Tuesday, March 29, 2022

The cat parasite Toxoplasma gondii might boost people's sexual attractiveness, possibly thru changes in facial symmetry

Borraz-León JI, Rantala MJ, Krams IA, Cerda-Molina AL, Contreras-Garduño J. 2022. Are Toxoplasma-infected subjects more attractive, symmetrical, or healthier than non-infected ones? Evidence from subjective and objective measurements. PeerJ 10:e13122. Mar 2022. https://doi.org/10.7717/peerj.13122

Abstract

Background: Parasites are among the main factors that negatively impact the health and reproductive success of organisms. However, if parasites diminish a host’s health and attractiveness to such an extent that finding a mate becomes almost impossible, the parasite would decrease its odds of reproducing and passing to the next generation. There is evidence that Toxoplasma gondii (T. gondii) manipulates phenotypic characteristics of its intermediate hosts to increase its spread. However, whether T. gondii manipulates phenotypic characteristics in humans remains poorly studied. Therefore, the present research had two main aims: (1) To compare traits associated with health and parasite resistance in Toxoplasma-infected and non-infected subjects. (2) To investigate whether other people perceive differences in attractiveness and health between Toxoplasma-infected and non-infected subjects of both sexes.

Methods: For the first aim, Toxoplasma-infected (n = 35) and non-infected subjects (n = 178) were compared for self-perceived attractiveness, number of sexual partners, number of minor ailments, body mass index, mate value, handgrip strength, facial fluctuating asymmetry, and facial width-to-height ratio. For the second aim, an independent group of 205 raters (59 men and 146 women) evaluated the attractiveness and perceived health of facial pictures of Toxoplasma-infected and non-infected subjects.

Results: First, we found that infected men had lower facial fluctuating asymmetry whereas infected women had lower body mass, lower body mass index, a tendency for lower facial fluctuating asymmetry, higher self-perceived attractiveness, and a higher number of sexual partners than non-infected ones. Then, we found that infected men and women were rated as more attractive and healthier than non-infected ones.

Conclusions: Our results suggest that some sexually transmitted parasites, such as T. gondii, may produce changes in the appearance and behavior of the human host, either as a by-product of the infection or as the result of the manipulation of the parasite to increase its spread to new hosts. Taken together, these results lay the foundation for future research on the manipulation of the human host by sexually transmitted pathogens and parasites.

Discussion

Limitations and future directions

Results showed that boys as young as age 3 generally valued strength more than girls: boys, on average, said it was more important to be strong than girls did, & were more likely to prefer strength-related occupations than girls

Early Gender Differences in Valuing Strength. May Ling D. Halim, Dylan J. Sakamoto, Lyric N. Russo, Kaelyn N. Echave, Miguel A. Portillo & Sachiko Tawa. Archives of Sexual Behavior, Mar 28 2022. https://link.springer.com/article/10.1007/s10508-021-02185-4

Abstract: Being strong is a prominent male stereotype that children learn early in life; however, it is unknown as to when children start to value being strong and when gender differences in valuing strength might emerge. In the current study, we interviewed an ethnically diverse sample of 168 3–5 year-olds (88 girls, 80 boys) to address this gap in the literature. Results showed that boys as young as age 3 generally valued strength more than girls: (1) boys, on average, said it was more important to be strong than girls did, and (2) boys were more likely to prefer strength-related occupations than girls. Boys were also more likely to select boys than girls as the gender who cares more about physical strength. Additionally, with age, both girls and boys demonstrated knowledge of the stereotype that boys care about physical strength, with girls also being less likely to associate being a girl with being strong. Overall, the results suggest that valuing physical strength starts in early childhood, and gender differences in valuing strength are evident at the eve of gender identity development. Possible implications for boys’ later well-being and health are discussed.


Individuals with higher income may exhibit profiles of adult personality development that more closely resemble aspects of a healthy personality

Income moderates changes in big-five personality traits across eighteen years. Vincent YS Oh, Ismaharif Ismail, Eddie MW Tong. European Journal of Personality, March 28, 2022. https://doi.org/10.1177/08902070221078479

Abstract: The role of income in adult personality change remains poorly understood. Using latent growth modeling, we performed exploratory analyses of how longitudinal trajectories of change in personal income and the Big Five personality traits would be related. We examined 4234 participants (2149 Males, 2085 Females; MT1age = 46.42, SDT1age = 13.36, age range at T1: 20–74 years) across three time points spanning 18 years using data from the Midlife in the United States study. Results indicated that starting levels of income moderated changes in four personality traits. Specifically, income moderated the slopes of openness to experience, extraversion, agreeableness, and neuroticism, such that for high-income individuals, openness to experience, extraversion, and agreeableness were less likely to decline and more likely to either increase or remain stable over time, while neuroticism was less likely to increase and more likely to remain stable over time. Conversely, personality traits were weaker predictors of income change as slopes of income were not moderated by starting levels of any of the personality traits. Moreover, changes in income were not correlated with changes in any of the personality traits. The findings suggest that individual differences in income could potentially explain diverging trajectories of personality change.

Keywords: big five, income, personality development, personality change, socioeconomic status


Women are unhappier than men in anxiety, depression, fearfulness, sadness, loneliness, & anger; are also less satisfied with many aspects of their lives such as democracy, the economy, the state of education and health services

The Female Happiness Paradox. David G. Blanchflower & Alex Bryson. NBER Working Paper 29893.  March 2022. https://www.nber.org/papers/w29893

Abstract: Using data across countries and over time we show that women are unhappier than men in unhappiness and negative affect equations, irrespective of the measure used – anxiety, depression, fearfulness, sadness, loneliness, anger – and they have more days with bad mental health and more restless sleep. Women are also less satisfied with many aspects of their lives such as democracy, the economy, the state of education and health services. They are also less happy in the moment in terms of peace and calm, cheerfulness, feeling active, vigorous, fresh and rested. However, prior evidence on gender differences in global wellbeing metrics – happiness and life satisfaction – is less clear cut. Differences vary over time, location, and with model specification and the inclusion of controls especially marital status. We also show that there are significant variations by month in happiness data regarding whether males are happier than females but find little variation by month in unhappiness data. It matters which months are sampled when measuring positive affect but not with negative affect. These monthly data reveal that women’s happiness was more adversely affected by the COVID shock than men’s, but also that women’s happiness rebounded more quickly suggesting resilience. As a result, we now find strong evidence that males have higher levels of both happiness and life satisfaction in recent years even before the onset of pandemic. As in the past they continue to have lower levels of unhappiness. A detailed analysis of several data files, with various metrics, for the UK confirms that men now are happier than women.


Monday, March 28, 2022

Genetic Link to Fear Memories Found Hiding Within Mice's "Junk DNA"

ADRAM is an experience-dependent long noncoding RNA that drives fear extinction through a direct interaction with the chaperone protein 14-3-3. Wei Wei et al. Cell Reports, Vol 38, Iss 12, Mar 22 2022. https://doi.org/10.1016/j.celrep.2022.110546

Highlights

• Targeted RNA sequencing reveals learning-induced lncRNAs in the adult brain

• ADRAM is critical for the formation of fear extinction memory

• ADRAM coordinates the epigenomic regulation of Nr4a

Summary: Here, we used RNA capture-seq to identify a large population of lncRNAs that are expressed in the infralimbic prefrontal cortex of adult male mice in response to fear-related learning. Combining these data with cell-type-specific ATAC-seq on neurons that had been selectively activated by fear extinction learning, we find inducible 434 lncRNAs that are derived from enhancer regions in the vicinity of protein-coding genes. In particular, we discover an experience-induced lncRNA we call ADRAM (activity-dependent lncRNA associated with memory) that acts as both a scaffold and a combinatorial guide to recruit the brain-enriched chaperone protein 14-3-3 to the promoter of the memory-associated immediate-early gene Nr4a2 and is required fear extinction memory. This study expands the lexicon of experience-dependent lncRNA activity in the brain and highlights enhancer-derived RNAs (eRNAs) as key players in the epigenomic regulation of gene expression associated with the formation of fear extinction memory.


Discussion

Here, we report the discovery of widespread experience-dependent lncRNA activity in the adult ILPFC, and further reveal a significant number of inducible eRNAs that respond selectively to fear extinction learning. This class of lncRNA was first discovered at scale more than a decade ago by the Greenberg group who identified thousands of sites outside known promoter regions in primary cortical neurons stimulated with KCl in vitro, which exhibited features of enhancer elements, including binding of CBP and the deposition of the histone modification H3K4me1 (). Transcriptional activity at these sites showed a positive correlation with downstream mRNA expression, suggesting a context-specific permissive relationship between eRNAs and their proximal mRNA partners.  went on to functionally characterize neuronal enhancers and identify another histone modification, H3K27ac, as a key marker of their active state. An overlay of our lncRNA capture-seq data with learning-induced enhancer signatures in the adult brain (), as well as our cell-type-specific ATAC-seq signatures in learning-activated Arc+ neurons, revealed that there are many experience-dependent lncRNAs in the ILPFC that are endowed with features of activity-inducible eRNAs. Notably, all six of the validated eRNA-associated protein-coding gene candidates have been shown to be involved in plasticity, suggesting that this class of lncRNA is, in general, permissively involved in the regulation of experience-dependent gene expression.
One of the most interesting findings of our study beyond the necessary role of ADRAM in fear extinction is that it binds directly to the Nr4a2 promoter; however, in doing so it does not form an R-loop or promote chromosome looping. trans-Acting lncRNAs are known to form triplex structures on double-stranded DNA using a Hoogsteen base-pairing rule in the DNA target (). These structures are distinct from R-loops and could represent a mechanism by which lncRNAs act in a combinatorial manner to simultaneously serve as both guides and scaffolds. Indeed, examination of the 1 kb upstream promoter sequence of NR4A2 revealed two sites proximal to the TSS, with 25 nucleotide long complementary sequences found within exon III of ADRAM. Notably, these sites overlap with G-quadruplex motifs that are predicted to enable triplex formation. These findings suggest that ADRAM functions as a guide via a direct interaction with the Nr4a2 promoter and may do so via the formation of an RNA:DNA triplex at sites of structural reactivity. Future studies will investigate whether dynamic DNA structure states are the key to how lncRNAs find their genomic targets to regulate gene expression in an experience-dependent manner.
The 14-3-3 family of evolutionarily conserved chaperone proteins is ubiquitously expressed in the brain and highly enriched at the synapse () being involved in a variety of neuronal processes, including synaptic plasticity (). Our discovery of a direct interaction between ADRAM and 14-3-3 extends the capabilities of this class of chaperones to include functional activity as both an RNA-binding protein and a molecule that exerts its influence through protein-protein interactions. This is not without precedent as many proteins are able to interact with RNA, DNA, and other proteins. For example, YY1 interacts with both RNA and DNA, as well as other proteins, to promote its role as a regulator at the Xist locus (). Together with the observation that 14-3-3 is involved in learning and memory (), and our demonstration of how 14-3-3 interacts with eRNA to facilitate gene expression in fear extinction, these findings advance our understanding of the functional importance of this class of chaperones in the brain.
Histone modifications at neuronal enhancers also appear to be a requirement for the induction of activity-dependent genes and are particularly important in the case of rapidly induced immediate-early genes (). We found a broad overlap with H3K27ac, an open chromatin ATAC signature in activated neurons, and the expression of lncRNAs. Previous work has shown that eRNA activity often precedes, and then drives, the expression of immediate-early genes, such as c-Fos, which occurs via a direct interaction with the histone acetyltransferase domain of CBP (). In addition, a large number of eRNAs have been shown to bind to CBP, correlating with the expression of downstream genes that require CBP for their induction (). Our data on the functional relationship between ADRAM, HDAC3, HDAC4, CBP, and Nr4a2 agree with these observations and, importantly, extend the findings to include the ILPFC where they are critically involved in fear extinction. Our conclusion is that ADRAM functions as both a guide and a scaffold to epigenomically regulate extinction learning-induced Nr4a2 expression. There are now many examples of multifunctional lncRNAs. For example, in dopaminergic neurons, antisense Uchl1 regulates the expression of Uchl1 in the nucleus and then shuttles to the cytoplasm where it promotes Uchl1 translation (). Furthermore, owing to its modular domain structure, Neat1 functions in cis to coordinate the deposition of learning-related repressive chromatin modifiers along the genome () and in trans to govern paraspeckle assembly by influencing phase separation ().
In summary, the discovery of an lncRNA that is required for fear extinction deepens our understanding of learning-induced epigenomic mechanisms by integrating the modular function of enhancer-derived lncRNAs with key epigenomic processes involved in memory, and answers the long-standing question of how certain HDACs and CBP coordinate to confer their influence on localized gene regulation with a high degree of state-dependent selectivity. LncRNAs therefore provide a bridge to link dynamic environmental signals with epigenomic mechanisms of gene regulation. Together, these findings broaden the scope of experience-dependent lncRNA activity, and underscore the importance of considering eRNAs in the adult cortex as potential therapeutic targets for fear-related neuropsychiatric disorders.

 Limitations of the study

In this work, we identify an enhancer-derived lncRNA that is necessary for the formation of fear extinction memory in male mice. However, an examination of ADRAM and Nr4a2 mRNA expression in the ILPFC after extinction learning in randomly cycling females revealed no increase in ADRAM expression in the female ILPFC. In contrast, Nr4a2 was induced by training in both males and females (Figure S9). These results indicate that, although Nr4a2 may be generally induced by experience in both sexes, it may not be regulated by ADRAM under conditions where successful extinction does not occur. With respect to sex differences in fear extinction, we have also previously found that male and female mice respond differently to the standard extinction protocol used in our laboratory (

) and that the electrophysiological signature in the prelimbic PFC during fear extinction is very different between males and females (

, 

). Therefore, it is highly plausible that there are female-specific molecular mechanisms that are involved in fear-related learning. Future studies on the role of lncRNAs in fear extinction in females will require the use of a sex-specific learning protocol to reveal brain region-specific molecular mechanisms underlying memory in these mice. In addition, although we have demonstrated that 14-3-3 is a key regulatory protein that interacts with ADRAM, there were other candidates identified by mass spectrometry that have not been validated. At this stage, these data should therefore be considered preliminary until further experiments are carried out. Finally, it is not yet known whether ADRAM is necessary for other forms of learning. 

Sunday, March 27, 2022

A decade ago, now-seminal work showed that children are strikingly unskilled at simple tool innovation; since then, a surge of research has replicated these findings across diverse cultures

After a decade of tool innovation, what comes next? Bruce S. Rawlings. Child Development Perspectives, March 24 2022. https://doi.org/10.1111/cdep.12451

Abstract: A decade ago, now-seminal work showed that children are strikingly unskilled at simple tool innovation. Since then, a surge of research has replicated these findings across diverse cultures, which has stimulated evocative yet unanswered questions. Humans are celebrated among the animal kingdom for our proclivity to create and use tools and have the most complex and diverse technology on earth. Our capacity for tool use has altered our ecological environments irrevocably. How can we achieve so much, yet tool innovation be such a difficult and late-developing skill for children? In this article, I briefly summarize what we know about the development of tool innovation, then discuss five outstanding questions in the field. With a focus on different empirical and theoretical perspectives, I argue that addressing these questions is crucial for understanding fully the ontogeny of one of humans’ most notable skills.


DOES FORMAL EDUCATION AFFECT INNOVATION?

In its 2020 Workplace Learning Report, LinkedIn, the global employment company, surveyed professionals in 18 countries, finding that creativity was employees’ most desired soft skill (LinkedIn, 2020). Surveys such as these highlight the increasing demand for innovative and creative skills as valuable economic resources and have motivated global research and educational initiatives exploring whether these skills can be taught in formal education settings (Qian et al., 2019). The impact of formal education on creativity and innovation remains a debated topic. Some argue that the focus of most educational institutions on norm following, rote learning, and standardized teaching and assessments inhibits creative and innovative expression (Goens & Streifer, 2013). Others contend that the experiences afforded by schools, such as wider social interaction, collaboration, and exposure to novel information, promote these skills (Sahlberg, 2009).

To my knowledge, no study has directly assessed the impact of formal education on innovation. However, indirect evidence suggests that exposure to and the quality of formal education may be influential. In one study, 8- to 18-year-olds from the Tsimane population of Amazonian Bolivia who attended high-quality schools outperformed children of the same age and region who went to low-quality schools on abstract reasoning and problem-solving tasks; also, the performance of the children who went to high-quality schools improved significantly more over time (Davis et al., 2021). In developmental studies and research with adults, richer and more diverse social experiences (which attending school presumably promotes) facilitate innovation (Baer et al., 2015; Rawlings, 2018). However, proponents of informal education correctly highlight the cognitive and social benefits of learning outside of school contexts (Sefton-Green, 2012), including how such learning relates to divergent thinking (Dahlman et al., 2013).

These findings are indirect observations, and it is difficult to draw strong conclusions about the relation between formal education and innovation without direct assessments. Given the importance of innovation as a major skill of the 21st century, whether schools can foster the next generation of innovative minds is a topic of global interest. Researchers should examine if and how school curricula, attendance, and academic achievement shape innovation. Even within formal educational settings, approaches to education vary, and work is needed to examine whether specific educational philosophies or activities (e.g., engaging in innovative problem solving, peer collaboration) promote innovation, and whether others (e.g., rote learning, standardized assessments) hinder it. Many schools promote convergent problem solving, focusing on single, correct solutions (e.g., in mathematical problem solving); how does this affect tool innovation? Does informal education shape innovation and if so, how? The globalization of formal education provides a unique and time-sensitive opportunity to document the impact of formal and informal education on the next generation of innovators.

CONCLUSION

Humans’ proclivity to make and use tools is one of our most distinguished skills, allowing us to survive and prosper in diverse and harsh environments. Particularly puzzling, then, is that tool innovation is such a difficult and late-developing skill. Although the field has made significant progress over the past decade, many outstanding questions remain, and using theoretically derived empirical research to answer them will allow us to make significant strides in our understanding of the development of tool innovation. However, doing so will require rigorous planning, and addressing each question posed here presents unique challenges.

Understanding why tool innovation is so difficult for children calls for disentangling the contributions of cognitive, social, and environmental factors through carefully designed experiments. It also requires introspection about the definitions and methods we currently use to assess tool innovation. Conducting cross-cultural work requires striking a balance between control and generalizability across populations, versus implementing culturally appropriate tool innovation measures, to draw fair comparative conclusions.

This is a difficult endeavor that can only be tackled by extensive piloting alongside collaboration with local researchers and community members. Understanding the trajectory of tool innovation abilities beyond childhood necessitates designing tasks and paradigms that ostensibly capture the same skills and processes in children, adolescents, and adults—a feat the field has yet to achieve. Studying how tool innovation transfers across domains will involve establishing a variety of appropriate measures of innovation and creativity, ideally with longitudinal data to document consistency over time. Finally, examining the association between formal education and innovative skills requires collating measures of school quality and educational philosophy, which vary meaningfully across samples as well as within and across nations. If these challenges are overcome, the field will move forward in a way not before seen. 

Professors are generally not seen as highly narcissistic, though they are viewed as more narcissistic than elementary school teachers

Perceptions of narcissism in college professors. Harry M. Wallace, Alejandro Carrillo & Jack Kelley. The Journal of Social Psychology, Mar 20 2022. https://doi.org/10.1080/00224545.2022.2050167

Abstract: We conducted three studies to examine perceptions of grandiose narcissism in college professors. Narcissism might appear incompatible with the profession if professors are viewed fundamentally as helpers or as introverted bookworms. Then again, people might expect professors to display big egos congruent with the prestige of their profession and their privileged public platforms. Our research indicates that professors are generally not seen as highly narcissistic according to the criteria of the Narcissistic Personality Inventory and the Narcissistic Admiration and Rivalry Questionnaire, though they are viewed as more narcissistic than elementary school teachers. More professor narcissism was expected at colleges that prioritize scholarly productivity over teaching excellence. Male professors were viewed as more narcissistic, but only for narcissism dimensions associated with interpersonal hostility and for judgments of whether professors are “narcissistic.” We discuss possible implications for narcissistic professors’ ability to exploit the gap between academic ideals and reward system realities.

Keywords: Narcissismprofessorteachingacademiastereotype


While 'misery loves company' is indeed borne out among certain populations within the sample, we find stronger and more widespread support for the opposite phenomenon, suggesting rather that ‘happiness hates company’

Does misery love company? An experimental investigation. Katherine Farrow, Gilles Grolleau, Lisette Ibanez. Oxford Economic Papers, Volume 74, Issue 2, April 2022, Pages 523–540, https://doi.org/10.1093/oep/gpab011

Abstract: The conventional wisdom summarized in the adage ‘misery loves company’ suggests that suffering can be made easier to bear if it is also shared by others. Given increasing interest in subjective well-being and happiness as constituents of national wealth and priorities in policy-making and organizational management, we empirically investigate the validity of this phenomenon in order to explore whether it may be possible to mitigate decreases in subjective well-being simply by leveraging social comparison. We implement an experimental survey designed to gauge the suitability of this strategy on a representative sample of approximately 2,000 US residents. Our results indicate that, while this hypothesis is indeed borne out among certain populations within the sample, we find stronger and more widespread support for the opposite phenomenon, suggesting rather that ‘happiness hates company’. These novel findings can inform policy interventions aiming to enhance well-being and point to promising avenues for further work.

JEL C90 - GeneralD03 - Behavioral Microeconomics: Underlying PrinciplesD60 - GeneralI31 - General Welfare


People with gender disphoria, particularly male-to-female, want to have children more than cisgenders

Fertility Desire and Motivation Among Individuals with Gender Dysphoria: A Comparative Study. Emre Durcan et al. Journal of Sex & Marital Therapy, Mar 25 2022. https://doi.org/10.1080/0092623X.2022.2053617

Abstract: Despite receiving Gender-Affirming Hormone Therapy or Gender-Affirming Surgery, which may adversely impact their fertility, people with Gender Dysphoria (GD) may desire to form families. In this study, we aimed to quantitatively display fertility desire from the perspective of these individuals, despite all the legal challenges they face. The single center, cross-sectional comparative study included individuals with GD and cisgender volunteers. A Sociodemographic Data Form, the Fertility Desire Data Form, the Childbearing Motivations Scale and the Fertility Desire Scale were used. Of the 414 participants, 171 were individuals with GD (110 FtM; 61 MtF) and 243 were cisgender volunteers (142 cis-males; 101 cis-females). While 22% of the people with GD stated that they had regrets about not undergoing fertility preservation, 16% stated that they would like this process if it were legal. People with GD, particularly MtF, want to have children more than cisgenders. Moreover, people with MtF exhibited less negative motivations toward becoming parents, despite having reservations regarding the socioeconomic aspect of parenthood. Our findings indicate that fertility desire in people with GD is not less in comparison to cisgender people. Healthcare professionals should not forget to offer fertility preservation options as part of clinical practice before Gender-Affirming Therapy.


We stick to our romantic relationships even when we discover "dealbreakers" in a partner that presumably make the person unsuitable as a mate

Dealbreakers, or dealbenders? Capturing the cumulative effects of partner information on mate choice. Samantha Joel, Nicolyn Charlot. Journal of Experimental Social Psychology, Volume 101, July 2022, 104328. https://doi.org/10.1016/j.jesp.2022.104328

Abstract: Entering and establishing a long-term relationship is typically a gradual process, as dating partners acquire information about each other over weeks or months. In contrast, existing mate selection paradigms (e.g., lab experiments, speed-dating) typically examine single brief encounters with real or potential mates. In the current research, we used a Choose Your Own Adventure design to examine how potential dealbreakers operate within the context of a broader relationship dynamic. In two studies, a combined total of 1585 participants read a story about a new dating relationship. At each of 17 junctures in the story, participants chose whether to continue dating or end the relationship. Potential dealbreakers were independently manipulated to be present or absent at each juncture, for a total of up to 17 negative pieces of information about the partner. Study 2 was a preregistered replication and extension of Study 1. On average, participants did not reject the hypothetical partner until several potential dealbreakers had been presented (M = 4.20 in Study 1, M = 3.68 in Study 2). Participants' self-reported dealbreakers consistently aligned with their in-story decisions. Even so, participants tended to encounter at least two of their own personal dealbreakers before choosing to reject (Study 2). Together, these studies highlight the sequential, iterative nature of partner evaluations, and illustrate a novel, accessible method for testing models of early relationship development.

Keywords: Romantic relationshipsMate choiceDealbreakersFledgling relationshipsRelationship developmentCompatibility


Saturday, March 26, 2022

Like adults, children aged 4-8 years and 8-14 years also perceived many illusory faces in objects to have a gender and had a strong bias to see them as male rather than female, regardless of their own gender identification

Wardle, Susan G., Louise Ewing, George L. Malcolm, Sanika Paranjape, and Chris I. Baker. 2022. “Children Perceive Illusory Faces in Objects as Male More Often Than Female.” PsyArXiv. March 25. doi:10.31234/osf.io/fhrbg

Abstract: Face pareidolia is the experience of seeing illusory faces in inanimate objects. Such illusory faces are frequently perceived to have characteristics along social dimensions such as age, gender and emotional expression, suggesting engagement of our face evaluation system. Recently it was shown that adults have a bias to see illusory faces as male more often than female. While children also experience face pareidolia, it is unknown whether they also perceive gender in illusory faces and if so, whether they also show a male bias. Here we investigated the perception of illusory faces and gender in a sample of 412 children and adults from 4 years to 80 years of age. The face pareidolia stimuli were 160 color photographs of illusory faces spontaneously observed in a variety of objects such as food, vehicles, and household items. Participants of all ages saw illusory faces in most stimuli. Like adults, children aged 4-8 years and 8-14 years also perceived many illusory faces in objects to have a gender and had a strong bias to see them as male rather than female, regardless of their own gender identification. These results provide evidence that the male bias for face pareidolia emerges relatively early in the lifespan, even before the ability to discriminate gender from facial cues alone is fully developed. Further, the existence of a male bias in children suggests that any social context that elicits the cognitive bias to see faces as male has remained relatively consistent across recent generations.



Sexual availability cues were judged most effective flirtation tactic when employed by women in short-term mating contexts, while laughing or giggling at someone's jokes was judged an effective flirtation tactic for both sexes

Perceived Effectiveness of Flirtation Tactics: The Effects of sex, Mating Context and Individual Differences in US and Norwegian Samples. Leif Edward Ottesen Kennair et al. Evolutionary Psychology, March 25, 2022. https://doi.org/10.1177/14747049221088011

Abstract: Flirting involves various signals communicated between individuals. To attract potential mates, men and women exhibit flirtatious behavior to get the attention of, and potentially elicit sexual or romantic interest from, a desired partner. In this first large, preregistered study of judgement of the effectiveness of flirtation tactics based on Sexual Strategies Theory, we considered the effects of flirter’s (actor) sex and mating contexts in addition to rater's (participant) sex across two cultures, Norway and the U.S. Culturally relevant covariates such as sociosexuality, extraversion, mate value, age, and religiosity were examined. Participants from Norway (N = 415, 56% women) and the US (N = 577, 69% women) responded to one of four different randomized questionnaires representing a factorial design considering either short-term versus long-term mating context and either female or male sex of actor. We found that sexual availability cues were judged more effective when employed by women in short-term mating contexts. Friendly contact, such as hugs or kissing on the cheek, was not. Cues to generosity and commitment were judged more effective when employed by men in long-term mating contexts. Humor was rated as more effective when used by men and in long-term contexts, and least effective when used by women in short term contexts. However, laughing or giggling at someone's jokes was an effective flirtation tactic for both sexes. Overall, predictions for culturally relevant covariates were not supported, but cultural differences were found in bodily displays, initial contact, and generosity. These findings dovetail neatly with findings from the self-promotion literature, and further support that flirtation is a universal mate signaling strategy.

Keywords: flirtation, sexual strategies theory, commitment, sexual availability, mate value, extraversion, sociosexuality, religiosity

This large-scale study attempts to measure the perceived efficacy of flirtation tactics across two cultures using Sexual Strategies Theory (SST), and provides valuable insights into flirting based on sex, mating context, and culture. There was consensus across the sexes as to which flirtation tactics are most effective and in which mating context they are most effective. In addition, the most robust SST hypotheses are supported in this study, in both samples as well as the total sample, dovetailing neatly with the findings from the work on other mate acquisition tactics (Bendixen & Kennair, 2015Schmitt & Buss, 1996), most recently in a Greek cultural context (Apostolou, Wang, & Gavriilidou, 2021). It also supports the established research on humor's role in attraction and mate value.

As was predicted (H1), flirtation tactics that included cues to sexual availability such as displaying the body, dressing sexy, and sexualized physical contact were judged as more effective when they are employed by women in a short-term mating context. Less sexual, friendly contact was not. The taxonomy of flirtation tactics has therefore become more finely differentiated with the post hoc analyses in this study, highlighting how different types of contact seeking behavior may be perceived as more or less friendly or sexual. It is important to note that H1 was formulated with more sexually laden physical contact behaviors in mind, and that the more the behaviors were in line with that reasoning the larger the sex difference was and thus the more the prediction was supported.

Additionally (H2–H4), flirtation tactics that included cues to generosity and commitment, like intimate conversation and spending time together, were judged as more effective when they were employed in a long-term mating context, specifically by men. In line with SST, both sex and mating context are relevant for flirtation tactics, especially these most robust predictions based on previous research. Overall, these data thus support work initiated by Schmitt and Buss (1996), creating consistency of findings on the effectiveness of different mate acquisition tactics within specific domains across time and culture.

The prediction that seeking attention and contact through comments, chats, and compliments would be more effective in a short-term context (H5) was not supported. However, these comments and compliments may be perceived, particularly by women, as a form of investment, just as intimate conversations were. Women did find these effective in a long-term context, just as they did intimate conversations. Verbal investment or committed attention, such as light conversations/chats, compliments, random comments, and texts, even if it is not prolonged or intimate, may signal continued (even if small) investment. Hess, Fannin, and Pollom (2007) identified three strategies men and women used for increasing closeness in romantic relationships; openness (willingness to share personal information, to seek out and share time together), attention (attending to and trying to remember the other's messages), and involvement (making the effort to be alone with the other). It is this effect that committed attention has on closeness that may be key to it being perceived as effective in long-term contexts.

The differences in humor (H6) were particularly interesting, even if they were expected. Humor production was rated as more effective when used by men and more effective in long-term contexts, and the least effective when used by women in short-term contexts. However, responding to humor through laughing or giggling (H7) was considered an equally effective flirtation tactic for both men and women. Laughing at someone's jokes, regardless of whom they are, is seen as effective flirting. In addition, there was no support for participant sex differences in perceptions of flirtation tactics (H8). Male participants did not find sexual availability tactics more effective than women.

Individual Differences

Overall, the predictions on individual differences, such as sociosexuality, extraversion, mate value, and religiosity, were not supported (H9–H12). More importantly, for the whole sample, the associations between these four variables and flirtation tactics were very small (see Table 5). Of these variables, sociosexuality showed the greatest effects. Yet, even then, the effect was small and it did not moderate the effects of other predictors. This is in line with Bendixen and Kennair (2015), who found significant associations with SOI and increased perceived effectiveness of sexual availability tactics on the one hand and reduced perceived effectiveness of signaling love and commitment tactics on the other. Further, Howell, Etchells, and Penton-Voak (2012) found that people high in sociosexuality, regardless of sex, perceived potential mates as more flirtatious. One would expect that those high in SOI would rate any number of tactics as more effective for flirting, and yet the strongest association was found in unrestricted participants rating generosity somewhat less effective. One issue here may be context. While Penke and Asendorpf (2008) studied flirting and SOI, they assumed this was with the goal of short-term mating, an assumption specifically acknowledged in a footnote in the study. In this study, flirting behaviors that were rated as more effective in long-term contexts in the sample as a whole were rated (albeit slightly) lower in effectiveness as SOI rose. If high SOI individuals do flirt with the express goal of short-term mating as Penke and Asendorpf (2008) assumed, their ratings would (and do) shift in this direction based on mating context. However, this still does not explain the lack of clear-cut differences in SOI ratings by mating context in the sample. Mating context may not have mattered for SOI ratings since short-term mating may be used to test for long-term mate potential (Schmitt & Buss, 1993). Overall, restricted as well as unrestricted individuals may be flirting to secure long-term mates. However, the individual factors may be primarily relevant for participants when they themselves are in a flirting situation.

Cultural Differences

It is important to note that some cultural differences were found in perceived flirting effectiveness. In particular, the US sample rated bodily displays and initial contact as more effective flirting techniques. The US participants also rated generosity as an effective strategy, but particularly male generosity in long-term mating contexts. While the U.S. and Norway may be expected to be similar, as they are both WEIRD (Western, Educated, Industrialized, Rich, and Democratic) samples (Henrich, Heine, & Norenzayan, 2010), they do meaningfully diverge on aspect relevant to the current topic; especially on gender equality, sexual liberalism (sociosexuality) and religiosity as found in this and in a comparable previous study (Bendixen et al., 2017). This may provide an interesting, albeit indirect insight; that some variation persists even in cultures meeting the restrictive criteria of WEIRD samples, and further investigation could identify specific cultural factors (like the items listed above) that trigger similar behavioral patterns in other cultures. However, these current research findings show that this cultural variation is overshadowed by consistent differences based on sex and mating context. Limitations and future research

Despite being a pre-registered study, the factorial design with participants being randomly assigned to one of four conditions, and having previous research to build upon, there are limitations involved in how specific such a plan for research is specified. In the current project we noticed that we should have been more detailed in how we defined specific groups of tactics: the factor analysis thus is post hoc and more specific than the preregistration. However, the preliminary analyses of the Norwegian results panned out in the American data. Thus, we have an internal replication; there were no interactions with nation. The universality and replicability of the current findings needs to be addressed in future studies, preferably employing non-WEIRD samples (Henrich, Heine, & Norenzayan, 2010). The current research included heterosexual participants only, which some might think is also a limitation. However, recent research with United States and Canadian participants indicates that sexual orientation does not predict flirting techniques (Clark, Oswald, & Pedersen, 2021).

Regarding the individual characteristics studied: SOI, mate value, extraversion, and religiosity, it appears that the hypothetical nature of the study plays a key role. Participants appear to be able to discern the effectiveness of a flirtation tactic regardless of their tendency or desire to engage in said tactic. While this seems like an obscure or insignificant observation, this is important for research in sexuality, especially in younger samples; a participant does not have to be actively engaging in a romantic or sexual behavior to recognize its effectiveness. In fact, by framing the study in this way, researchers can remove obstacles that are found in studying performed behaviors. For example, Penke and Asendorpf (2008) found that behaviors in high SOI individuals were limited by their relationship status and their partners’ sexual preferences. Those limitations were removed in this current experimental framework.

There are many diverse possible behaviors that may be included under the heading of flirtation tactics (Wade & Feldman, 2016). While some of these are verbal and others non-verbal, still others may be categorized according to different domains of content, such as generosity or sexual availability, as in this study. While the current work attempted to organize and categorize a varied cache of flirtation tactics, more work on the taxonomy of the many possible different flirtation tactics is warranted, building on the current factor analysis. In addition, the combination of these categories can be explored. Men and women often combine tactic categories to test and increase their effectiveness; men may combine generosity and intimate conversation to indicate multileveled investment, women may combine laughing at jokes and physical touch to indicate interest more effectively. These combinations warrant further study. Such combination might also include the added effect of a factor that seemed fundamental in the Norwegian dataset, but that, alas, was not included in the American study: Smiling and establishing eye contact. These and other more precise future predictions will be informed by better defined groups of tactics.