Yawning Is More Contagious in Pregnant Than Nulliparous Women

Yawning Is More Contagious in Pregnant Than Nulliparous Women. Naturalistic and Experimental Evidence. Ivan Norscia, Lucia Agostini, Alessia Moroni, Marta Caselli, Margherita Micheletti-Cremasco, Concetta Vardé & Elisabetta Palagi. Human Nature, Jul 13 2021. https://rd.springer.com/article/10.1007/s12110-021-09404-w

Abstract: Contrary to spontaneous yawning, which is widespread in vertebrates and probably evolutionary ancient, contagious yawning—yawning triggered by others’ yawns—is considered an evolutionarily recent phenomenon, found in species characterized by complex sociality. Whether the social asymmetry observed in the occurrence of contagious yawning is related to social and emotional attachment and may therefore reflect emotional contagion is a subject of debate. In this study we assessed whether yawn contagion was enhanced in pregnant women, a cohort of subjects who develop prenatal emotional attachment in preparation for parental care, via hormonal and neurobiological changes. We predicted that if yawn contagion underlies social and emotional attachment, pregnant women would be more likely to contagiously yawn than nonpregnant, nulliparous women of reproductive age. We gathered data in two different settings. In the experimental setting, 49 women were exposed to video stimuli of newborns either yawning or moving their mouth (control) and we video-recorded the women during repeated trials to measure their yawning response. In the naturalistic setting, 131 women were observed in a social environment and their yawning response was recorded. We tested the factors influencing the yawning response, including the reproductive status (pregnant vs. not pregnant). In both settings, yawn contagion occurred significantly more in pregnant than nonpregnant women. By showing that pregnant women were most likely to respond to others’ yawns, our results support the hypothesis that the social variation observed in yawn contagion may be influenced by emotional attachment and that yawning in highly social species might have been coopted for emotional contagion during evolution.

Discussion

The results from both the experimental and the naturalistic data converge in indicating that women’s reproductive status had an effect on contagious yawning, which was more likely to occur in pregnant than in nulliparous women (here defined as women who were not pregnant and had no children). As a matter of fact, pregnant women were more likely to respond than nulliparous women to both video yawns of unknown infants in the experimental trials and live yawns from adults in the naturalistic setting (Tables 2 and 3; Figs. 3 and 5). This finding, presented for the first time with this study, provides support to the Emotional Bias Hypothesis (EBH) because yawn contagion was highest in the category of women characterized by enhanced social attachment predisposition, owing to the biological and psychological changes typical of the gestation period (Barba-Müller et al. 2019; Brandon et al. 2009; Tichelman et al. 2019).

Since yawn contagion has been found to vary across the day (Giganti and Zilli 2011), we checked whether our yawning response sampling could be biased by the time periods during which the data were collected, depending on the availability of the study subjects. In neither setting did we find a significant effect (Tables 1 and 3), probably because the majority of the data was collected in the morning and in the afternoon (with little data collected at the very extremes of the day).

The use of a twofold approach, involving both experimental and naturalistic data collection, allowed the verification of the possible effect of different variables on yawn contagion. The results of the experimental trials show that the yawning response was significantly higher in the yawning than in the control video condition (Table 1; Fig. 2). This finding confirms that yawn contagion was present in the cohort of human subjects considered in this study (nulliparous and pregnant women) since it has been found in other segments of the population (Arnott et al. 2009; Provine 1989, 2005).

Yawn contagion may be affected by selective, top-down attentional biases (Massen and Gallup 2017), in addition to bottom-up, stimulus-driven attention (Attentional Bias Hypothesis, ABH; Palagi et al. 2020). Therefore, in the experimental setting we checked for selective attention to the stimulus and we found no significant influence of the time of attention to the stimulus source (video screen) on yawning (Table 1), which was high overall in both yawning and control video conditions, as well as in pregnant and nulliparous women. This finding reduces the probability that in our sample a selective attention bias may have accounted for the differences between stimulus (yawning/control) and reproductive status (pregnant/nulliparous) conditions. This is line with evidence indicating, directly or indirectly, that contagious yawning in humans may depend on bottom-up more than top-down selective attention (Norscia et al. 2020; for a review see Palagi et al. 2020). Age is another variable known to possibly affect yawn contagion rates (Bartholomew and Cirulli 2014). In our case, in the experimental setting there was a nonsignificant trend of the influence of age in the yawning response, possibly because the women under study fell within the relatively short reproductive age.

In the naturalistic setting we could verify the effect of a social bond between the trigger and the potential responder on the yawning response. Although the bond was restricted to two categories (strangers and acquaintances) owing to data constraints, and despite showing an inverse correlation with reproductive status, the bond had a significant effect on yawn contagion, which was more likely between subjects who knew each other than between strangers. This finding is in agreement with previous literature showing that relationship quality has an influence on yawn contagion, whose likelihood increases as the strength of the social bond increases (from strangers to acquaintances, friends, and lastly to family members; Norscia and Palagi 2011; Norscia et al. 2016). Norscia et al., (2020) found no difference between strangers and acquaintances when the yawns were heard but not seen, although friends and family responded at significantly higher rates than did those in the other categories. In the absence of the visual cue, it is probably more difficult for the potential responders to discern between subjects with whom they have reduced or no familiarity.

Importantly, our results from the experimental trials show that reproductive status (pregnant/nulliparous) had a significant effect on the yawning response in the yawning video condition but not in the control video condition (cf. Tables 2 and 3). Therefore, only yawning resulting from contagion—and not spontaneous yawning—was affected by pregnancy in our sample. Historical accounts report an increase of spontaneous yawning in the case of certain diseases (e.g., puerperal fever or hemorrhage; Walusinski 2010), and excessive yawning has indeed been indicated as a possible marker of disease in humans (Thompson and Simonsen 2015). Progesterone increases daytime drowsiness and sleeping time (Won 2015) and so it may increase spontaneous yawning rate during pregnancy. In this respect, we cannot exclude that the yawning stimulus might have preferentially primed the yawning motor response in pregnant women also because they experienced increased fatigue (despite showing similar levels of sleep to those of nulliparous women). An investigation on how spontaneous rates vary within subjects across pregnancy, possibly in relation to fatigue and tiredness, and how contagious yawning varies depending on the stimulus (e.g., babies/adults)—with hormonal and neurobiological correlates—could better clarify the above issues.

Overall, the different yawning response of pregnant women relative to women with no children can fall within the broad range of the behavioral changes that start occurring during pregnancy, such as motor activity and dietary choice variations (Crozier et al. 2009; Gradmark et al. 2011). Compared with childless women, pregnant women show increased sensitivity to emotional signals and facial expressions. For example, pregnant women were found to perceive infant cries in more differentiated ways than women with no offspring (Bleichfeld and Moely 1984; Yoshiaki 1985). As gestation progresses, pregnant women also show enhanced ability to encode and process emotional faces, especially related to distress (an emotional state; Keltner et al. 2019) as an evolutionary adaptation to motherhood, which requires hypersensitivity to emotional threat signals and contagion (Osório et al. 2018; Pearson et al. 2009). Our results fit with this scenario because they indicate enhanced responsiveness of pregnant women to yawning, which has been linked (with various degrees of evidence) to anxiety and distress in human and nonhuman primates (from lemurs to apes: e.g., Baker and Aureli 1997; Coleman and Pierre 2014; Leone et al. 2014; Palagi et al. 2019; Thompson 2014, 2017; Thompson and Bishop 2012; Zannella et al. 2015). Thompson (2014) has posited that cortisol (involved in the stress response) may be involved in yawn contagion, at least under certain situations. Another hypothesis, not mutually exclusive to the cortisol hypothesis, may be that yawn contagion is, to a certain extent, under the influence of oxytocin, considering that enhanced emotional recognition is one of the effects of oxytocin, whose levels largely increase during pregnancy (Domes et al. 2007; Preston 2013). In particular, oxytocin appears to increase the accuracy of the recognition of faces displaying angry and happy emotions, especially in women (Yue et al. 2018). Mariscal et al., (2019) found that yawn contagion in autism spectrum disorder (ASD) children was positively related to the blood concentration of oxytocin. The possible relationship between oxytocin and yawn contagion is supported by evidence that yawn contagion in humans follows the empathic gradient (sensu Preston and de Waal 2002), being highest between closely bonded subjects (Norscia and Palagi 2011; Norscia et al. 2020). Some features typical of mother-infant attachment, such as social recognition, bonding, and affiliation, are maintained in adulthood and promoted by oxytocin, which has been found to increase trust (Kosfeld et al. 2005), generosity (Zak et al. 2007), altruism (de Dreu et al. 2010), and both cognitive and affective empathy (Rodrigues et al. 2009; Shamay-Tsoory et al. 2013; Smith et al. 2014; Uzefovsky et al. 2015). One of the future steps is to evaluate the possible covariation between oxytocin and yawn contagion in both pregnant and nulliparous women. Beyond incorporating hormones, further studies could involve postmenopausal versus pregnant women and check how mothers react when they see their own fetus yawning on the echograph screen.

The possible connection between yawn contagion and increased social and emotional bonding is also suggested by the fact that some of the areas that seem to be involved in yawn contagion (such as the ventromedial-prefrontal cortex, superior temporal sulcus, amygdala, insula, posterior cingulate, and precuneus; Nahab et al. 2009; Platek et al. 2005; Schürmann et al. 2005) are also involved in mother-infant care, in mother’s enhanced sensitivity to the baby, and maternal brain changes occurring during pregnancy (Barba-Müller et al. 2019; Hoekzema et al. 2017; Kikuchi and Noriuchi 2015; Preston 2013; Rifkin-Graboi et al. 2015).

In summary, by showing increased occurrence of yawn contagion in pregnant women—a cohort of subjects that is specifically “programmed” to recognize and respond to others’ emotions—this study provides support for the hypothesis that yawn contagion may, at least under certain circumstances, underlie emotional contagion (EBH; Palagi et al. 2020). This process is considered by some scholars a basic form of empathy and occurs when an emotion is transferred from one individual to another, possibly via a motor perception–action mechanism, involving the matching of facial expressions and the resonance of the emotions that underlie such expressions (de Waal and Preston 2017).

The perception–action and the offspring care model both predict that subjects can preferentially attend the stimuli coming from closely bonded others, particularly caregiving individuals such as pregnant women toward babies (Preston 2013; Preston and de Waal 2002). Visual, top-down attention has limited effect on yawn contagion and does not follow a consistent familiarity trend in hominines because other factors, such as dominance, can come into play (Lewis et al. 2021; Norscia et al. 2020; Palagi et al. 2020). Hence, a possible bonding hypothesis between EBH and ABH is that yawn contagion can be influenced by emotional bonding and attention, mainly directed through bottom-up mechanisms.

Importantly, not all contagious yawning is triggered by emotional resonance, and that is not the point in question here. Contagious yawning also occurs between strangers (Norscia and Palagi 2011), and some people are consistently not susceptible to others’ yawns (Bartholomew and Cirulli 2014; Platek et al. 2003; Provine 1986, 1989). Contagious yawning is a form of yawning and—as such—can be related to nonemotional, individual and/or environmental factors, such as time of the day (Giganti and Zilli 2011), age (Bartholomew and Cirulli 2014), and possibly temperature (Gallup and Eldakar 2011). The perception–action mechanism itself is based on a theory in motor control that assumes that our physical motor acts are primed in the brain by observation of those in others, even if they do not bear emotional cues (Preston and de Waal 2002). Thus, contagious yawning can also be a nonemotional motoric response. The pivot around which this study revolves is the possible mechanism leading to the social variations observed in the occurrence of contagious yawning. Although still under debate (Adriaense et al. 2020; Massen and Gallup 2017), various physiological, neuroethological, and psychological studies sustain the possible connection between the social asymmetry of yawn contagion and emotional bonding. Some of the brain areas that appear to be involved in yawn contagion (Nahab et al. 2009; Platek et al. 2005; Schürmann et al. 2005) seem to overlap with those involved in emotional processing of internal and external stimuli and empathy (Palagi et al. 2020) and—importantly—with the maternal brain (Barba-Müller et al. 2019; Hoekzema et al. 2017; Kikuchi and Noriuchi 2015; Rifkin-Graboi et al. 2015). Highest levels of yawn contagion are associated with increased oxytocin levels (i.e., ASD children; Mariscal et al. 2019), enhanced social bonding (i.e., between friends and family; Norscia and Palagi 2011), and maternal prenatal bonding (i.e., in pregnant women; present study). Lower yawn contagion rates in association with levels of autistic traits were found to be related to attentive rather than background emotional empathy deficits (Helt et al. 2021). Finally, another study found that subjects who yawned in response to observing others’ yawns exhibited significantly higher empathy scores (Franzen et al. 2018).

Hence, although we cannot discard the possibility that other priming and motor mechanisms may also underlie the social asymmetry of yawn contagion, the hypothesis that this behavior has been coopted during evolution for emotional contagion still stands and gains further support. 

Predicting Others’ Social Interaction Preferences: What to Do, for How Long, and How Often; how people make inferences about other people’s preferences, as well as the consequences of making incorrect inferences

Predicting Others’ Social Interaction Preferences: What to Do, for How Long, and How Often. Peggy J. Liu, Theresa A. Kwon. Current Opinion in Psychology, July 13 2021. https://doi.org/10.1016/j.copsyc.2021.07.001

Abstract: We present a three-dimensional what, how long, and how often framework to discuss three main inferences about other people’s preferences for repeated social interactions over time: (1) what to do together, (2) how long to spend together on each occasion, and (3) how often to spend time together. For each dimension, we discuss when and how people make inferences about other people’s preferences, as well as the consequences of making incorrect inferences. The three dimensions are conceptually independent; however, decisions made on one dimension can sometimes affect dimensions made on others. More research is needed on the interplay between multiple dimensions, including on how inferences made about preferences and decisions on one dimension affect inferences about preferences and decisions on other dimensions.

Keywords: relationshipssocial inferencesjoint consumptionshared consumptionchoices for others

Short-term mating orientation as a predictor of alcohol use and risky sexual behavior

Short-term mating orientation as a predictor of alcohol use and risky sexual behavior. Susanna V. Lopez et al. Journal of American College Health, Jul 9 2021. https://doi.org/10.1080/07448481.2021.1947836

Abstract

Objectives: Sexual Strategies Theory suggests people fall on a continuum between having short-term mating orientation (STMO) and long-term mating orientation. One way STMO individuals signal mating goals is via risky drinking. The current study therefore aims to investigate drinks per week (DPW) as a mediator between STMO and risky sexual behavior (RSB), with gender as a moderator between STMO and DPW.

Participants: Undergraduate students (N = 300) from a Midwestern university during Fall 2019.

Method: Participants completed questionnaires assessing STMO, DPW, and RSB frequency.

Results: A moderated-mediation model indicated DPW significantly mediated the relationship between STMO and RSB. Positive associations were found among all three variables. Gender was not a moderator between STMO and DPW.

Conclusions: Mating orientation was a correlate of alcohol use and RSB for women and men, contributing to the literature identifying STMO as an indicator of those in need of substance use and RSB intervention.

Keywords: Alcoholcollege studentsmating strategiesrisky sexual behavior

Understanding woman’s interest in sexual activity beyond a narrow window during which sex can lead to conception: The dual sexuality framework

Understanding Women's Estrus and Extended Sexuality: The Dual Sexuality Framework. Steven W Gangestad et al. In book: D. M. Buss and P. Durkee (Eds.), Handbook of Human Mating, Oxford University Press. July 2021. https://www.researchgate.net/publication/352916307

We humans share many homologies with our fellow mammals, such as a single heart, warm-bloodedness, and mammary glands. We have also evolved a host of distinctly human features, such as unusually large brains relative to body size, a developmentally late transition to a reproductive state, bipedalism, and substantial levels of paternal care and provisioning. Unusual features within the hominin lineage are signatures of the niche that humans evolved to occupy, distinguishing us from close relatives. These features demand our attention as we aspire to understand what it means to be human (e.g., Kaplan et al., 2000; Tooby & DeVore, 1987). One such feature is the extension of a woman’s interest in sexual activity beyond a narrow window during which sex can lead to conception, to which female sexual interest is typically limited in spontaneously-ovulating mammals (e.g., Nelson, 2000; Symons, 1979; Alexander & Noonan, 1979).

Women are sexually active across the reproductive cycle, but not necessarily sexually responsive to precisely the same stimuli and contexts across the cycle. In this chapter, we lay out the dual sexuality framework for understanding women’s sexuality. This framework proposes that women’s sexuality during phases of the cycle when conception is possible differs from their sexuality during phases when conception is not possible. This perspective puts theoretical constraints on the ways that conceptive and non-conceptive sexuality can be understood. Within these constraints, multiple, contrasting psychological designs are possible. Research that can adjudicate between alternative possible psychological designs promises to hone our understanding of human mating in ways that extend far beyond the domain of women’s phase-specific sexuality.

Individuals exhibiting higher levels of Narcissism are not only less knowledgeable but also more interested in politics and more likely to participate when given the opportunity

From 2020... The Dark Side of Politics: Participation and the Dark Triad. Philip Chen, Scott Pruysers, Julie Blais. Political Studies, April 28, 2020. https://doi.org/10.1177/0032321720911566

Abstract: Personality traits are one piece in the larger puzzle of political participation, but most studies focus on the Five-Factor Model of personality. We argue that the normative implications of the influence of personality on politics are increased when the personality traits being studied correlate with negative social behaviors. We investigate the role of the Dark Triad on political participation as mediated through political beliefs such as interest and knowledge. We find that Psychopathy and Narcissism are positively associated with political interest, but Narcissism is also negatively associated with political knowledge. In addition, both Psychopathy and Narcissism exert a direct, positive influence on participation. Our results imply that individuals exhibiting higher levels of Narcissism are not only less knowledgeable but also more interested in politics and more likely to participate when given the opportunity.

Keywords: personality, political behavior, participation

Why some hesitate more: Cross-cultural variation in vaccine hesitancy, vaccine trust, and COVID-19 vaccine acceptance rates are mainly driven by differences in the prevalence of conspiratorial thinking across countries

Why some hesitate more: Cross-cultural variation in conspiracy beliefs, belief in science, and vaccine attitudes. Gul Deniz Salali,  Mete Sefa Uysal. Jul 2021. https://doi.org/10.1101/2021.07.09.21260228

Abstract

Background Countries differ in their levels of vaccine hesitancy (a delay in acceptance or refusal of vaccines), trust in vaccines, and acceptance of new vaccines. In this paper, we examine the factors contributing to the cross-cultural variation in vaccine attitudes, measured by levels of 1) general vaccine hesitancy, 2) trust in vaccines, and 3) COVID-19 vaccine acceptance.

Methods We examined the relative effect of conspiracy mentality, belief in COVID-19 conspiracies, and belief in science on the above-mentioned vaccine attitudes in the UK (n= 1533), US (n= 1550), and Turkey (n= 1567) through a quota-sampled online survey to match the population for age, gender, ethnicity, and education level. 

Results We found that belief in COVID-19 conspiracies and conspiracy mentality were the strongest predictors of general vaccine hesitancy across all three countries. Belief in science had the largest positive effect on general vaccine trust and COVID-19 vaccine acceptance. Although participants in Turkey demonstrated the lowest level of vaccine trust, their belief in science score was significantly higher than participants in the US, suggesting that belief in science cannot explain the cross-cultural variation in vaccine trust. The mean levels of conspiracy mentality and agreement with COVID-19 conspiracies were consistent with the country-level differences in general and COVID-19 vaccine attitudes. Demographic variables did not predict vaccine attitudes as much as belief in conspiracies and science.

Conclusions Our findings suggest that cross-cultural variation in vaccine hesitancy, vaccine trust, and COVID-19 vaccine acceptance rates are mainly driven by differences in the prevalence of conspiratorial thinking across countries.

Native German women do not help immigrant Muslim women with a lemon bag that teared if they perceive the holder to favor sex inequality

Donghyun Danny Choi et al, The Hijab Penalty: Feminist Backlash to Muslim Immigrants. American Journal of Political Science, Jul 8 2021. https://onlinelibrary.wiley.com/doi/10.1111/ajps.12627

Abstract: Why do native Europeans discriminate against Muslim immigrants? Can shared ideas between natives and immigrants reduce discrimination? We hypothesize that natives' bias against Muslim immigrants is shaped by the belief that Muslims hold conservative attitudes about women's rights and this ideational basis for discrimination is more pronounced among native women. We test this hypothesis in a large-scale field experiment conducted in 25 cities across Germany, during which 3,797 unknowing bystanders were exposed to brief social encounters with confederates who revealed their ideas regarding gender roles. We find significant discrimination against Muslim women, but this discrimination is eliminated when Muslim women signal that they hold progressive gender attitudes. Through an implicit association test and a follow-up survey among German adults, we further confirm the centrality of ideational stereotypes in structuring opposition to Muslims. Our findings have important implications for reducing conflict between native–immigrant communities in an era of increased cross-border migration.

Popular version (extracts): https://phys.org/news/2021-07-hijab-effect-feminist-backlash-muslim.html

The intervention went like this: A woman involved in the study approached a bench at a train station where bystanders waited and drew their attention by asking them if they knew if she could buy tickets on the train.

She then received a phone call and audibly conversed with the caller in German regarding her sister, who was considering whether to take a job or stay at home and take care of her husband and her kids. The scripted conversation revealed the woman's position on whether her sister has the right to work or a duty to stay at home to care for the family.

At the end of the phone call, a bag she was holding seemingly tears, making her drop a bunch of lemons, which scatter on the platform and she appeared to need help gathering them.

In the final step, team members who were not a part of the intervention observed and recorded whether each bystander who was within earshot of the phone call helped the women collect the lemons.

They experimentally varied the identity of the woman, who was sometimes a native German or an immigrant from the Middle East; and the immigrant sometimes wore a hijab to signal her Muslim identity and sometimes not.

They found that men were not very receptive to different messages regarding the woman's attitude toward gender equality, but German women were. Among German women, anti-Muslim discrimination was eliminated when the immigrant woman signaled that she held progressive views vis-à-vis women's rights. Men continued to discriminate in both the regressive and progressive conditions of the experiment.

It was a surprise that the experimental treatment did not seem to make a big difference in the behavior of men towards Muslim women.

"Women were very receptive to this message that we had about Muslims sharing progressive beliefs about women's rights, but men were indifferent to it," says Sambanis. "We expected that there would be a difference, and that the effect of the treatment would be larger among women, but we did not expect that it would be basically zero for men."

[...]

The results are surprising from the perspective of the prior literature, which assumed that it is very hard for people to overcome barriers created by race, religion, and ethnicity. At the same time, this experiment speaks to the limits of multiculturalism, says Sambanis. "Our work shows that differences in ethnic, racial, or linguistic traits can be overcome, but citizens will resist abandoning longstanding norms and ideas that define their identities in favor of a liberal accommodation of the values of others," he says.

The Friends-to-Lovers Pathway to Romance: Prevalent, Preferred, and Overlooked by Science

The Friends-to-Lovers Pathway to Romance: Prevalent, Preferred, and Overlooked by Science. Danu Anthony Stinson, Jessica J. Cameron, Lisa B. Hoplock. Social Psychological and Personality Science, July 12, 2021. https://doi.org/10.1177/19485506211026992

Abstract: There is more than one pathway to romance, but relationship science does not reflect this reality. Our research reveals that relationship initiation studies published in popular journals (Study 1) and cited in popular textbooks (Study 2) overwhelmingly focus on romance that sparks between strangers and largely overlook romance that develops between friends. This limited focus might be justified if friends-first initiation was rare or undesirable, but our research reveals the opposite. In a meta-analysis of seven samples of university students and crowdsourced adults (Study 3; N = 1,897), two thirds reported friends-first initiation, and friends-first initiation was the preferred method of initiation among university students (Study 4). These studies affirm that friends-first initiation is a prevalent and preferred method of romantic relationship initiation that has been overlooked by relationship science. We discuss possible reasons for this oversight and consider the implications for dominant theories of relationship initiation.

Keywords: romantic relationships, close relationships, friendship, dating, relationship initiation

I have never been on a date and probably never will…I have always done the friends-to-lovers pathway, where you just start sleeping with your best friend and then move in…Sometimes I really regret this, and get jealous of people who get pretty and put on their best selves, and go outside to have adventures with strangers.

—Tumblr user @elodieunderglass (2017)

General Discussion

Our results reveal that psychologists have largely overlooked the most prevalent and desirable form of relationship initiation. Even though two thirds of the nearly 1,900 participants in the studies that we meta-analyzed in Study 3 reported friends-first initiation, and even though 47% of the university age participants in Study 4 claimed that friends-first initiation is the best way to initiate a relationship, just 18% of the studies that we located in our literature search actually focused on this method of initiation. Notably, our impression is that many of these studies covered friends-first initiation in a brief or peripheral manner. Given the paucity of research on friends-first initiation, it is not surprising that the textbooks we coded only cited two articles that focused on friends-first research at all, and these works exclusively focused on friends-with-benefits relationships. This means that the field of close relationships has only a partial understanding of how romantic relationships actually begin.

There are certainly flaws in our research that should be addressed in future studies. Our research concerning the prevalence of friends-first initiation was based on retrospective reports. Such reports are easy to collect, but they can be biased by subsequent experience, and this threat to validity may be particularly salient for emotionally charged experiences like romance (Holmberg et al., 2004). Longitudinal, prospective studies may be better suited to studying friends-first initiation. In addition, although the samples we included in Study 3 lived in different regions of Canada and the United States and comprised both younger and older adults, our samples were still relatively WEIRD (i.e., Western, Educated, Industrialized, Rich, & Democratic; Henrich et al., 2010) and most samples did not include singles. Future research should examine cultural differences in the prevalence of friends-first initiation and other forms of initiation that may not be commonly recognized in the West, but which may be similarly overlooked by extant scientific theories and data. Further, although our analyses in Study 3 suggested that friends-first initiation is more common among same gender/queer couples than among couples that include a man and a woman—perhaps due to group differences in the size of the available dating pool, differing scripts concerning intimacy and communication, and fluid understandings of gender, among other reasons (e.g., Rose, 2000)—our sample size for the former group was very small (N = 84 across four samples; see the OSM), and we did not explicitly assess sexual orientation. Although our results are not definitive, they do support prior observations made about same-sex romantic relationship formation (Diamond, 2003). Nevertheless, future research examining the prevalence of various relationship-initiation strategies should include all sexual orientations. Research should also examine whether friends-first initiation is preferred among older adults, as our sample in Study 4 comprised university students. Finally, we did not define “friendship” for any of our participants, so our results may be biased by participants’ ability to self-define a relationship that lacks a precise and shared cultural definition to begin with (e.g., VanderDrift et al., 2016). Future research should seek to document the characteristics of friendships that do and do not lead to romance and to ensure that our prevalence rate is not potentially inflated by some participants’ excessively broad interpretation of friendship.

But to achieve these important goals and develop a science of relationship initiation that truly reflects people’s behavior, researchers may need to take a cold, hard look at the reasons why the field has overlooked friends-first initiation in the first place (and yes, we include ourselves in this critique). As we explained in the introduction, it is difficult to study social–psychological phenomena that occur spontaneously and in private, and it is easier to use experimental paradigms that enhance scientific control. Yet researchers’ preference for these methods may have shaped the very questions we think to ask, a kind of “tail wags the dog” situation that may have diverted attention away from friends-first initiation. Thus, researchers and funding agencies need to invest in more longitudinal studies that offer the possibility of capturing different types of relationship initiation as they spontaneously occur.

Moreover, as we explained in the introduction, implicit heterosexist biases hinder relationship science (Rose, 2000) and that may help to explain researchers’ relative neglect of friends-first initiation. For example, despite convincing evidence that passion-based intimacy can arise from friendship-based intimacy among same-gender friends (e.g., Diamond, 2003), it may not have occurred to researchers that such a thing could also happen in platonic friendships between heterosexual men and women. Moreover, if people assume that men and women cannot be platonic friends because sexual attraction inevitably gets in the way, and if researchers assume that everyone desires and prioritizes romantic relationships over friendships and singlehood (but see Bay-Cheng & Goodkind, 2016; Fisher & Sakaluk, 2020; Fisher et al., 2021), it may be difficult to conceive of the possibility that heterosexual men and women might maintain a platonic friendship for months or even years, like our Study 4 participants, before romantic feelings start to blossom. Interrogating and overcoming these and other heterosexist assumptions about relationships may be the first step to developing a science of relationship initiation that truly reflects the full diversity of human experience.

The gulf between the fields’ excessive scientific focus on dating initiation and people’s frequent lived experiences of friends-first initiation also has important implications for theories of relationship formation and maintenance. Researchers may need to revisit the validity of dominant models of relationship formation, including risk-regulation theory (Cameron et al., 2010; Stinson et al., 2015), sexual strategies theory (e.g., Eastwick et al., 2018), and assortative mating (e.g., Fletcher et al., 2000; Hoplock et al., 2019), all of which were devised by studying dating initiation, and all of which may apply differently, or not at all, to the process of friends-first initiation (see Hunt et al., 2015). Moreover, researchers should examine whether people exhibit systematic preferences for one type of initiation or another, and whether psychological variables like attachment (Mikulincer & Shaver, 2020), sociosexuality (e.g., Gangestad & Simpson, 1990), life history (e.g., Belsky, 2012), or personality (e.g., McNulty, 2013) predict that preference. They may also need to examine whether these same variables moderate the success of each type of initiation, and whether such variables moderate the trajectory of relationships that form via dating or friends-first initiation. As such, studying friends-first initiation may be a fruitful enterprise that not only promises to expand extant theories of relationship initiation, but which also promises to shed light on new aspects of relationship initiation that could shift our understandings of how romantic relationships begin and progress.

Moral inference is not only sensitive to whether people make moral decisions, but also to features of decisions that reveal their suitability as a relational partner

The relational logic of moral inference. Molly J. Crockett, Jim A.C. Everett, Maureen Gill, Jenifer Z. Siegel. Advances in Experimental Social Psychology, July 12 2021. https://doi.org/10.1016/bs.aesp.2021.04.001

Abstract: How do we make inferences about the moral character of others? Here we review recent work on the cognitive mechanisms of moral inference and impression updating. We show that moral inference follows basic principles of Bayesian inference, but also departs from the standard Bayesian model in ways that may facilitate the maintenance of social relationships. Moral inference is not only sensitive to whether people make moral decisions, but also to features of decisions that reveal their suitability as a relational partner. Together these findings suggest that moral inference follows a relational logic: people form and update moral impressions in ways that are responsive to the demands of ongoing social relationships and particular social roles. We discuss implications of these findings for theories of moral cognition and identify new directions for research on human morality and person perception.

Keywords: MoralityInferenceMentalizingSocial cognitionCharacterJudgmentPerceptionImpression formation

Dark Triad traits in a sample of 318 seafarers from Croatia

Dark Triad traits and attitudes toward communication and coordination in seafarers. Krešimir Jakšić, Toni Bielić, Jelena Čulin. Personality and Individual Differences, Volume 182, November 2021, 111091. https://doi.org/10.1016/j.paid.2021.111091

Highlights

• Dark Triad model of personality was confirmed in the sample of seafarers.

• Psychopathy is negatively related to seafarers' attitudes toward shipboard communication and coordination.

• Narcissism is positively related to seafarers' attitudes toward shipboard communication and coordination.

Abstract: Research on seafarers' personality traits is sparse, and little is known about the influence of personality traits on seafarers' behaviour on board. An important aspect of seafarer behaviour on board is effective communication and coordination with other crew members. Since previous research has associated Dark Triad traits with ineffective team performance, the study aimed to examine the relationship between these traits and attitudes toward communication and coordination on board in a sample of 318 seafarers from Croatia. The results of the study show that psychopathy has a negative relationship with seafarers' attitudes toward communication and coordination on board, while narcissism has a positive relationship with the same construct. Practical implications are given.

Keywords: SeafarersPersonalityDark TriadCommunicationCoordination

"Including Social Security and retirement wealth in the wealth concept results in significantly lower top shares and less growth in the concentration of wealth."

Wealth Concentration in the United States Using an Expanded Measure of Net Worth. Lindsay Jacobs, Elizabeth Llanes, Kevin Moore, Jeffrey P. Thompson, and Alice Henriques Volz. Federal Reserve Bank of Boston, Research Department Working Paper 21–6. Jul 2021. https://www.bostonfed.org/publications/research-department-working-paper/2021/wealth-concentration-in-the-united-states-using-an-expanded-measure-of-net-worth.aspx

Abstract: Defined benefit (DB) pensions and Social Security are two important resources for financing retirement that are often excluded from data, resulting in incomplete measures of wealth and representations of household wealth concentration. In this paper, the authors estimate an expanded measure of wealth that includes DB pensions and future Social Security benefits and show how that inclusion affects estimates of wealth inequality in the United States as well as trends over time. They further illustrate the impact Social Security has on these measures by simulating distributions under a scenario in which expected future Social Security Trust Fund shortfalls are addressed through a reduction in benefit payouts.

Key Findings

Even for the median household in the wealth distribution, the present value of defined benefit (DB) pensions and Social Security benefits accounts for more than half of all wealth.

Including DB pensions and Social Security benefits in measures of wealth results in markedly lower wealth concentration and moderates trends toward higher wealth inequality over time.

More specifically, the “90/50 ratio”—the ratio of wealth held by those at the 90th percentile of wealth to those at the 50th percentile—is reduced by nearly half for the 50–59 age group (from 13.4 to 6.8 in 2019) and for the 40–49 age group (10.7 to 6.4) when the estimated value of Social Security benefits are included in measures of wealth.

The “50/10 ratio” falls from 13.1 to 4.3 among those aged 40 to 49 and from 21.3 to 4.2 for the 50–59 age group when Social Security benefits are included.

The share of wealth held by the top 5 percent of the distribution drops from about 72 percent to 51 percent when the value of defined contribution (DC) plans and DB pensions are included in measures of wealth; it falls even further, to 45 percent, when Social Security benefits for those aged 40 to 59 are included.

Simulations of a policy scenario that reduces Social Security benefits to 75 percent of current benefit levels increases, by various measures, the share of wealth held at the upper end of the distribution

Matrimonial ads published in France, 1928-1994: Economic criteria were progressively replaced by personality criteria; in the search for a long-term partner, non-material needs are more palatable than material ones?

From Material to Non-Material Needs? The Evolution of Mate Preferences through the Twentieth Century in France. The Journal of Economic History, July 7 2021. https://doi.org/10.1017/S0022050721000322

Abstract: This paper studies the evolution of mate preferences throughout the twentieth century in France. I digitized all the matrimonial ads published in France’s best-selling monthly magazine from 1928 to 1994. Using dictionary-based methods, I show that mate preferences were mostly stable during the Great Depression, WWII, and the ensuing economic boom. These preferences started transforming in the late 1960s when economic criteria were progressively replaced by personality criteria. The timing coincides with profound family and demographic changes in French society. These findings suggest that, in the search for a long-term partner, non-material needs have replaced material ones.

Sex differences in anger states after violent video game play & the relationship of empathy and emotional invalidation as pre-aggressive predictors in young adults: Only females showed increased levels of state anger

Sex differences in anger states after violent video game play and the relationship of empathy and emotional invalidation as pre-aggressive predictors in young adults. Jessica O. Morrison, Meredith Elzy, Laura Jelsone-Swain. Personality and Individual Differences, Volume 182, November 2021, 111060. https://doi.org/10.1016/j.paid.2021.111060

Abstract: Previous research indicates that anger and aggressive behavior may increase with exposure to violence, particularly from playing violent video games. However, this literature is mixed with few studies examining individual differences that account for these inconsistencies. Therefore, we conducted a within-subjects experiment examining state anger in young adults after violent and nonviolent video game play. Importantly, we examined how individual differences involving levels of empathy, childhood emotional invalidation, anger traits, and sex may relate to state anger outcomes. Our results suggest that sex differences play a role in anger states after violent video game play. Specifically, only females showed increased levels of state anger. Lower empathy was a strong predictor of increased anger expression, and emotionally invalidating childhood environments was related to higher levels of trait anger. Implications from these results may include a possible buffering role that empathy and childhood emotional validation have in anger outcomes, while emphasizing the importance of examining individual differences and their outcomes resulting from playing violent video games.

Keywords: Violent video gamesAngerEmpathyEmotional InvalidationSex differences

The sympathetic plot, featuring a goal-directed protagonist who confronts obstacles, overcomes them, and wins rewards, builds interest by confronting a protagonist with a problem and induces satisfaction when the problem is solved

The Sympathetic Plot, Its Psychological Origins, and Implications for the Evolution of Fiction. Manvir Singh. Emotion Review, July 8, 2021. https://doi.org/10.1177/17540739211022824

Abstract: The sympathetic plot—featuring a goal-directed protagonist who confronts obstacles, overcomes them, and wins rewards—is ubiquitous. Here, I propose that it recurs because it entertains, engaging two sets of psychological mechanisms. First, it triggers mechanisms for learning about obstacles and how to overcome them. It builds interest by confronting a protagonist with a problem and induces satisfaction when the problem is solved. Second, it evokes sympathetic joy. It establishes the protagonist as an ideal cooperative partner pursuing a goal, appealing to mechanisms for helping. When the protagonist succeeds, they receive rewards, and audiences feel sympathetic joy, an emotion normally triggered when beneficiaries triumph. The capacities underlying the sympathetic plot evolved for learning and cooperation before being co-opted for entertainment.

Keywords: empathy, evolution, fiction, pleasure, sympathy, universals

The 2D:4D magnitude and its sexual dimorphism remained stable throughout the ontogeny; both sex and population origin were permanent reliable predictors of 2D:4D, whereas average digit length was not

Sex, population origin, age and average digit length as predictors of digit ratio in three large world populations. Marina Butovskaya, Valentina Burkova, Yulia Apalkova, Daria Dronova, Victoria Rostovtseva, Dmitriy Karelin, Ruzan Mkrtchyan, Marina Negasheva & Valery Batsevich. Scientific Reports volume 11, Article number: 8157. Apr 14 2021. https://www.nature.com/articles/s41598-021-87394-6

Abstract: Recently, a number of authors have claimed that sexual dimorphism in the second-to-fourth digit ratio (2D:4D) is simply dependent on digit length and is an artifact of allometry. The goal of our study is to verify the validity of these assumptions. The study sample comprised 7,582 individuals (3,802 men and 3,780 women) from three large world populations: Europeans (n = 3043), East Africans (n = 2844), and Central Asians (n = 1695). The lengths of the second and fourth digits on both hands were measured. Digit ratios were computed according to standard procedures. Analyses were conducted separately for each hand for the whole sample and in succession for the three large populations. Additionally, we separately tested four age cohorts (≤ 13, 14–18, 19–30, and 31 ≥ years) to test the effect of developmental allometry. The second and fourth digits showed strong positive linear relationships on both hands, and demonstrated an increase with age; digit length in women from the youngest age cohort was longer or equal to that of men, and shorter than men in older age cohorts. However, the 2D:4D magnitude and its sexual dimorphism remained stable throughout the ontogeny. To test for an allometric effect on 2D:4D, the average digit lengths were calculated. Both sex and population origin were permanent reliable predictors of 2D:4D, whereas average digit length was not. Height was applied as another measure of allometric effect on the limited sample (≤ 30 years) from the European population, along with sex and age. No allometric effect was observed in this case. We conclude that sex differences in 2D:4D are not an artifact of allometry.

Discussion

The main conclusion of our study is that 2D:4D ratios on the right and left hands were sexually dimorphic for the whole sample, as well as separately for all three tested populations. This was not the case with the second and fourth digits and their averages. The effect sizes, Cohen’s d of sex differences for the 2D:4Ds, as well as for the second and fourth digits, and averages for both digits ranged from small to medium. We demonstrate that for the whole sample, as well as for separate populations, every 0.9 cm increase in the second digit was related to a 1.0 cm increase in fourth digit. The digit lengths (second and fourth) increased substantially from childhood to adulthood, and there was a strong positive correlation between second and fourth digits across individuals. These findings are in accordance with those of earlier studies43. Sexual dimorphism in digit lengths, evident in human adults, was not observed in prepubertal children, which is again in line with previously reported data48.

The developmental allometry effects were tested in four age cohorts, with special emphasis on younger subsamples. This was conducted in accordance with the knowledge about the intensive growth of fingers in this period, as well as existing data on changes in growth patterns from childhood to young adulthood. The fourth age cohort (older adults) was substantially underrepresented and contained an insufficient number of individuals of European and Asian origin. Hence, we refrained from drawing specific conclusions for this age cohort.

For the whole sample, Cohen’s d for the 2D:4D ratios and digit lengths were of comparable sizes. In the case of separate prepubertal, pubertal, and young adult age cohorts, the situation was radically different. The data on sex differences in digit lengths in prepubertal and pubertal cohorts were in accordance with general expectations that females reach puberty considerably earlier than males68,69,70. On average, these results resulted in one to two-year differences71. Females in the prepubertal age cohort had significantly longer second digits and significantly higher 2D:4D ratios on both hands than males, whereas no sex differences for the fourth digits on both hands were found. For the prepubertal sample, the effect sizes for 2D:4D (right and left hand) were approximately 0.5 standard deviations, while for separate and average digits, the effect sizes were four times lower at the minimum.

Obvious population differences need to be considered. For prepubertal children in the African population, both the second and fourth digits were significantly longer in females, whereas for Europeans of the same age cohort, this was true only for the second digit; for Asians, no sex differences in digit length were present for prepubertal children. For the second age cohort, both fingers became significantly longer in males for Europeans and Asians, but were of equal lengths in males and females from the African sample. These differences suggest that respondents from African samples matured slower, and developmental processes in this population had different trajectories than their European and Asian peers. In young and older adults, both the second and fourth digits on both hands were significantly longer for males in all three populations. The 2D:4D ratio magnitude of sex differences essentially remained stable throughout ontogeny (in all four age cohorts) and of medium effect size. According to the logic of Lolli et al.41,42, the 2D:4D values would have to decrease with an increase in digit length, particularly in prepubertal and pubertal samples. In reality, the 2D:4Ds were remarkably stable with age, despite the increase of second and fourth digit length during ontogeny and the reversions in finger lengths in males and females that occurred during puberty.

Our results based on cross-sectional data are in line with other cross-sectional data, as well as with longitudinal studies30. Our data simultaneously revealed some population-specific variations in ontogenetic trajectories. In particular, in the African sample, female digits remained longer than male digits until 15–16 years of age (mid-adolescence), while in European and Asian samples, finger lengths were inversed before the age of 14 and remained longer in males than in females in all older ages. The differences obtained for Africans may be caused by specific life history trajectories with slower maturation, resulting from a mixture of environmental and social stressors, including malnutrition, a high risk of infections, and limited access to modern medical assistance in rural African populations72,73,74,75,76.

The GLM ANCOVA tests conducted in our study demonstrated the significant effects of sex and population origin (medium size), and a small effect size for age as predictors of 2D:4D. However, the average finger length was not a significant predictor for the right 2D:4D in accordance with recently reported data for adult Hadza males by other authors77. The effect of height as another potential marker of allometry on 2D:4D has not been detected in a limited sample of respondents until the age of 30; however, the data on height were tested for Europeans only. We do not know if the same peculiarities will be present in other large world populations as well as in older age cohorts. More data in this respect will be needed in the future to confirm these results.

Many previous studies have demonstrated that population/ethnic origin may be an important predictor for the 2D:4D ratio36,37,78,79,80,81,82, and our data support these conclusions. Along with numerous environmental factors, the heritability factor needs to be considered in this respect83,84,85. In particular, twin studies provide an estimate of approximately 60%76. Another support in favour of the inheritance of digit ratios has recently been presented by Chuvashian studies85,86. The clear familial aggregation of 2D:4D ratio variation in the Chuvashians, with significant parent–offspring and sibling correlations, was unrelated to common environmental effects. Hence, along with the various environmental and socio-cultural factors, certain genetic effects also need to be considered and tested with more care in the future.

In this study, we refrained from analysing the right-left difference in 2D:4D (D[R-L]). This was done deliberately, not only to limit the amount of information for analysis, but also for the following reasons: 1. the lack of studies on the validity of this marker; 2. using asymmetry in digits two and/or four may cause biases in the associations between asymmetry and digit ratios87; and 3. currently expressed concerns regarding the utility of D[R-L] as an indicator of prenatal androgen exposure22.

In summary, our data suggest that there is no reason to reject the sexual dimorphism of 2D:4D associated with both prenatal and postnatal factors. Hence, we should not throw the baby out with the bathwater. The sex differences in second and fourth digit lengths were not stable within ontogeny, and even reversed in adulthood, whereas 2D:4D ratios remained unchanged since six years of age. The ontogenetic transformations in finger lengths in boys and girls do not make the sex effect on 2D:4D less statistically significant. The effect size of sex was higher than the average digit length in all cases, and height (in the case of Europeans, less than 30 years of age). The theory according to which the sex difference in 2D:4D has been driven by the sex difference in digit length may have arisen from a misunderstanding and incorrect assumption ignoring the human growth pattern trajectory. The stability of 2D:4D may be an example of homeostasis of form, and our data completely support J. Manning and B. Fink’s idea30. Another important conclusion is that the degree to which androgenisation (2D:4D being a potential proxy) affects particular behaviour or morpho-physiological conditions may be population- and situation-specific and culturally mediated. Our data, along with currently accumulated information from different world populations, call for treating the allometric effect on 2D:4D with caution. It is worth stressing the importance of differentiation between the static and developmental allometry effects, and the necessity of considering as many factors as possible (genetics, particularly population origin, environmental and social factors affecting maturation, urbanisation effects, etc.) while searching for explanations of 2D:4D sex differences30,88. Populations currently undergoing rapid transformations due to global and local changes must be treated with special care. Representatives of different age cohorts may differ in their maturation patterns, particularly the timing and duration of growth morphological changes. Due to the small to medium effect sizes that are usually obtained, studies using 2D:4D may need to consider very large sample sizes in order to be of practical use89. However, 2D:4D remains a useful measure of sexual dimorphism for anthropologists. Along with a set of other sexually dimorphic traits, it may be used in projects dealing with ecological and socio-cultural transformations in growth and development in contemporary representatives from large- and small-scale societies.

Adolescent boys are less attentive in classroom settings than girls, but boys’ visuospatial abilities compensate for their relatively poor in-class attentive behavior in learning mathematics

Boys’ visuospatial abilities compensate for their relatively poor in-class attentive behavior in learning mathematics. David C. Geary, Mary K. Hoard, Lara Nugent. Journal of Experimental Child Psychology, Volume 211, November 2021, 105222. https://doi.org/10.1016/j.jecp.2021.105222

Highlights

• In-class attentive behavior is an important predictor of mathematics achievement.

• Adolescent boys are less attentive in classroom settings than girls (d = −.34).

• Controlling for attentive behavior, boys have advantages in mathematics achievement.

• The sex difference in mathematics achievement is fully mediated by spatial abilities.

Abstract: The mathematics and reading achievement of 322 adolescents (159 boys) was assessed in seventh and eighth grades, as were their intelligence, working memory, and spatial abilities. Their seventh- and eighth-grade mathematics and English language arts teachers reported on their in-class attentive behavior. The latter emerged as an important predictor of achievement, but more so for mathematics than for reading. Boy were less attentive in classroom settings than girls (d = −.34) and performed better than expected in mathematics given their level of engagement in the classroom. Boys’ better-than-expected mathematics achievement was related to advantages on visuospatial measures (ds = .28–.56), which fully mediated a sex difference in mathematics (ds = .27–.28) but not in reading achievement, with control of in-class attentive behavior. The results suggest that boys’ advantages in visuospatial skills compensate for lower levels of classroom engagement in the learning of mathematics but not in reading competencies.

David Schmitt's take: "if boys paid more attention..."controlling for in-class attentive behavior resulted in advantage for boys in math achievement (ds = .27 & .28 in seventh & eighth grades, resp)...no effects on reading"; sex diffs fully mediated by mental rotation abilities

Keywords: Mathematics achievementIn-class attentionSex differencesSpatial abilitiesAttention deficit disorderHyperactivity