Sniffing the human body volatile hexadecanal blocks aggression in men but triggers aggression in women; our results imply that sniffing babies may increase aggression in mothers but decrease aggression in fathers

Sniffing the human body volatile hexadecanal blocks aggression in men but triggers aggression in women. Eva Mishor et al. Science Advances, Vol 7, Issue 47. Nov 19 2021. DOI: 10.1126/sciadv.abg1530

Abstract: In terrestrial mammals, body volatiles can effectively trigger or block conspecific aggression. Here, we tested whether hexadecanal (HEX), a human body volatile implicated as a mammalian-wide social chemosignal, affects human aggression. Using validated behavioral paradigms, we observed a marked dissociation: Sniffing HEX blocked aggression in men but triggered aggression in women. Next, using functional brain imaging, we uncovered a pattern of brain activity mirroring behavior: In both men and women, HEX increased activity in the left angular gyrus, an area implicated in perception of social cues. HEX then modulated functional connectivity between the angular gyrus and a brain network implicated in social appraisal (temporal pole) and aggressive execution (amygdala and orbitofrontal cortex) in a sex-dependent manner consistent with behavior: increasing connectivity in men but decreasing connectivity in women. These findings implicate sex-specific social chemosignaling at the mechanistic heart of human aggressive behavior.

Discussion

Impulsive aggression is a major factor in the human condition, yet how exactly aggression is triggered or blocked in the human brain remains unclear (11, 12). Moreover, real-world human impulsive aggression is one of the most sexually dimorphic behaviors (40), yet what brain mechanisms underlie this dimorphism also remains unclear (12). In animals ranging from insects to rodents, aggression is sexually dimorphic at levels ranging from genes to cells, and this dimorphism in aggression has been linked to dimorphism in the olfactory system (41). Here, we find the same in humans. We observed that sniffing a body volatile, namely, HEX, significantly decreased aggression in men yet significantly increased aggression in women. In both men and women, HEX increased brain activity in the AG, a cross-modal integrating hub involved in social cognition (42). In other words, in humans, like in rodents, a “social odor” activates the “social brain.” Moreover, HEX modulated functional connectivity between these substrates of social appraisal (AG) and a network previously associated with aggression. This included modulation of functional connectivity with the temporal pole (TP), an area similarly implicated in social appraisal (43) and aggression (44), and modulation of functional connectivity with the amygdala and OFC, namely, substrates implicated in aggressive execution (10, 12). All this modulation occurred in a sex-dependent manner consistent with behavior: HEX increased connectivity in men but decreased it in women. Thus, HEX may lead to increased or decreased aggression through increased or decreased control by the AG over the amygdala through a circuit involving the TP and OFC. This modulation of social behavior through modulation of functional brain connectivity was similarly observed following intranasal administration of oxytocin, which reduced OFC connectivity with the amygdala, and in this may have reduced negative emotional arousal (45). This further points to what may be considered a physiological counterpart of this brain mechanism: As stress increases, men become more aggressive and women become less aggressive (46). As stress decreases, men become less aggressive and women become more aggressive (47). In this manner, a non–sex-specific effect of HEX on the stress response (always reducing stress) may evolve into a sex-specific effect of HEX on aggression (increased aggression in women yet decreased aggression in men).

The above detailed neuroanatomy and mechanism may underlie a direct circuit from reception to action without the mediation of conscious perception. This echoes rodent circuitry, where OR37B projections bypass the olfactory cortex and connect directly to the paraventricular nucleus of the hypothalamus, where HEX reduces activity in corticotrophin-releasing cells, thus reducing activation of the hypothalamus-pituitary-adrenal axis (16). Although we cannot trace connectivity of a single olfactory receptor subtype in humans, it is tempting to liken the downstream activation in the absence of olfactory cortex activation we observed in response to HEX to the circuit detailed in rodents.

The sex dimorphism in our behavioral and brain results dovetails with previous findings obtained using functional brain imaging (48) and EEG (15) to depict a level of functional brain sex dimorphism in response to social odors that is not matched by any other sensory stimulus that we are aware of. Human functional brain responses to basic auditory and visual cues are generally nondissociable by sex (49), yet here, we could use them alone to discriminate men from women at 79.6% accuracy. This begs the question: what behavioral setting could underlie selection for a body volatile that increases aggression in women but decreases it in men? Or in other words, what could be the ecological relevance of these results? In this respect, we call attention to the setting of infant rearing. Parents across cultures are encouraged to sniff their babies (50), an action that activates brain reward circuits in women (51). Our results imply that sniffing babies may increase aggression in mothers but decrease aggression in fathers. Whereas maternal aggression has a direct positive impact on offspring survival in the animal world (52), paternal aggression has a negative impact on offspring survival (53). This is because maternal aggression (also termed maternal defense behavior) is typically directed at intruders, yet paternal aggression, and more so nonpaternal male aggression, is often directed at the offspring themselves (54, 55). If babies had a mechanism at their disposal that increased aggression in women but decreased it in men, this would likely increase their survival. With the hypothesis in mind that HEX provides babies with exactly such a mechanism, we first note that infant rearing is the one social setting where humans have extensive exposure to conspecific feces, a rich source of HEX (22). We also turned to a recently published analysis of baby-head volatiles (56), yet in contrast to our hypothesis, this report did not mention HEX. We turned to the authors of that report, who explained that the published analysis was not tuned to the near semivolatile range of HEX. With our question in mind, they (now coauthors T.U. and M.O.) sampled an additional 19 babies (fig. S10A), using gas chromatography (GC) × GC–mass spectrometry, and observed that HEX is one of the most abundant baby-head volatiles, evident in 17 of the 19 babies (fig. S10, B and C). Moreover, they also searched for the two additional known ligands of OR37, namely, pentadecanal and heptadecanal, and found both, albeit at levels much lower than HEX. Pentadecanal was evident in 15 babies but only at an average peak area of 56% that of HEX, and heptadecanal was evident in 16 babies but only at average peak area of 45.5% that of HEX (HEX greater than pentadecanal and peptadecanal: Kruskal-Wallis χ2 = 7.65, df = 2, P = 0.02) (fig. S10C). This outcome renders our overall ecological hypothesis plausible and retrospectively supports our selection of HEX as a testing target. In summary, babies emit HEX from their head. This is expected to trigger aggression in women but block aggression in men, and both of these impacts are expected to increase baby survival.

Given all the above, should we label HEX as a human pheromone? Sniffing human bodily secretions such as sweat and tears drives assorted behavioral and physiological effects (7, 24), and body odors may reflect assorted emotional states (57), including aggression (13, 14), but the identity of specific molecular components involved in human social chemosignaling has remained elusive (58). Moreover, the current view on human social chemosignals is that, to the extent that they exist, they likely entail alterations in the ratios of components in complex body odor bouquets and not single molecular species (59). Yet, here, we identify one component, namely, HEX, whose effects can be seen as consistent with those of a mammalian pheromone (60). Previously, the steroidal molecules estratetraenol (EST) and androstadienone (AND) had been proposed as human pheromones, yet this labeling was often rejected, primarily because EST and AND do not clearly trigger or block behavior, nor do they have obvious ecological relevance (59, 61). Here, HEX had a pronounced effect on behavior and, moreover, on the behavior of aggression, a domain dominated by pheromonal communication in most mammals (3). The notion of pheromonal communication was once considered dependent on a functional vomeronasal system, a system that humans may not have (62). More recent views, however, blur this distinction and highlight pheromonal communication through the main olfactory system as well (63–65). Given all this, we think that had we presented an equivalent set of results obtained from mice, very few would argue the pheromone label. In turn, if HEX is a human pheromone, is it a cuing pheromone that is emitted consistently by the sender or a signaling pheromone that is emitted only during appropriate behavioral context (61)? Here, we reach at the primary limitation of this study: Although we think of HEX as a signal, we did not measure its emission as a function of behavior. Had we measured HEX emission under different conditions and found that its emission increased under the endurance of aggression, this would have closed the loop of a signaling pheromone. Such an effort, however, was far beyond the scope of the current study and remains the key missing component for labeling HEX a human signaling pheromone.

Beyond this, we would like to acknowledge several additional limitations in this study: First, although we used various control conditions across experiments (eugenol, mineral oil, and blank air), we did not test any other potential OR37 ligands. The rationale for selecting HEX was detailed in Introduction, but future testing of additional potential ligands remains an important question. Second, we do not know whether the concentrations of HEX that we used were physiological. This is because we do not know the concentrations that humans emit (the existing reports are relative), and we do not know the concentration that actually reached our participants using the current paradigms (e.g., experiment 1 sniff-jar versus experiment 2 olfactometer). Third, regarding our imaging results, we reiterate that correlation is not causation. We identify a brain pattern associated with HEX, and it is tempting to suggest that this pattern is responsible for the observed effects, yet this can only be proven by experiments where the brain mechanism is perturbed, experiments that are very difficult to conduct in human participants. Last, we also acknowledge that our suggested ecological relevance in infant rearing was not directly tested in this study. One may note that there are various forms of aggression, and whereas our tasks measured interpersonal aggression, our infant-rearing hypothesis alludes to paternal/maternal aggression. Thus, although we think it is a plausible hypothesis, it remains to be experimentally verified, and here serves only as an example of possible ecological relevance for our results.

Despite the above limitations, we conclude in stating that sniffing the body odor constituent HEX blocks aggression in men but triggers aggression in women. HEX may exert its effects by modulating functional connectivity between the brain substrates of social appraisal and the brain substrates of aggressive execution. This places chemosignaling at the mechanistic heart of human aggression and poses but one added example to the rapidly growing body of evidence implicating social chemosignaling as a major, albeit mostly subconscious, power in human behavior.

Immigration quotas in the 20s targeted “undesirable” nationalities to stem the inflow of low-skilled Eastern and Southern Europeans; this study measure effects in inventions and scientific production

Moser, Petra and San, Shmuel, Immigration, Science, and Invention. Lessons from the Quota Acts (March 21, 2020). SSRN: http://dx.doi.org/10.2139/ssrn.3558718

Abstract: Immigration quotas in the 1920s targeted “undesirable” nationalities to stem the inflow of low-skilled Eastern and Southern Europeans (ESE). Detailed biographical data for 91,638 American scientists reveal a dramatic decline in the arrival of ESE-born scientists after the quotas. Under the quotas, an estimated 1,165 ESE-born scientists were lost to US science. To identify effects on invention, we use k-means clustering to assign scientists to unique fields and then compare changes in patenting by US scientists in the pre-quota fields of ESE-born scientists with changes in other fields where US scientists were active inventors. Baseline estimates imply a 68 percent decline in invention. Decomposing this effect, we find that the quotas reduced both the number of US scientists working in ESE fields and the number of patents per scientist. Firms that employed ESE-born scientists experienced a 53 percent decline in invention. The quotas’ effects on invention persisted into the 1960s.

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Naturalization data indicate a dramatic decline in the arrival of new ESE-born scientists after the quotas. Until 1924, arrivals of new ESE-born immigrant scientists were comparable to arrivals from Northern and Western Europe (WNE), who were subject to comparable pull and push factors of migration.1 After the quotas, arrivals of ESE-born scientists decline significantly while arrivals from Northern and Western Europe continue to increase. Combining data on naturalizations with information on scientists’ university education and career histories, we estimate that 1,165 ESE-born scientists were lost to US science under the quota system. At an annual level, this implies a loss of 38 scientists per year, equivalent to eliminating the entire physics department of a major university each year between 1925 and 1955. For the physical sciences alone, an estimated 553 ESE-born scientists were lost to US science.

To estimate the effects of changes in immigration on US inventions, we compare changes in patenting per year after 1924 in the pre-quota fields of ESE-born US scientists with changes in patenting in other research fields in which US scientists were active inventors before the quotas. This identification strategy allows us to control for changes in invention by US scientists across fields, for example, as a result of changes in research funding. Year fixed effects further control for changes in patenting over time that are shared across fields. Field fixed effects control for variation in the intensity of patenting across fields, e.g., between basic and applied research.

Baseline estimates reveal a large and persistent decline in invention by US scientists in the pre-quota fields of ESE-born scientists. After the quotas, US scientists produced 68 percent fewer additional patents in the pre-quota fields of ESE-born scientists compared with the prequota fields of other US scientists. Time-varying effects show a large decline in invention by US scientists in the 1930s, which persisted into the 1960s. Importantly, these estimates show no preexisting differences in patenting for ESE and other fields before the quotas.

Special case of Paul Erdős:

A case study of co-authorships for the prolific Hungarian-born mathematician Paul Erdős illustrates how restrictions on immigration reduced collaborations between ESE-born scientists and US scientists. Erdős moved to the United States as a post-doctoral fellow at Princeton, and became a professor at Notre Dame, travelling and collaborating with many US scientists. As a Hungarian citizen, however, Erdős was denied a re-entry visa by the US immigration services in1954, and not granted re-entry until 1963. To examine how these denials affected Erdős’ collaborations with US scientists, we collect the location of Erdős top 100 coauthors at the time  of their first collaboration. These data show that Erdős’ collaborations shifted away from the United States when he was denied re-entry. Between 1954 and 1963, 24 percent of Erdős’ new co-authors were US scientists, compared with 60 percent until 1954. These patterns are confirmed in a broader analysis of patents by co-authors and co-authors of co-authors of ESEborn scientists, which indicates a 26 percent decline in invention by scientists who were directly or indirectly influenced by ESE-born scholars. 

These findings cast doubt on claims that a low-tax, low-regulation capitalism will generate extreme capital accumulation, & that persistent wealth equalization requires large shocks to capital coming from wars or progressive taxation

Wealth and History: An Update. Daniel Waldenström. CEPR DP16631, October 2021. cepr.org/active/publications/discussion_papers/dp.php?dpno=16631

Abstract: This paper analyzes new evidence on long-run trends in aggregate wealth accumulation and wealth inequality in Western countries. The new findings suggest that wealth-income ratios were lower before World War I than previously claimed, that wealth concentration fell over the past century and has remained low in Europe but increased in the United States, that wealth has changed from being dominated by elite-owned fortunes to consist mainly of popular wealth, and that capital shares in national income have been relatively stable over time, especially in the postwar era. These findings cast doubt on claims that a low-tax, low-regulation capitalism will generate extreme capital accumulation, and that persistent wealth equalization requires large shocks to capital coming from wars or progressive taxation. Instead, institutions that promote household wealth accumulation from below appear to be key for understanding the long-run evolution of wealth in Western societies.

Keyword(s): capital share, economic history, Wealth Inequality, Wealth-income ratios

JEL(s): D30, E21, N30

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Popular version: Wealth and history: A reappraisal Daniel Waldenström. November 17 2021. https://voxeu.org/article/wealth-and-history-reappraisal#.YZc-lJKvR6E.twitter

Revised historical wealth-income ratios

Figure 1 shows aggregate private wealth-income ratios in six countries for which consistent, long-run evidence is available: France, Germany, Spain, Sweden, the UK, and the US. The series of Piketty and Zucman show wealth-income ratios being historically high in 19th century Europe, around 600–800% of national income, and dramatic drops during the world wars after which they stayed low until the 1980s when they increased substantially.

The revised and new country series for Europe produces a different picture, especially for the pre-WWI period. The new German series has a wealth-income ratio of 500% instead of 600%, and the new UK series shows 450% instead of 700%. For newly added Spain and Sweden, pre-WWI wealth-income ratios are around 450–500% of national income (the series of France and the US have not been re-examined). The main reasons that the revised German and UK series differ from those of Piketty and Zucman is the use of new sources and adjusted computational assumptions (see Waldenström 2021 for further discussion). Looking at the 20th century, the new series present a less volatile trend, with some variation around the world wars but without any lasting trend breaks (except for Germany). The post-1990 increases are observed in both older and newer series.

Male researchers more often value and engage in research mainly aimed at scientific progress, which is more cited; females more often value & engage in research mainly aimed at contributing to societal progress, which has more abstract views (usage)

Gender differences in the aims and impacts of research. Lin Zhang, Gunnar Sivertsen, Huiying Du, Ying Huang & Wolfgang Glänzel. Scientometrics volume 126, pages 8861–8886, Nov 2021. https://link.springer.com/article/10.1007/s11192-021-04171-y

Abstract: This study uses mixed methods—classical citation analysis, altmetric analysis, a survey with researchers as respondents, and text analysis of the abstracts of scientific articles—to investigate gender differences in the aims and impacts of research. We find that male researchers more often value and engage in research mainly aimed at scientific progress, which is more cited. Female researchers more often value and engage in research mainly aimed at contributing to societal progress, which has more abstract views (usage). The gender differences are observed among researchers who work in the same field of research and have the same age and academic position. Our findings have implications for evaluation and funding policies and practices. A critical discussion of how societal engagement versus citation impact is valued, and how funding criteria reflect gender differences, is warranted.

Holding heavily invested political beliefs makes individuals reluctant to update their beliefs in the face of contradictory information; providing ambiguous information caused them to become further divided based on their political ideology

Updating Politicized Beliefs: How Motivated Reasoning Contributes to Polarization. Siyan Su. Journal of Behavioral and Experimental Economics, November 20 2021, 101799. https://doi.org/10.1016/j.socec.2021.101799

Highlights

• This experiment examined the effect of the political significance of information on motivated belief updating

• Holding heavily invested political beliefs makes individuals reluctant to update their beliefs in the face of contradictory information

• Providing subjects with ambiguous information caused them to become further divided based on their political ideology

• Subjects’ biased incorporation of new evidence is consistent with theories of belief-based utility, confirmation bias, and motivated reasoning

Abstract: This paper examines how the political significance of information can affect subjects’ perceived reliability of that information and their motivated belief updating. In this study, 1,222 subjects were randomly assigned to receive low-reliability, high-reliability, or ambiguous information about neutral and political questions. For each question, subjects were first asked to give a numerical estimate. After receiving new information, subjects had the opportunity to update their previous numerical estimates, and then, they reported their perceived reliability of the information they received. I observed that subjects were more reluctant to update their beliefs for politically significant questions compared to neutral questions. I also found that subjects were more likely to discredit and reject new information when it challenged their preexisting ideology, indicating that one's rooted political beliefs can distort the belief updating process. In addition, subjects drew different conclusions from ambiguous information depending on their political ideology, illustrating how ambiguity may lead to greater polarization. Finally, I discuss possible explanations for subjects’ biased integration of new information using motivated reasoning and belief-based utility theories. The results of this study contribute to the understanding of why people remain divided on politically charged issues.

Keywords: belief updatingbelief-based utilitymotivated reasoningconfirmation biasambiguous informationbelief polarization

Social Networks Facilitate Informed Option Trading? Evidence from Alumni Reunion Networks

Cheong, Harvey and Kim, Joon Ho and Münkel, Florian and Spilker III, Harold D., Do Social Networks Facilitate Informed Option Trading? Evidence from Alumni Reunion Networks (February 27, 2021). Journal of Financial and Quantitative Analysis (Forthcoming), https://ssrn.com/abstract=3795685

Abstract: Material private information transmits through social networks. Using manually collected information on networks of alumni reunion cohorts, we show that hedge fund managers connected to directors of firms engaged in merger deals increase call option holdings on target firms before deal announcements. Effects are larger when reunion events for connected cohorts occur just before announcements. Independent directors, directors with short tenure, and directors with low stock ownership are more likely to transmit information. Our results are robust to confounding factors and alternative specifications. These findings highlight the role of social networks as channels of private information dissemination.

Keywords: Informed Trading, Social Networks, Hedge Funds, Mergers & Acquisitions, Options

JEL Classification: D82, G11, G12, G14, G34, L14, Z13

Loosening the definition of culture... An investigation of gender and cultural tightness: We find that American women felt their gender culture is “tighter” than men

Loosening the definition of culture: an investigation of gender and cultural tightness. Alexandra S. Wormley et al. Current Research in Ecological and Social Psychology, November 14 2021, 100021. https://doi.org/10.1016/j.cresp.2021.100021

Highlights

• Cultural tightness has previously been studied at the national or regional level.

• We find that American women felt their gender culture is “tighter” than men.

• This gender difference is mediated by gender related threats, in line with theories about tightness as a way of managing ecological threats

• We find a lack of measurement invariance comparing tightness in men and women in Singapore, pointing to a need for future work refining measurement

Abstract: To date, the study of cultural tightness has been largely limited to exploring the strictness of social norms and the severity of punishments at the level of nations or regions. However, cultural psychologists concur that humans gather cultural information from more than just their nationality. Gender is a cultural identity that confers its own social norms. Across three studies using multi-method designs, we find that American women feel the culture surrounding their gender is “tighter” than that for men, and that this relationship is mediated by perceived gender-related threats to the self. However, in a follow-up study in Singapore, we do not find measurement invariance, suggesting future work is necessary to refine the study of gender tightness cross-culturally. We close with an important discussion of understanding how tightness looks across a variety of cultural identities and introduce a novel, qualitative method for the study of the tightness of social norms within groups.

Keywords: gendertightness-loosenessculturepsychology

Discussion

Across hundreds of US participants, we found robust evidence for a difference in perceived tightness and looseness across men and women, such that women perceived greater tightness using a modified, 4 item scale and qualitatively reported more gender norms for themselves (Studies 1-2). Further, in line with ideas about tightness functioning to manage threat, we found that gender-specific threats mediated the relationship between gender and tightness (Study 3). This is in line with previous work which has suggested the broader adaptive purpose of cultural tightness is to manage environmental and social threats to the group. However, here we apply this to gender within a given society in a novel way.

We attempted to replicate in a tight country, Singapore. We had thought perhaps national tightness might moderate the relationship between gender and tightness, such that a gender difference might appear in relatively loose cultures (like the US) but not in a culture in which there are very tight norms for everyone (like Singapore). We could not explore these novel questions because of bad model fit and a lack of measurement invariance. Once the measurement is sorted out in future work, we think that will open questions of how individuals, with their many cultural identities, manage competing expectations and prioritize certain parts of their identity (say, national identity) over others (like gender).

Other cultural dimensions may provide insight as to why Singaporean men and women reported similar numbers of norms in an open-ended prompt. Gender egalitarianism which varies by country is (somewhat paradoxically) known to increase gender differences since the equality allows the genders to pursue their different, respective goals (Schwartz & Rubel-Lifschitz, 2009). Singapore is higher than the United States on egalitarianism (Schwartz, 2007), suggesting that we should expect Singapore to have larger differences in gender norms than the United States. An interesting future direction would examine gender and tightness in societies that vary in gender equality and in tightness at the national level; we propose an interesting set of comparisons could be New Zealand (relatively loose, relative gender equality), Ukraine (relatively loose, relative gender inequality), Austria (relatively tight, relative gender equality), and India (relatively tight, relative gender inequality) (Gelfand et al., 2011; Schwartz, 2007). Do women report greater feelings of tightness in unequal societies? Do they report differences in the kinds of norms they must follow in comparison to men?

Additionally, our work presents a new qualitative method for studying cultural tightness. In having participants record social norms, we gain not only a proxy for the cognitive accessibility of social norms in their mind, but the content of these norms. This allows us to further dive into what threats are managed by social norms, revealing a cross-cultural convergence upon the importance of affiliation and appearance-related norms for women especially. Thus, we add yet another measure to the growing number of ways to capture perceptions of social norms and cultural tightness (Mu et al., 2015; Uz, 2015).

Theoretically, the most exciting prospect this line of research offers is the idea that tightness varies across different cultural identities, with identity-related threat as a mediator. What other differences might we then expect? Do African-Americans or other minority ethnic groups report tighter cultural norms than their White counterparts (US Census Bureau, 2019)? Do Jewish people, who have historically faced immense religious persecution (Phillips, 2018), have tighter norms than Christians do? Is a long history of threats needed to shape norm tightness or can tightness be affected by recent current threats to identity (e.g., a wave of hate crimes)? Do transgender individuals, who face four times the amount of violent crime as cisgender ones (Rude, 2021), have tighter in-group norms? Further, since threat influences cultural tightness, might norms be specific to the domain of threat? For example, in an environment where women outnumber men, might men face stricter mating norms (Bleu et al., 2012)?

Beyond replicating in other countries, gender differences in cultural tightness should be investigated from a more representative sample because student participants may not be entirely representative of the population. The consistent evolution of gender norms in developed countries means that generational, and perhaps social class, differences are likely to exist. Further, these studies cannot rule out the fact that women may overperceive norms in comparison to men. Is the observed difference in gender tightness due to a difference in sensitivity to threat or differences in actual threats? There is reason to think it may be beneficial for women to be especially attuned to the social landscape and the rules within it, in the same way they seem attuned to threat (Brebner, 2003; Burani & Nelson, 2020). To rule this out, women could be compared to men in their reporting of norms within other cultural contexts, like the workplace or the nation.

The tightness-looseness continuum represents an exciting trait of cultural groups that lie outside the traditional conception of “culture.” Through a mixed-method design, we establish that while other cultural groups may differ on these traits, special attention must be paid to measurement and the proper application of scales across group types. We leave the reader with two tools for continuing the study of gender and tightness—the GTS and the Gender Norm Perception Task—and further it beyond gender to other cultural identities.

US and activism of sexual minorities: Lesbians and gay men were registered at greater rates than heterosexuals; transgender people were the least likely to be registered to vote, though this may be due to the vote-validation process itself

Voter Registration Rates and Traits by Sexual Orientation and Gender Expression. Dakota Strode, Andrew R Flores. Public Opinion Quarterly, nfab042, November 15 2021. https://doi.org/10.1093/poq/nfab042

Abstract: Studies of lesbian, gay, bisexual, and transgender (LGBT) people suggest that they are more politically engaged and active compared to cisgender and heterosexual people. However, knowing the voter registration rates of eligible LGBT Americans has been elusive because the U.S. Census Bureau does not document sexual orientation or gender identity in the Current Population Survey and existing estimates are limited based on small sample sizes or on self-reports, which have social desirability biases. The 2016 and 2018 Cooperative Congressional Election Survey merges respondents to their official voter status as contained in state voter files, which overcomes biases in self-reported registration status. We provide demographics and estimates of voter registration rates by sexual orientation and gender expression. Many gaps in registration rates are attributable to demographic differences between groups, though lesbians and gay men were registered at greater rates than heterosexuals even after adjusting for demographics. Transgender Americans were the least likely to be registered to vote, though this may be due to the vote-validation process itself.

Personality, intelligence and belief in astrology: Narcissism was surprisingly the strongest predictor, and intelligence showed a negative relationship with belief in astrology

Even the stars think that I am superior: Personality, intelligence and belief in astrology. Ida Andersson, Julia Persson, Petri Kajonius. Personality and Individual Differences, November 20 2021, 111389. https://doi.org/10.1016/j.paid.2021.111389

Abstract: Belief in astrology is on the rise, although the reasons behind this are unclear. We tested whether individual personality traits could predict such epistemically unfounded beliefs. Data was collected for 264 participants through an anonymous online survey shared on social media. The survey consisted of four instruments: Belief in Astrology (BAI), the Big Five personality traits (IPIP-30), narcissism (SD3) and intelligence (ICAR16-R3D). Data analysis was done with multiple linear regression. Narcissism was surprisingly the strongest predictor, and intelligence showed a negative relationship with belief in astrology. Overall, our novel results suggest that something as innocent as astrology could both attract and possibly reinforce individual differences.

Keywords: Belief in astrologyPseudoscienceBig fiveNarcissismIntelligence

4. Discussion

The present study aim was to investigate how individual differences relate to belief in astrology. The main result showed that the higher the narcissism, perhaps surprisingly, the higher the belief in astrology. The positive association is possibly due to the self-centred worldview uniting them, though this must be examined in further research. Furthermore, cultural aspects of millennials may emphasize the uniqueness of individuals which might lead to a more egocentric view of the world, and thus relate to narcissistic traits. Further, since astrological predictions and horoscopes tend to be positively framed, this reinforces grandiose feelings and thus might appeal even more to narcissists. Note that narcissistic traits correlated with the belief that astrology is supported by science (Table 1), which leads to a speculation that narcissists may generally be more fact resistant.

Other interesting findings was that the higher the level of intelligence, the lower the belief in astrology (see Musch & Ehrenberg, 2002), as well as that agreeable people tend to report believing in astrology more. Seeing how most personality predictors were small in magnitude, this leaves room for many other variables influencing belief in astrology. Speculatively, additional predictors could be cohort-effects, educational levels, occupations, and others.

4.1. Limitations

As with most survey designs, social desirability bias, common method bias, and the use of self-report may be an issue. Another limitation was that we had no control over who participated in the study, thus introducing a potential selection bias. In the same vein, we do not know how much participants know about astrology. Also, since the vast majority were younger women recruited through social media the sample is not generalisable to a broader population. Another possible concern in the present study is the use of short versions of the scales, especially Openness which showed a low internal consistency and did not show expected effects in the regression model. One indication of this is that openness and intelligence did not correlate significantly in the present study (see Table 1). Lastly, most of the reported effects were acknowledgeable small (Gignac & Szodorai, 2016), which leaves room for both type I-errors as well as for the influence of other variables, outside individual differences.

Changes in Penile-Vaginal Intercourse Frequency and Sexual Repertoire from 2009 to 2018: Findings from the National Survey of Sexual Health and Behavior

Changes in Penile-Vaginal Intercourse Frequency and Sexual Repertoire from 2009 to 2018: Findings from the National Survey of Sexual Health and Behavior. Debby Herbenick, Molly Rosenberg, Lilian Golzarri-Arroyo, J. Dennis Fortenberry & Tsung-chieh Fu. Archives of Sexual Behavior, Nov 19 2021. https://link.springer.com/article/10.1007/s10508-021-02125-2

Abstract: Solo and partnered sexual behaviors are relevant to health, well-being, and relationships. Recent research shows that sexual frequency has declined in the U.S. and in other countries; however, measurement has been imprecise. We used data from 14- to 49-year-old participants in the 2009 and 2018 waves of the National Survey of Sexual Health and Behavior (NSSHB), a confidential U.S. nationally representative survey that is conducted online. We aimed to: (1) assess changes in frequency of past-year penile-vaginal intercourse and (2) examine combinations of past-year sexual behaviors for each of the two waves. We hypothesized that we would observe lower frequency of penile-vaginal intercourse (PVI) from 2009 to 2018 and that we would observe greater engagement in sexual repertoires involving non-coital partnered behaviors (e.g., partnered masturbation, oral sex) in 2018 as compared to 2009. Participants were 4155 individuals from the 2009 NSSHB (Adolescents: 406 females, 414 males; Adults: 1591 women, 1744 men) and 4547 individuals from the 2018 NSSHB (Adolescents: 416 females, 411 males; Adults: 2007 women, 1713 men). Compared to adult participants in the 2009 NSSHB, adults in the 2018 NSSHB were significantly more likely to report no PVI in the prior year (28% in 2018 vs. 24% in 2009). A similar difference in proportions reporting no PVI in the prior year was observed among 14–17-year-old adolescents (89% in 2018 vs. 79% in 2009). Additionally, for both adolescents and adults, we observed decreases in all modes of partnered sex queried and, for adolescents, decreases in solo masturbation.

Discussion

The present study used data from two waves of US nationally representative survey data to examine changes in sexual frequency and sexual repertoire between 2009 and 2018. Our research adds to the literature by using detailed measures of sexual behaviors beyond oral, vaginal, and anal intercourse; we did this in order to examine whether an explanation for declines in coital frequency might be explained by increases in non-coital behaviors. However, in addition to finding decreased PVI frequency in 2018 as compared to 2009, we found significant decreases across all partnered sexual behaviors assessed and, for adolescents, decreases in the proportion of adolescents reporting solo masturbation in the prior year as well. Overall, our findings are consistent with studies from multiple countries that have documented declines in sexual frequency. Because our sample was limited to individuals ages 14–49, we were unable to examine sexual behavior trends among people aged 50 and older. However, our findings align with studies that have found greater proportions of young people reporting no partnered sexual behaviors in the prior year (e.g., Burghardt et al., 2020; Ghaznavi et al., 2019; Ueda & Mercer, 2019; Ueda et al., 2020).

Other than Natsal and ASHR, most population-representative studies examining sexual frequency trends have not included those under age 18 and thus less has been known at the population level about sexual trends among younger adolescents. Our study extends the literature by including adolescents as young as 14 years old in our analytic sample (the youngest participants in Natsal and ASHR were 16 years old). Findings from our research also align with the US Youth Risk Behavior Survey (YRBS) which has demonstrated declining rates of high school students reporting having ever had sex over a similar period of time (e.g., 46% in 2009 vs. 38% in 2019) (Centers for Disease Control & Prevention, 2020a). The lower rates of adolescents’ reports of solo masturbation and PVI in 2018 are striking and deserve further study. These differences aren’t trivial: for example, the proportion of adolescents reporting neither solo nor partnered sexual behaviors (Latent Class 2) increased from 28.8% of young men and 49.5% of young women in 2009 to 43.3% of young men and 74.0% of young women in 2018.

A number of potentially convergent social and cultural changes may contribute to these substantial shifts in young people’s sexual behaviors. Widespread internet connectivity and emerging new technologies have added a new medium for providing sexual experiences outside of physical sex with a partner (e.g., sexting, easy access to sexually explicit media) (Doring et al., 2017; Twenge et al., 2017; Wright, 2013; Wright et al., 2013). Alcohol use has decreased among adolescents (Miech et al., 2019), and many young people have been engaged in conversations about sexual consent (such as through the #MeToo movement led by Tarana Burke, the Obama/Biden administration’s It’s On Us campaign, and recent high profile rape cases) (e.g., Armstrong & Mahone, 2017; PettyJohn et al., 2019). Also, more contemporary young people identify with non-heterosexual identities—including asexual identities—and more young people identify in gender expansive ways (Newport, 2018; Watson et al., 2020). It is also possible that secular trends reflect a tendency to have over-reported sexual behavior in earlier years, with more accurate reporting now as people become more comfortable with online presentations of themselves. These are among the many potential influences on adolescent sexual development and expression; subsequent research might examine how each of these may be contributing to changing patterns of sexual frequency and repertoire at the population level. Greater investment in understanding adolescent sexual development beyond risk is warranted, including how adolescents form, sustain, and interpret intimate relationships.

In terms of young adults, some research suggests that increasing use of computer games and social media may be implicated in young adults’ declining sexual activity (Lei & South, 2021). A recent analysis of 18–23-year-olds in 2007–2017 waves of the Transition to Adulthood Supplement of the Panel Study of Income Dynamics found that increased use of computer games, decreased alcohol use, decreased earnings, and declines in romantic relationship formation explained 76% of the decline in sexually active young adults in their sample (Lei & South, 2021). The median age at first marriage in the USA has also increased (US Census, 2020). It is worth noting that many published reports of adult sexual behavior (including ours) begin by describing the potential positive contributions of sex to health and quality of life. Media coverage of declining sexual activity tends to be similarly imbued with a sense that—in spite of risks that include unintended or mistimed pregnancy, sexually transmitted infections, and/or sad or lonely feelings connected to sex—partnered sex is generally pleasurable, joyful, connecting, and/or beneficial and thus declines in partnered sex among adults may be concerning (e.g., Feder, 2020; Julian, 2018). The age-old question on how much sex is too much and how little sex is not enough comes to mind. Given the impacts of the COVID-19 pandemic on physical and mental health, sexual behavior, relationships, and (for youth) in-person school and extracurricular activities, ongoing population-level research on sexual development and behaviors will be important (Finnerty et al., 2021; Rosenberg et al., 2021).

Positive aspects of adolescent partnered sex are less often highlighted. For example, in the section of the 2019 YRBS report that shows sexual behavior trends over time, the row that shows declining percentages of high school students who have “ever had sex” also features a green symbol (similar to the US traffic light system) which the legend describes as moving “in right direction” (Centers for Disease Control & Prevention, 2020b). The line between adolescence and adulthood has always been tenuous—perhaps particularly so when it comes to sexual behavior—but we must continue to interrogate how declining adolescent sexual activity is in the “right direction” yet declining adult sexual activity warrants concern. Solo and partnered adolescent sexual exploration are developmentally normative, offer opportunities for learning and joy, and are supportive of adult sexual development (Hensel et al., 2011; Robbins et al., 2011; Tolman & McClelland, 2011). Our findings have implications for those in policy roles, who might consider other helpful metrics of understanding changes in adolescent sexual experience—as an example, tracking the proportion of adolescent sex that is wanted, consensual, and even pleasurable may be illuminating.

Findings from our study also extend the existing literature by including solo masturbation among participants’ sexual behaviors. For both adults and adolescents, we found a latent class that was marked by engaging in solo masturbation. This highlights the important role of masturbation in people’s sexual expression; however, we note that the proportion of adolescents in the solitary masturbation Latent Class 1 decreased in 2018 compared to 2009, while the proportion reporting neither solo nor partnered sex increased. The 2009/2019 NSSHB waves did not ask participants how they feel about their sexual lives or whether they would like to have more sex or less sex than they are having; however, we note that Ueda and Mercer (2019) found that most Natsal participants who reported no prior year partnered sex but who did have prior partnered sexual experience were not dissatisfied with their sexual lives. Subsequent research should include more questions about people’s own subjective assessments of their sexual lives and feelings about their solo and partnered sexual behaviors.

Similarly, we need to understand more about how people’s subjective feelings about the sex they’ve experienced may shape their subsequent choices about sex. At the population level, the 2009 NSSHB demonstrated that anal intercourse had nearly doubled in lifetime prevalence since the National Health and Social Life Survey of the early 1990s. However, anal sex remained infrequent overall in any given year (though much more frequent among gay and bisexual men) (Dodge et al., 2016; Herbenick et al., 2010a). Anal sex has generally been rated as unappealing among US adults (Herbenick et al., 2017), and several qualitative studies examining anal intercourse between women and men found that—although anal sex behaviors were pleasurable to some—anal sex was often marked by pressure, coercion, lack of communication, fear, and pain among women (e.g., Fahs & Gonzalez, 2014; Fahs et al., 2015; Herbenick et al., 2015, 2019a, 2019b; Jozkowski et al., 2014). Given these experiences, it is perhaps not surprising to have observed a decrease in anal intercourse between the 2009 and 2018 NSSHB, but that does not explain other decreases across all partnered sexual behaviors queried.

Recent research suggests that some sexual behaviors sometimes described as aggressive or as “rough sex” may have grown in prevalence in the USA, including choking during sex (which is technically a form of strangulation) (Herbenick et al., 2020; Herbenick et al., 2021a). Like anal sex behaviors, choking/strangulation is often wanted, asked for, and/or perceived as pleasurable (Herbenick et al., 2021a, 2021b). However, being choked/strangled has also been identified by many women as an example of something a partner has done during sex that made them feel scared (Herbenick et al., 2019a, 2019b), which is not surprising given that choking/strangulation is a common feature of sexual assault, intimate partner violence, and (in rare cases) is lethal even as part of consensual sex (e.g., Mcquown et al., 2016; Roma et al., 2013; Sendler, 2018). Subsequent research might examine the extent to which partnered sex may be declining, at least for some subset of the population, as a result of experiencing unpleasant or frightening experiences during otherwise consensual sex (e.g., being hit, punched, slapped, or choked without consent, or as a form of sexual compliance).

Strengths and Limitations

Our study was subject to several strengths and limitations. Among our strengths, we used data from the 2009 and 2018 waves of the NSSHB, a US nationally representative probability survey. The NSSHB is unique in that it includes items related to both sexual frequency and repertoire as well as a detailed assessment of solo and partnered sexual behaviors, which allowed for an examination of specific behavioral trends over two time periods. Other US national surveys, such as the GSS, YRBS, National Survey of Family Growth, and the National Longitudinal Study of Adolescent to Adult Health, are more limited in the scope of sexual behavior items assessed (Centers for Disease Control & Prevention, 2020a, 2020b; Harris et al., 2009; NORC at the University of Chicago, 2016). Both the 2009 and 2018 NSSHB waves were conducted through online, confidential surveys which has been shown to facilitate the reporting of sensitive behaviors. Among our limitations is that—in terms of frequency of sex—we were limited to comparisons of PVI (i.e., frequency of other sexual behaviors had not been assessed in both waves). Also, neither wave included an oversample of individuals who identify as lesbian, gay, bisexual, or asexual and thus—being a general population survey—findings largely reflect majority groups (e.g., heterosexual identified people). This becomes particularly apparent in examining the LCA classes, for which PVI loaded heavily on three of the four adult classes and two of the four adolescent classes. This is likely a fair representation of sex between males and females, given prior research showing the prevalence of PVI in many combinations of sex between women and men, and other research describing the intercourse imperative (Herbenick et al., 2010b; Richters et al., 2006). However, it does mean that these LCA classes do not reflect the rich diversity of all US adolescents and adults. Subsequent research might investigate similar constellations of intimate and/or sexual behaviors among dedicated samples of LGBTQ + individuals and/or among general population samples with sufficiently sized oversamples of LGBTQ + individuals.

Similarly, although the 2009/2018 NSSHB waves included a broad range of sexual behaviors for comparison, we would have liked to have been able to compare additional behaviors across waves but did not have additional items common among the two waves (e.g., kissing, cuddling, sex toy use, sexting, reading erotica, and/or watching pornography). As the NSSHB is focused on sexuality, we also did not have measures of more general behaviors (e.g., media use, substance use, mental health, physical health, perceived racism, political stress, etc.) that could have shed light on potential changes in sexual behaviors from 2009 to 2018. Finally, although our findings may help clinicians contextualize questions or concerns their clients have about how often people have sex, it is left to the client–clinician relationship, and to people themselves, to examine contexts of pleasure and satisfaction.

Mask-wearing improves the performance on a test that measures the capacity to infer other people mental states from their eye gaze

Trainin, N., & Yeshurun, Y. (2021). Reading the mind with a mask? Improvement in reading the mind in the eyes during the COVID-19 pandemic. Emotion. Nov 2021. https://doi.org/10.1037/emo0001014

Abstract: The necessity to wear facial masks in public during the COVID-19 pandemic generated a unique situation where the eyes' importance as a visual source of information about individuals’ mental and emotional states greatly increased. In this study, we tested the hypothesis that experience in looking in interlocutor’s eyes (as a result of mask-wearing) will be correlated with enhanced performance on “reading the mind in the eyes test” (RMET). To test this, 87 participants performed an online version of the RMET at 2 different timepoints: when the mandatory mask wearing rules were put in place and a month later. We found that reported tendency to look at interlocutors' eyes, combined with experience in interacting with other people wearing masks, explained individual differences in RMET performance. Moreover, we found that individual’s tendency to look at interlocutors' eyes was correlated with change in performance in reading the mind in the eyes over this month. These results suggest that in addition to individual’s interest and motivation in understanding other’s mental state, continuous everyday experiences can result in an improved capacity for reading mental and emotional states by looking into individuals' eyes.