Data from 99 countries: More time was spent enhancing beauty by women (almost 4 h a day, on average) than by men (3.6 h a day), & by the youngest participants (and contrary to predictions, also the oldest)

Predictors of enhancing human physical attractiveness: Data from 93 countries. Marta Kowal et al. Evolution and Human Behavior, September 6 2022. https://doi.org/10.1016/j.evolhumbehav.2022.08.003

Abstract: People across the world and throughout history have gone to great lengths to enhance their physical appearance. Evolutionary psychologists and ethologists have largely attempted to explain this phenomenon via mating preferences and strategies. Here, we test one of the most popular evolutionary hypotheses for beauty-enhancing behaviors, drawn from mating market and parasite stress perspectives, in a large cross-cultural sample. We also test hypotheses drawn from other influential and non-mutually exclusive theoretical frameworks, from biosocial role theory to a cultural media perspective. Survey data from 93,158 human participants across 93 countries provide evidence that behaviors such as applying makeup or using other cosmetics, hair grooming, clothing style, caring for body hygiene, and exercising or following a specific diet for the specific purpose of improving ones physical attractiveness, are universal. Indeed, 99% of participants reported spending >10 min a day performing beauty-enhancing behaviors. The results largely support evolutionary hypotheses: more time was spent enhancing beauty by women (almost 4 h a day, on average) than by men (3.6 h a day), by the youngest participants (and contrary to predictions, also the oldest), by those with a relatively more severe history of infectious diseases, and by participants currently dating compared to those in established relationships. The strongest predictor of attractiveness-enhancing behaviors was social media usage. Other predictors, in order of effect size, included adhering to traditional gender roles, residing in countries with less gender equality, considering oneself as highly attractive or, conversely, highly unattractive, TV watching time, higher socioeconomic status, right-wing political beliefs, a lower level of education, and personal individualistic attitudes. This study provides novel insight into universal beauty-enhancing behaviors by unifying evolutionary theory with several other complimentary perspectives.

Keywords: Evolutionary theoryMating market perspectivePathogen stressAppearanceSelf-modificationSocial media usage

4. General discussion

Many scholars have called for a large-scale study on primarily non-Western samples to comprehensively examine predictors of activities aimed at improving physical attractiveness in humans (see, e.g., Bradshaw and DelPriore, 2021; Davis and Arnocky, 2020; Wagstaff, 2018). The present multi-national investigation addressed this core need by testing evolutionarily-driven hypotheses, alongside several other influential hypotheses regarding beauty-enhancing behaviors that have not been jointly and empirically verified in a large-scale global investigation.

4.1. Mating market perspective

We observed that globally, while both sexes spent approximately an average of 4 h a day on behaviors specifically aimed at improving their attractiveness, women reported spending an average of 23 more minutes a day enhancing their beauty than did men. The effect size of this gender difference was moderate compared to other predictors and in general, corroborates the results of previous studies (see, e.g., Biesterbos et al., 2013; Corson, 1972; Ficheux et al., 2016; Gunn, 1973). For instance, cosmetics generally increase women's attractiveness as rated by themselves (Anchieta et al., 2021) and by others (e.g., Tagai, Ohtaka, and Nittono, 2016). Future studies are still needed to disentangle whether the main motive to increase one's attractiveness for women is to attract other mates, retain a current mate (Davis and Arnocky, 2020), increase one's social status (Bradshaw and DelPriore, 2021), or a combination of these and other factors.

Apart from cosmetics usage, we show that many other activities are undertaken across cultures to increase physical attractiveness (Davis and Arnocky, 2020). One such activity is physical exercise. Previous studies found that men exercise more than women do (Deaner and Smith, 2013; Hsu and Valentova, 2020; Mafra, Castro, and Lopes, 2016; Sallis, Zakarian, Hovell, and Hofstetter, 1996), and that men's motivation to exercise, at least in part, stems from their desire to increase their attractiveness (Antonova and Merenkov, 2020). We observed the same pattern of results in our study. The mating market perspective provides a plausible explanation for this phenomenon: physical training increases male formidability and strength, which, in ancestral times, were related both directly and indirectly to ancestral males' and their partners' fitness (Sell et al., 2009; von Rueden et al., 2008). Strength is often closely connected to men's bodily attractiveness (Lidborg, Cross, & Boothroyd, 2022; Sell, Lukazsweski, and Townsley, 2017), as is muscularity (Frederick and Haselton, 2007). Fat-free muscle mass has been linked to having more sex partners (Lassek and Gaulin, 2009). However, when all types of activities aimed at increasing one's beauty were considered here, it was still women who spent more time daily enhancing their appearance compared to men, which confirms the first hypothesis.

The current study partly corroborated our second hypothesis. The results showed a U-shaped relationship between the intensity of beauty-enhancing behaviors and age, but only among women. This implies that middle-aged women spent the least amount of time improving their attractiveness (see Fig. 3). To put this into perspective, 18-year-old women spent 63 more minutes a day enhancing their appearance than did 44-year old women, whereas 60-year-old women spent 30 more minutes than did 44-year old women, on average. This effect size was large compared to other predictors. According to the mate preferences perspective, younger individuals of reproductive age should be more interested in attracting potential mates because their own reproductive potential is relatively high (Fitzgerald et al., 1998; World Health Organization, 2006). Once reaching a certain age, an individual may realize the footprint of time on their face and body (e.g., wrinkles, graying hair, weight gain; Winterich, 2007). Ficheux et al. (2016) found that older French people used more cosmetics than their younger counterparts. Women aged 40 years or older who wear make-up appear younger than same-aged women who do not wear make-up (Russell et al., 2019), though this effect is not present among women aged 30 years or less. Notably, the perceived adverse effects of time on appearance are often more severe in the case of women than men (Gerbner, Gross, Signorielli, and Morgan, 1980; Lauzen and Dozier, 2005), which is in line with the results of the present study, as age was unrelated to time spent enhancing attractiveness by men.

Surprisingly, we found evidence against the third hypothesis: being in a relationship was linked to more, not less, intense beauty-enhancing behaviors. However, after a closer inspection, we observed that dating individuals spent more time improving their appearance than did single people (on average 24 min more a day), married people (26 min more), and individuals in committed relationships (29 min more). This result is especially interesting, as it may explain the inconsistent findings of past research (see, e.g., Fisher et al., 2009; Mafra et al., 2020; Miguel and Buss, 2011; Perilloux and Buss, 2008). The mating market perspective surmises that individuals who are not pair-bonded are highly interested in finding a potential mate (Buss, 2015). Hence, dating individuals may fall into this category, as they are actively pursuing a potential partner. Conversely, individuals in committed relationships including marriage are already pair-bonded, and thus, are typically less interested in finding a new mate. At the same time, single individuals may opt not to pursue a mate and conscientiously decline using any strategies (including self-modification) to acquire one. The present results do question previous hypotheses on improving one's appearance as a tactic to retain current partners (Davis and Arnocky, 2020). It seems that such a motive, among many others previously identified in the literature, such as intrasexual competition (Mafra et al., 2020; Varella, Valentova, and Fernández, 2017), social prestige (Mileva, 2016), and status-seeking (Blake, 2021), might be less pronounced compared to the motive of attracting a potential partner. Thus, to disentangle the influence of relationship status on beauty enhancing behaviors, researchers should control the type of relationship more specifically–not only controlling whether individuals are in a relationship, but also whether they are currently courting.

4.2. Pathogen prevalence

We found evidence for the fifth hypothesis and less consistent evidence for the fourth. Individuals with a more severe history of transmittable diseases spent relatively more time improving their appearance, but the relationship between country-level pathogen prevalence and beauty-enhancing behaviors only emerged when using the pathogen prevalence index from Fincher et al. (2008), but not from Murray and Schaller (2010). The effect size for the individual level pathogen history was moderate compared to other predictors. Interestingly, the link between time spent enhancing one's attractiveness and individual history of transmittable diseases was more pronounced for men than women. It is noteworthy that the immunosuppressive effects of circulating testosterone, that are higher in men than women, may make men more vulnerable to pathogens than women (Furman et al., 2014; Giefing-Kröll, Berger, Lepperdinger, and Grubeck-Loebenstein, 2015).

The pathogen prevalence index (Murray and Schaller, 2010), which was introduced as a country-level predictor variable, was drawn from historical data on the severity of transmittable diseases in given countries. It may be that the effects of modernization and globalization are slowly leveling traditional inequalities in access to health care. Thus, countries that struggled with severe diseases in the past (e.g., Burkina Faso, Burundi, and the Central African Republic; Bhargava, Jamison, Lau, and Murray, 2001) may now provide better healthcare for their citizens (WHO, 2000). We conclude that it might be preferred to consider more contemporary approaches to computing pathogen prevalence (Fincher et al., 2008) when analyzing phenomena that are strongly affected by the current socio-environmental conditions more than those of the distant past (i.e., behaviors aimed at increasing one's physical attractiveness; Blake, 2022; Mafra et al., 2020).

When considering an individual's history of pathogen stress, we observed that those who suffered from more transmittable diseases in their lifetimes also spent more time enhancing their beauty than did those who reported a more favorable health history. On average, those who suffered from one or more diseases spent as much as 1.5 h more improving their appearance compared to those who did not encounter any severe infections in their lifetimes. Physical attractiveness can indicate the absence of underlying diseases (Tybur and Gangestad, 2011; but see Jones, Holzleitner, and Shiramizu, 2021), and it may be that people are aware of this link (Gray and Boothroyd, 2012; Henderson and Anglin, 2003). Indeed, Fink et al. (2017) showed that ratings of facial healthiness correlate with ratings of facial attractiveness. On the other hand, individuals who are perceived as unhealthy and less attractive might evoke negative psychological and physiological responses (e.g., disgust; Principe and Langlois, 2011; Schein and Langlois, 2015). Individuals who have undergone severe diseases may have more visible perceived imperfections (e.g., asymmetries or flawed skin condition; Samson, Fink, and Matts, 2010). As evidenced by Wakeda, Okamura, Kawahara, and Heike (2020), such individuals might be more motivated to cover these imperfections to present themselves as healthier (and more attractive) than they actually are. An alternative but not mutually exclusive explanation would be that performing beauty-enhancing behaviors by individuals who suffered from infectious diseases might simply take more time than performing those same behavior by their counterparts who did not suffer from health and body devastating diseases. While using make-up is a relatively simple behavior for women, men might have to go to greater lengths to achieve the same level of attractiveness enhancement, hence the observed larger effect sizes for men than women with a history of pathogen stress. However, one needs to keep in mind that relatively few individuals have suffered from any of the nine transmittable diseases tested here, and thus, this result needs to be cautiously interpreted.

4.3. Biosocial role theory

We found support for both the sixth and seventh hypotheses: women from countries with lower (vs. higher) gender equality and women conforming (vs. not conforming) to traditional gender roles spent more time enhancing their attractiveness. Interestingly, the effect size for gender role equality on an individual-level was large, while moderate on a country-level. Our results align with early studies demonstrating a link between attitudes toward gender roles and attitudes toward one's body (Freedman, 1984; Striegel-Moore, Silberstein, and Rodin, 1986). Jackson, Sullivan, and Rostker (1988) observed that cultural standards about beauty affect women who adhere to stereotypical gender roles more than they affect those who have less favorable attitudes toward stereotypical gender roles. Furthermore, Shipley, O'donnell, and Bader (1977) provided evidence that women who decided to augment their breasts through an invasive surgery were more prone to comply with traditional gender roles than were women in the control group.

Women from more gender-equal countries and with more gender-equal personal attitudes may be less pressured to comply with the belief that beauty is a prerequisite of the feminine gender role (Buote et al., 2011; Fredrickson and Roberts, 1997). Instead, they may fulfill themselves differently, going beyond the traditional feminine stereotype (Jameson, 2012). The role of gender equality on beauty ideals is an active and important avenue of research that must now aim to include women from a broader range of cultures. Our results show similar relationships are also found among men. The more gender-equal the country and the higher men's individual levels of endorsement of gender equal roles, the less time men spent enhancing their physical attractiveness. This result is especially interesting when considering that, stereotypically and traditionally, men are thought to be less interested in their appearance relative to women (IIsser, 2020). However, other factors may come into play for such men. For instance, because upper body strength has been hypothesized to serve an important role in our evolutionary past (Puts, 2010), and still today, more muscularized men are considered more masculine (McCreary, Saucier, and Courtenay, 2005). Hence, men who wish to be perceived as masculine may be particularly interested in performing physical exercises (Galli, Petrie, Reel, Chatterton, and Baghurst, 2014; Yeung, Massar, and Jonas, 2021). Attaining a muscular body might be less important for men who do not conform to stereotypical gender roles (Readdy, Cardinal, and Watkins, 2011).

Considering all men and women in our study, those from the least gender-equal countries devoted on average one and a half hours more improving their attractiveness compared to those from the most gender-equal countries. This gap was even larger for individual-level endorsement of gender roles. Participants who had the lowest scores on the gender equality scale (that is, those who supported gender roles) devoted on average two hours more per day enhancing their physical attractiveness compared to those who had the highest scores on the gender equality scale (that is, those who did not support traditional gender roles).

4.4. Cultural media perspective

Results of the current study support both the eighth and nineth hypotheses: individuals who spent more time on social media and watching TV also spent more time enhancing their attractiveness. Most researchers agree that the media often conveys unrealistic physical ideals (Barlett, Vowels, and Saucier, 2008; Levine and Murnen, 2009; Thompson and Stice, 2001), that are also often unattainable for the average person (Grogan, 2016). Confronting one's body with the photo-retouched silhouettes of models may trigger many negative feelings and behaviors, including anxiety, depressive symptoms, body dissatisfaction, and eating disorders (Fardouly and Vartanian, 2015; Mills, Musto, Williams, and Tiggemann, 2018). Apart from evoking affective responses, watching idealized media images may also expose one to more advertisements aimed at appearance-enhancing products and may in turn increase a willingness to comply with the widespread canon of beauty (de Vries, Peter, Nikken, and de Graaf, 2014; Gambla, Fernandez, Gassman, Tan, and Daniel, 2017), that, presumably, may help to explain the strong link between media exposure and time spent improving one's attractiveness in the current research. However, given the correlational nature of this research, we cannot rule out the possibility that the direction of causality may be reversed, such that people who choose to invest more time improving their appearance are thus more prone to use social media, or the possibility that a third unknown factor may explain the link between beauty-enhancing behaviors and social media usage.

Interestingly, we observed that spending time on social media was more strongly related to enhancing one's beauty than was watching TV. In fact, social media usage was the strongest predictor of beauty-enhancing behaviors among all predictors. Furthermore, watching TV was more strongly related to physical attractiveness enhancing behaviors among women than men, while social media usage explained more variance in these behaviors among men than women. These results are in line with those of previous studies (see e.g., Sampasa-Kanyinga, Colman, Goldfield, Hamilton, and Chaput, 2020; Sorokowski et al., 2016). We also found that participants who spent the most time watching TV spent 1 h more time daily enhancing their attractiveness than did those who spent the least amount of time watching TV, on average. In comparison, those who spent the most time on social media spent 2 h more per day improving their looks than did those who spent the least amount of time on social media, on average.

Our results seem to corroborate those of previous studies highlighting an exceptionally strong negative link between social media usage and well-being, that is particularly worrisome given the stark rise in social media usage in the past decade. For instance, engaging in social media activity is linked to negative mood (Mills et al., 2018), poor academic performance (Abdulahi, Jalil, Lumpur, Samadi, and Gharleghi, 2014), chronic sleep deprivation (Abi-Jaoude, Naylor, and Pignatiello, 2020), and the possible emergence of depression, anxiety, and other mental disorders (Cataldo, Lepri, Neoh, and Esposito, 2021). Although some studies focus on counteracting these adverse effects (see, e.g., Fardouly and Holland, 2018; Tiggemann and Anderberg, 2020), more actions, especially from policymakers, are needed to protect the mental health of social media users.

4.5. Individualism-collectivism continuum

We found support for the eleventh but not tenth hypotheses: personal individualistic attitudes were positively related to the amount of time spent enhancing one's beauty, but country-level individualism scores were not. However, the effect size for individual-level attitudes toward individualism and collectivism was negligible compared to other predictors. Moreover, this effect was mainly driven by women, as the individualism score was not related to time spent enhancing attractiveness among men. The most individualistically oriented women spent half an hour more time improving their attractiveness than the most collectivistically-oriented women, on average.

Interestingly, our results contradict some previous findings. For instance, recent statistics revealed that people in Asia, where collectivism is, on average, more common than individualism, vigorously pursue beauty standards and spend the most money on skincare (Euromonitor, 2021), even compared with the leading Western economies that are more individualistic (e.g., USA or UK). Furthermore, one-third of women between the ages of 19 and 29 from South Korea (a collectivistic country) report undergoing aesthetic surgery (Gallup Korea, 2015; Hu, 2018). On the other hand, although individuals adhering to more individualistic values may be less prone to undergoing plastic surgeries (Frederick and Gan, 2015), as it is less of a cultural norm compared to some more collectivistic Asian countries (Heidekrueger et al., 2017), people with individualistic attitudes might nevertheless be more willing to perform other types of activities explored in the current study (e.g., body hygiene, caring for diet, exercising, hair grooming, clothing style).

4.6. Other factors

We observed a positive link between time spent enhancing beauty and higher socioeconomic status (stronger effect for men), lower education (but only among women), right-wing political beliefs (but only among women), and a U-shaped relationship for self-assessed attractiveness (stronger effect for men). Notably, only self-assessed attractiveness was moderately linked to self-modification, while the remaining predictors (socioeconomic status, attained level of education, and political beliefs) had small effect sizes.

Previous research has produced conflicting results about the relationship between self-assessed attractiveness and beauty-enhancing behaviors. On one hand, individuals with higher self-esteem (which is a predictor of higher self-assessed attractiveness; Bale, 2010) reported using fewer cosmetics (Fares et al., 2019). On the other hand, individuals who considered themselves more attractive spent more time improving their looks (Antonova and Merenkov, 2020). Our results shed more light on this matter by providing evidence that those who believe in their very high attractiveness care the most for their appearance, followed by those who consider themselves as very unattractive, with those who believe they look average spending the least amount of time improving their attractiveness. As we cannot infer causation from correlation, future studies could experimentally investigate whether enhancing one's beauty increases self-assessed attractiveness or rather that more beautiful individuals are more willing to increase (or maintain) their attractiveness (for some preliminary evidence on the first prediction, see Anchieta et al., 2021).

As for the explanation of other predictors, we hypothesize that individuals of a relatively higher socioeconomic status may have more time and money to improve their appearance, whereas higher education may work as a buffer against focusing excessively on one's appearance, while instead focusing on other traits and skills. Nevertheless, high education is usually linked to higher socioeconomic status (Boshara, Emmons, and Noeth, 2015), so the opposite results for these two variables require investigation in further studies. Finally, regarding political views, is it possible that physical attractiveness might be more important for relatively more conservative individuals. For instance, some researchers have found that right-wing politicians appear more attractive than left-wing politicians (Berggren, Jordahl, and Poutvaara, 2010) and right-wing political beliefs tend to be conservative (Karwowski et al., 2020). This hypothesis likewise requires further investigation.

4.7. Summary, limitations, and future directions

Several decades ago, a preoccupation with one's body image was thought to be a typically female issue (van Lennep, 1957). However, more recent studies provide converging evidence that men also care for their looks (Antonova and Merenkov, 2020; Kowal and Sorokowski, 2022; Mafra et al., 2016). Indeed, we show that only 0.003% of women or men indicate not doing anything to improve their appearance, and only 1% (among whom half were men) report spending <10 min a day enhancing their beauty. In comparison, 99% of the nearly one-hundred thousand people in our cross-cultural sample report spending >10 min a day enhancing their physical appearance, and on average around 4 h daily. Thus, we conclude that beauty-enhancing behavior is a universal phenomenon.

This may not come as a surprise, as previous studies provide abundant evidence that attractiveness can be beneficial in manifold ways and that humans are concerned with physical attractiveness, largely because of the social and reproductive benefits it can confer. For instance, more attractive individuals are often treated more positively (Langlois et al., 2000), are preferred as potential partners (Walter et al., 2020) and friends (Vannatta, Gartstein, Zeller, and Noll, 2009; Zakin, 1983), are perceived as healthier (Fink et al., 2017) and as more competent (Etcoff, Stock, Haley, Vickery, and House, 2011), are more likely to be hired for jobs (Cash and Kilcullen, 1985), earn higher tips as servers (Parrett, 2015), earn higher salaries both at the early stage of the career (Dossinger, Wanberg, Choi, and Leslie, 2019) and from a lifetime perspective (Scholz and Sicinski, 2015), are more popular as athletes (Mutz and Meier, 2016), receive a higher endorsement in politics (Berggren et al., 2010), and report higher psychological well-being and lower levels of distress and depression (Gupta, Etcoff, and Jaeger, 2016).

However, when it comes to factors linked to the intensity of beauty-enhancing behaviors, the matter becomes more complex, as many aspects come into play. Apart from evolutionary theory, here we provide support for several other perspectives that have attempted to describe and explain who devotes more energy to enhancing one's appearance, and why. Importantly, these theories are not mutually exclusive. Instead, when considering them jointly, they offer a valuable and extensive (but not exhaustive) theoretical framework for analyzing activities aimed at increasing one's looks. Each perspective adds another piece to the puzzle by suggesting a distinctive (and as our results show, a significant) explanation for why a given social or demographic group should be particularly interested in improving their beauty. The mate preference perspective appeals to the human evolutionary past and sexual selection pressures that have shaped different mating strategies between the sexes (Buss, 2015; Tooby, 2018; Tooby and Cosmides, 1990; Walter et al., 2020). The pathogen prevalence approach suggests that humans have an evolved ability to detect cues of transmittable diseases, especially in pathogen-rich environments (Murray and Schaller, 2010), and one way to advertise one's health (i.e., a lack of pathogens) is through improving one's physical appearance (Tybur and Gangestad, 2011). The biosocial role theory concerns the influence of physiological differences and gender constructs on forming the propensity of women to comply with the pursuit of feminine beauty (Eagly and Wood, 1999; Wood and Eagly, 2012). The cultural media approach relates to the influence of mass media in pressuring people to conform to the westernized canon of beauty (Murnen and Seabrook, 2012; Stephens et al., 1994; Xu et al., 2010). The individualism-collectivism continuum refers to how an individual relies on others, either caring more for the welfare of their group or caring more for their personal aspirations and goals (Markus and Kitayama, 1991), which may be consequential when devoting time and energy to one's appearance.

Although the current study sheds new light on beauty-enhancing behaviors, it is not free of limitations. First, the research was conducted mostly with the use of virtual survey tools, rather than in person. Many researchers highlight the importance of advanced methods for screening and filtering careless responses in online surveys (see, e.g., DeSimone, Harms, and DeSimone, 2015; Wood, Harms, Lowman, and DeSimone, 2017) and thus, we excluded responses from participants who failed the attention check. Second, while our sample included a large number of countries (i.e., 93), it is not exhaustively representative of all human cultures. Moreover, even less representative are samples from less modernized countries, where access to Internet is relatively more limited than in more industrialized countries, in turn limiting the probability of participants from such samples being invited to participate in the study (Batres and Perrett, 2014). Third, our participants were primarily well-educated (65% obtained a bachelor's degree or higher), and most of them were women (67%). Fourth, our data are not experimental and thus, no causal conclusions can be made. Further studies could include a longitudinal design to explore intra-individual variability of self-modification practices. Fifth, most of our participants were cis-gender and heterosexual. It is important to replicate the present study on a more sexually diverse sample. Future studies could also provide some interesting insight on self-modification in dyadic relationships, depending on the partners' mate value: does a larger gap between the mate values of partners predict more intense beauty-investments? Sixth, although we emphasized to participants in written instructions to indicate time spent on a given beauty-enhancing activity only if it is performed for appearance-enhancing reasons (and not, for example, for health reasons), we cannot exclude the possibility that some participants miscounted time spent on various activities. Indeed, our study's greatest limitation is self-reported data, which is susceptible to biases and errors.

Our open-access dataset provides an excellent opportunity to further test a manifold of interesting hypotheses. Therefore, we encourage scholars to analyze it (the dataset is publicly available under the link https://osf.io/sh3an/) to shed even more light on attractiveness enhancing behaviors. One could, for instance, focus on the relationship between activities aimed at increasing one's appearance and country-level variables, such as income inequality (Blake and Brooks, 2019) or the modernization index (Zhang and He, 2015), and individual-level variables pertaining to, for instance, partners' relationships, such as durability of marriages (Parker, Durante, Hill, and Haselton, 2022) and marital satisfaction (Kowal, Groyecka-Bernard, Kochan-Wójcik, and Sorokowski, 2021). Finally, it is important to emphasize that the established boundaries among the theoretical perspectives examined in this study are in fact blurry, as the theories share many similarities in their rationale for beauty-enhancing behaviors. The theories thus provide a framework for hypothesis testing and should not necessarily be considered as opposing one another, but rather, as complimentary.

The impact of social media on beliefs or actual outcomes has been either non-existent or inconclusive; people who believe in conspiracies gravitate toward groups that espouse these

Processes of Persuasion and Social Influence in Conspiracy Beliefs. Dolores Albarracin. Current Opinion in Psychology, September 5 2022, 101463. https://doi.org/10.1016/j.copsyc.2022.101463

Abstract: If conspiracy beliefs were an individual process, no conspiracy theory would be alike. Instead, these beliefs are promoted by individuals or social groups through the media or informal channels of communication, leading to identical beliefs being espoused by different people and social groups. This paper reviews the role of the social influence as a basis for conspiracy beliefs and describes the role of legacy media, discussions with others, and social media, as well as the underlying informational and normative mechanisms. The role of trust is also considered, including how trust in science can increase vulnerability to conspiracy theories by opening audiences up to the influence of pseudo-scientists. Mitigating the impact of these influences will require research attention to processes that go beyond correction, elucidating the interpersonal consequences of corrections within contemporary information wars.

Pedestrians gave more than twice as much money to the guy wearing higher-class symbols than they did to the one wearing lower-class symbols, which were perceived as of elevated competence, trustworthiness, similarity to the self, and perceived humanity

The influence of signs of social class on compassionate responses to people in need. Bennett Callaghan, Quinton M. Delgadillo and Michael W. Kraus. Front. Psychol., August 25 2022. https://doi.org/10.3389/fpsyg.2022.936170

Abstract: A field experiment (N = 4,536) examined how signs of social class influence compassionate responses to those in need. Pedestrians in two major cities in the United States were exposed to a confederate wearing symbols of relatively high or low social class who was requesting money to help the homeless. Compassionate responding was assessed by measuring the donation amount of the pedestrians walking past the target. Pedestrians gave more than twice (2.55 times) as much money to the confederate wearing higher-class symbols than they did to the one wearing lower-class symbols. A follow-up study (N = 504) exposed participants to images of the target wearing the same higher- or lower-class symbols and examined the antecedents of compassionate responding. Consistent with theorizing, higher-class symbols elicited perceptions of elevated competence, trustworthiness, similarity to the self, and perceived humanity compared to lower-class symbols. These results indicate that visible signs of social class influence judgments of others’ traits and attributes, as well as in decisions to respond compassionately to the needs of those who are suffering.

General discussion

As economic inequality rises in many parts of the world, and countries such as the United States roll back social safety net programs (Piketty, 2014), the responsibility for dealing with inequality’s deleterious impacts (Wilkinson and Pickett, 2009) has increasingly fallen to economically precarious individuals themselves or to private citizens exercising compassion, defined as concern for the suffering of others and the motivation to help improve their circumstances (e.g., Goetz et al., 2010; Gilbert, 2017; Mascaro et al., 2020). Building on prior research and theorizing in the rich tradition of research on sympathy, empathy, and compassion (Batson et al., 1989; Cialdini et al., 1997; Oveis et al., 2010), the current research examined the tendency for people to respond compassionately (or not) in the presence of those who were apparently suffering or, at least, made salient a concern with suffering related to poverty and homelessness (i.e., a panhandler), in two cities in the United States. The current research suggests that people respond more compassionately, and perceive such individuals more favorably, when they signal higher–relative to lower–social status through physical appearance. This pattern of results arose even though all confederates and targets appeared to be generally low in status, and it arose in an experimental, but ecologically valid, context where participants shared their own money.

This research also contributes to a longstanding body of research suggesting that non-verbal status cues influence behavior on the part of others (e.g., Bickman, 1971; Tracy et al., 2018). That symbols of high social class more than doubled the donations of pedestrians over a 4-h period indicates their power in shaping initial judgments of others’ basic human traits and in eliciting compassionate responses in everyday life. Importantly, our results align with past theory and research suggesting that high status signaling provides many direct benefits to individuals, including grooming and mating partners in non-human primates (Sapolsky, 2004). This research adds received generosity, among humans, to this list of benefits.

Interestingly, mere novelty and noticeability of the higher status confederate do not seem to explain observed differences in generosity. In the field experiment, the mere frequency of the interactions did not differ by condition; in Study 2, in fact, participants were in fact more likely to attend to the lower status target. Instead, the quality of these interactions and their outcomes (as indicated by the analysis of extreme donations) differed. Anecdotally, this qualitative distinction bears out. When people did go out of their way to speak to the confederate, the higher status one received comments such as “I usually don’t give money to people on the street, but you seem like a nice guy.” In one case, a pedestrian (also donned in a business suit) even dropped a business card into the higher status confederate’s collection cup–a tacit invitation for the confederate to seek employment, rather than a trivial one-time donation.

As discussed, the large donations of $5 or $10, given their size and exclusive presence in the relatively higher status trials, likely contribute substantially to some of the effects we observe in the field study. Much like the interactions sketched above, these donations might also represent a qualitative shift in how donors approached the situation: they may have donated $5 or $10 in the hopes of more effectively meeting the confederate’s immediate perceived needs, as such an amount would be more appropriate than more common donation amounts (e.g., $1 or less) for most self-care and survival needs, such as purchasing a meal. Thus, these donations might be particularly representative of compassionate responding insofar as they are intended to effectively and (depending on participants’ construal of the situation) immediately alleviate suffering. However, they also suggest the possibility of theoretical accounts we did not fully theorize. For instance, it is possible that status signaling is most effective at eliciting high-variance responding; in other words, signaling higher status might not strongly impact tendencies to engage in compassion in general, but, rather, impacts tendencies to engage in extreme–as defined in relation to more typical donation amounts–acts of compassion (again, however, use of the word “extreme” might be misleading, as these donations might also be described as simply independently sufficient to meeting the goals at hand).

It is also possible that this pattern of results reflects an unobservable moderation effect. Perhaps, for instance, the effects of status signaling are most pronounced among those who are more inclined to acts of extreme generosity to begin with. Alternatively, this effect might be attributable to the presence of stronger effects among participants who are higher in SES themselves. The design of the field experiment study did not allow us to assess the SES of passersby, and, thus, whether participants’ own social class characteristics contributed to decisions to respond compassionately to the confederate. As indicated by the overall low levels of subjective SES attributed to the target in the perceptual study, it is likely that the higher status confederate was perceived as closer to participants, in terms of socioeconomic standing, than the lower status confederate across the board (excluding those who are themselves poor or unhoused). Still, however, the perceptual study does suggest meaningful differences in self-other similarity according to status signaling condition, and the possibility that signalers who better “match” the status of perceivers benefit from even greater compassion than those who merely signal higher status has received mixed empirical support (see, e.g., Goodman and Gareis, 1993). Thus, it is possible that high status signals appealed specifically to passersby of particularly high SES and who, due to greater access to financial resources, may have stood to lose less through larger donations or simply regarded higher amounts of money as an appropriate default for donation (as a proportion of the money they had on hand, for instance). Though it may be difficult to measure individual differences such as predispositions toward extreme generosity in a field study context, future replications of this research might employ methods of subjectively coding participant SES (e.g., Bickman, 1971) or systematically varying the SES characteristics of the research sites (e.g., Goodman and Gareis, 1993) in order to determine the regularity with which these extreme donations occur and whether they are given disproportionately by those of higher socioeconomic standing.

Together, these qualitative experiences and extreme donation profile provide some support for the general pattern observed in Study 2, and support a central tenet of theories of compassion: that compassionate responding hinges on the reputation of targets, especially with respect to their likelihood of engaging in reciprocal cooperation with other prosocial individuals (Goetz et al., 2010). The present research adds signals of social class as a possible cue that reliably elicits such reputational perceptions.

Moreover, high status signals increased specific judgments of competence, trustworthiness, humanity, and self-other similarity. Thus, the results of the current studies suggest that poor individuals who adopt these symbols might be seen as more effective at converting gifts into intended outcomes (such as personal advancement or care), as less likely to engage in behaviors that might be seen as making them blameworthy for their plight (e.g., drug or alcohol use; see Goetz et al., 2010), and as more likely to use those gifts for intended means rather than as a strategy to accrue undeserved wealth. In short, such signals may make one appear more deserving of compassion (Goetz et al., 2010).

A closely related alternative explanation for the current set of results, which more strongly emphasizes the perceived ability (rather than the inclination) to engage in future prosocial behavior by the confederate, is that participants were more likely to see the higher status confederate’s need state as temporary, rather than chronic. Consistent with certain evolutionary accounts of reciprocal altruism (e.g., Sugiyama and Sugiyama, 2003; Tracy et al., 2018), the perceived combination of high temporary need and high baseline competence may have biased individuals toward helping the higher status confederate in his time of need because he was perceived as more able to help others, or “pay it forward,” when he had the opportunity to do so. Given that the high and low status targets were strongly discriminated along the lines of competence, this alternative explanation is plausible. Future research is needed, however, to determine whether such perceptions of ability to engage in future acts influence compassionate responding independent of perceptions of deservingness.

In a similar vein, our field study operationalizes compassion as costly helping behavior–a common method of doing so within the social-psychological literature and one that avoids many of the biases inherent in self-report measures (Mascaro et al., 2020). Our second study also includes a number of social perceptions that index deservingness, an antecedent to compassion in prevailing theoretical accounts of the construct (e.g., Goetz et al., 2010). While this research demonstrates the influence of status signaling on theoretically important perceptions of a target (Study 2) and responses toward a confederate (Study 1), this research does not measure compassion, as a subjective psychological state, directly. Nor does the second study measure compassionate responding directly, as in Study 1. Thus, the two studies taken together show a pattern that is consistent with a theoretical account emphasizing compassion: one in which status signaling affects particular theoretical antecedents of compassionate responding (i.e., warmth, competence, self-other similarity, and ascribed humanity), which then influence compassion and compassionate responding. However, these results do not necessarily confirm that status signaling directly influences perceptions linked to deservingness and, subsequently, compassion and compassionate responding.

To address this theoretical gap, future research might attempt to measure compassion directly and demonstrate that signaling relatively higher (as compared to lower) status–by way of heightened perceptions of deservingness–heightens self-reported compassion for those suffering in the relevant context as well as subsequent compassionate responding (i.e., donations). In doing so, researchers should be mindful of best-practices in the measurement and definition of this complex emotion (Gilbert, 2017; Mascaro et al., 2020). For instance, such research might attempt a multi-method approach to conceptualizing and measuring compassion that synthesizes quantitative reports of one’s own and others’ mental states, physiological measurements, and observations of behavior (e.g., Mascaro et al., 2020). Additionally, such research might take care to distinguish compassion from subjective and emotional states–such as distress, sadness, and love–that are sometimes used interchangeably with compassion in the literature (e.g., Goetz et al., 2010; Gilbert, 2017). Second, in order to test the full theoretical model we have proposed here, future research should manipulate status signaling and measure both the antecedents we propose and compassion (or compassionate responding) within the same study. Such a study could at least determine whether the key variables related to deservingness mediate the effect of status signaling on compassion. Ideally, future research could also manipulate these mediators to establish a truly causal chain of effects (Spencer et al., 2005).

It is also possible, however, that conditional differences in confederate behavior contributed to differences in generosity on the part of passersby. The confederate was not blind to condition or hypotheses, and previous research suggests that donning high status sartorial signals can change the behavior of even naïve participants (Kraus and Mendes, 2014). Though this is a possibility, we minimized this likelihood by having the confederate behave consistent with standardized instructions. Moreover, that a follow-up study elicited theoretically relevant patterns of perception from passive observers suggests that the effect of status signaling on generosity observed in the field is at least partially driven by perceiver judgments. Finally, even if the behavior of the confederate did subtly differ between conditions, such subtle differences would need to compete with the cacophony of stimuli that individuals normally encounter when walking down a busy street in New York or Chicago, so the context in which we chose to conduct our field experiment also mitigates concerns with experimenter effects.

Indeed, it was partially because we expected multiple competing demands on the attention of passersby that we chose to manipulate comparatively obvious visual cues (combined with spoken statements to draw attention), rather than other cues that also signal status, such as vocal pitch (e.g., Gregory and Webster, 1996), accent (e.g., Labov, 2006; Kraus et al., 2019), or cultural signifiers of aesthetic taste (Bourdieu, 1984). Nonetheless, these other modalities represent interesting potential avenues for future research.

Similarly, those who did attend to visual cues of status also likely perceived other superficial but potentially important characteristics, such as those that indicate membership in particular social identity groups. It is interesting to speculate about how these other characteristics of the confederate (i.e., an individual generally perceived to be White and male) may have impacted the effect of status signaling on compassionate responding. For example, membership in other social categories might modify the results observed in these experiments. Theoretical accounts suggest that symbols of social status influence perception similarly across race and gender (Major and O’Brien, 2005), but previous research also finds that social status and race or gender may interact in subtle ways to produce marked differences in status-linked outcomes, such as health and mortality rates (Case and Deaton, 2015) or experienced bias and discrimination (e.g., Goff and Kahn, 2013; Rivera and Tilcsik, 2016). Future research would need to determine if high status symbols confer the same benefits to members of other intersecting social groups as they apparently do for White men.

Future research might also measure how different characteristics of the giving context moderate how status symbols influence outcomes. For instance, some research has found that in contexts where individuals are already motivated to engage in prosocial behavior and are deciding how to distribute their resources, symbols of high status are negatively related to the receipt of altruism (Tracy et al., 2018). These researchers suggest that opposite patterns of effect with respect to status and altruistic behavior might arise depending on whether potential actors are deciding to engage in altruistic behavior in the first place or are deciding how to engage in such behavior. We echo these researchers’ calls for further investigation into this distinction as a potential moderator of the effect of status signaling on compassionate responding (p. 527). We also note that our results regarding the influence of status signaling manipulations on compassionate responses are perhaps bounded to compassionate responding in contexts involving the alleviation of suffering related to poverty and homelessness and to such responses enacted through brief, interpersonal exchanges. Thus, we caution generalizing these results to compassion directed toward other ends or within impersonal contexts, such as online behavior (see, e.g., Tracy et al., 2018).

Finally, we also acknowledge some ambiguity with respect to how participants themselves interpreted donating in the field experiment. As noted, the confederate only told participants that collected funds would be donated to charity if they had asked; few people interacted directly with the confederate in this way, and this pattern did not differ by condition. However, because we were constrained by ethical considerations in terms of what we could tell participants and the field context of the experiment made us unable to probe participants about their inferences regarding the confederate at the time they decided to donate (or not), we still do not know (as discussed) whether individual participants perceived the confederate as the primary benefactor of their donations or as an intermediary.

Even for participants operating under the latter assumption, however, the relevant behavior of donating nonetheless reflects the broader construct of compassionate responding, as those who donated were either donating directly to the target or helping him in his objective to raise money for charity (a goal that is aligned with the reduction of suffering). To this point, previous research has treated explicit contributions to third-party charities as an index for helping behavior directed toward a confederate (Pandey, 1979), and even those who donated under the assumption that the funds would be donated placed significantly more trust in the higher status than the lower status confederate–despite the lack of any guarantee the money would go to charity. Again, such a result is consistent with our overall theoretical expectation that relevant compassionate responding would be directed toward those presumed to be more honest and prosocial themselves, and it would at least appear that signaling status influenced decisions to engage in costly helping behavior (likely driven by differential patterns of social perception) regardless of how participants interpreted the situation. Still, the influence of status signaling on compassionate responding might depend on whether those signaling higher status themselves or third parties are the primary beneficiaries. Future research might investigate this distinction more explicitly.

These limitations and open questions notwithstanding, this research adds to existing models that highlight compassion, sympathy, and perceptions of deservingness as primary causes of compassionate responding (e.g., Goetz et al., 2010). Importantly, our results suggest that social status–and its accompanying interpersonal judgments–enters prominently into such processes. Ironically, low status individuals who appear to need the most help may end up receiving less of it than those who appear higher in status and more abundant in resources.

These results also have direct implications for rising levels of economic inequality in society. Given research suggesting that economic inequality and its negative consequences increase when social status is more visible (Nishi et al., 2015; DeCelles and Norton, 2016), the current findings suggest that status symbols expressed through sartorial displays or other non-verbal behaviors are potential mechanisms for the perpetuation of economic inequality. We found that even among those engaging in ostensibly selfless behavior, individuals were more likely to enter into economic relationships with others who appeared higher, rather than lower, in social status. Given the high degree to which neighborhoods, professional networks, and daily life are stratified by social class, behaviors guided by status signaling can accrue and concentrate wealth and opportunity among a privileged few–further perpetuating inequality (see also Kraus et al., 2019).

These results may also hold implications for addressing economic inequality on a broader societal scale. As indicated by similar research in this domain, cross-status interactions in everyday life can perpetuate inequality by impacting support for social policy aimed at addressing it (Sands, 2017). Nonetheless, such policies are arguably likely to garner the most efficient redistributive outcomes, especially when one considers the alternatives. If subtle interpersonal cues, like clothing or similar indicators of status, shape the behavior of individual actors outside the context investigated in the current research, mechanisms of redistribution that rely on idiosyncratic preferences or the behavior of well-meaning individuals more broadly–such as large donations from wealthy donors to particular individuals or organizations–may be inefficient or underserve those who need the most assistance, whether such needs are met directly or through intermediaries (e.g., charities).

Those from denigrated groups, such as those suffering from homelessness, need monetary assistance despite lacking the ability to transmit status symbols that, as our results suggest, may make certain forms of compassionate responding (i.e., spur-of-the-moment donations) more likely. Moreover, not all charitable organizations aimed at helping such individuals may be equally adept at appealing to wealthy donors or motivating such individuals to donate in the first place. Depending on how far one may extrapolate the results reported here, our research suggests that such a process might require an understanding of how to leverage high status signals (on the part of charities themselves) or how to portray those in need in ways that emphasize their humanity, warmth, competence, and similarity to potential givers. By contrast, codified inequality-reducing policies (such as progressive taxation) do not rely on the generosity of individuals to meet their aims. Unfortunately, even well-meaning generosity, if dispatched at the level of individuals, may be biased by processes of person-perception that direct resources on the basis of attributes other than who is most needy or how resources can best be distributed.

IQ is a positive predictor of participation and spending in horse wagering; in addition, high IQ is associated with choosing more complex (high variance) betting products

Does IQ predict engagement with skill-based gambling? Large-scale evidence from horserace betting. Niko Suhonen, Jani Saastamoinen, David Forrest, Tuomo Kainulainen. Journal of Behavioral Decision Making, September 4 2022. https://doi.org/10.1002/bdm.2300

Abstract: We examine how measured intelligence, referred to as IQ, predicts a consumer's decisions on whether to participate in online horse wagering, how much to spend on those bets, and which horserace betting products to consume. We combine three individual-level archival data sets from Finland, including all online horse bets during a 1-year period from the state-sanctioned monopoly operator, the Finnish Defence Forces' IQ test scores from male conscripts born between 1962 and 1990 (N = 705,809), and administrative registry data on socioeconomic status, income, and education for these men. An analysis of male bettors (N = 15,488) shows that IQ is a positive predictor of participation and spending. In addition, high IQ is associated with choosing more complex (high variance) betting products. We find that these results are driven primarily by numerical IQ.

6 CONCLUSION

6.1 Discussion

This paper demonstrates that IQ, and especially its numerical ability subcomponent, is positively associated with an individual's decisions relating to participation in and expenditure on horse betting, and with a relative preference for complex betting formats. It is plausible that intelligent persons and those with numerical ability gain satisfaction from absorbing themselves in tasks involving “crunching numbers,” such as horse wagering. Consequently, our study provides empirical support for treating decisions on gambling as aspects of consumer behavior (Conlisk, 1993), at least in the case of skill-based gambling, as opposed to the proposition that gambling stems from behavioral biases (Barberis, 2012).

Consistent with Forrest and McHale (2018), our analyses suggest that IQ, and particularly numerical IQ, predicts participation in horse wagering. To some extent, this result is also congruent with Grinblatt et al. (2011) who find that IQ is positively correlated with an individual's decision to invest in the stock market, because skill-based forms of gambling and stock markets tend to attract similar individuals in terms of motivation and personality attributes (Arthur et al., 2016). As high-IQ men tend to spend more on horse betting products than low-IQ men do, our findings may also reflect the intellectual challenge quality of horse betting, as suggested by Binde (2013).

On the other hand, our results appear to be at odds with Gong and Zhu (2019), as none of their three measures of cognitive ability were significant predictors of which gamblers choose to engage in skill-and-chance games (as opposed to pure chance games, defined by them as comprising bingo, scratchcards, lottery, and keno). However, their list of skill-and-chance products included slot machines. Slot machines typically offer games where the outcome is random and tends to be generally regarded as a chance-based game (Stevens & Young, 2010). Furthermore, their data were a self-reported survey. Consequently, these aspects warrant caution when our results are compared with those presented in Gong and Zhu (2019).

Consistent with the hypothesis that a motivation for betting is the intellectual challenge (Binde, 2013; Johnson & Bruce, 1997, 1998), our results suggest that individuals seek to match their betting choice to their own level of IQ. Since high-IQ individuals appear to respond more to price (Grinblatt et al., 2016), it is fair to assume that these individuals in our context are likely to be aware of the lower take-out on easy products and in any case the different levels of take-out are clearly signaled by the operator. In particular, this result suggests that high numerical IQ consumers enjoy the intellectual challenge provided by complex betting formats and are willing to pay a greater take-out to play them. Consequently, their stronger preference for complex bets could reflect a genuine preference, which is consistent with intelligent persons exhibiting preference for performing challenging tasks (Cacioppo & Petty, 1981).

It is also possible to define the take-out rate as one of several “structural characteristics” which distinguish different gambling products from each other (Newall et al., 2021). When viewed purely through the lens of expected value, complex betting formats might appear as less attractive than simple ones (Newall et al., 2021), particularly for those bettors with a high numerical ability. In our approach, however, take-out is not regarded as a structural characteristic of the product, because it is not inherent to the product, but rather is a price chosen by the supplier in response to the nature of demand. In our findings, bettors with higher cognitive skills choose to purchase more complex products despite their high take-out rate. This implies that degree of complexity is the “structural characteristic,” and it is one for which they are willing to pay a higher price.

The administrative registry data facilitated the inclusion of controls reflecting demographic and socioeconomic status, which allowed us to draw conclusions about horse betting. For example, spending tends to increase with income, but slowly. This mirrors previous findings for gambling spend in general (Rude et al., 2014) and for lottery games (Combs & Spry, 2019) and implies that lower income individuals tend to allocate a higher share of their income to gambling (Castrén et al., 2018). Regarding age, engagement with horse betting appears to peak in middle-age, again similar to findings about participation in gambling generally (Welte et al., 2011). But whether the relatively greater engagement with horse betting in Finland among the middle-aged represents a cohort effect or a generational effect cannot be inferred from 1 year of data.

6.2 Limitations and future research

This paper has some limitations. Foremost, our data set includes only data on horse betting. Hence, our results may not generalize to other forms of gambling, most notably chance-based gambling. Further, we are unable to analyze propensities to problem gambling. Although some studies suggest that low IQ correlates with problem gambling (e.g., Hodgins et al., 2012; Rai et al., 2014), other factors that we could not observe are also likely to be relevant. For example, Parker et al. (2008) highlighted the role of emotional intelligence as a protective factor against the risk of developing problems.

The FDF data set also has some limitations. First, individuals have different incentives to effort when completing the test, which may bias IQ test scores. That is, if a conscript wishes to avoid training for a non-commissioned officer, which is more likely if he or she performs well in the IQ test, he or she may purposely underperform in the test. In addition, our measures of IQ may not be directly comparable to other studies, as IQ or cognitive ability is often operationalized in very different ways, depending on a study and its context. Second, some males are exempt from military service and some opt for non-military service instead. Third, the sample excludes the female population. Fourth, IQ scores were measured between 6 and 34 years prior to the betting transactions recorded in the study. To the extent that IQ can change over an adult's lifetime, this introduces measurement error into the analysis. Finally, the data are from a limited time interval and from a single country.

Our results open avenues for future studies. Rather than examining only a general measure of IQ, future studies should examine how the separate subcomponents of IQ predict consumer decision making. Intelligence and numerical ability could be instrumental in decisions relating to consumption, investment, and life outcomes in general. Future studies could also yield insight into theories of risk-taking behavior by addressing correlations between IQ and a person's risk preferences.

6.3 Concluding remarks

This paper demonstrates that a person's IQ predicts his engagement with horse betting. Our results show that IQ, and especially its numerical ability subcomponent, is positively correlated with participation in and expenditure on horse betting, and a relative preference for complex betting formats. These findings are consistent with skill-based gambling, or at least horse betting, being consumption of entertainment, which intelligent individuals enjoy. Thus, it is plausible that intelligent persons and those with numerical ability gain satisfaction from absorbing themselves in tasks involving “crunching numbers,” such as horse wagering.

Exogenous administration of testosterone increased impulsivity in heterosexual men, increasing preference for the smaller-sooner option, and inducing steeper discounting for the delayed option

Exogeneous testosterone increases sexual impulsivity in heterosexual men. Yin Wu et al. Psychoneuroendocrinology, September 5 2022, 105914. https://doi.org/10.1016/j.psyneuen.2022.105914

Highlights

• Exogenous administration of testosterone increased preference for the smaller-sooner option.

• Exogenous administration of testosterone induced steeper discounting for the delayed option.

• Exogenous administration of testosterone increases impulsivity for sexual rewards in heterosexual men.

Abstract: Testosterone has been hypothesized to promote sexual motivation and behavior. However, experimental evidence in healthy humans is sparse and rarely establishes causality. The present study investigated how testosterone affects delay of gratification for sexual rewards. We administered a single dose of testosterone to healthy young males in a double-blind, placebo-controlled, between-participant design (N = 140). Participants underwent a sexual delay discounting task, in which they made a choice between a variable larger-later option (i.e., waiting longer to view a sexual picture for a longer duration) and a smaller-sooner option (i.e., waiting for a fixed shorter period of time to view the same picture for a shorter duration). We found that testosterone administration increased preference for the smaller-sooner option and induced steeper discounting for the delayed option. These findings provide direct experimental evidence that rapid testosterone elevations increase impulsivity for sexual rewards and represent an important step towards a better understanding of the neuroendocrine basis of sexual motivation in humans.

Keywords: androgenimpulsivitysexual rewardintertemporal choicemating

A machine-predicted brain sex score explains individual differences in cognitive intelligence and genetic influence in young children; sex identified with a 93pct success

The sexual brain, genes, and cognition: A machine-predicted brain sex score explains individual differences in cognitive intelligence and genetic influence in young children. Kakyeong Kim, Yoonjung Yoonie Joo, Gun Ahn, Hee-Hwan Wang, Seo-Yoon Moon, Hyeonjin Kim, Woo-Young Ahn, Jiook Cha. Human Brain Mapping, April 26 2022. https://doi.org/10.1002/hbm.25888

Abstract: Sex impacts the development of the brain and cognition differently across individuals. However, the literature on brain sex dimorphism in humans is mixed. We aim to investigate the biological underpinnings of the individual variability of sexual dimorphism in the brain and its impact on cognitive performance. To this end, we tested whether the individual difference in brain sex would be linked to that in cognitive performance that is influenced by genetic factors in prepubertal children (N = 9,658, ages 9–10 years old; the Adolescent Brain Cognitive Development study). To capture the interindividual variability of the brain, we estimated the probability of being male or female based on the brain morphometry and connectivity features using machine learning (herein called a brain sex score). The models accurately classified the biological sex with a test ROC–AUC of 93.32%. As a result, a greater brain sex score correlated significantly with greater intelligence (rho-fdr < .001, (eta sub p)**2= .011–.034; adjusted for covariates) and higher cognitive genome-wide polygenic scores (GPSs) (rho-fdr < .001,  (eta sub p)**2 < .005). Structural equation models revealed that the GPS-intelligence association was significantly modulated by the brain sex score, such that a brain with a higher maleness score (or a lower femaleness score) mediated a positive GPS effect on intelligence (indirect effects = .006–.009; p = .002–.022; sex-stratified analysis). The finding of the sex modulatory effect on the gene–brain–cognition relationship presents a likely biological pathway to the individual and sex differences in the brain and cognitive performance in preadolescence.

4 DISCUSSION

We report the novel relationship between brain sex difference, cognitive performance, and shared genetic influence in an admixed American population of prepubertal children. As trained on the grey matter morphometric and white matter connectomes, our machine learning models showed the accurate classification of sex with over 93.32% ROC–AUC in a replication set. Furthermore, the individual variability of the sexual brain development, indexed by the brain-based sex score, showed significant correlations with general intelligence and the inherited genetic influence on general intelligence, the cognitive GPSs. Moreover, the SEM showed that the effect of the cognitive GPSs on cognitive outcomes was modulated by the brain sex score significantly in females and with a similar trend in males. Thus, this study indicates the critical role of brain sex in cognitive performance in prepubertal children, influenced by genetic factors, providing a biological account for the individual variability of neurocognition.

Our study departs from the prior literature on sex differences in intelligence in children by showing the role of the continuum of brain sex on cognitive performance. Literature shows that the group sex differences in mind and behaviors, such as hormonal influences (Vuoksimaa, Kaprio, Eriksson, & Rose, 2012), brain differences (Ostatníková et al., 2010), cultural influences (Penner & Paret, 2008), gender stereotypes (Stoet & Geary, 2012), and biopsychosocial interactions (Haier, Karama, Leyba, & Jung, 2009; Miller & Halpern, 2014). In intelligence, however, literature shows mixed findings of sex differences (Dykiert, Gale, & Deary, 2009). Some show that males have advantages (Irwing & Lynn, 2005; Jackson & Philippe Rushton, 2006; van der Linden, van der Linden, Dunkel, & Madison, 2017) in general intelligence over females, while others show females have advantages over males (Keith, Reynolds, Patel, & Ridley, 2008). These mixed findings may allude to large individual variability in intelligence within sex. Indeed, a recent seminal study shows the biological underpinnings of the individual variability in behavioral phenotypes in adolescents (Vosberg et al., 2020). This study presents an estimate of the continuum of sex based on the brain and body traits, which predicts within each sex the individual variability in sex hormones, personality traits, and internalizing–externalizing behaviors. In line with this, our study further demonstrates the utility of multimodal brain imaging combined with machine learning in estimating an individual status of brain sex. For example, our method permitted the accurate estimation of an individual's developmental status of the brain sex and revealed that the brain sex estimates varied across individuals even within the narrow age range. The discovery of the correlation of the brain sex variability with the genetic and cognitive variables further reflects that this novel estimate may represent a critical neurobiological process.

Another pattern to note is the greater association of crystallized intelligence (the ability that is acquired throughout life: i.e., knowledge, facts, and skills) with the brain-based sex, as well as GPSs for cognitive capacity, compared with fluid intelligence (the ability to reason and solve problems in novel situations; a trend towards significance). These findings are partially in line with prior genetic research showing that crystallized intelligence is greatly associated with genetic influence than fluid intelligence (Christoforou et al., 2014; Genç et al., 2021). Furthermore, since learning attitude (i.e., reading books) may be genetically inherited (Krapohl et al., 2014; Olson, Vernon, Harris, & Jang, 2001), it adds to the genetic propensity of crystallized intelligence. Taken together, these empirical findings including ours may challenge the historical conceptualization that fluid intelligence may be more driven by genes and crystallized intelligence by the environment (Cattell, 1971).

Our structural equation models show the potential relationships among the genes, brain sex, and cognition. The results indicate that a higher brain maleness score (a lower femaleness score) positively modulates the positive effect of the cognitive GPS on general intelligence significantly in both sexes. Considering that the modulatory effect remains significant after controlling for several potential confounding factors of the brain and cognitive performance, this GPS-brain sex-intelligence pathway has a significant statistical association. These results thus suggest the novel role of brain sex in children, linking the genetic influence to cognitive performance.

Then, what is the biological account of the modulatory effects of the brain sex on the genetic influence on cognitive performance: that is, positive toward maleness and negative toward femaleness? Literature shows that sex chromosomes play a crucial role in cognitive performance (Bender, Puck, Salbenblatt, & Robinson, 1990; Hong & Reiss, 2014; Warling et al., 2020). However, since we did not include the sex chromosomes when constructing the GPSs (following the common practice of the GWAS designs to boost statistical power), it might not fully explain the differences in the mediation effects across sex. Alternatively, we speculate that the different expression patterns of autosomal variants across sex (Boraska et al., 2012; Wijchers & Festenstein, 2011; Zuo et al., 2015) may account for the modulatory effects of sex. Indeed, in line with this speculation, recent literature highlights sex differences in brain transcriptomes related to schizophrenia and alcohol effects (Hitzemann et al., 2021; Hoffman et al., 2022). Future research may test the association between sex differences in genetic expression in the brain and neurocognitive development.

Note that only females showed a significant correlation between brain-based sex score and cognitive GPSs, whereas males showed a marginally significant correlation after correction for multiple comparisons. We think this should not be interpreted as the female-only effect of the cognitive GPSs in the brain sex development. Rather, it should be noted that their effect sizes were similar across sex (in educational attainment GPS) and the models combining males and females showed the significant correlations of the brain-based sex score and cognitive GPSs (in educational attainment and cognitive performance GPSs). Furthermore, regardless of the modulatory effects of sex, in both females and males, the influence of the cognitive GPSs on cognition was positive. This is in line with the literature in adults (Lee et al., 2018; Savage et al., 2018). Taken together, we think that the genetic underpinnings of cognitive development might be related to sex differentiation in the brain. Therefore, our integrative analysis reveals the subtle relationships among sex, genes, brains, and cognition, otherwise undetectable. We suggest this is a novel biological pathway to individual differences in brain sex. It may be interesting to test whether this pathway is related to epigenetic effects of environmental factors, such as early life stress.

This study confirms that biological sex can be classified accurately based on morphometric and white matter connectivity. A recent study with ABCD data show that the biological sex was classified with 89.6% accuracy in the replication set using a deep neural network trained on ABCD T1-weighted structural MRI (Adeli et al., 2020). Our study extends this prior work by showing the additive classification performance increase with the diffusion white matter connectomes. This performance increase perhaps presents that the multimodal MRI effectively accounts for the heterogeneous developmental trajectories of grey and white matter (Giedd et al., 1999). It further shows the importance of the multimodal MRI approach in accurate delineation of brain development status.

Our brain features exclude the total volumes of the brain, grey and white matter, of which the sex differences have been reported (Ruigrok et al., 2014). Though the whole brain volume difference between sexes may be a biological aspect, we reasoned that the measures of gross anatomy would confound the brain–cognition relationship. Therefore, beyond the sex difference in the gross anatomy, this study shows that the patterns of the grey matter and white matter fibers are associated with the continuum of brain sex.

In testing the relationships among the brain sex, cognitive ability, and the genetic influence on cognitive ability, we focused on the cognitive GPSs. However, our discovery of the significant tripartite correlation among the brain-based sex score, total brain volume, and intelligence may lead to a question whether the genetic underpinning of cognitive ability is related to that of the total brain size. Indeed, a recent GWAS meta-analysis reveals an overlap of GWAS hits between cognitive intelligence and brain size in 5 genomic loci (Jansen et al., 2020). We hope that future research may test the moderation effect of sex on the genetic influence on brain size and its impact on cognitive intelligence.

In our study, we found no significant relationship among our key variables with salivary measures of sex hormones. Given the prepubertal stages of the participants, the negative statistical findings may reflect that the gene–brain sex–cognition relationship is not significantly related to the effects of sex hormones. Literature shows a complex relationship between the level of sex hormones and cognitive intelligence (Castanho et al., 2014; Gurvich, Hoy, Thomas, & Kulkarni, 2018). Though different sex hormonal levels across the sexes are observed from the prepubertal ages (Courant et al., 2010), the actual effect of the sex hormones on cognitive intelligence (or its modulation) may not appear until puberty (Shangguan & Shi, 2009).

This study shows a novel relationship among genetic factors, brain sex, and cognitive intelligence. The link between genome-wide factors and cognitive ability has been shown in previous studies. Cognitive GPSs account for general cognitive ability up to 3.5% in pre-adolescence children (Allegrini et al., 2019), 11% of the variance in general intelligence, and 16% of the variance in educational achievement in adolescents (Selzam et al., 2017). Extending this literature, our study shows that an individual's degree of brain sex may modulate the impact of the genetic factor on cognitive intelligence. Since this modulatory effect is positive toward brain maleness and negative toward brain femaleness, it adds another source of sex and individual variability in intelligence. This inference also presents the benefit of using the brain data as an endophenotype in assessing the genotype–phenotype association (Glahn, Thompson, & Blangero, 2007). Taken together, brain sex is linked to the inherited genetic influence of cognition, accounting for a novel pathway to the individual difference in cognitive intelligence in preadolescence.

In contrast to the multiethnic participants, the SEM in the European-ancestry participants only showed nonsignificant indirect effects of brain sex score. The discrepant results may not be easily reconciled. It should be noted that the cross-ethnic transferability of our cognitive GPS based on the European-ancestry GWAS remains to be validated. However, our cognitive GPS was rigorously adjusted for the potential ethnic confounding. Our result of the significant modulatory effects in the admixed American participants needs to be interpreted with caution.

This study shows the novel relationships among brain sex, cognition, and cognitive GPSs. The brain sex score based on grey matter morphometric and white matter connectivity may represent a neurodevelopmental process in preadolescence related to the inherited genetic influence on cognitive intelligence and unrelated to sex hormonal levels. This study thus provides a novel framework for future research in neurocognitive development and mental disorders.

Hire ambitious people: Bright- and dark-side personality and work engagement

Furnham, A., Robinson, C., & Haakonsen, J. M. F. (2022). Hire ambitious people: Bright- and dark-side personality and work engagement. Journal of Individual Differences, Sep 2022. https://doi.org/10.1027/1614-0001/a000380

Abstract: Is work engagement, like job satisfaction, primarily a function of personality? In total, 397 working adults completed a short, reliable, three-facet model of work engagement, a short IQ test, various self-ratings, a Big Five (bright-side) personality scale, and a measure of the personality disorders (dark-side). Work engagement was related to age, intelligence, positive self-ratings, and all the personality variables. A regression analysis revealed six variables significantly related to total work engagement: sex, age, IQ, ratings of personal ambitiousness, trait Neuroticism and Cluster A personality disorders. Regressions onto each of the three facets of work engagement showed slightly different findings, yet in each, older people with lower Cluster A scores and who rated themselves as ambitious scored higher on all facets. Over a third of the variance was explained in each regression. In every analysis, the rating of ambitiousness was most strongly related to work engagement. Implications and limitations are acknowledged.