Four patterns of dark personalities: The troublemaker, the self-absorbed, the manipulator, and the exploiter

Into the heart of darkness: A person-centered exploration of the Dark Triad. Matthew J.W.McLarnon. Personality and Individual Differences, Volume 186, Part A, February 2022, 111354. https://doi.org/10.1016/j.paid.2021.111354

Highlights

• Past person-centered Dark Triad research has mostly found ordered profiles.

• This study uses advanced factor analyses to identify an optimal measurement model.

• Person-centered analyses using optimal factor scores show profiles that are unique.

• Thus, person-centered approaches may be viable for continuing Dark Triad research.

• Future research should, however, use advanced factor models of the Dark Triad.

Abstract: Previous research has sought to leverage person-centered methods (i.e., latent profile analysis; LPA) to examine the Dark Triad, which has aimed to illuminate subgroups of individuals who demonstrate distinct patterns of the Dark Triad variables. However, past research has predominantly concluded that variable-centered analyses may be better suited for the Dark Triad. Yet, other research has described how advanced factor analyses can more comprehensively identify the complex and nuanced multidimensionality and sources of variance underlying the Dark Triad. This study applies these modern factor analysis methods, namely bifactor exploratory structural equation modeling (B-ESEM), which subsequently facilitates the more effective extraction of unique, configurationally-distinct profiles of the Dark Triad. In particular, across two large datasets (n = 13,271 and 1042), results showed evidence for four distinct profiles and highlight relations with several theoretically interesting covariates, thereby providing evidence of construct validity of the Dark Triad profiles. Person-centered approaches may, therefore, be viable for future Dark Triad research. However, it is recommended that factor scores from the B-ESEM, if identified as optimal, be used as input for the person-centered analyses.

Sin good purchases are highly concentrated with 10% of households paying more than 80% of taxes on alcohol and cigarettes; the two most taxed clusters comprise 8% of households, pay 68% of sin taxes, are older, less educated, and lower income

 Who Pays Sin Taxes? Understanding the Overlapping Burdens of Corrective Taxes. Christopher Conlon, Nirupama L. Rao & Yinan Wang. NBER Working Paper 29393, October 2021. https://www.nber.org/papers/w29393

Abstract: We find that sin good purchases are highly concentrated with 10% of households paying more than 80% of taxes on alcohol and cigarettes. Total sin tax burdens are poorly explained by demographics (including income), but are well explained by eight household clusters defined by purchasing patterns. The two most taxed clusters comprise 8% of households, pay 68% of sin taxes, are older, less educated, and lower income. Taxes on sugary beverages broaden the tax base but add to the burdens of heavily taxed households. Efforts to increase sin taxes should consider the heavy burdens borne by few households. 

Men with larger neck musculature are rated as stronger, more masculine, and higher in fighting ability and short-term attractiveness

Caton, Neil R., and David M. G. Lewis. 2021. “Intersexual and Intrasexual Selection for Neck Musculature in Men: Attractiveness, Dominance, and Actual Fighting Success.” PsyArXiv. November 3. doi:10.31234/osf.io/yez3t.   

Abstract: Countless organisms are equipped with physiological armor that reduce damage from opponents. Because humans have sustained a long evolutionary history of hand-to-hand combat, selection would have been placed on morphological structures which reduce rotational acceleration to the head and increase the likelihood of victory. Grounded in over 60 years of sports performance theory and recent theoretical work in evolutionary biology, geometric morphometric analyses revealed that larger neck musculature in professional combatants (N = 715) was associated with greater real-world fighting success, after for adjusting for allometry (Study 1). Because sexual dimorphism emerges from selection on morphological structures that improve men’s fighting success, we then discovered that the human neck is the most sexually dimorphic feature of human anatomy when compared to 91 other anatomical features (N = 6,068; Study 2). This male-biased sexual dimorphism held after controlling for these 91 allometric measurements, and held across every world region (Africa, Asia, Europe, Oceania, and North, Central, and South America). Because human psychological systems consequently evolved to attend to men’s secondary sexual characteristics, we discovered that men (N = 564 stimuli) with larger neck musculature (Study 3: geometric morphometrics; Study 4: physiological neck strength; Study 5: photorealistic stimuli) are rated (N = 772 raters) as stronger, more masculine, and higher in fighting ability and short-term attractiveness, after accounting for allometry. Combined, our research introduced a new secondary sexual characteristic to the biological, anthropological, and psychological sciences: the human neck.

Despite chimpanzee mothers continuing to care for and transport dead infants for days, weeks, or even longer, chimpanzees find the smell of decaying corpses aversive

Putrescine-- a chemical cue of death—is aversive to chimpanzees. James R. Anderson, Hanling Yeow, Satoshi Hirata. Behavioural Processes, November 3 2021, 104538. https://doi.org/10.1016/j.beproc.2021.104538

Highlights

• In chimpanzees and other primates, mothers often carry their dead infants.

• It is unclear whether chimpanzees find the smell from decaying corpses aversive.

• We presented chimpanzees with a dead bird, a glove, and putrescine, ammonia, or water.

• Chimpanzees showed most avoidance in the putrescine condition.

• The odour of putrescine—associated with decaying corpses—is aversive to chimpanzees.

Abstract: As in many other species of nonhuman primates, chimpanzee mothers with a dead infant may continue to care for and transport the infant for days, weeks, or even longer. The bereaved females do this despite what humans perceive as the foul odour from the putrefying corpse. Putrescine is a major contributor to the “smell of death,” and it elicits behaviours aimed at getting rid of the source of the smell, or escape responses in mammals including humans. However, it has never been shown that the odour of putrescine is aversive to chimpanzees. To address this question, we visually presented six adult chimpanzees with the corpse of a small bird, or a stuffed glove, in association with putrescine, ammonia, or water, and recorded the chimpanzees’ reactions. The apes spent significantly less time near the object when it was paired with putrescine than the other substances, although they showed no signs of increased arousal or anxiety. We interpret the findings as evidence of an aversion to the smell of death in chimpanzees, discuss the implications for understanding the continued maternal-like behaviour of bereaved female chimpanzees, and suggest future research directions for the field of comparative evolutionary thanatology.

Keywords: death, mother-infant bond, olfactionPan troglodtyesthanatology

Whereas conscientiousness was more strongly associated with academic than job performance, extraversion & neuroticism were less strongly associated with academic performance

Big five personality traits and performance: A quantitative synthesis of 50+ meta-analyses. Ethan Zell,Tara L. Lesick. Journal of Personality, October 23 2021. https://doi.org/10.1111/jopy.12683

Abstract

Objective: The connection between personality traits and performance has fascinated scholars in a variety of disciplines for over a century. The present research synthesizes results from 54 meta-analyses (k = 2028, N = 554,778) to examine the association of Big Five traits with overall performance.

Method: Quantitative aggregation procedures were used to assess the association of Big Five traits with performance, both overall and in specific performance categories.

Results: Whereas conscientiousness yielded the strongest effect (ρ = 0.19), the remaining Big Five traits yielded comparable effects (ρ = 0.10, 0.10, −0.12, and 0.13 for extraversion, agreeableness, neuroticism, and openness). These associations varied dramatically by performance category. Whereas conscientiousness was more strongly associated with academic than job performance (0.28 vs 0.20), extraversion (−0.01 vs 0.14) and neuroticism (−0.03 vs −0.15) were less strongly associated with academic performance. Finally, associations of personality with specific performance outcomes largely replicated across independent meta-analyses.

Conclusions: Our comprehensive synthesis demonstrates that Big Five traits have robust associations with performance and documents how these associations fluctuate across personality and performance dimensions.

Sexual desire functions as a mechanism encouraging investment in partners who are perceived to be worth pursuing and retaining

Sexual Desire Mediates the Relationship-Promoting Effects of Perceived Partner Mate Value. Gurit E. Birnbaum, Yaniv Kanat-Maymon, Erica B. Slotter & Laura B. Luchies. Archives of Sexual Behavior, Nov 2 2021. https://link.springer.com/article/10.1007/s10508-021-02060-2

Abstract: Although sexual desire for one's partner is theorized to serve as a gut-level indicator of partner mate value that motivates investment in valued partners, there is scant empirical evidence to support this hypothesis. Five studies addressed this possibility, examining whether experiencing sexual desire encouraged the enactment of relationship-promoting behaviors and whether perceptions of partner mate value motivated this proposed process. In a pilot study and Study 1, participants relived an activity they experienced with their partner, which was either sexual or non-sexual. Then, participants rated their desire to engage in sex and other non-sexual relationship-promoting activities with their partner (pilot study) and their partner's responsiveness to personal disclosures. Participants’ enacted responsiveness was also evaluated by judges (Study 1). Results showed that experiences of desire enhanced relationship-promoting tendencies. Using experimental, daily experiences, and longitudinal methods, Studies 2–4 extended these findings, indicating that both manipulated and perceived partner mate value predicted desire, which, in turn, was associated with engagement in relationship-promoting behaviors. These findings demonstrate that sexual desire functions as a mechanism encouraging investment in partners who are perceived to be worth pursuing and retaining.

Blacks and Hispanics are significantly less likely than whites to describe themselves as “anti-racist,” and only the “very liberal” are more likely than other political orientations to identify with the label

Who Identifies as Anti-Racist? Racial Identity, Color-Blindness, and Generic Liberalism. Samuel L. Perry, Kenneth E. Frantz, Joshua B. Grubbs. Socius, November 2, 2021. https://doi.org/10.1177/23780231211052945

Abstract: Although decades old, the terms “anti-racism/antiracism” and “anti-racist/antiracist” have grown in usage by scholars, authors, and activists to convey the necessity of active opposition to racial injustice. But as the terms have become more mainstream, researchers have yet to examine the social and ideological correlates of actually describing oneself as “anti-racist.” Drawing on nationally representative survey data fielded at the height of national interest in “antiracist/anti-racist” language, the authors find that Blacks and Hispanics are significantly less likely than whites to describe themselves as “anti-racist,” and only the “very liberal” are more likely than other political orientations to identify with the label. Considering ideological correlates, progressive racial ideology is the strongest predictor of identifying as “anti-racist.” However, the second strongest correlate is describing oneself as “color-blind.” Analyses of quadratic terms suggests that this correlation is curvilinear for nonwhites but more linear for whites. Although originally conveying more radical and subversive ideals, those currently most likely to self-describe as “anti-racist” are white progressives with what we call “generically liberal” racial views.

Keywords: antiracist, antiracism, whiteness, color-blindness, liberals

Discussion and Conclusions

Although the past decade has witnessed a traceable explosion of interest in “anti-racism/antiracism” or “anti-racist/antiracist” language coinciding with the proliferation of anti-racist books, campaigns, and curricula, social scientists had yet to examine the social and ideological correlates and antecedents of actually identifying with the label “anti-racist.” Using nationally representative data fielded at the height of interest in anti-racist/anti-racism terms, we find that whites are the group most likely to identify with the label, as opposed to Blacks or Hispanics. Moreover, only the “very liberal” were more likely than other Americans to identify with the term. But although progressive racial views are strongly associated with self-describing as “anti-racist,” among the strongest predictors was also identifying as “‘colorblind’ when it comes to race.” In fact, color-blindness was an even stronger predictor of identifying as “anti-racist” than willingness to confront a racist friend or a rejection of old-fashioned racism. When we analyzed nonlinearity with quadratic terms, we found that the association between color-blindness and identifying as “anti-racist” was curvilinear for nonwhites (those who strongly reject or strongly affirm color-blindness are more likely to self-describe as “anti-racist”) yet still largely linear and positive for whites. Our findings thus paint a picture of progressive whites (not minorities) self-describing as “anti-racist,” particularly those characterized by a more “generic liberalism” on racial issues (i.e., a liberalism that affirms any racial attitudes that seem liberal, rather than explicitly race critical or radical).

Findings from this study extend our understanding of the current racial landscape in the United States in several key ways. First, they fill an important gap in showing that as “anti-racism” and “anti-racist” language has proliferated in the past decade (see Figures 1 and 2), there is evidence that white Americans (the targets of anti-racist books, campaigns, and curricula) are indeed the ones heeding the call. However, there is less evidence that such efforts are either influencing critically engaged whites or attracting them. Rather the whites who self-describe as “anti-racist” may be more likely to self-identify as “very liberal,” but their liberalism is of a more generic variety. They support progressive racial policies (on surveys), oppose old-fashioned racism, and would confront a friend who told a racist joke. Yet they are also strongly more likely than other Americans to identify with color-blindness, suggesting that such Americans, characterized by what we call “generic liberalism,” simply affirm any views that sound racially progressive. Although color-blindness is most often contrasted with anti-racist ideals and praxis as antagonists (e.g., Bonilla-Silva 2018; Mueller 2020), white Americans who affirm an “anti-racist” identity may simply see color-blindness as an ideal they wish to affirm rather than a construct that critical race or whiteness scholars identify as problematic and insufficient to address racial injustice.

Another key finding that became apparent when trends were plotted out is that Americans on the whole—even those who rejected progressive racial views, would not confront a racist friend, or held old-fashioned racist views—would describe themselves as “anti-racist.” Perhaps even more than the connection with color-blindness, this suggests that most Americans, even those who hold racist views, want to reject identification with overt racism or explicit racists. Thus, the term “anti-racist” may ultimately lend itself to being co-opted by whites who simply wish to maintain a view of themselves as decent people. To be sure, it may be possible that respondents were reading “anti-racist” as simply someone who is against racism. (In that case, who would not be against racists or racism in general?) Yet the fact that Black and Hispanic respondents, who would almost certainly be against racists or racism, were less likely than whites to describe themselves as “anti-racist” suggests that the terminology did in fact resonate in ways that we would predict if respondents were somewhat aware of how the language has been deployed in popular culture, books, campaigns, and curricula.

Unlike Croll’s (2007) analysis, which demonstrated that white racial identity was associated with more conservative and more progressive racial attitudes in a U-shaped fashion, we found that nonwhites who either strongly rejected or strongly affirmed color-blind identity were more likely to identify as “anti-racist.” This pattern suggests that the survey is capturing different ways of relating to “anti-racist” identity for nonwhites. There are some who fully embrace the more race-critical and subversive implications of anti-racist identity and thus reject color-blindness as insufficient and antithetical to racial justice. And there are others who (like whites) affirm color-blindness as they also affirm anti-racist identity, reflecting a more generically liberal interpretation of the latter. Future studies should further explore this dynamic with large enough sample sizes of nonwhites to sufficiently disaggregate racial categories to discern different patterns for Blacks, Hispanics, Asians, and perhaps other nonwhite racial groups as well.

On the topic of future studies, several limitations of this study are worth addressing to chart a path for future research. First, as acknowledged earlier, concepts such as “anti-racist” and “color-blind” can be vague depending on each respondent’s level of familiarity with thinking and literature on racial issues. Future studies would ideally incorporate qualitative interview data that would allow research participants to unpack such concepts in their own words and analyze patterns of meaning both within and across racial and ethnic groups.

Second, though the survey placed “anti-racist” in quotation marks to indicate an identity or label rather than a general disposition (someone who dislikes racists), and authors still frequently use the hyphenated term “anti-racist” (e.g., Jewell 2020; Oluo 2019), Figure 1 shows that the term that has grown the most in usage over the past decade is “antiracist” without the hyphen. This may more aptly convey the idea of a formal identity (see Bonilla-Silva 2018 or Kendi 2019). Future surveys on this topic should thus use the unhyphenated version to test for a difference.

Third, the survey did not ask about respondents’ level of exposure to anti-racist books, campaigns, or curricula where they would learn how the language of “anti-racism” or “color-blindness” is often used in such circles. Although we did take educational attainment into account, future studies would ideally include more pointed measures inquiring about Americans’ relative exposure to race literature.

Finally, one potential limitation has to do with the unique timing of the survey, just before a presidential election and during the coronavirus disease 2019 pandemic. Racial rhetoric and attitudes were already intensified following George Floyd’s murder in May 2020 (Williams 2021), and these tensions could have potentially been exacerbated or uniquely shaped because of a racially polarizing election and collective anxiety over the pandemic, which studies have also shown was interpreted through a racial lens (Perry 2022, Perry et al. 2021). Thus, future studies in years ahead may uncover somewhat different effects simply by the timing.

In this same vein, it is worth speculating about the future of “anti-racist/antiracist” language and identity as the growth of such writing, campaigns, and curricula continues. On one hand, studies have shown that there has been some white backlash to anti-racist movements such as Black Lives Matter since the summer of 2020 (Williams 2021), suggesting that the initial momentum that compelled liberal whites to embrace anti-racist ideals and praxis may have either faded in response to Joe Biden’s election or because even liberal whites began to feel uncomfortable with the slogans of “abolish the police” or “reparations” (Crabtree 2020; Johnson 2020; Pew Research Center 2020). Thus, data that might track identification with anti-racism/antiracism over time might find a peak in 2020, followed by an ebb like we document in Figure 2. Another possibility is that the term “anti-racist/antiracist” simply takes on the color-blind liberalism of white Americans and essentially becomes the same as being “nonracist” (Bonilla-Silva 2018:15). Ultimately, data tracking such trends are necessary to map identification with these terms onto current events over time.

Individuals can purposely change their vocal behaviour in attempt to sound more attractive and to facilitate courtship success; women do better at this

Vocal modulation in human mating and competition. Susan M. Hughes and David A. Puts. Philosophical Transactions of the Royal Society B: Biological Sciences. November 1 2021. https://doi.org/10.1098/rstb.2020.0388

Abstract: The human voice is dynamic, and people modulate their voices across different social interactions. This article presents a review of the literature examining natural vocal modulation in social contexts relevant to human mating and intrasexual competition. Altering acoustic parameters during speech, particularly pitch, in response to mating and competitive contexts can influence social perception and indicate certain qualities of the speaker. For instance, a lowered voice pitch is often used to exert dominance, display status and compete with rivals. Changes in voice can also serve as a salient medium for signalling a person's attraction to another, and there is evidence to support the notion that attraction and/or romantic interest can be distinguished through vocal tones alone. Individuals can purposely change their vocal behaviour in attempt to sound more attractive and to facilitate courtship success. Several findings also point to the effectiveness of vocal change as a mechanism for communicating relationship status. As future studies continue to explore vocal modulation in the arena of human mating, we will gain a better understanding of how and why vocal modulation varies across social contexts and its impact on receiver psychology.

Conscientious individuals were more likely to maintain social distance and less likely to contract COVID-19; Agreeable individuals were more likely to comply with social distancing requirements yet more likely to contract COVID-19

Personality and early susceptibility to COVID-19 in the United Kingdom, Satoshi Kanazawa. Journal of Community & Applied Social Psychology, October 27 2021. https://doi.org/10.1002/casp.2578

Abstract: This paper takes advantage of a unique dataset with a prospectively longitudinal, nationally representative sample (n = 5,178) that began in 1958 and has information on COVID-19 health status in 2020 to examine the effect of Big Five personality traits on compliance with social distancing requirements and contraction of COVID-19. The results show some consistency with epidemiological recommendations (Conscientious individuals were more likely to maintain social distance and less likely to contract COVID-19; men were less likely to comply and more likely to contract) but more inconsistency (Agreeable individuals were more likely to comply with social distancing requirements yet more likely to contract COVID-19; Open and Neurotic individuals were no less likely to comply yet more likely to contract COVID-19). The results highlight the importance of Big Five personality factors for behaviour in the global pandemic and may call into question the universal effectiveness of social distancing requirements for all individuals. However, the small number of confirmed cases of COVID-19 during the early months of the pandemic requires caution in interpretation of the results. 

3 DISCUSSION

To the best of my knowledge, this is the first study to examine the effect of Big Five personality factors on the actual contraction of COVID-19, rather than compliance with various government mandates (social distancing, handwashing, etc.) or attitudes towards COVID-19. It is also the first study of personality and COVID-19 conducted in the United Kingdom. Taking advantage of an ongoing, prospectively longitudinal study with a large, nationally representative sample in the United Kingdom, with information on the respondents for their entire lives (62 years), I examined the association between Big Five personality factors (measured 11 years prior) and compliance with the government mandate on social distancing as well as actual COVID-19 health status and symptoms.

The analyses of the National Child Development Study (NCDS) data replicated earlier findings on the positive effect of Conscientiousness and Agreeableness on compliance (Abdelrahman, in press; Blagov, 2021; de F Carvalho et al., 2020; Götz et al., 2021; Zajenkowski et al., 2020), but did not replicate the earlier findings of a positive effect of Neuroticism (Abdelrahman, in press; Blagov, 2021; Götz et al., 2021) or a negative effect of Extraversion (de F Carvalho et al., 2020; Götz et al., 2021). In fact, Extraversion was the only Big Five factor that was not significantly associated with any of the dependent measures examined here.

Just as any study that uses a longitudinal cohort dataset, sample attrition and selection bias are potential problems in the current study. For example, NCDS respondents who participated in the May 2020 COVID-19 survey were healthier at Sweep 9 in 2013 than those who did not. On self-perceived health (1 = poor, 2 = fair, 3 = average, 4 = good, 5 = excellent), 4.4% of those who participated in the 2020 survey rated themselves “excellent” compared with 3.6% of those who did not, and .9% of those who participated in the 2020 survey rated themselves as “poor” compared with 2.9% of those who did not. The mean self-perceived health was significantly higher among the 2020 participants than non-participants (3.51 vs. 3.16, t = −15.848, p < .001). Thus, it is possible that some of the Sweep 9 participants who did not participate in the COVID-19 survey may have suffered (or even died) from COVID-19. However, this particular problem is not specific to the COVID-19 survey. NCDS respondents who participated in Sweep 9 survey in 2013 were healthier at Sweep 8 in 2009 than those who did not, and the difference was greater in 2013, when there was no global pandemic; 18.4% of those who participated in Sweep 9 rated their health “excellent” compared with 1.0% of those who did not, and the mean self-perceived health was significantly higher among the Sweep 9 participants than non-participants (3.53 vs. 3.16, t = −11.537, p < .001). So non-random sample attrition by health appears to be constant and not specific to the times of global pandemics. However, the fact that the NCDS sample consists entirely of a single age group (age 62 in 2020) may potentially limit the generalizability of my findings to younger or older populations.

Perhaps the most striking finding in the analyses presented above was that many of them were seemingly inconsistent with the public health recommendations from epidemiologists and the legal requirements imposed by the government throughout the world (including the United Kingdom). Citizens in all nations were and still are required to maintain social distance in order to prevent the spread of the coronavirus and reduce the risk of infection. Some of the results above were consistent with this recommendation and requirement. More Conscientious individuals were more likely to comply with the requirement to maintain social distance, and they were less likely to contract COVID-19 and suffer from fewer COVID-19 symptoms. Similarly, men were significantly less likely to comply and significantly more likely to contract (albeit with no more symptoms). In sharp contrast, however, more Agreeable individuals were more likely to comply with social distancing requirements yet at the same time more likely to contract COVID-19 and suffer from a larger number of COVID-19 symptoms. In addition, more Open and more Neurotic individuals were no less likely to comply with the social distancing requirements, yet they were more likely to contract COVID-19 and suffer from a larger number of COVID-19 symptoms. The results suggested that the public health recommendations may not be universally effective for all individuals at all times and may instead need to be tailored for different individuals of varied personality types.

However, the very small number of confirmed cases of COVID-19 in the NCDS data (n = 19; .4%) during the early months of the pandemic in May 2020 (although the total of “confirmed” and “medically advised” cases was much larger; n = 296, 5.7%) requires caution in interpreting the results of the current analyses. More research and attempts at replication are clearly necessary to examine the effect of personality factors on COVID-19 contraction further, particularly in later months of the pandemic, to capture a larger number of confirmed cases in a nationally representative sample. Towards this end, CLS began Wave 2 of the COVID-19 survey in September 2020, and Wave 3 in January 2021.

Compared to heterosexuals, lesbians were more likely to report having sex 0–1 times per month & were less likely to report having sex greater than once per month; the authors reject the label “lesbian bed death”

Debunking Lesbian Bed Death: Using Coarsened Exact Matching to Compare Sexual Practices and Satisfaction of Lesbian and Heterosexual Women. David A. Frederick, Brian Joseph Gillespie, Janet Lever, Vincent Berardi & Justin R. Garcia. Archives of Sexual Behavior, Nov 1 2021. https://link.springer.com/article/10.1007/s10508-021-02096-4

Abstract: The current study examined the prevalence and correlates of over 50 sexual practices in a national survey of heterosexual and lesbian women in relationships. Coarsened exact matching was used to create comparable samples of heterosexual (n = 2510) and lesbian (n = 283) women on six demographic factors, including relationship length. Heterosexual and lesbian women were equally likely to be sexually satisfied (66% heterosexual women vs. 68% lesbian women). Compared to heterosexuals, lesbians were more likely to report having sex 0–1 times per month (11% vs. 23%) and were less likely to report having sex greater than once per month (89% vs. 77%). Among women who had been in relationships for longer than 5 years, heterosexual women were less likely than lesbian women to report having sex 0–1 times per month (15%; 42%). This steeper drop in sexual frequency among lesbian women than heterosexual women has pejoratively been labeled lesbian bed death. Rather than accept the label “lesbian bed death” as characterizing these sexual relationships, we turn our attention to what we call lesbian bed intimacies: the myriad ways that lesbian women incorporate behaviors promoting emotional connection, romance, and mood setting, as well as relying on a wide variety of specific sexual acts (e.g., use of sex toys) and sexual communication. Compared to heterosexual women, lesbian women were more likely to usually to always receive oral sex during sex in the past month (28%; 47%) and to use sex toys in the past year (40%; 62%). In their last sexual encounter, lesbian women were more likely to say “I love you” (67%; 80%), have sex longer than 30 min (48%; 72%), and engage in gentle kissing (80%; 92%). These intimacies likely help explain why sexual satisfaction was similar in these groups despite notable differences in sexual frequency.

Shorter height and long-bone growth in the arms and legs were more evident among sao praphet song—who are both sexually oriented towards men and markedly feminine

An anthropometric study of sexual orientation and gender identity in Thailand. Malvina N. Skorska, Lindsay A. Coome, Diana E. Peragine, Madison Aitken & Doug P. VanderLaan. Scientific Reports volume 11, Article number: 18432. Sep 16 2021. https://www.nature.com/articles/s41598-021-97845-9

Abstract: The biodevelopment of psychological sex differentiation is putatively reflected in several anthropometrics. We examined eight anthropometrics in 1404 Thai participants varying in sex, sexual orientation, and gender identity/expression: heterosexual men and women, gay men, lesbian women, bisexual women, sao praphet song (transgender birth-assigned males), toms (transgender birth-assigned females), and dees (birth-assigned females attracted to toms). Exploratory factor analyses indicated the biomarkers should be analyzed independently. Using regressions, in birth-assigned males, less male-typical second-to-fourth digit ratios in the left hand were associated with sexual orientation towards men regardless of gender identity/expression, whereas shorter height and long-bone growth in the arms and legs were more evident among sao praphet song—who are both sexually oriented towards men and markedly feminine. In birth-assigned females, there were no clear sexual orientation effects, but there were possible gender-related effects. Groups of individuals who tend to be more masculine (i.e., toms, lesbians) showed more male-typical patterns on weight and leg length than some groups of individuals who tend to be less masculine (i.e., heterosexual women, dees). Thus, it appears the various anthropometrics inform separate biodevelopmental processes that differentially relate to sexual orientation and gender identity/expression depending on the measure in question as well as birth-assigned sex.

Discussion

This study examined a comprehensive set of putative anthropometric biomarkers of brain and behavioral sex differentiation in the largest and most diverse sample to date. Using EFA, the several biomarkers previously independently associated with sexual orientation and/or gender identity/expression were reduced to three factors: body size (i.e., height, leg length, arm length, and weight had the highest loadings), hand ratio (i.e., right and left hand width-to-length ratios had the highest loadings), and digit ratio (i.e., left and right 2D:4D had the highest loadings). However, we were not able to demonstrate that these factors were invariant across groups, indicating that the manner in which these biomarkers relate to one another varies in relation to sex, sexual orientation, and gender identity/expression. Further, contrary to the possibility that the sex difference in 2D:4D reflects allometry38,39, lower 2D:4D among individuals assigned male at birth than those assigned female at birth was not associated with greater physical size with respect to the average length of the second and fourth digits, hand length, or height. Based on these observations, one cannot conclude that the various biomarkers examined here reflect some latent biodevelopmental process(es) influencing sex differentiation. Instead, the present analysis suggests they may each provide unique insights. Thus, examining individual biomarkers should be considered as a tenable approach when investigating their associations with traits such as sex, sexual orientation, and gender identity/expression.

Importantly, heterosexual sex differences were found for each of the individual biomarkers. Consistent with prior research in the West12,30,34,49, compared with heterosexual women, heterosexual men were taller, heavier, had longer arms and legs, had wider hands, and lower 2D:4D than heterosexual women. Thus, we were able to confirm that these biomarkers were sex-differentiated as expected among Thais, suggesting they may be useful to study in relation to sexual orientation and gender identity/expression in this population. Within-sex differences, where found, were generally consistent with the notion that developmental processes underlying the biomarkers are associated with sexual orientation and/or gender identity/expression—although the patterns of group differences varied by biomarker and by birth-assigned sex.

Among individuals assigned male at birth, height, the long bones, weight, and left 2D:4D were associated with group differences. Specifically, heterosexual men were taller and had longer arms and legs than sao praphet song. These differences could reflect differential androgenic effects on long bone growth at the prenatal and/or pubertal window(s) of development. Long bone growth is influenced in part by androgens acting on androgen receptors, and epiphysial closure is influenced by estrogens50,51. Sex differences in these biomarkers generally appear during puberty, with surges in androgens influencing their development during prenatal and pubertal development17. Social factors (e.g., stress, nutrition, social roles) have also been related to the development of these biomarkers17,18,19,36. Processes such as these that are tied to height and the growth of long bones within the prenatal and pubertal windows may, therefore, be implicated in these group differences. Gay men were intermediate relative to heterosexual men and sao praphet song on these measures but did not differ significantly from either group. This pattern could reflect a “dosage” effect, but such an interpretation is tentative in the absence of significant group differences. In any case, it appears that differences from heterosexual men in height and long bone growth are more evident among the androphilic birth-assigned males who are more markedly feminine in their gender expression (i.e., sao praphet song) in the current sample. In this respect, our findings parallel those of prior Western research suggesting smaller body size among androphilic birth-assigned males who are more feminine25,41. Our findings, however, do not align with other Western research that has found that gay men were shorter than heterosexual men20,21,22,24, although degree of femininity was not assessed in these samples.

Regarding weight, gay men weighed less than heterosexual men, supporting some previous studies in the West24,30. Furthermore, sao praphet song weighed marginally less than heterosexual men (p = 0.051, see Table S16), which aligns with the shorter stature of sao praphet song relative to heterosexual men, and providing some support for one Western study of transgender same-sex attracted birth-assigned males25. Gay men did not show significant skeletal differences (i.e., height, long bone growth) but nevertheless weighed less than heterosexual men, suggesting that this group difference likely resulted from differences in muscle and fat mass. Indeed, compared with heterosexual men, gay men are more likely to use diet pills, diet, purge, fast to lose weight, be dissatisfied with their appearance, and experience eating disorders52,53,54. However, the extent to which such tendencies also apply to gay men in Thailand is not known, and so this interpretation should be considered speculative.

We also found that, compared with heterosexual men, left 2D:4D was significantly greater among both gay men and sao praphet song, who did not differ significantly from one another. Digit ratio is argued to develop mostly under the influence of prenatal androgen exposure, given fetal 2D:4D sex differences55, but also via some genetic influence56, with no evidence indicating sociocultural influences10. The pattern of group differences suggests these biodevelopmental processes are linked to a sexual orientation effect whereby androphilia in birth-assigned males is associated with more female-typical digit ratio, regardless of whether gender expression is relatively feminine. As such, this pattern runs contrary to a recent study that reported digit ratio was more female-typical among gay men who expressed feminine gender role behavior57. Further, meta-analyses have suggested digit ratio is more female-typical (vs. heterosexual men) among trans women16, but not gay men12 (but see findings with an adolescent sample58). Given the discrepant findings, it will be important for future research to continue to examine digit ratio in relation to both sexual orientation and gender identity/expression.

Of note, the present study found group differences for left, but not right, 2D:4D. Prior research similarly found sex assigned at birth and sexual orientation digit ratio differences are more apparent in one hand than the other (i.e., either non-existent or smaller in effect size in one hand); however, effects have typically been more apparent on the right, not left, hand2,12,58,59. An exception is a Japanese study of digit ratio that reported a male sexual orientation difference on the left, but not right, hand60. Thus, although we did not find associations between digit ratio and male sexual orientation in both hands, such effects are commonly found in only one hand, or are found to be stronger in one hand, and the group differences observed in left, but not right, 2D:4D among individuals assigned male at birth in the current study are consistent with research in another Asian population. Reasons why this might be the case for certain populations requires further research.

Regarding hand ratios, we did not find any group differences among heterosexual men, gay men, and sao praphet song. As such, our findings did not replicate those of an earlier study that reported lower hand width-to-length ratios among gay, compared with heterosexual, men30. Of the anthropometrics that have been studied in relation to male sexual orientation, hand ratios have been examined seldomly, and to our knowledge have not been examined in relation to gender identity/expression. Further research is needed to determine whether hand ratios are likely to be informative of biodevelopmental processes influencing male sexual orientation and/or gender identity/expression.

Among individuals assigned female at birth, group differences on the various biomarkers did not correspond to differences in androphilic vs. gynephilic sexual orientation but instead tended to correspond to gender-related differences. Toms, who are more masculine-presenting than the other birth-assigned female participants, were heavier than heterosexual women, lesbians, and dees, who are all more feminine-presenting. There is some research suggesting that more masculine (butch) lesbians have greater circulating testosterone levels, higher waist-to-hip ratios, more masculine digit ratios, and greater recalled childhood gender-nonconforming behavior than more feminine (femme) lesbians and heterosexual women2,61,62. Thus, the weight result may support some role of androgens in the development of tom identity, although there was no support for a dosage effect and interpretative caution is warranted given the only difference in 2D:4D is opposite to what would be expected (see below).

We also found that toms and lesbians had longer legs than dees. Despite these group differences in leg length, there were no differences among the birth-assigned female groups in height, corroborating most previous findings suggesting no relationship between height and sexual orientation in females20,21,22, cf.23 and suggesting leg length may be the more relevant proxy to consider among females (also see30). The leg length pattern observed here might reflect that more male-typical leg length has a biodevelopmental association with attraction to feminine partners (as displayed by toms and lesbians) vs. masculine partners (as displayed by dees). That said, if such were the case, one would expect heterosexual women to show shorter legs as well given they are, relatively speaking, attracted to masculine men. Alternatively, these leg length differences may be related to gender role expression. In Thailand, the gender role behavior of toms and lesbians appears to be relatively more masculine than that of heterosexual women and dees, and dees are less masculine than heterosexual women48. Thus, group differences in degree of masculine gender role expression might account for why only dees and not heterosexual women had shorter leg length than toms and lesbians.

There were also some unexpected group differences among individuals assigned female at birth. First, contrary to the prediction that more masculine groups would show lower 2D:4D, toms had higher left 2D:4D than lesbian women. That said, lack of support for our prediction is not necessarily out of step with other literature given recent meta-analytic findings suggesting no differences in 2D:4D between heterosexual women and trans men16. As such, processes contributing to digit ratio might not be related to the development of masculine identity among individuals assigned female at birth. Second, heterosexual women had lower (more feminine) right-hand width-to-length ratios than dees. Hand development is thought to be influenced by androgens modulating specific homeobox genes63, with some evidence also pointing to hand use during childhood26,64. Given dees were the only group of female gynephiles who had more masculine right-hand ratios than heterosexual women, this finding provided relatively weak evidence of female sexual orientation being influenced by such mechanisms.

Overall, the current pattern of results for individuals assigned female at birth may support some role of elevated androgens in the development of toms and lesbians—although there was no clear support for a dosage effect and interpretative caution is warranted given several null differences from female comparators (e.g., lack of difference with heterosexual women in leg length). In any case, the body of evidence for a biological basis to the development of sexual orientation and gender identity/expression in females cannot be discounted2,65,66 and the present findings suggest that gender-related factors should continue to be assessed in biomarker studies of sexual orientation and gender identity/expression in individuals assigned female at birth. Moreover, further research examining cross-cultural (in)consistencies in biomarker expression patterns among birth-assigned females is needed. Given previous suggestions that sexual orientation and gender identity/expression are more fluid and/or influenced by sociocultural factors among birth-assigned females than males45,67,68,69, one might expect more inconsistency in biomarker patterns across populations among the former. In other words, there are potentially more factors beyond biological mechanisms of sex differentiation contributing to female, compared with male, sexuality and gender identity/expression. If so, among female groups within particular populations, these alternative factors may to some extent obscure group differences related to biological mechanisms.

Limitations

Biomarkers provide an indirect assessment of the mechanisms purported to influence sex differentiation of the brain and behavior, including sexual orientation and gender identity/expression. Future research examining how these biomarkers relate to brain sex differences or, where possible, longitudinal studies that measure these mechanisms directly and link them to later behavioral outcomes would be valuable. Previous studies have shown measurement of 2D:4D and sex differences in 2D:4D to be impacted by indirect (e.g., photocopies) versus direct measurement70,71. Given we employed a direct method of measurement, group differences may be impacted in future replications of this work. Also, an EFA approach to studying a comprehensive set of biomarkers in both sexes and in relation to both sexual orientation and gender diversity has not been reported in studies of Western samples, making it somewhat difficult to compare the current EFA-based results to previous studies conducted with Western samples. Thus, replication of this approach in a Western sample is an important future direction.

Convenience and non-random sampling, primarily in an urban center, was utilized in the current study, which limits generalizability of our findings to the general Thai population, rural Thailand, or other non-Western cultures. We note, however, that although representative samples would be worthwhile to collect, these tend to suffer from small sample sizes of sexually and gender diverse participants21. Also, although the final sample size was comparatively large for studies in this literature, group sizes were relatively smaller for bisexual women and lesbian women, which might reflect that it is more normative in Thai culture for same-sex attracted females to identify with the categories of dees or toms rather than the more Western-style categories of bisexual and lesbian45. Other groups could not be included due to their small sample size (i.e., bisexual men, transgender men). We were unable to examine biomarkers in sao praphet song primarily attracted to women, or toms primarily attracted to men. These gaps may be due to cultural norms surrounding the gender identification and sexual preferences of third/nonbinary gender individuals within Thai society45. More targeted approaches to recruiting may facilitate broader and larger samples in which such groups are represented and would benefit the aim of disentangling sexual orientation from gender identity.