انزجار پاتوژن زنان با پیش بینی اولویت برای مردانگی صورت میتواند مختص به سن و طراحی مطالعه باشد

Abstract Facial masculinity in men is thought to be an indicator of good health. Consistent with this idea, previous research has found a positive association between pathogen avoidance (disgust sensitivity) and preference for facial masculinity. However, previous studies are mostly based on young adult participants and targets, using forced-choice preference measures; this begs the question whether the findings generalise to other adult age groups or other preference measures. We address this by conducting three studies assessing facial masculinity preferences of a wider age range of women for a wider age range of male faces. In studies 1 and 2, 447 and 433 women respectively made forced choices between two identical faces that were manipulated on masculinity/femininity. In study 1, face stimuli were manipulated on sexual dimorphism using age-matched templates, while in study 2 young face stimuli were manipulated with older templates and older face stimuli were manipulated using young templates. In the full sample for study 1, no association was found between women's pathogen disgust and masculinity preference, but when limiting the sample to younger women rating younger faces we replicated previous findings of significant association between pathogen disgust and preference for facial masculinity. Results for study 2 found no effect of pathogen disgust sensitivity on facial masculinity preferences regardless of participant and stimuli age. In study 3, the facial masculinity preferences of 386 women were revealed through their attractiveness ratings of natural (unmanipulated) faces. Here, we did not find a significant association of pathogen disgust on facial masculinity preferences, regardless of participant and stimuli age. These results call into question the robustness of the link between women's pathogen avoidance and facial masculinity preference, and raise questions as to why the effect is specific to younger adults and the forced-choice preference measure.

. Introduction Recent research has identified a link between women's pathogen avoidance and stronger preference for facial masculinity in a mate. For instance, DeBruine, Jones, Tybur, Lieberman, and Griskevicius (2010) conducted two studies investigating the link between women's pathogen disgust and their preference for facial masculinity. In study 1, 345 women were shown 20 pairs of the same face; one had been manipulated to be more masculine and the other more feminine. This study utilised a forced-choice preference measure where participants were asked which face they found more attractive. Results were that women higher in pathogen disgust (but not sexual or moral disgust) were more likely to choose the masculinised face as more attractive. In study 2, 74 women were given a choice between two unmanipulated faces that had been pre-chosen based on rated facial masculinity/femininity. Again, it was found that women with high pathogen disgust were more likely to choose the masculine face. This effect appears to persist across several levels of analysis, not only across individuals with differences in pathogen disgust predicting masculinity preference (DeBruine et al., 2010b and Jones et al., 2013), but also across countries with different levels of national health predicting mean levels of masculinity preference for that nation (DeBruine et al., 2010a and Penton-Voak et al., 2004), and in response to pathogen cues (Lee and Zietsch, 2011 and Little et al., 2011). The prominent theory behind these findings is that male facial masculinity is an indicator of good health and that women high in pathogen avoidance are therefore more likely to prefer a facially masculine partner. According to this theory, testosterone is an immunosuppressant and is also required in high levels to develop masculine facial features; as such, only males with good immune functioning are able to support the high levels of testosterone necessary to develop a masculine face. In this way, facial masculinity in men is thought to serve as an honest indicator of good health (Folstad and Karter, 1992 and Zahavi, 1975). Consistent with this theory, facial masculinity has been found to be associated with objective (Gangestad et al., 2010, Rantala et al., 2012, Rhodes et al., 2003 and Thornhill and Gangestad, 2006) and perceived health (Rhodes et al., 2003 and Scott et al., 2008). However, the underlying mechanism for this preference is unclear. Facial masculinity in men may represent heritable genetic quality that improves offspring's fitness; however, this ‘good genes’ theory has recently been questioned (Scott, Clark, Boothroyd, & Penton-Voak, 2013), and recent evidence suggests that the genes increasing male facial masculinity are detrimental to female attractiveness, reinforcing doubt regarding the link between masculinity and good genes (Lee et al., 2014). Alternatively, indicators of good health may instead be preferred for more direct benefits (Scott et al., 2013 and Tybur and Gangestad, 2011). For instance, men with cues to good health may be less likely to succumb to sickness themselves, reducing potential disease transmission to the choosing female. Also, one's ability to acquire resources is hampered while ill, and additional effort/resources are required to nurse a sick individual back to health. We note that it is also possible that facial masculinity may not represent past or current immunocompetence, but may still be associated with good genes or other direct benefits (e.g., facial masculinity may be associated with ability to physically compete intrasexually; (Puts, 2010). However, theory describing the association between pathogen avoidance and masculinity preference relies on facial masculinity being (or once being) associated with some health benefit (either directly or indirectly). Despite several studies finding a link between women's pathogen avoidance and their preference for facial masculinity, the research has some limitations. First, studies supporting this association solely rely on a forced-choice task (i.e., participants are required to choose between two targets that differ on the trait of interest which is more attractive; (DeBruine et al., 2010a, DeBruine et al., 2010b, Jones et al., 2013, Little et al., 2011 and Penton-Voak et al., 2004). Lee et al. (2013), which used a ratings paradigm, found no association between women's pathogen disgust and revealed preference for facial masculinity when 422 women rated realistic dating profiles. This could suggest that the influence of facial masculinity may be limited to the forced-choice study design. Second, research in this area has also focused on young adults and often neglects older individuals. To illustrate this, the range of mean participant age of studies investigating the link between pathogen avoidance and preference for masculinity is 18.6 to 25.3 years (DeBruine et al., 2010a, DeBruine et al., 2010b, Jones et al., 2013, Lee and Zietsch, 2011, Lee et al., 2013, Little et al., 2011 and Penton-Voak et al., 2004). Also, when reported, the age of facial stimuli used to assess masculinity preference is of young adults. Research investigating the link between health and facial masculinity has also been limited to participants in early adulthood or late adolescence (Gangestad et al., 2010, Rantala et al., 2012, Rhodes et al., 2003 and Thornhill and Gangestad, 2006). Such an overrepresentation of young adults is problematic for several reasons: first, it is unclear if facial masculinity remains a cue to health in older men even though facial masculinisation, and hence the purported link with immunocompetence, occurs primarily during adolescence. Although evidence for a link between facial masculinity and health has been drawn only from samples of younger men, it has been implicitly assumed that facial masculinity indicates good health in male faces in general. If this were the case, we would expect that women's pathogen disgust should predict preference for facial masculinity regardless of age of the male. Second, restricting assessment of masculinity preferences to samples of young adults might obscure important evidence regarding the underlying mechanism for preferring facial masculinity. Young adults differ in motivations and priorities in mate preference compared to older individuals; for example, younger women within the reproductive age range may place greater importance on genetic quality compared to older women (Little et al., 2010). Therefore, we may expect a different pattern of results when testing different age groups, which in turn has implications for understanding the underlying mechanisms for preferring facial masculinity. To address these limitations, we conducted three studies investigating the association between women's pathogen disgust and their preference for facial masculinity. In all three studies we include a much wider age of participants and target faces than has been included in previous studies. Studies 1 and 2 used a force-choice design with target faces manipulated on sexual dimorphism. Study 1 manipulated sexual dimorphism using morphological differences between male and female faces that matched the age of the stimuli, while in study 2 younger stimuli were manipulated on sexual dimorphism based on differences between older faces and older stimuli were manipulated based on differences between younger faces. Study 3 revealed preference for facial masculinity through attractiveness ratings (as oppose to using a forced-choice design) in natural (unmanipulated) faces.

0. Results We first analysed the two face sets separately; however, the pattern of results of both sets was fairly similar, so we report here an analysis that combined both face sets (for the results of the analyses where face sets were kept separate, see the Supplementary Materials available on the journal's Website at www.ehbonline.org). In order to combine face sets, stimuli ages from face set 2 were dichotomised to as closely match face set 1 as possible (0 = 18–35 years; 1 = 36–55 years). The intra-class correlation (i.e., the proportion of the total variance that is between-rater variance) for attractiveness rating was .29. For full information on the random effects from the HLM analysis for the combined face sets, see the Supplementary Materials (available on the journal's Website at www.ehbonline.org). The fixed effects from the HLM analysis are reported in Table 4. We found main effects of all predictors; overall, older participants and those with lower pathogen disgust gave higher attractiveness ratings. Younger and more feminine stimuli also received higher attractiveness ratings. Importantly, and contrary to previous work, we did not find an overall significant interaction between pathogen disgust and facial masculinity on attractiveness ratings, and the association was not significantly moderated by either participants' age or stimuli age. Also, contrary to the results from study 1, the relationship between pathogen disgust and preference for facial masculinity remained non-significant when only looking at younger participants' (< 35 years old) ratings of younger stimuli (< 35 years old). Thus, when not using the forced-choice paradigm, we find no evidence for an association between pathogen disgust and preference for facial masculinity regardless of the age of the participants or stimuli. Table 4. HLM (γ) coefficients (with standard errors) and associated t statistics for estimated fixed effects. γ (SE) t (approx. df) p-Value Intercept − .01 (.03) − .23 (382) .820 Pathogen disgust − .14 (.03) − 5.24 (382) < .001⁎⁎⁎ Participant's age .10 (.03) 3.60 (382) .004⁎⁎ Facial masculinity − .03 (.01) − 4.51 (382) < .001⁎⁎⁎ Stimuli age group − .82 (.02) − 39.28 (382) < .001⁎⁎⁎ Participant's age × facial masculinity .004 (.01) .56 (382) .572 Participant's age × stimuli age group .07 (.03) 3.33 (382) .009⁎⁎ Pathogen disgust × participant's age − .06 (.03) − 2.21 (382) .028⁎ Pathogen Disgust × Facial Masculinity .003 (.01) .40 (382) .686 Pathogen disgust × stimuli age group .004 (.02) .22 (382) .823 Facial masculinity × stimuli age group .03 (.01) 2.49 (382) .013⁎ Pathogen disgust × participant's age × facial masculinity .01 (.01) 1.38 (382) .168 Pathogen disgust × participant's age × stimuli age group .000 (.02) .02 (382) .983 Pathogen disgust × facial masculinity × stimuli age group .003 (.01) .30 (382) .767 Participant's age × facial masculinity × stimuli age group − .01 (.01) − 1.26 (382) .206 Pathogen disgust × participant's age × facial masculinity × stimuli age group .01 (.01) .63 (382) .530 ⁎ P < 0.05. ⁎⁎ P < 0.01. ⁎⁎⁎ P < 0.01. Table options There were also three significant two-way interactions; as these are not pertinent to the main hypotheses the nature of these interactions are only described briefly here. First, older participants rated older faces significantly less negatively compared to younger participants. There was also a significant interaction between stimuli age and facial masculinity, such that facial masculinity was not associated with attractiveness in older faces, but was negatively associated with attractiveness in younger faces. Finally, there was a significant interaction between participants' age and pathogen disgust, such that younger participants with high pathogen disgust gave higher attractiveness ratings compared to all older participants, or young participants with low pathogen disgust. This pattern of results is specific to pathogen disgust, and not sexual or moral disgust. Some evidence to suggested perceived masculinity from subjective ratings might measure a different construct to objective structural masculinity (Scott, Pound, Stephen, Clark, & Penton-Voak, 2010). To address this we ran an additional analysis using objectively derived facial masculinity scores from landmark coordinates. Here, we found a significant positive correlation between rated masculinity and objective masculinity in men (r = .38, p < .001). The pattern of results for objective masculinity, pathogen disgust, participant age and stimuli age is the same pattern found with rated masculinity reported above, which suggests that results are not specific to subjectively rated masculinity. For full details of analyses conducted with objective facial masculinity see the Supplementary Materials (available on the journal's Website at www.ehbonline.org).