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→Body: Added pre-print Lidborg et al. meta-analysis on the link between masculine phenotypical traits and mating success and RS
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<span style="font-size:125%">'''References:'''</span> | <span style="font-size:125%">'''References:'''</span> | ||
* Goldstein RB, Dawson DA, Stinson FS, Ruan WJ, Chou SP, Pickering RP, Grant BF. 2008. ''Antisocial Behavioral Syndromes and Body Mass Index Among Adults in the United States: Results from the National Epidemiologic Survey on Alcohol and Related Conditions.'' Compr Psychiatry. 49(3): 225–237. [[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2730646/ FullText]] | * Goldstein RB, Dawson DA, Stinson FS, Ruan WJ, Chou SP, Pickering RP, Grant BF. 2008. ''Antisocial Behavioral Syndromes and Body Mass Index Among Adults in the United States: Results from the National Epidemiologic Survey on Alcohol and Related Conditions.'' Compr Psychiatry. 49(3): 225–237. [[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2730646/ FullText]] | ||
===Examining 91 studies, bodily masculinity was predictive of men's mating and reproductive success=== | |||
Lidborg et al. conducted a meta-analysis of several studies that examined the effects of various measures of physical masculinity (k = 91, N = 155,348). | |||
The main objective of the meta-analysis was to examine two separate hypotheses about the evolutionary functions of phenotypically masculine traits in men; both in a historical and contemporary context. | |||
The researchers examined the effects of physical masculinity on two (somewhat overlapping) domains; namely, how much these traits benefitted men in either having greater [[reproductive success]] (more offspring), or sexual success, measured by recording participant's self-reported lifetime sexual partner count, copulation frequency, and age at sexual debut, among other things. | |||
Effect sizes of the studies included in the analysis were standardized and measured by Pearson's ''r'', and the outcomes for each of the measures of phenotypical masculinity are reproduced below, in the data section. | |||
Overall, body masculinity, height, Testosterone level, a deeper voice and 2:4D Digit Ratio (the ra, a purported measure of prenatal testosterone exposure, were all significantly predictive of mating success, while facial masculinity was not. | |||
Of the various measures of physical masculinity that were examined, only body masculinity was found to be significantly associated with men's [[reproductive success]]. | |||
<span style="font-size:125%">'''Data:'''</span> | |||
{| class="wikitable" | |||
! colspan="6" style="font-family:serif !important;;" | Correlations between physical masculinity and mating success (bolded indicates significant effect) | |||
|- | |||
| style="font-family:serif !important;;" | Facial masculinity | |||
| style="font-family:serif !important;;" | Body masculinity | |||
| style="font-family:serif !important;;" | Digit ratio | |||
| style="font-family:serif !important;;" | Vocal Pitch | |||
| style="font-family:serif !important;;" | Height | |||
| style="font-family:serif !important;;" | T levels | |||
|- | |||
| style="font-family:serif !important;;" | r = .080 | |||
| style="font-weight:bold; font-family:serif !important;;" | r = .133 | |||
| style="font-weight:bold; font-family:serif !important;;" | r = .034 | |||
| style="font-weight:bold; font-family:serif !important;;" | r = .132 | |||
| style="font-weight:bold; font-family:serif !important;;" | r = .057 | |||
| style="font-weight:bold; font-family:serif !important;;" | r = .097 | |||
|} | |||
{| class="wikitable" | |||
! colspan="6" style="text-align: center; font-family:serif !important;;" | Correlations between physical masculinity and reproductive success (bolded indicates significant effect) | |||
|- | |||
| style="text-align: center; font-family:serif !important;;" | Facial masculinity | |||
| style="text-align: center; font-family:serif !important;;" | Body masculinity | |||
| style="text-align: center; font-family:serif !important;;" | Digit ratio | |||
| style="text-align: center; font-family:serif !important;;" | Vocal Pitch | |||
| style="text-align: center; font-family:serif !important;;" | Height | |||
| style="text-align: center; font-family:serif !important;;" | T levels | |||
|- | |||
| style="text-align: center; font-family:serif !important;;" | r = .072 | |||
| style="text-align: center; font-weight:bold; font-family:serif !important;;" | r = .119 | |||
| style="text-align: center; font-family:serif !important;;" | r = .053 | |||
| style="text-align: center; font-family:serif !important;;" | r = .093 | |||
| style="text-align: center; font-family:serif !important;;" | r = .011 | |||
| style="text-align: center; font-family:serif !important;;" | r = .039 | |||
|} | |||
<span style="font-size:125%">'''Discussion:'''</span> | |||
The two hypotheses the researchers were examining were the idea that masculine features are an honest signal of 'good genes', such as a more robust immune system (similar to the proposed function of a Peacock's ornamented tail and plumage), as they are argued to be costly for the organism to manifest and bear, thus they are claimed to denote and advertise the quality of the organism. This is known as the 'handicap hypothesis'. | |||
The other hypothesis they examined was the male-male intrasexual competition hypothesis. | |||
This argues that physical masculinity is particularly beneficial to men in allowing them to out-compete male rivals for sexual opportunities, resources, and social status. | |||
The fact that bodily masculinity was the only significant predictor of mating success in this dataset implies that the intrasexual competition hypothesis is more valid than the handicap hypothesis, as bodily masculinity was the only trait that was predictive of reproductive success, whereas facial masculinity wasn't associated with either mating or reproductive success. | |||
These two hypotheses overlap somewhat and are not mutually exclusive. One would also expect a 'higher quality' organism to ascend in [[dominance hierarchies]] with greater ease. | |||
However, whether such traits are even indicative of 'good genes' at all is uncertain. In particular, it has been strongly disputed whether facial masculinity is associated with better immune functioning at, with Scott et al. (2013), among others, arguing that the evidence seeming to demonstrate such a link is tenuous and speculative at best. | |||
It is not known whether a curvilinear association with facial masculinity may account for this lack of an effect, i.e., it could be that a 'moderate' level of facial masculinity is ideal in terms of achieving sexual success, and a high level of facial masculinity is detrimental. However, the researchers noted that a small, but significant, effect would be expected in regards to sexual or mating success if this were the case, but such an effect was nonexistent. | |||
While the correlations between masculine features and mating/reproductive success overall were weak, these small correlations could exert a stronger influence over the course of one's lifetime and in large populations, especially when the potential influence of early [[Matthew effect|feedback loops]] on one's lifetime mating or reproductive success are taken into account. | |||
There was also significant heterogeneity of effect sizes across various studies, that is some studies found stronger effects, some negative effects, and some null/weak effects. | |||
<span style="font-size:125%">'''Quotes:'''</span> | |||
* ''The strongest associations with mating outcomes were seen in terms of body masculinity (r= .133, 95% CI: [0.091, 0.176]), voice pitch (r= .132, 95% CI: [0.061, 0.204]), and testosterone levels (r= .097, 95% CI: [0.070, 0.125]); moderation analyses showed that these three effects did not significantly differ from each other (p> .05). Height and 2D:4Dwere also significant predictors of mating success, but showed significantly smaller effect sizes than body, voice or testosterone levels (height: r= .057, CI: [0.027, 0.087]; 2D:4D: r= .034, CI: [0.000, 0.069]). The relationship between facial masculinity and mating success was not significant (r= 0.080, 95% CI: [-0.003, 0.164]).'' | |||
* ''In the second set of analyses, we tested the hypothesis that masculine traits and testosterone levels positively predict reproductive success. As Tables 3 and 4 show, relationships were in the predicted direction,but body masculinity was the only significant predictor (r = .119, 95% CI: [0.058, 0.182).'' | |||
* ''As the only trait in our analysis that is consistently (and most strongly) correlated with fitness outcomes across populations, body masculinity is the only trait we can conclude appears to be under present selection in naturally fertile populations [...] Since traits such as strength and muscularity are associated with formidability, this finding lends support to the male-male competition hypothesis.'' | |||
* ''We suggest that immunocompetence perspectives on masculinity, whilst appealing in many ways, should still be regarded as speculative, and that other perspectives–and other traits–should be the subject of greater attention for researchers studying human mate preferences (Scott IML et al. 2013).'' | |||
<span style="font-size:125%">'''References:'''</span> | |||
* Lidbord LH, Cross CP, Boothroyd LG. 2020. ''Masculinity matters(but mostly if you’re muscular):A meta-analysis of the relationships between sexually dimorphic traits in men and mating/reproductive success''. Preprint copy. [[https://doi.org/10.1101/2020.03.06.980896 Abstract]][[https://www.biorxiv.org/content/10.1101/2020.03.06.980896v1.full.pdf FullText]] | |||
* Scott IML, Clark AP, Boothroyd LG, Penton-Voak IS. 2013. ''Do men’s faces really signal heritable immunocompetence?''. Behavioral Ecology, 24: pp 579–589. [[https://doi.org/10.1093/beheco/ars092 FullText]] | |||
==<span style="font-family:'Linux Libertine, Georgia, Times, serif'; font-size:40px; font-weight: normal;">''Penis''</span>== | ==<span style="font-family:'Linux Libertine, Georgia, Times, serif'; font-size:40px; font-weight: normal;">''Penis''</span>== | ||