will play a less important role in evoking jealousy. In contrast, it was expected that a rival’s WHR will continue to evoke jealousy among women as they get older, particularly because, regardless of age, men tend to prefer women who signal health, youth and fertility (e.g., Buunk, Dijkstra, Kenrick, & Warntjes, 2001; Kenrick & Keefe, 1992). We further examined if jealousy evoked by rivals with varying a WHR’s and SHR’s differed depending on one’s own WHR or SHR. Finally, we examined how the WHR and SHR of the rivals affected perceptions of attractiveness, physical dominance, and social dominance.
