Rolf Degen summarizing... Many of the features that serve as cues for old age are also signs of masculinity, and female faces are perceived as more masculine as they become older

How facial aging affects perceived gender: Insights from maximum likelihood conjoint measurement. Daniel Fitousi. Journal of Vision November 2021, Vol.21, 12. https://doi.org/10.1167/jov.21.12.12

Abstract: Conjoint measurement was used to investigate the joint influence of facial gender and facial age on perceived gender (Experiment 1) and perceived age (Experiment 2). A set of 25 faces was created, covarying independently five levels of gender (from feminine to masculine) and five levels of age (from young to old). Two independent groups of observers were presented with all possible pairs of faces from this set and compared which member of the pair appeared as more masculine (Experiment 1) or older (Experiment 2). Three nested models of the contribution of gender and age to judgment (i.e., independent, additive, and saturated) were fit to the data using maximum likelihood. The results showed that both gender and age contributed to the perceived gender and age of the faces according to a saturated observer model. In judgments of gender (Experiment 1), female faces were perceived as more masculine as they became older. In judgments of age (Experiment 2), young faces (age 20 and 30) were perceived as older as they became more masculine. Taken together, the results entail that: (a) observers integrate facial gender and age information when judging either of the dimensions, and that (b) cues for femininity and cues for aging are negatively correlated. This correlation exerts stronger influence on female faces, and can explain the success of cosmetics in concealing signs of aging and exaggerating sexually dimorphic features.

General discussion

I find that facial gender and age are not perceived independently of each other. For 14 of 16 observers, judgments of gender (or age) were contaminated by age (or gender) according to a saturated observer model. Generally, the results suggest that female faces are perceived as more masculine as they become older; and young faces (age 20 and 30) are judged as older as they become more masculine. Why do aging and gender interact? The answer is rooted in the perceptual structure of the faces themselves. Perception of facial gender and age rely on shape and texture cues (Brown & Perrett, 1993; Bruce & Langton, 1994; Burton et al., 1993). The correlations between these phenotypic aspects can be readily demonstrated in our set of synthetic face stimuli (Figure 1), and they are likely present in real faces.3 Facial aging is conveyed by morphological cues (Berry & McArthur, 1986; Burt & Perrett, 1995; George & Hole, 2000; O’Toole et al., 1997) such as a) an increase in the size of the jaw, b) thinning of the lips, and c) an increase in the distance between the eyebrow and the eyes. Textural cues for aging particularly affect the skin: a) skin tone becomes darker, b) it has more wrinkles, c) its luminance contrast decreases, and d) its pigmentation becomes yellower. Many of these shape and texture cues also signal masculine features (Brown & Perrett, 1993; Bruce & Langton, 1994; Burton et al., 1993; Russell, 2009). Men have bigger jaws, their lips are thinner, and their eyebrows are closer to their eyes than females; moreover, they tend to have darker skin with lower contrast (Russell, 2010; Tarr et al., 2001). The upshot is that many of the features that serve as cues for old age are also signs of masculinity. The current study shows that cues for age and for gender have the strongest interactive influence when faces are either young or feminine. 

A comment is in order regarding the relations between skin lightness and gender in the current experimental setting. Despite my great efforts to eliminate the correlation between skin lightness and gender, feminine skin tone created by FaceGen were slightly lighter than masculine faces. One may argue that this undermines the current conclusions because observers could have used skin lightness as a cue for gender. However, one should note that such a confound may reflect an ecologically valid cue because a) in real population female skin reflectance is 2 to 3 percentage points above that of male skin (Rahrovan et al., 2018), and b) FaceGen relies on a representative sample of real people (Inversions, 2008). Moreover, a study by Macke and Wichmann (2010) also attempted to remove textural cues for gender (including lightness), but it seems that these authors could not prevent this built-in confound. In their caption to their Figure 1 they admit that: “For some men with strong beard growth, like the gentlemen in the rightmost column, this meant that there was a slightly darker region around the mouth – at least from an introspective point of view a reasonable cue to gender” (p. 6). The upshot is that it is difficult to equate experimentally the skin lightness of feminine and masculine faces due to natural differences. Future studies may be able to circumvent this confound, but then an issue may arise as to whether such faces reflect the statistical structure of real-world faces. 

Evolution, cosmetics, and facial aging

From an evolutionary stand point, the current findings make sense. Fertility in young females may be signaled by cues for femininity and cues for age. The correlation between the two types of cues lead to informational redundancy that increases the chances that information about fertility is transmitted efficiently and correctly to potential mates. This idea can also explain the success of cosmetics (Russell, 2010) and its higher prevalence among women (Etcoff et al., 2011; Russell, 2009). Sexual attractiveness and anti-aging are two main goals of the cosmetics industry, and the current study can explain why. Signals of femininity are positively correlated with attractiveness (O'Toole et al., 1998), and as we have shown here are also negatively correlated with age. This finding can explain the biological incentive for using cosmetics to highlight sexually dimorphic attributes of femininity, but also to conceal cues for old age. Both serve as signals of fertility and are expressed on the same facial cues. For example, Russell (2009) demonstrated the existence of a sex difference in facial contrast that affects the perception of gender. Females have greater luminance contrast between the eyes, lips and the surrounding skin than men. Russell (2009) showed that cosmetics consistently increase facial contrast and thus are functioning to exaggerate feminine features and consequently their attractiveness. Notably, skin contrast also differs between young and old faces and serves as a cue for age (Berry & McArthur, 1986; Burt & Perrett, 1995; George & Hole, 2000; O’Toole et al., 1997). Lower levels of contrast signal old age. Thus, cosmetics not only exaggerates sexually dimorphic attributes, but also decreases perceived age. Etcoff et al. (2011) found that the influences of cosmetics go even farther than that, exerting dramatic positive effects on judgments of competence, likability, and trustworthiness. 

Nonveridical perception of facial gender and age

The present study reveals that facial age and gender are not perceived veridically, but are subjected to major influences of context. Context here refers to the contamination of each dimension by the other. In this sense, each face has a specific gender (age) level that sets a unique context for the perception of its age (gender). This finding is in accordance with the mentioned effects of cosmetics on perceived gender (Etcoff et al., 2011; Russell, 2009), and also with several recent adaptation studies that found that the appearance of both age (O’Neil & Webster, 2011) and gender (Schweinberger et al., 2010) can be altered through adaptation to a previous face. For example, a neutral-gender face seems to be male after adaptation to a female face (Schweinberger et al., 2010). Similarly, adapting to an old face causes faces of intermediate age to appear younger (O’Neil & Webster, 2011). These context effects imply that the internal representations that govern facial age and gender are dynamic and are sensitive to previous experience and correlational structures in the faces themselves. I have recently proposed a ‘face file’ approach to face recognition (Fitousi, 2017a, 2017b), which assumes that faces are stored as temporary episodic representations with detailed featural information about the face’s gender, age, identity, and emotion. These features are bound to each other (e.g., male+young) and can be updated momentarily. Face files can be used to account for the context-dependent nature of facial age and gender (Fitousi, 2017a, 2017b). 

Age and gender are essential for what social scientists call person ‘construal’ (Bodenhausen & Macrae, 1998; Fiske & Neuberg, 1990; Freeman & Ambady, 2011; Macrae & Bodenhausen, 2001), the process by which social agents construct coherent representations of themselves and others. These representations are used by observers to guide information processing and information generations towards others. According to the dynamic interactive model by Freeman and Ambady (2011) the initial presentation of a face launches simultaneous activation of several competing social categories (e.g., age, gender, race). Along the accrual of evidence, the pattern of activation gradually sharpens into clear interpretation (young female), while other alternatives are inhabited. According to this framework, a confluence of perceptual (bottom-up) and cognitive–social (top-down) factors can generate various types of interactions among social facial dimensions such as facial age and gender. The dynamic–interactive model can account for a large body of research that has documented interactive patterns in face categorization including the current findings (Cloutier et al., 2014; Freeman et al., 2012; Johnson et al., 2012). One crucial goal made explicit by the dynamic-interactive model is the need to distinguish between lower (perceptual) and higher (stereotypes, attitudes, expectations) sources of bias in face categorization (Becker et al., 2007). The former are yielded by correlated phenotypic traits in the sensory cues themselves (skin texture and cues for age), whereas the latter are generated by learned associations or social expectations that can be located in the ‘head’ of the observer. 

The integral/separable distinction and MLCM

The application of the MLCM approach (Knoblauch et al., 2014) to psychological dimensions raises a caveat concerning a more general issue in psychology—the concept of perceptual independence. Garner proposed a fundamental distinction between integral and separable dimensions (Garner, 1962, 1970, 1974a, 1974b, 1976, 1991). This distinction is a pillar of modern cognitive science (for review see Algom & Fitousi, 2016). Objects made of integral dimensions, such as hue and saturation are perceived in their totality and cannot be readily decomposed into their constituent dimensions. Objects made of separable dimensions, such as shape and color, can be readily decomposed into their constituent dimensions. The integral–separable distinction cannot be decided based on the verdict of only one procedure. There is the risk that a theoretical concept (e.g., separability) would be only a restatement of the empirical result (Fitousi, 2015; Von Der Heide et al., 2018). 

To avoid circular reasoning, Garner has noted the need for converging operations (Garner et al., 1956). Several methodologies have been used to support the integral–separable distinction: a) Garner’s speeded classification task (Garner, 1974b), b) similarity scaling (Attneave, 1950; Melara, 1992), c) information theory (Fitousi, 2013; Garner, 1962; Garner & Morton, 1969), d) general recognition theory (GRT Ashby & Townsend, 1986; Fitousi, 2013; Townsend et al., 2012; Maddox & Ashby, 1996), and e) system factorial technology (SFT Townsend & Nozawa, 1995). Take method b) for example, in which observers are asked to rate the similarity of two objects (Hyman & Well, 1967). It has been often found that for integral objects similarity is computed according to a Euclidian distance metric, and for separable objects similarity is computed according to a city-block distance metric (Melara, 1992). It has also been shown that the outcome from the similarity procedure accords well with the Garner task results (Algom & Fitousi, 2016). 

Recently, Rogers et al. (2016) and Rogers et al. (2018) have proposed that the MLCM can be used as a converging operation on the notion of integrality–separability. A case in point in their studies is the color dimensions of chroma and lightness (Munsell, 1912). In the Garnerian tradition, these dimensions are considered as classic integral dimensions: a) they produce Garner interference (Garner & Felfoldy, 1970) and b) they obey a Euclidian distance metric in similarity scaling (Burns & Shepp, 1988). If indeed the dimensions are dependent in processing, then an additive or saturated observer MLCM models should best describe the data. Rogers et al. (2016) found that the additive observer model best described the data. Lightness negatively contributed to perception of chroma for red, blue, and green hues (but not for yellow). These results are important because they demonstrate the utility of the MLCM in providing converging evidence on the notion of integrality–separability, and in identifying the internal representations that govern color dimensions. They are also highly informative in uncovering the specific pattern of dimensional interaction. One would have expected integral dimensions to be best fitted by saturated observer model rather than additive observer model. Hence, the application of multiple related methodologies to investigate questions of perceptual independence is of great practical and theoretical importance in sharpening and explicating our concepts. 

The Garnerian edifice is rich in theoretical insights that can illuminate issues in MLCM, and vice versa. This can lead to a cross-fertilization of both methods. For example, an important caveat raised in the Garnerian tradition concerns the direction of interaction between a pair of dimensions. Integrality is not a symmetric concept. Dimension A can be integral with dimension B, while dimension B can be separable from dimension A (Fitousi & Algom, 2020). This notion can be readily applied to studies in MLCM. When judging dimension A and ignoring dimension B, observers can exhibit a complete independent observer model. However, when judging dimension B and ignoring dimension A, observers can exhibit an additive or saturated observer model. Moreover, Garnerian theorizing highlights the role of relative discriminability in determining the direction of asymmetry (Melara & Mounts, 1993). Often the more discriminable dimension intrudes on the less-discriminable dimension (Fitousi & Algom, 2006). It has been shown that relative discriminability can be altered by the researcher and determine the direction of interaction. Therefore, to provide a fair test of independence the dimensions should be equally discriminable (Algom et al., 1996). These factors might also be important in MLCM modeling. 

Future work should test in detail the exact relations between notions of integrality–separability in the Garner tradition and the notions of MLCM. It is not immediately clear for example, that independence in the two approaches is the same. When the dimensions of facial age and gender were subjected to the Garner test Garner (1974b) by Fitousi (2020), they were found to be separable dimensions. But the application of the MLCM to the same dimensions supported their dependency. Why age and gender can appear as separable dimensions in the Garner paradigm and as integral or interactive dimensions (Algom et al., 2017; Algom & Fitousi, 2016) in the MLCM? The solution to this caveat comes by assuming that perceptual independence is not a unitary concept, but rather a nomenclature pointing to various types of independence (Ashby & Townsend, 1986; Fitousi, 2013, 2015; Fitousi & Wenger, 2013). This idea has been originally developed by Garner and Morton (1969) and Ashby and Townsend (1986). It seems that conjoint measurement gauges different types of independence than the Garner paradigm. Future studies may be able to understand the relations between these two approaches. 

Personal relative deprivation fosters a belief that economic success is zero-sum, and that this is true regardless of participants’ household income, political ideology, or subjective social class

Ongis, M., & Davidai, S. (2021). Personal relative deprivation and the belief that economic success is zero-sum. Journal of Experimental Psychology: General, Dec 2021. https://doi.org/10.1037/xge0001144

Abstract: Why do people view economic success as zero-sum? In seven studies (including a large, nationally representative sample of more than 90,000 respondents from 60 countries), we explore how personal relative deprivation influences zero-sum thinking—the belief that one person’s gains can only be obtained at other people’s expense. We find that personal relative deprivation fosters a belief that economic success is zero-sum, and that this is true regardless of participants’ household income, political ideology, or subjective social class. Moreover, in a large and preregistered study, we find that the effect of personal relative deprivation on zero-sum thinking is mediated by lay perceptions of society. The more people see themselves as having been unfairly disadvantaged relative to others, the more they view the world as unjust and economic success as determined by external forces beyond one’s control. In turn, these cynical views of society lead people to believe that economic success is zero-sum. We discuss the implications of these findings for research on social comparisons, the distribution of resources, and the psychological consequences of feeling personally deprived.

Mental Health and Well-being Profile of Young Adults Using Social Media: YouTube users are the most likely to have poorer mental health outcomes; Instagram and Snapchat users tend to have higher well-being

Di Cara, Nina H., Lizzy Winstone, Luke Sloan, Oliver Davis, and CMA Haworth. 2021. “The Mental Health and Well-being Profile of Young Adults Using Social Media.” PsyArXiv. November 30. doi:10.31234/osf.io/3bqvz

Abstract: The relationship between mental health and social media has received significant research and policy attention. However, there is little population representative data about who social media users are which limits understanding of confounding in associations between mental health and social media. Here we profile users of Facebook, Twitter, Instagram, Snapchat and YouTube from the Avon Longitudinal Study of Parents and Children population cohort (N=4,083). We provide estimates of demographics and mental health and well-being outcomes by platform. We find that users of different platforms and frequencies are not homogenous. User groups differ primarily by sex and YouTube users are the most likely to have poorer mental health outcomes. Instagram and Snapchat users tend to have higher well-being. Relationships between use-frequency and well-being differ depending on the specific well-being construct measured. The reproducibility of future research may be improved by stratifying by sex and being specific about the well-being constructs used.

The perception of lower mate availability was associated with decreased life satisfaction, but an oversupply of potential mates also made some uncomfortable (choice overload, especially of those who are good catches)

The Influence of Sex Ratio and Perception of Mate Availability on Psychological Health. Rosenbach, Naomi. Hofstra University, ProQuest Dissertations Publishing, 2022. 28774896. Aug 2021. https://www.proquest.com/openview/0e611481cbc3dbe91211f359da573e0c/1?pq-origsite=gscholar&cbl=18750&diss=y

Abstract: Pair bonding, or long-term adult romantic relationship, was advantageous in ensuring offspring survival and adult protection in the evolutionary environment, thus humans have evolved with strong mating and pair bonding motivations (Belsky, 1999; Fraley, Brumbaugh & Marks, 2005; Fraley & Shaver, 2000). Because successes and failures in meeting adaptive goals is correlated with emotional and psychological health (Nesse, 2016; Plutchik, 2003), decreased or thwarted mating opportunity should theoretically impact wellbeing. Sex ratio refers to the number of males relative to females in a given population and significantly influences mating opportunity. When sex ratio is skewed, the oversupplied sex experiences a dearth in mating opportunity (Guttengang & Secord, 1983). The minimal research that has been conducted in this area suggests that population sex ratio and mating opportunity influence wellbeing (Tucker & Mitchel-Kernan, 1989) yet more research is necessary to gain a better understanding of the psychological impact of sex ratio.

This study examined whether population specific sex ratio and perceived mate availability influenced a variety of mental health outcomes and dating strategies in the young adult, single, population. The main sample consisted of 647 participants (332 male and 315 female) who responded to an online survey with items measuring depression, anxiety, positive and negative affect, life satisfaction, self-esteem and mating flexibility. Mate value, religious and cultural beliefs were assessed as moderating variables. Additionally, some mating and commitment strategies were explored. The hypotheses that young adults who live in an area with less mate availability or who simply perceive there to be an undersupply of available mates would have more negative psychological outcomes were partially supported. Perceived sex ratio and actual sex ratio differentially impacted males and females. For males, perception of lower mate availability was associated with decreased life satisfaction, decreased positive affect, and decreased choosiness in mating criteria. For females, an actual oversupply of females was associated with decreased life satisfaction. Mate value was found to moderate the relationship between perceived sex ratio and anxiety, depression, and negative affect for both males and females. For those low in mate value, decreased opposite sex availability was associated with an increase in anxiety, depression, and negative affect. This pattern reversed for those high in mate value, where perceived increased opposite sex availability was associated with increased depression, anxiety, and negative affect. This latter, unexpected finding suggests that there may be psychological costs for those both high and low in mate value when there is an imbalance in sex ratio. Additionally, perceived sex ratio impacted some dating commitment strategies. For example, those who perceived there to be a dearth of opposite sex availability reported that they would be more “willing to settle for a less than ideal mate out of desperation”. These findings suggest that skewed sex ratio not only impacts sociological constructs such as mating strategies and behaviors but can also impact psychological constructs and individual wellbeing. These findings can help those in the clinical and counseling field better understand how sex ratio and mate availability influence wellbeing. Given that mate acquisition is a significant life goal for young adults, clinicians working with that population should assess for beliefs surrounding mating opportunity.

Overall people share the widespread belief that women are less entitled to sexually pleasurable experiences than men in both casual and relationship contexts

The Role of Gendered Entitlement in Understanding Inequality in the Bedroom. Verena Klein, Terri D. Conley. Social Psychological and Personality Science, November 29, 2021. https://doi.org/10.1177/19485506211053564

Abstract: Five studies (using U.S. samples) examined whether men’s higher entitlement contributes to a sexual pleasure gap that disadvantages women. Participants indicated that men receive more sexual pleasure from their partners, whereas women provide more pleasure (Study 1a). Participants believed that men have more of a right to experience orgasm in both hook-up and relationship encounters and attributed higher negative affect to the male target than to the female target when the target did not experience an orgasm in a sexual scenario (Study 1b). In concert with the idea that pleasure is a privilege that men are perceived as being more entitled to, participants preferred men’s orgasm when forced to choose between the male and the female partner in an orgasm allocation task (Study 1c) and in an experiment (Study 2). Study 3 examined why people believe that men are more entitled to pleasure than women. Men’s higher sense of entitlement as an obstacle to gender equality in sexuality is discussed.

Keywords: entitlement, gender inequality, sexuality, gender differences, deservingness, fairness

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Overall people share the widespread belief that women are less entitled to sexually pleasurable experiences than men in both casual and relationship contexts.

Childhood socioeconomic status positively related to dispositional greed (luxury hypothesis), instead of negatively related (scarcity hypothesis); relationship was found for only-children, not for children with siblings

Further tests of the scarcity and luxury hypotheses in dispositional greed: Evidence from two large-scale Dutch and American samples. Karlijn Hoyer, Marcel Zeelenberg & Seger M. Breugelmans. Current Psychology, Nov 25 2021. https://link.springer.com/article/10.1007/s12144-021-02467-z

Abstract: A recent, large-scale study among Chinese adolescents found that childhood socioeconomic status (CSES) was positively related to dispositional greed (i.e., the “luxury hypothesis”), instead of negatively related (i.e., the “scarcity hypothesis”; Liu et al., 2019c). This relationship was found for only-children, not for children with siblings. The generalizability of these findings may be limited, due to China’s one-child policy and socioeconomic policies which may have led to fewer differences in wealth. We replicated this research in two other cultural contexts that represent markedly different socioeconomic policies in order to test its generalizability: the Netherlands (Study 1, N = 2367, 51.3% female, Mage = 54.06, SD = 17.90), and the USA (Study 2, N = 999, 50.1% female, Mage = 33.44, SD = 12.28). Hierarchical multiple regressions were conducted to test the association between CSES and greed. We mostly replicated the findings by Liu et al. (2019c): CSES was positively related to greed in both studies (“luxury hypothesis”) and there was a moderating effect of siblings in Study 1, but not in Study 2. Implications for theories on greed as well as future research on the association between CSES and greed are discussed.

General Discussion

The aim of our research was to examine the relationship between the economic circumstances at childhood (i.e., growing up poor or wealthy) and adult dispositional greed. In a large study with Chines adolescents Liu et al. (2019c) found support for the Luxury hypothesis, the idea that growing up wealthy would be related to higher levels of dispositional greed in adults (based on initial findings of Poluektova et al., 2015, and Lea et al., 1995). Liu et al. did not find support for the competing Scarcity hypothesis, the idea that growing up poor would be related to higher levels of dispositional greed (based on initial findings by Krekels, 2015, and Chen, 2018). Liu et al. (Liu et al., 2019c, p. 38) stated that “It would be beneficial to test our model in other countries in which the number of children per family is generally more diversified.” Thus, we replicated the study in a large-scale, representative Dutch sample (i.e., the LISS panel). We further replicated the study in a large-scale U.S. American sample, via Prolific. Compared to the Chinese adolescent sample used by Liu et al. (2019c), both our samples had a larger variety in the number of siblings that people have and came from countries that have a longer history of capitalism, likely resulting in more pronounced differences in wealth experienced when growing up.

Replicating Liu et al. (2019c), we found support for the luxury hypothesis in both of our samples. That is, dispositional greed was positively associated with childhood socioeconomic status, implying that the more people reported growing up wealthy, the greedier they were as adults.

We found a moderating role of number of siblings on the relationship between CSES and greed in our Dutch sample in Study 1, replicating the second finding of Liu et al. (2019c), but we did not find this in the American sample of Study 2. More specifically, Study 1 found that the positive relationship between greed and CSES was stronger for children with few siblings than for children with more siblings. This suggests that when children grow up with a lot of resources and also do not need to share these with their siblings, they might become greedier later in life. This is in line with the resource dilution model, which postulates that the more children there are in a family, the more resources are divided among offspring (Blake, 1981). However, our data also heed caution to interpreting the relation between greed and family size: The relationship disappeared when analyzing only the younger generation, but the interaction effect was present for the older generation. This disappearance might be driven by the decrease in family size over the past decades in (Western) European societies. In the American sample in Study 2, the correlation between age and number of siblings was non-significant, and we also did not find a relation between greed and family size in the results of the regression analysis. This difference in findings concerning the role of family size in our Dutch and American samples might be related to a variety of factors. The USA and the Netherlands represent markedly different political systems and policies, and there are personality differences between both countries (Eigenhuis et al., 2015). We will not speculate here about what specifically might be causing the differences found in our studies, but leave it up to future research to delve more specifically into the role of the family make-up when growing up in affecting adult greed. Despite this precaution, we do believe that these results together shed initial light on the origins of greed and on the environmental factors that may contribute to the psychological development of greed.

Contrary to Liu et al. (2019c), our results from Study 1 were not robust to controlling for both gender age (but they were in Study 2). The relationship between greed and age does not seem to be a straightforward one. On the one hand, we did find greed to be negatively correlated with age in both studies, which is consistent with earlier studies on adults cited earlier. On the other hand, Liu et al. found a positive relationship between greed and age, r(3200) = .14, p < .001. Interestingly, this is consistent with earlier findings of Seuntjens et al. (2016), who also had adolescent participants, and found that age and dispositional greed correlated positively, r(3899) = .04, p < .05 These findings fit with a suggestion by Liu et al. (2019c) about an inverted U-shape relationship between greed and age, but our data cannot provide conclusive evidence for such a relationship. Ideally, a future, longitudinal study should investigate the underlying mechanism of differences in greed over the years.

Limitations and Future Research

The replication of the luxury hypothesis suggests two further questions for research into how childhood experiences are related to adult greed. First is the relationship between greed of parents and their children. Greedy parents might create an environment where greed is the norm. In addition, they might deliberately decide to have fewer children (so that they do not have to share their resources), leaving their children with fewer siblings. Second is the possibility for identification and intervention. Given that dispositional greed is likely to develop at an early age and is associated with various harmful and undesirable outcomes later in life (Liu et al., 2019a; Seuntjens et al., 2016, 2015, 2019; Zeelenberg et al., 2020), Liu et al. (2019b) made a case for a mindful parenting intervention to help adolescents to develop more positive core self-evaluations and reduce adolescent greed. They found that embracing mindful parenting enriches adolescents’ self-evaluations, which prevent them from becoming greedy.

In this article, we closely replicated Liu et al. (2019c) and hence, measured CSES with the commonly used scale of Griskevicius et al. (2011). Notably, in several studies subjective assessments of (C)SES were more predictive of decision-making, psychological functioning and health-related factors than more objective indicators (see for example, Adler et al., 2000; Singh-Manoux et al., 2005; Thompson et al., 2020), and empirical evidence has suggested that retrospective reports are accurate (see for example, Brewin et al., 1993; Hardt & Rutter, 2004). Nevertheless, a subjective retrospective scale, such as CSES, does not necessarily reflect the “objective” SES at time of childhood (e.g., the memories of childhood could be prone to change). Thus, it could be informative to follow Krekels (2015) and re-examine the link between greed and CSES using a more objective operationalization of CSES, such as, parental occupation, parental education, and parental income during childhood. Longitudinal studies could be used to investigate the development of the greedy disposition, and to overcome the limitations of retrospective measurements.

Despite the consistent results regarding the subjective CSES measure and dispositional greed that were found in this research and in Liu et al. (2019c), the relation between current SES and dispositional greed is less clear. CSES is often related to SES: Children from low-SES backgrounds are more likely to become low-SES adults, and vice versa (see for example, Chen & Miller, 2012; Brady & Matthews, 2002). Both Krekels (2015) and Seuntjens et al. (2015) found that dispositional greed was unrelated to current income. In the Study 2, we found a correlation between current SES and dispositional greed, but SES had no additional effect when Childhood-SES, number of siblings and their interaction were accounted for. Clearly, more research is needed here. 

Flynn Effect... Louisville Twin Study (longitudinal data collected continuously from 1957 to 1999): Overall gains equaled approximately three IQ points per decade

Genetically informed, multilevel analysis of the Flynn Effect across four decades and three WISC versions. Evan J. Giangrande, Christopher R. Beam, Deborah Finkel, Deborah W. Davis, Eric Turkheimer. Child Development, November 11 2021. https://doi.org/10.1111/cdev.13675

Abstract: This study investigated the systematic rise in cognitive ability scores over generations, known as the Flynn Effect, across middle childhood and early adolescence (7–15 years; 291 monozygotic pairs, 298 dizygotic pairs; 89% White). Leveraging the unique structure of the Louisville Twin Study (longitudinal data collected continuously from 1957 to 1999 using the Wechsler Intelligence Scale for Children [WISC], WISC–R, and WISC–III ed.), multilevel analyses revealed between-subjects Flynn Effects—as both decrease in mean scores upon test re-standardization and increase in mean scores across cohorts—as well as within-child Flynn Effects on cognitive growth across age. Overall gains equaled approximately three IQ points per decade. Novel genetically informed analyses suggested that individual sensitivity to the Flynn Effect was moderated by an interplay of genetic and environmental factors.

Short-term mating was unrelated or even negatively related to reproductive success; long-term mating predicted a greater number of children and children's children

Phenotypic Signals of Sexual Selection and Fast Life History Dynamics for the Long-Term but Not Short-Term Mating. Janko Međedović. Evolutionary Psychology, November 29, 2021. https://doi.org/10.1177/14747049211057158

Abstract: Mating patterns are crucial for understanding selection regimes in current populations and highly implicative for sexual selection and life history theory. However, empirical data on the relations between mating and reproductive outcomes in contemporary humans are lacking. In the present research we examined the sexual selection on mating (with an emphasis on Bateman's third parameter – the association between mating and reproductive success) and life history dynamics of mating by examining the relations between mating patterns and a comprehensive set of variables which determine human reproductive ecology. We conducted two studies (Study 1: N = 398, Study 2: N = 996, the sample was representative for participants’ sex, age, region, and settlement size). The findings from these studies were mutually congruent and complementary. In general, the data suggested that short-term mating was unrelated or even negatively related to reproductive success. Conversely, long-term mating was positively associated with reproductive success (number of children in Study 1; number of children and grandchildren in Study 2) and there were indices that the beneficial role of long-term mating is more pronounced in males, which is in accordance with Bateman's third principle. Observed age of first reproduction mediated the link between long-term mating and number of children but only in male participants (Study 2). There were no clear indications of the position of the mating patterns in human life history trajectories; however, the obtained data suggested that long-term mating has some characteristics of fast life history dynamics. Findings are implicative for sexual selection and life history theory in humans.

Keywords: short-term mating, long-term mating, fitness, reproductive ecology, sexual selection, life history theory

General Discussion

Variation in mating behavior is certainly one of the crucial determinants of variance in fitness itself. Interestingly, the empirical data on the associations between mating and reproduction as a prerequisite for the analysis of selection regimes acting on mating, including sexual selection, are surprisingly lacking, especially in industrial and postindustrial human populations. This topic is of high importance, not only from the viewpoint of sexual selection, but life history theory in humans as well, together with the potential demographic implications. In order to explore the role of mating in reproductive ecology we conducted two studies with samples which differ in important reproductive characteristics (including the mean age of participants in two samples) and assessing different outcomes related to the environment and reproductive events. Despite the large differences between the samples the results were relatively congruent: 1) long-term mating turned out to be beneficial to fitness, while in contrast, short-term mating was either non-associated or even negatively associated to fitness; 2) long-term mating showed enhanced adaptive benefits for males compared to females; 3) age of first reproduction was the crucial mediating variable in the link between long-term mating and fitness in males; 4) short and long-term mating did not show unambiguous life history dynamics in the context of the fast/slow continuum; however, the obtained findings suggested that long-term mating had more consistent associations with the fast life history dynamics. The data show promising potential in understanding the reproductive ecology of mating in post-industrial humans as well as patterns of sexual selection in contemporary human populations.

Sexual Selection on Mating

Present findings revealed crucial differences in short and long-term mating regarding their relations with fitness: long-term mating showed more positive associations with fitness compared to short-term mating, where no relations or even negative relations with fitness were observed. In Study 1, long-term mating was positively associated with reproductive success and the total desired number of children; it was positively associated both with the number of children and grandchildren in Study 2. In both studies, longer partner relationships were related to an earlier age of first reproduction which turned out to be the crucial mediator between long-term mating and fitness for male participants. The findings that individuals with higher time spent in romantic relationships have higher fitness as well are in accordance not only with the previous findings obtained in post-industrial, WEIRD population (Međedović, 2021) but with the data obtained in rural, natural fertility population - Pimbwe tribe of West Tanzania (Borgerhoff Mulder & Ross, 2019). In contrast, short-term mating was related to delaying reproduction in Study 1 and a lower number of children in Study 2.

We examined Bateman's three coefficients (Arnold & Duvall, 1994; Bateman, 1948) in order to estimate the presence of sexual selection: variance in mating, reproduction, and the association between mating and reproduction. Of course, we should be cautious in the interpretation of variance in mating and fertility: reliable estimations of these parameters should involve representative samples. Our samples were not representative of the Serbian population, although the sample examined in Study 2 had several characteristics of representativeness. Having in mind the problems of results generalizability, it is interesting to mention that all of the effects detected were in congruence with the sexual selection theory: the variation in mating (observed in Study 1 and 2), reproductive success (Study 2) and the finding of higher associations between mating and reproduction in males compared to females (Study 1 and 2). These findings are in accordance with several previous empirical studies (Borgerhoff Mulder & Ross, 2019; Brown et al., 2009; Courtiol et al., 2012; Jokela et al., 2010), although none one of these studies were conducted in industrial and post-industrial human populations. This is particularly interesting since theory and previous data show that sexual selection is weaker in monogamous, compared to polygamous societies (Moorad et al., 2011). Hence, although probably with lower intensity, sexual selection still operates in contemporary humans; more precisely, selection primarily acts to enhance male effort in long-term mating.

Can Mating Patterns Indicate Life History Trajectories?

Apart from sexual selection, mating patterns could be a part of human life history dynamics: correlated traits and events which are associated with fitness. Due to differences in ecological conditions and individual characteristics, humans (like other species as well) may have different pathways of fitness maximization, which are often labeled as fast and slow (Del Giudice et al., 2015). However, there are two opposite hypotheses of the role that mating patterns play in life history dynamics: one assumes that short-term mating represents a part of fast life history trajectory (Belsky et al., 1991; Chisholm, 1999), while the other posits the same role for long-term mating (Gangestad & Simpson, 2000). Both hypotheses have acquired some empirical support but it seems that there are more findings which corroborate the former one (Chua et al., 2016; Copping & Campbell, 2015; Kogan et al., 2015; Lukaszewski, 2015; Schmitt, 2005). The present data did not provide findings which may unambiguously support either of these hypotheses. However, the present data was more in line with strategic pluralism theory (Gangestad & Simpson, 2000). Short term mating showed the signatures of both fast and slow life history while long-term mating exhibited more consistent fast life history dynamics. Indeed, the present data is in the accordance with recent predictions that long-term mating may indicate faster life history dynamics (Sear, 2020): having longer romantic relationships can facilitate reproductive success by higher frequency of sexual intercourse in steady relationships (Twenge et al., 2017) or avoiding the cost of switching partners on reproductive fitness (Brown et al., 2009).

Why were there no clearer associations between mating and life history? Well, the view of life history as a singular slow-fast dimension may be an oversimplifying framework for the analysis of human life histories. Recently, several critiques of the slow-fast life history continuum's existence have been published (Royauté et al., 2018; Stearns & Rodrigues, 2020; Zietsch & Sidari, 2020). Furthermore, empirical data showed that the latent space of life history indicators probably cannot be reduced to a single slow-fast dimension, i.e. it is much more complex and consists of several largely unrelated factors (Međedović, 2020a; 2020b; Richardson et al., 2021). The relations between the parameters of reproductive ecology and childhood environment obtained in the present study (i.e. low magnitude correlations with a high number of non-significant associations) are in contrast to the existence of a singular slow-fast continuum as well. Hence, it is questionable if this simple slow-fast life history theoretical framework is useful for understanding of the mating patterns’ role in life history dynamics. This is why it has been suggested that researchers should invest more effort in linking behavioral traits (like mating patterns) with the specific life history tradeoffs than trying to incorporate them in a rigid and oversimplifying fast-slow continuum (Sear, 2020).

Limitations and Future Directions

There are several important limitations of the present research. As we have already mentioned, the samples of participants the data were collected on were not representative, which limits the generalization of the data (although, the Study 2 was conducted on a large sample which was representative in several demographic parameters). The variation of the reproductive success in Study 1 was diminished which represents a potential obstacle to the generalization of the findings. Additional socio-demographic measures would be useful in the context of present topic - especially the estimate of participants’ income. Participants’ education levels were above the average in the present research; we can reasonably assume that the same holds for their income as well because education and economic status are positively correlated. Hence, the research findings cannot easily generalize to the participants with low education and socioeconomic status. The conducted studies were cross-sectional, which prevents causal inferences from the data; this is a limitation of previous studies in this topic as well. Despite the fact that early fertility is positively associated with completed fertility we should take the measure of reproductive success from Study 1 with caution. We did not use objective information about the participants’ childhood environment but the subjective estimations of ecological characteristics: future research may analyze objective indicators of environment like mortality rates, characteristics of the healthcare system or childhood environmental instability. Furthermore, parental fitness was not controlled for in the present research; future studies should not only control for parental reproductive success but examine the parental influence on mating in offspring, since there is a parent-offspring conflict regarding the mate choice (Buunk et al., 2008).