Women in consensually non-monogamous relationships reported earlier pubertal development; CNM individuals also reported more social and ethical risk-taking, less aversion to germs, and greater interest in short-term mating

Life History and Multi-Partner Mating: A Novel Explanation for Moral Stigma Against Consensual Non-monogamy. Justin K. Mogilski et al. Front. Psychol., January 21 2020. https://doi.org/10.3389/fpsyg.2019.03033

Abstract: Life history theory (LHT) predicts that individuals vary in their sexual, reproductive, parental, familial, and social behavior according to the physical and social challenges imposed upon them throughout development. LHT provides a framework for understanding why non-monogamy may be the target of significant moral condemnation: individuals who habitually form multiple romantic or sexual partnerships may pursue riskier, more competitive interpersonal strategies that strain social cooperation. We compared several indices of life history (i.e., the Mini-K, the High-K Strategy Scale, pubertal timing, sociosexuality, disease avoidance, and risk-taking) between individuals practicing monogamous and consensually non-monogamous (CNM) romantic relationships. Across several measures, CNM individuals reported a faster life history strategy than monogamous individuals, and women in CNM relationships reported earlier pubertal development. CNM individuals also reported more social and ethical risk-taking, less aversion to germs, and greater interest in short-term mating (and less interest in long-term mating) than monogamous individuals. From these data, we discuss a model to explain how moral stigma toward non-monogamy evolved and how these attitudes may be mismatched to the modern environment. Specifically, we argue that the culture of sexual ethics that pervades contemporary CNM communities (e.g., polyamory, swinging) may attenuate risky interpersonal behaviors (e.g., violent intrasexual competition, retributive jealousy, partner/child abandonment, disease transmission) that are relatively more common among those who pursue multi-partner mating.

Discussion

We compared self-report indices of life history across men and women within monogamous, open, and multi-partner romantic relationships. Collectively, our results suggest that pursuit of CNM is associated with a faster life history strategy. Individuals within open and multi-partner relationships reported lower scores (i.e., a faster life history) on the Mini-K than those in monogamous relationships. Open individuals also reported lower scores on the HKSS than both monogamous and multi-partner individuals, who were no different from one another.

That individuals within CNM relationships report a faster life history makes sense in light of previous research on the association between faster life histories and promiscuous mating systems. CNM individuals’ preference for multiple sexual and romantic partners has been documented across several samples (Morrison et al., 2013; Rodrigues et al., 2016, 2017, 2019; Mogilski et al., 2017, 2019; Balzarini et al., 2018b) and is replicated again in this study using an alternative measure of sociosexuality (i.e., the MMSO) that separately measures affinity toward short- and long-term partnerships. We found that those in multi-partner relationships reported a more STMO than those in open and monogamous relationships, and open individuals reported a more STMO than monogamous people. Interestingly, those in multi-partner relationships also reported less interest in long-term committed romantic relationships than monogamous, but not open, individuals. It is possible that CNM individuals, and particularly those that maintain several concurrent romantic relationships, form fewer enduring partnerships than those in monogamous relationships. However, this is not consistent with prior research. Séguin et al. (2017) found that individuals within polyamorous relationships reported longer relationships than those in monogamous and open relationships, and all three relationship types reported similar levels of partner commitment. Similarly, Mogilski et al. (2017) compared relationship length between monogamous and CNM individuals’ primary and secondary relationships. Although they found that monogamous relationships tended to be older than secondary relationships, CNM primary relationships tended to be older than monogamous relationships. This suggests that those in CNM relationships regularly form long-term enduring relationships but are perhaps selective about with whom they maintain those relationships. That is, people who form multi-partner relationships may desire and actively seek a variety of intimate partners, but only maintain partnerships if they are of high quality. Balzarini et al. (2017) reported that primary partnerships tend to entail more commitment than secondary partnerships, and Mitchell et al. (2014) likewise found that polyamorous individuals report greater commitment to one partner than the other. Alternatively, LTMO may differ across different types of CNM. We did not collect data to distinguish different types of multi-partner relationships, but individuals interested in polyamory (i.e., multiple emotionally intimate relationships) may be more oriented toward long-term relationships than those interested in exclusively sexual extradyadic relationships.

Our complementary findings suggest that life history differences between monogamous and CNM individuals extend beyond sociosexuality. Women within multi-partner, but not open, relationships reported earlier sexual debut than women within monogamous relationships. There were no differences in self-reported pubertal timing among men. This is consistent with research showing that early sexual maturity is associated with a faster life history in women (Byrd-Craven et al., 2007; James et al., 2012; also see Hehman and Salmon, 2019), particularly within western industrialized societies (Sear et al., 2019). Scores on the PVDS also revealed that individuals within CNM and monogamous relationships did not differ in their perceived infectability. However, monogamous individuals reported greater germ aversion than both multi-partner and open individuals, while the latter were equally averse. This is consistent with work showing that those who score higher on the Mini-K (i.e., slow life history) report greater pathogen, sexual, and moral disgust than those who score lower (Frederick et al., 2018). For slow strategists, this aversion may motivate protective avoidance of risks that threaten long-term well-being. For fast strategists, a higher threshold for disgust would allow them to capitalize on opportunities despite possible risks (e.g., exposure to disease, interpersonal exploitation). However, these individuals may likewise fail to avoid sexual disease risk, which may become a community health issue. Finally, we also observed that those in multi-partner and open relationships scored higher than monogamous people on social and ethical (though not health) risk-taking. This suggests that CNM individuals may be more likely to disregard how their behaviors are perceived by or affect the well-being of others, but supports research showing that those in CNM relationships tend to be conscientious about sexual health (Conley et al., 2012, 2013b). Collectively, these findings suggest that differences in life history between monogamous and CNM individuals do not merely reflect differences in sociosexuality. Rather, people who are interested in pursuing a CNM relationship may be predisposed to a faster life history strategy.

CNM, Morality, and Sexual Ethics

Knee-jerk condemnation of CNM can produce wrongful discrimination that harms personal and community well-being. For instance, those in CNM relationships typically report being more secretive about their non-primary (or pseudo-non-primary) partners (Balzarini et al., 2019), presumably to avoid third-party punishment. Indeed, Conley et al. (2012) found that women who fear condemnation are less willing to accept an offer of casual sex that they would otherwise enjoy pursuing. This fear of judgment can cause anxiety that prevents those who practice CNM from seeking sexual health services (e.g., STD testing), particularly within rural communities where reputation can be more easily tracked (Kirkman et al., 2015). Moreover, therapists and clinicians who assume that monogamy is a universal relationship ideal may inadvertently marginalize or mistreat patients who are oriented toward multi-partner mating (see Finn et al., 2012; Brandon, 2016; van Tol, 2017; Cassidy and Wong, 2018). In fact, Schechinger et al. (2018) found that CNM individuals reported that therapy was more helpful when therapists were more affirmative about their relationship structure (e.g., did not make an issue of their relationship structure when it was not relevant).

It is possible that moral stigma toward CNM (see Moors et al., 2013) stems from aversion to the high-risk, competitive interpersonal strategies that are characteristic of a fast life history (see Wang et al., 2009; Figueredo and Jacobs, 2010; Kruger, 2010; Griskevicius et al., 2011). Commitment to a faster life history strategy can lead to greater risk-taking (Hampson et al., 2016; Mishra et al., 2017), impulsivity (Frankenhuis et al., 2016; Maner et al., 2017), and aggression against others (Figueredo et al., 2018). Also, robust indicators of faster life history, such as paternal absenteeism and adolescent fertility, predict national rates of criminal violence (Minkov and Beaver, 2016), child maltreatment, and homicide (Hackman and Hruschka, 2013). Moral condemnation of multi-partner mating may thereby occur when condemners believe that monogamy prevents competitive contests for mates, enhancing cooperation within groups and reducing negative physical and mental health outcomes. In other words, though fast life history traits can help individuals cope with an unpredictable environment (Figueredo and Jacobs, 2010; Frankenhuis et al., 2016; Young et al., 2018), they may conflict with the optimal social strategy pursued by slow life history strategists. Baumard and Chevallier (2015) argue that fast life history behaviors may be moralized to the extent that slow strategists promote cooperation, self-regulation, and restricted sociosexuality, and condemn “fast” behaviors such as selfishness, conspicuous sexuality, and materialism. By espousing moral values that promote delayed gratification, sexual monogamy, and altruism, slow life history strategists may condemn multi-partner mating to create stable, cohesive communities that invest in long-term reciprocity and extended prosociality.

Although our data support the conclusion that CNM is associated with fast life history traits, it is important to note that our study assesses dispositional tendencies and not how these tendencies are modified by cultural practices within the CNM community. People who prefer multi-partner mating may have a proclivity toward pursuing a faster life history, but most modern CNM communities have well-developed guidelines for pursuing multi-partner relationships safely and ethically (see Anapol, 1997; Wosick-Correa, 2010; Deri, 2015; Hardy and Easton, 2017). Sexual ethics within CNM communities, including effective birth control methods, may help manage and diminish the traditional costs of competitive, high-risk, promiscuous mating environments. CNM individuals take precautions to attenuate distress caused by a partner’s extradyadic involvement (Jackson and Scott, 2004; McLean, 2004; Visser and McDonald, 2007). Those in CNM relationships are just as (or more) likely to practice safe sexual practices than people in monogamous relationships (Conley et al., 2012, 2013b; Lehmiller, 2015). They are also expected to practice open communication, honesty, emotional intimacy, and consent-seeking to reduce the threat of partner defection or resource diversion. Scoats and Anderson (2019) interviewed men and women who engaged in mixed-sex threesomes and found that open communication reduced feelings of exclusion. Similarly, Aguilar (2013) studied two communal living groups practicing polyamory and reported that both cultures discouraged aggression and competition among males within the community.

By reducing the social anxiety that accompanies multi-partner competition, individuals within CNM relationships may experience relationship and health outcomes on par with (or better than) those who pursue monogamy. Those within multi-partner relationships that include ethical treatment of and consent among partners typically experience more positive relationship and health outcomes than those who pursue non-consensual non-monogamy (i.e., adultery; Levine et al., 2018). Compared to those in monogamous relationships, CNM individuals report experiencing less emotional jealousy (Mogilski et al., 2019), and spend less time actively trying to retain their mate (Mogilski et al., 2017, 2019), which may alleviate conflict in relationships where one or both partners desire extradyadic intimacy. Indeed, people with an unrestricted sociosexuality report greater satisfaction within CNM relationships than they do in monogamous relationships (Rodrigues et al., 2016; Fairbrother et al., 2019), and report less preoccupation with constraining relationship forces (i.e., feeling obligation rather than desire toward a partner), which is associated with greater self-reported quality of life (Rodrigues et al., 2019). Stults (2018) also found that gay and bisexual men involved in multi-partner mating reported that the conflict resolution strategies of CNM improved their relationship satisfaction, communication, and trust. This suggests that CNM may improve, rather than dissolve, cooperation and well-being within certain populations – a feature that should be valued by those who fear how public acceptance of CNM might affect social cohesion.

Limitations and Future Directions

The most notable limitation of this research is that it does not assess the influence of measured morality or sexual ethics on behavior within CNM relationships, and these are constructs that should be examined further in future work. Our results should not be interpreted as support for condemnation against CNM. Rather, our data highlight how those with a proclivity toward CNM may possess personality traits that predispose them to take risks, pursue multi-partner mating, and disregard pathogens. CNM may therefore not foster these traits, but rather provide an environment where people can ethically express them. Without strict ethical guidelines for how to handle multiple concurrent romantic relationships, people may pursue multi-partner mating in a manner that produces social disharmony. For example, in sub-Saharan and Muslim populations where polygamy is socially acceptable, women in polygamous relationships experience more spousal mistreatment, abuse, and mental health concerns than those in monogamous relationships (Hassouneh-Phillips, 2001; Özer et al., 2013). Children from these polygynous families also report more mental health and social difficulties, poorer school achievement, and poorer paternal relationships than those from monogamous families (Al-Krenawi et al., 2002; Al-Krenawi and Slonim-Nevo, 2008). Within these populations, these negative outcomes seem to arise when there is competition, hostility, jealousy, and little communication among partners. However, when effort is invested into building respectful and congenial relationships among partners, these outcomes improve (Al-Krenawi, 1998). This suggests that the dynamic of a multi-partner relationship may be a better predictor of relationship functioning than its structure (Elbedour et al., 2002). CNM ethical practices may likewise reduce conflict among those who pursue multi-partner relationships. Specifically, CNM’s culture of compassionately enforced sexual ethics may provide an outlet for fast life history strategists to pursue their preferred strategy in a manner that reduces its negative impact on others’ well-being.

This research highlights the need to identify and quantify a formal taxonomy of CNM ethics. Although a number of popular guides exist (e.g., Anapol, 1997; Hardy and Easton, 2017), there is no unified scientific examination of the diverse strategies that CNM practitioners use to manage multi-partner relationships. The most obvious ethical guideline that differentiates CNM from other forms of non-monogamy is its namesake: consent. However, this is too broad a concept to capture the myriad of ethical considerations that may arise within a multi-partner relationship. For example, Peoples et al. (2019) presented case studies of two married men who pursued extramarital partnerships with and without the consent of their spouse. They documented that both men, regardless of spouse consent, engaged in antagonistic and exploitative relationship practices, such as deception, partner neglect, and divestment from childcare, which subsequently produced relationship conflict. This suggests that consent-seeking is a nominal feature of CNM relationships and that ethical pursuit of multi-partner mating may instead require a multifaceted approach that addresses the diverse array of anxieties and exploitations that can produce suffering within romantic and interpersonal relationships.

It may be fruitful to begin this investigation by examining how CNM practices complement the recurrent, domain-specific adaptive issues that have shaped humans’ evolved psychology. Natural selection has shaped psychological adaptations that protect against cuckoldry and partner abandonment (Buss and Schmitt, 1993, 2019), interpersonal exploitation (Buss and Duntley, 2008; Duntley, 2015), and infection by disease (Al-Shawaf et al., 2015; Tybur and Lieberman, 2016). Although these adaptations may have enhanced reproductive success, they do not necessarily enhance well-being (Kováč, 2012), nor may they function optimally within a modern environment (Li et al., 2018). It is possible that the sexual ethics of CNM, paired with modern sexual health technologies, reduce the need for humans to rely on psychological mechanisms of disgust and moral condemnation to regulate sexual risk-taking and other features of a faster life history. For example, proscribing hostility among partners within CNM relationships may reduce intrasexual competition and its consequences on public health (see Kruger, 2010; Tybur et al., 2012). Future research should compare CNM individuals who adhere or not to the ethical principles espoused by the greater community and assess whether adherence tends to improve relationship functioning, particularly among those who have a predisposition to disregard others’ well-being.

Another limitation of this study is that it did not examine a complete array of life history traits. It also relies exclusively on self-report measures, which are vulnerable to revisionism and faulty memory. The validity of the Mini-K and HKSS as self-report measures of life history variation is contested (see Dunkel and Decker, 2010; Figueredo et al., 2013, 2015; see also Copping et al., 2014; Richardson et al., 2017), though our complementary measures provide convergent evidence that CNM is associated with a faster life history. Nevertheless, future research should examine a wider collection of behavioral measures of life history within CNM populations and consider which features of a fast life history are most endemic to CNM populations. Research should also address whether life history features are invariant across different CNM populations and subcultures (e.g., swinging vs. polyamory vs. religious polygamy). People within polyamorous relationships are typically viewed as more moral and responsible than those in swinging and open relationships (Matsick et al., 2014). To the extent that polyamorous relationships are defined by multiple close, emotionally intimate bonds, these relationships (and the people within them) may be seen as less socially disruptive. Similarly, we did not assess whether our participants had children, which can substantially shape relationship behaviors and attitudes (e.g., Barbaro et al., 2016; Flegr et al., 2019).

Finally, there are several methodological issues that should be considered when interpreting this data. First, several of our measures had low Cronbach’s alphas, including the MMSO and the ethical, health/safety, and social risk-taking facets of the DOSPERT. Similarly, our measure of pubertal development relied on self-report responses, which may be biased by retrospection. Research designs that rely on alternative, well-validated measures of psychological and social functioning (e.g., psychophysiological assessment; social relations modeling) administered within laboratory or naturalistic settings may help to improve the quality of life history and CNM research more broadly.

Dating apps users had a higher short-term mating orientation than non-users (more frequent behavior, higher desire, & more positive attitude); simultaneously, those apps seem not a bad (nor good) option for finding long-term love

Barrada JR, Castro A, Fernandez del Rio E, Ramos-Villagrasa PJ (2021) Do young dating app users and non-users differ in mating orientations? PLoS ONE 16(2): e0246350. Feb 2 2021. https://doi.org/10.1371/journal.pone.0246350

h/t David Schmitt dating apps users had a higher short-term mating orientation than non-users (more frequent behavior, higher desire, and more positive attitude)...no differences in long-term orientation as a function of use/non-use

Abstract: In recent years, dating apps have changed the way people meet and communicate with potential romantic and/or sexual partners. There exists a stereotype considering that these apps are used only for casual sex, so those apps would not be an adequate resource to find a long-term relationship. The objective of this study was to analyze possible individual differences in the mating orientations (short-term vs. long-term) between users and non-users of dating apps. Participants were 902 single students from a mid-size Spanish university, of both sexes (63% female, and 37% male), aged between 18 and 26 years (M = 20.34, SD = 2.05), who completed a battery of online questionnaires. It was found that, whereas dating apps users had a higher short-term mating orientation than non-users (more frequent behavior, higher desire, and more positive attitude), there were no differences in the long-term orientation as a function of use/non-use. Considering this, dating apps are a resource with a strong presence of people interested on hooking-up while, simultaneously, not a bad (nor good) option for finding long-term love.

Discussion and conclusions

The development of dating apps in recent years has generated some debates, especially related to the motivations for their use. Usually, it has been considered that dating apps were used for casual sex, although other studies have shown that the reasons for their use are more diverse and complex and may include, among others, the search for long-term romantic relationships [2–9]. In the attempt to contribute information to this debate, the objective of this study was to analyze possible differences in the mating orientations in a sample of single young university students depending on whether or not they were users of dating apps.

In response to the main objective of the study, differences were found between users and non-users of dating apps in the three dimensions of short-term orientation–especially in sociosexual behavior–but not in long-term orientation. That is, among app users, it is comparatively easier to find more unrestricted sexually-oriented people, whereas users and non-users do not differ in their interest in maintaining a long-term romantic relationship.

This allows several conclusions to be drawn. First, according to the existing literature and the constructs evaluated, it seems logical that those who use dating apps, many who are open to casual sex, will score higher in the three dimensions of sociosexuality than those who do not use them [9,17]. Secondly, the absence of differences in the long-term orientation indicates that the orientations are not exclusive and contrary to each other [24,25]. Dating apps users, although open to short-term relationships, are not reluctant to long-term mating. This converges with previous results as longitudinal higher likelihood of forming romantic the longitudinal by Tinder users [34] or that previous use is not related to being single [10]. This pattern of results opens the door to the perception that there may be flexibility in mating orientations and preferences and that they can coexist simultaneously in people seeking both a casual relationship and a romantic relationship [24].

Thirdly, among the contributions of the article should be highlighted the assessment of sociosexuality from a multidimensional point of view, distinguishing between behavior, attitudes, and desire, following the recommendations of other authors [15,38]. It has been shown that the three dimensions of the construct, understood as short-term orientation, correlate positively and directly with each other and inversely with the long-term orientation, although the intensity of the association varies, being more powerful in attitudes and less powerful in sociosexual behavior and desire. This points to the need to step away from the conceptualization of unrestricted sociosexuality as equal to short-term mating orientation and restricted sociosexuality as equal to long-term mating orientation [29]. As we previously noted, restricted sociosexuality is better understood as lack of short-term orientation, what is not equivalent to long-term orientation.

In addition, as regards the prevalence of use of dating apps among the participants in the last three months, 20.3% of users were found among those who were singles (12.7% of the total sample), which represents a medium-low prevalence compared to other studies [2,3,5–7], although it should be noted that, in these studies, sampling was aimed at finding people who used dating apps [1].

Of the other results obtained, the most relevant, although it was beyond the main objective of the study, were the differences found in the long-term orientation between single men and women. Contrary to our expectations, men scored slightly higher than women in this variable. A greater long-term orientation had usually been found in women [16,20,21,24,28]. As this is the first study of its kind to be carried out in Spain, it is difficult to identify the causes and determine whether this is a cultural pattern or whether it simply responds to the characteristics of the study sample. In any case, this result seems to suggest that women are increasingly owners of their sexuality and of the decisions that have to do with it, moving away from the effects of traditional double standard [23].

Also contrary to expectations, a relationship was found between age and short-term orientation, but not with long-term relationships. The existing literature defends that people go changing progressively their preferences when they grow up, involving in long-term relationships [22]. However, due to the limited age range of the participants of the present study, this variation cannot be seen in the interests and behaviors of university students. Finally, we found that while heterosexual participants were more oriented to long-term mating, sexual minorities were more inclined towards short-term mating. This result was already present in the literature [33].

The study has a number of limitations. The use of dating apps was evaluated without delving into the variety of uses, from those who used it on a single afternoon as a joke among friends to those who used it for months looking for a romantic relationship. So, what we treated a unitary (self-reported) behavior–dating apps use–included, in fact, important differences in motivations or intensity. Other limitations were related to the representativeness of the sample and the generalization of the results. Among the final participants, the sample was mostly female, aged between 18 and 26, single and from a single university, making the results difficult to generalize to all university students and, still less to young non-university students.

Concerning to sexual orientation, two aspects should be noted. First, the high proportion of participants from sexual minorities, more than 30% of the final sample. This could be considered as a lack of representativeness of our sample. We consider that an alternative interpretation is possible. This study shares with previous studies the same sampling approach and population (Spanish university students with the same age range and from the same university). We will show the time of data collection and the proportion of sexual minority participants: November 2018, 27.0% [14], December 2017, 22.5% [9], May 2016, 14.7% [38], April 2016, 12.7% [35], October 2013, 8.6% [39]. A clear trend is found. The proportion of sexual minority participants is steadily increasing in our samples.

We can imagine two options to explain this. First, our surveys are not just biased by sexual orientation (higher probability of participation for non-heterosexual people), but also that bias is growing. We cannot find any theoretically plausible explanation for this potential change of bias across time. Second, in fact in the population of university students (Spain, a single university) the presence of non-heterosexuality is increasing. This second alternative would imply that the large number of non-heterosexual participants is not a problem of representativeness of the samples.

This hypothesis may be supported by data on the prevalence of persons from sexual minorities found in other studies, which can be exemplified in that of Rahman et al. [40], who assessed the prevalence of women´s and men´s sexual orientation in 28 nations and found similar proportions to those of the present study, both in Spain (73% vs. 27%) and in other countries (e.g., United States, Australia, Finland). There seems to be a trend toward greater self-identification as a member of sexual minorities, paralleling the decrease in stigma and the improvement in the quality of life of these people, especially in countries with more tolerant laws, as is the case in Spain [41]. However, further research is needed to clarify this point. And, in any case, in our regression analyses we included sexual orientation as covariate. In addition, to facilitate the analyses, we decided to group participants into heterosexuals and non-heterosexuals, thus losing the nuances related to the behavior of members of sexual minorities.

Similarly, our study shares with other studies based on self-selected samples and self-reported measures the fact that the results may be limited by response and recall bias. Finally, like most literature on the subject, this study is cross-sectional. It would be interesting to design longitudinal investigations, to assess the development and stability/change, both in the use of dating apps and in mating orientations and their associations.

Despite these limitations, the study is considered to meet the objective posed and answers the question that prompted it. Users of dating apps have a greater short-term orientation than non-users, with no differences in long-term orientation. Thus, it can be said that both types of orientations and relationships are expressions of sexuality that can coexist, that they are not considered as excluding and that, regardless of the type of people’s sexual relations, the important thing is that they are healthy, performed in a context of mutual respect. With regard to the objective of the study, summarizing: dating apps seem to be good for casual sex and not bad for finding long-term love.

Comparison of fatigue-related impairment to drug and alcohol-related impairment: Findings suggest that work and driving performance is significantly impaired after less than 5 h prior sleep

How much sleep do you need? A comprehensive review of fatigue related impairment and the capacity to work or drive safely. D.Dawson M.Sprajcer M.Thomas. Accident Analysis & Prevention, Volume 151, March 2021, 105955. https://doi.org/10.1016/j.aap.2020.105955

Rolf Degen's take: Findings suggest that work and driving performance is significantly impaired after less than 5 h prior sleep

Highlights

• Comparison of fatigue-related impairment to drug and alcohol-related impairment.

• A review of fatigue-related performance impairment.

• Findings suggest that work and driving performance is significantly impaired after less than 5 h prior sleep.

• The concept of ‘deemed impaired’ is introduced in the context of fatigue-related impairment.

Abstract: In developed countries, deaths attributable to driving or working while intoxicated have steadily declined over recent decades. In part, this has been due to (a) public education programs about the risks and (b) the deterrence value associated with penalties and prosecutions based on an individual being ‘deemed impaired’ if they exceed a proscribed level of blood alcohol or drug concentration while driving/working. In contrast, the relative proportion of fatigue-related accidents have remained stubbornly high despite significant public and workplace education. As such, it may be useful to introduce the legal principle of ‘deemed impaired’ with respect to fatigue and/or sleep loss. A comprehensive review of the impairment and accident literature was performed, including 44 relevant publications. Findings from this review suggests that a driver or worker might reasonably be ‘deemed impaired’ once the amount of sleep falls below five hours in the prior 24. Building on the legal principles first outlined in recent New Jersey legislation (Maggie’s Law), this review argues that an individual can reasonably be ‘deemed impaired’ based on prior sleep wake behaviour. In Maggie’s Law, a driver can be indirectly ‘deemed impaired’ if they have not slept in the prior 24 h. Based on the extant literature, we argue that, relative to drug and alcohol intoxication, this may be overly conservative. While roadside measurement of fatigue and prior sleep-wake behavior is not yet possible, we suggest that public education programs should provide specific guidance on the amount of sleep required and that post-accident forensic examination of prior sleep wake behaviours may help the community to determine unsafe behaviours and liability more objectively than is currently the case.

Keywords: FatigueDrink drivingImpairmentLaw

Evolutionary perspectives on the mechanistic underpinnings of personality

Chapter 19 - Evolutionary perspectives on the mechanistic underpinnings of personality. Aaron W. Lukaszewski. The Handbook of Personality Dynamics and Processes, 2021, Pages 523-550. https://doi.org/10.1016/B978-0-12-813995-0.00019-4

Abstract: Evolutionary theory is the organizing framework for the life sciences because of its unique value in deriving falsifiable predictions about the causal structure of organisms. This chapter outlines the relationships of evolutionary principles to the study of phenotypic variation and defines two distinct paradigms for personality science. The first of these, dimensional cost-benefit analysis (DCBA), entails analyzing the reproductive cost-benefit tradeoffs along inductively derived personality dimensions (e.g., the Big Five) to derive predictions regarding adaptively patterned variation in manifest trait levels. The second paradigm, ground-up adaptationism (GUA), requires building models of specific psychological mechanisms, from the ground-up, including their variable parameters that result in manifest behavioral variation. After evaluating the strengths and limitations of these paradigms, it is concluded that (1) inductively derived dimensions of person description should not serve as the field's explanatory targets; (2) GUA represents the most powerful available framework for elucidating the psychological mechanisms, which comprise human nature and produce its diverse range of behavioral variants; and (3) the goals of adaptationist evolutionary psychology are the same as those guiding personality psychology's next era: to identify the mechanisms that comprise the mind, figure out how they work, and determine how they generate behavioral variation.

Keywords: AdaptationismDifferential psychologyEvolutionEvolutionary psychologyIndividual differencesPersonalitySocial cognition

High neuroticism & low conscientiousness had the strongest link to dementia risk; low extraversion, openness, and agreeableness were also related to increased risk

Is Personality Associated with Dementia Risk? A Meta-Analytic Investigation. Damaris Aschwanden et al. Ageing Research Reviews, February 6 2021, 101269. https://doi.org/10.1016/j.arr.2021.101269

Rolf Degen's take: Meta-analysis: Individuals high in neuroticism and those low in conscientiousness carry a higher risk of dementia

Highlights

• We conducted five separate meta-analyses with 8-12 studies (N = 30,036 to 33,054).

• High neuroticism & low conscientiousness had the strongest link to dementia risk.

• Low extraversion, openness, and agreeableness were also related to increased risk.

• No evidence of publication bias was found.

• The associations did not vary by dementia assessment or follow-up time.

Abstract: This study provides a quantitative synthesis of the prospective associations between personality traits (neuroticism, extraversion, openness, agreeableness, conscientiousness) and the risk of incident Alzheimer’s disease and related dementias. We conducted five separate meta-analyses with 8-12 samples (N = 30,036 to 33,054) that were identified through a systematic literature search following the MOOSE guidelines. Higher neuroticism (HR = 1.24, 95% CI [1.17, 1.31]) and lower conscientiousness (HR = 0.77, 95% CI [0.73, 0.81]) were associated with increased dementia risk, even after accounting for covariates such as depressive symptoms. Lower extraversion (HR = 0.92, 95% CI [0.86, 0.97]), openness (HR = 0.91, 95% CI [0.86, 0.96]), and agreeableness (HR = 0.90, 95% CI [0.83, 0.98]) were also associated with increased risk, but these associations were less robust and not significant in fully adjusted models. No evidence of publication bias was found. The strength of associations was unrelated to publication year (i.e., no evidence of winner’s curse). Meta-regressions indicated consistent effects for neuroticism, openness, and conscientiousness across methods to assess dementia, dementia type, follow-up length, sample age, minority, country, and personality measures. The association of extraversion and agreeableness varied by country. Our findings indicate robust associations of neuroticism and conscientiousness with dementia risk.

Keywords: Personality traitsdementiaAlzheimer’s diseasemeta-analysisneuroticismconscientiousness

We found that children were more likely to punish the perpetrator of selfishness than to compensate the victim - justice was more retributive than distributive

Children favor punishment over restoration. Katherine McAuliffe  Yarrow Dunham. Developmental Science, February 2 2021. https://doi.org/10.1111/desc.13093

Abstract: Why do people punish selfish behavior? Are they motivated to punish perpetrators of selfishness (retribution) or to compensate the victims of selfishness (restoration)? Developmental data can provide important insight into these questions by revealing whether punishment of selfishness is more retributive or restorative when it first emerges. Across two studies, we examined costly third‐party intervention in 6‐ to 9‐year‐olds. In Study 1, children learned about a selfish actor who refused to share with a recipient. Children then chose to (1) punish the selfish actor by rejecting their payoff (retribution); (2) compensate the victim of selfishness by equalizing payoffs between the perpetrator and victim (restoration); or (3) do nothing. We found that children were more likely to punish than compensate in response to selfishness, suggesting that intervention in this context is more retributive than restorative. In Study 2, we tested third‐party intervention in the face of generosity which, like selfishness, can lead to unequal outcomes. As in Study 1, children in this context could reject unequal payoffs, thereby depriving the recipient of the advantageous payoff but having no effect on the actor. Children could also use compensation in this context, equalizing the payoffs between actor and recipient. We found that children did not punish inequality that stemmed from generosity, suggesting that the retributive punishment in Study 1 was specifically targeting selfishness rather than inequality more generally. These results contribute to the debate on the function of third‐party punishment in humans, suggesting that retributive motives towards selfish transgressors are privileged during ontogeny.

Weak empirical support to say that problems with punishment (increases in escape & avoidance responses, punishment‐induced aggression, countercontrol, etc) are necessarily ubiquitous, long‐lasting, or specific to punishment

Punishment and its putative fallout: A reappraisal. Rafaela M. Fontes  Timothy A. Shahan. Journal of the Experimental Analysis of Behavio, December 6 2020. https://doi.org/10.1002/jeab.653

Abstract: In his book Coercion and Its Fallout Murray Sidman argued against the use of punishment based on concerns about its shortcomings and side effects. Among his concerns were the temporary nature of response suppression produced by punishment, the dangers of conditioned punishment, increases in escape and avoidance responses, punishment‐induced aggression, and the development of countercontrol. This paper revisits Sidman's arguments about these putative shortcomings and side effects by examining the available data. Although Sidman's concerns are reasonable and should be considered when using any form of behavioral control, there appears to be a lack of strong empirical support for the notion that these potential problems with punishment are necessarily ubiquitous, long‐lasting, or specific to punishment. We describe the need for additional research on punishment in general, and especially on its putative shortcomings and side effects. We also suggest the need for more effective formal theories of punishment that provide a principled account of how, why, and when lasting effects of punishment and its potential side effects might be expected to occur or not. In addition to being necessary for a complete account of behavior, such data and theories might contribute to improved interventions for problems of human concern.

Conclusion and Future Directions

Sidman's opposition to the use of aversive control, and more specifically to the use of punishment, was clear in his writings (e.g., Sidman, 1993, 2000, 2011). Although his concerns are reasonable and highlight important aspects to be considered when using any form of behavior control, the literature reviewed above suggests a lack of strong empirical support for the notion that these shortcomings and side effects are ubiquitous, long‐lasting, or specific to punishment. The transitory nature of response suppression produced by punishment does not appear to be an inherent issue with punishment and depends on many aspects of the environment and the contingency. In addition, although stimuli associated with unconditioned punishers can indeed become punishers themselves, such effects are not indiscriminately generalized to other stimuli present and do not necessarily persist once the contingency is suspended. Similarly, increases in escape and avoidance can be observed during punishment, but the occurrence of such responses is not necessary for punishment to suppress responding. Increases in aggressive behavior in the presence of aversive stimulation have also been shown to be a reliable effect; however, it is not necessarily or exclusively a result of punishment procedures. As with conditioned punishment effects, the occurrence of punishment‐induced aggression seems to be impacted by the organism's control of the punishment delivery. Lastly, although anecdotal examples of countercontrol have been described in the literature, countercontrol has not been empirically investigated and it remains unclear when or how such behavioral strategies might develop.

The lack of undesirable side effects associated with the use of punishment has also been noted in the applied literature (e.g., Brantner & Doherty, 1983; Harris, 1985; Johnston, 1972; van Oorsouw et al., 2008). Indeed, the use of punishment‐based interventions typically has been related to increases in positive behavior (e.g., Bostow & Bailey, 1969; Firestone, 1976; Risley, 1968; van Oorsouw et al., 2008). For example, Matson and Taras (1989) reviewed 382 applied studies employing different punishment procedures during interventions with individuals with developmental disabilities and concluded that the results reviewed did not provide evidence supporting the occurrence of undesirable side effects. Instead, the majority (93%) reported positive side effects during punishment interventions, such as increases in social behavior and responsiveness to the environment. Furthermore, the severity of the undesirable side effects, to the extent that they occur, was considered less harmful than the target behavior to be treated by punishment (Matson & Taras, 1989).

Given the considerations above, one wonders if opposition to the use of punishment might reflect a more general cultural tendency to regard its use as inherently bad. Such a view of punishment could be one of the reasons for the apparent decline in punishment research over the years (e.g., Bland et al., 2018; Johnston, 1991). Thus, the first step to renew the interest in punishment as a scientific topic is to acknowledge that aversiveness is not intrinsic to punishment but instead is contextually dependent (Leitenberg, 1965b; Perone, 2003). As noted by Perone (2003), the distinction between positive reinforcement and aversive control can be a matter of perspective, and every situation can be interpreted in terms of positive reinforcement or aversive control. As Sidman (1989/2000) noted, the use of deprivation to increase the efficacy of positive reinforcers might also be considered coercive. Thus, such concerns should not be taken as a reason to avoid seeking a better understanding of punishment (Vollmer, 2002).

Regardless of how one feels about Sidman's (1993, 2000, 2011) and others’ (e.g., Skinner, 1953, 1974) view of punishment, punishment‐based procedures are effective in reducing the behavior of several species, in both basic and applied settings (see Lerman & Vorndran, 2002 for a review). Indeed, punishment is a valuable method in the treatment of problem behavior, and is commonly used in such settings (e.g., Hagopian et al., 1998; Hanley et al., 2005; Lerman & Vorndran, 2002; Lydon et al., 2015; Matson & Taras, 1989; Risley, 1968; Thompson et al., 1999). However, much remains unknown about punishment and its potential side effects. These empirical and theoretical gaps emphasize the need for more research on punishment (e.g., Horner, 2002; Johnston, 1991; Todorov, 2001, 2011). The potential benefits of an increased understanding of punishment and its potential side effects could be manifold.

First, an improved understanding of punishment and its putative side effects could help shine an empirical light on preconceptions about the “dangerousness” of punishment. As noted above, there is a lack of strong empirical support for many of the putative shortcomings and side effects of punishment. In cases where those side effects do occur, many questions remain unanswered. For example, it is unclear under what circumstances punishment generalizes to other stimuli present during its presentation and if punishment effects generalize with unconditioned punishers besides shock. Much also remains unknown about the interactions between punishment and reinforcement. Better understanding such interactions could improve our understanding of decision‐making processes more generally by providing information about how organisms make trade‐offs between different types of consequences. Understanding such trade‐offs could provide important information about potential side effects of punishment. As one example, it is unknown if the availability of other sources of positive or negative reinforcement impacts the frequency of punishment‐induced aggression. Lastly, the complete lack of research on countercontrol makes clear the need for additional research on this potential side effect of punishment before it is considered in arguments against the use of punishment.

Second, additional research on punishment could contribute to the development of a well‐grounded quantitative theory of punishment. As discussed above, both the competitive‐suppression and direct‐suppression models have failed to adequately account for punishment data. Furthermore, to the extent that punishment side effects do occur, a good quantitative theory of punishment should provide a principled account of how, why, and when they occur. As just one example, response recovery is a robust and reliable phenomenon that needs to be accounted for by a quantitative model of punishment. If habituation indeed plays a role in response recovery during punishment, a theory of punishment will need to incorporate a formal account of habituation in order to predict the conditions under which recovery should be expected to occur.

Furthermore, a science of behavior cannot be complete without understanding how aversive consequences contribute to behavior control (e.g., Critchfield & Rasmussen, 2007; Johnston, 1991; Magoon & Critchfield, 2008; Vollmer, 2002). Punishment is a biological, behavior‐regulation mechanism critical for learning to stop engaging in maladaptive behavior (e.g., Todorov, 2011; Vollmer, 2002). Regardless of whether or not one believes that punishment should ever be a part of explicitly arranged contingencies, it will always be a part of natural ones. Thus, it is critical that punishment be effectively integrated into more general formal theories of behavior. But for that to happen, the amount of rigorous data related to punishment and its potential side effects needs to increase substantially. Not only would such data and theories be valuable in their own right, but they could also meaningfully improve applications to problems of human concern.

Finally, our call for increased empirical and theoretical work on punishment should not be misconstrued as a disregard for concerns about the use of punishment on ethical and humanitarian grounds. Nor should this call for additional research be mistaken as an argument for more widespread use of punishment‐based practices. Instead, our goal in highlighting empirical and theoretical gaps in the literature is to emphasize the need for a more complete understanding of punishment and its putative pitfalls before adopting or abandoning its use.

Humans tend to share food more generously than money and other objects: Preliminary evidence

Humans tend to share food more generously than money and other objects: Preliminary evidence. Agnieszka Sorokowska  Michalina Marczak  Michał Misiak  Anna Oleszkiewicz  Agnieszka Niemczyk  Monika Wróbel  Piotr Sorokowski. European Journal of Social Psychology, February 5 2021. https://doi.org/10.1002/ejsp.2747

Abstract: Food sharing is an especially important component of human cooperation, trust and altruism, and certain characteristics of food as compared to other objects may increase the likelihood of food transfers to other individuals. Consequently, people should exhibit higher generosity when sharing food than when sharing other goods (like money or inedible items). We tested this prediction in a series of natural experiments. In Study 1, we found that people (N = 114) were more likely to buy a bread‐roll for a confederate dressed up as a poor‐looking person than to give money for a bread‐roll or money to this person. In Study 2, 239 participants were more likely to donate food than non‐food items such as hygienic products or school accessories to a social welfare center. Finally, in Study 3, 226 subjects could share perishable, edible items (apples), coupons for apples or inedible items (pens) with fellow students, and there were no significant differences in generosity between these conditions. Overall, our results suggest that humans might exhibit a food sharing preference in certain conditions, especially when they share objects that belong to them and when they have a choice between sharing food‐ and non‐food items. However, further studies are necessary to confirm this notion, explore the characteristics of food that make sharing it particularly probable and to understand potential mechanisms underlying this tendency.

What makes It Difficult to keep an Intimate Relationship: Clinginess was reported as a more common source of relationship strain by women, bad sex was reported as a more common source of relationship strain by men

What makes It Difficult to keep an Intimate Relationship: Evidence From Greece and China. Menelaos Apostolou and Yan Wang. Evolutionary Psychology, January-March 2021: 1–12. https://journals.sagepub.com/doi/10.1177/1474704920987807

h/t David Schmitt What makes It Difficult to keep an Intimate Relationship: Evidence From Greece and China..."Clinginess was reported as a more common source of relationship strain by women, while bad sex was reported as a more common source of relationship strain by men

Abstract: Keeping an intimate relationship is challenging, and there are many factors causing strain. In the current research, we employed a sample of 1,403 participants from China and Greece who were in an intimate relationship, and we classified 78 difficulties in keeping an intimate relationship in 13 factors. Among the most common ones were clinginess, long work hours, and lack of personal time and space. Clinginess was reported as a more common source of relationship strain by women, while bad sex was reported as a more common source of relationship strain by men. Fading away enthusiasm, bad sex, infidelity and children were reported as more important by older participants, while lack of personal time and space, and character issues were reported as more important by younger participants. The factor structure was similar in the Greek and in the Chinese cultural contexts, but there were also differences. In addition, there were significant interactions between the sample and the sex. For instance, for the non-monogamous factor, men gave higher scores than women in both samples, but the difference was much more pronounced in the Greek sample.

Keywords: singlehood, keeping an intimate relationship, mismatch problem, mating

Discussion

Our analysis indicated that there were at least 13 factors that caused strain in keeping an intimate relationship. Among the highest rated ones were clinginess, long work hours, and lack of personal time and space. Women rated clinginess higher than men, while men rated bad sex higher than women. Older participants rated fading away enthusiasm, bad sex, infidelity and children higher, and lack of personal time and space and character issues lower than younger participants. Married people tended to give higher scores to several factors, such as fading away enthusiasm, than people in a relationship. The factor structure was similar in the Greek and in the Chinese cultural contexts, but there were also differences. For instance, the “Character issues” factor was rated higher in the Greek sample, while lack of effort was rated higher in the Chinese sample. There were also significant interactions between the sample and the sex. For instance, for the non-monogamous factor, men gave higher scores than women in both samples, but the difference was much more pronounced in the Greek sample.

Our study was designed with the purpose of identifying the most common sources of relationship strain among people who were actually in a relationship. For a factor to be rated highly, it had to be both frequent and strenuous. If a factor was frequent, but caused little strain, participants would probably tend to disagree that it caused them difficulties in keeping their relationship. Similarly, if a factor was a source of considerable strain, but it was rare, most participants would disagree that it caused them strain to their relationship. Nevertheless, if a factor was both frequent and strenuous, many participants would agree that it caused them strain to their relationship. In effect, at the top of our hierarchy were factors that were both common and strenuous.

Our findings indicate that there are no factors which cause difficulties to most people in keeping an intimate relationship, but most people are affected by one or more. More specifically, we can see that all the factors had a mean score below the middle of the scale, and frequencies close to 20%. However, more than 65% of the participants indicated that at least one factor caused them difficulties, and more than one in five indicated that four or more factors caused them difficulties. We also need to say that our data constitute a snapshot of the difficulties that people faced at the time of the study. Accordingly, although about one in three participants indicated that they did not face any of the difficulties examined here, they may had done so in the past, or may do so in the future.

In our theoretical framework, one main source of relationship strain is the adoption of a non-monogamous mating strategy. As indicated by the “Infidelity” factor, the adoption of such a strategy by one partner, if detected, is likely to trigger negative feelings to the other, which would make the continuation of the relationship difficult. As indicated by the “Not monogamous” factor, the adoption of such a strategy makes also being with one partner difficult. These factors however, were located at the bottom of the hierarchy, suggesting that they were not the most common sources of relationship strain. One reason is that, non-monogamous mating strategies are adopted only by a small proportion of the population. Another reason is that, people, when act on such strategies, take precautions not to be detected (see also Buss, 2000), and if they succeed in doing so, their mating strategy may not cause strain to the relationship. In effect, although infidelity is potentially a source of very strong relationship strain, it is relatively rare, and when it occurs, it is likely to go undetected, which could explain why many participants did not indicate that it caused them difficulty in keeping their intimate relationship.

On the other hand, the partner-monitoring mechanisms constitute a much more common source of relationship strain. In particular, the “Clinginess” was reported to be the most common source of difficulties. The “Character issues,” part of which was jealousy, was also reported as a common source of relationship strain. The “Lack of personal time and space” is the consequence of the functioning of the partner-monitoring mechanisms, and was reported as the third more common difficulty. These findings are expected, because these mechanisms have a preemptive function; that is, they protect people from having their partners to act on a non-monogamous mating strategy, and for doing so, they need to be always “on.” To put it differently, they could not have a preemptive function if they are triggered only when the partner is cheating.

Another reason that factors, such as the “Clinginess” and the “Lack of personal time and space,” top the hierarchy of difficulties is the mismatch problem. Mechanisms that give rise to clinginess have been optimized for a context where people were heavily dependent on their partners, so they had higher tolerance in being closely monitored. Similarly, the “Character issues,” the “Not making compromises,” and the “Violence and addictions” are also likely to reflect the mismatch problem, as traits, such as violent disposition and inflexibility, were more likely to be tolerated in the ancestral than in the modern context. Furthermore, since partners are relatively independent from each other, the contemporary environment requires more mating effort in order to keep an intimate relationship. Yet, mechanisms involved in regulating mating effort have evolved in the ancestral context where less of this effort was required, which could explain, why the “Lack of effort” was a common difficulty in keeping an intimate relationship in the contemporary context.

Long work hours was the most common relationship-resources depleting factor, ranking second in the hierarchy of difficulties. This finding probably reflects the reality that job demands in contemporary societies are high, requiring many hours to be devoted to work, which are deducted from the relationship. Children constitute another relationship-resources depleting factor, which was located near the bottom of the hierarchy. This rank is probably due to the fact that our sample was relatively young, so most participants did not have children. We would expect financial difficulties to arise as a separate factor, which was not the case. Similarly, Apostolou and Wang (2020) did not find financial difficulties as a separate factor causing difficulties in keeping an intimate relationship. One possibility is that participants considered financial difficulties to arise from other factors, such as having children, as Apostolou and Wang (2020) have found, or from the character of the partner, as indicated in the current study.

The “Fading away enthusiasm” and the “Bad sex” factors, have most probably multiple explanations. In particular, the adoption of a non-monogamous mating strategy may involve reduction in enthusiasm and sexual satisfaction with the current partner that would motivate people to seek other partners. Furthermore, in the ancestral context where people were heavily dependent on their partners, the levels of enthusiasm and sexual pleasure received from a long-term partner required for keeping an intimate relationship, were most probably lower than in the modern context where people are less dependent on their partners. Thus, mechanisms responsible for generating enthusiasm and for regulating sexual behavior, may not work optimally in the modern environment. In addition, relationship-resources depleting factors, may also be at play here. For instance, working long hours may lead to physical exhaustion, which in turn, would negatively affect the quality of sex.

Our original prediction that men would face more difficulties in keeping their relationship was partially supported. In particular, for the pooled sample, men scored higher than women, but the result was significant only if Bonferroni correction was not applied. On the other hand, our prediction that women would face more difficulties in keeping a relationship arising from the infidelities of their partners was not supported. One possibility is that men are more likely to adopt a cheating mating strategy than women, but they are more efficient in hiding it. Future research could enable a better understanding of the difficulties that infidelity causes in keeping an intimate relationship.

Age was also significant for several factors. The largest effects were for the “Children” and the “Bad sex” factors, with older participants giving higher scores than younger ones. With respect to the former, this effect is predominantly explained by older participants being more likely to have children than younger ones. With respect to the latter, quality and quantity of sexual contact may deteriorate as people spend more time in their relationship, with age acting as a proxy of time spent in it. Another reason is that libido declines as people get older (Travison et al., 2006), which has a negative impact on the quality and quantity of sex they have with their partners.

We also found that married participants tended to give higher scores to a number of factors than people in a relationship. The most likely explanation is that, when they first enter in a relationship, people are overwhelmed by emotions, such as romantic love, which lead them to overlook or tolerate factors that negatively affect the relationship. As years go by, these emotions reside and these factors become more taxing for the relationship. Thus, the more time people spend in a relationship, the higher the strain arising from different factors becomes. Most likely, participants who were married have spent more time in a relationship than participants who were not married, so marital status acted as a proxy of time being in a relationship. Future studies could disentangle marital status from time being in a relationship effects by measuring both variables.

Consistent with our original prediction, the factor structure was similar in the Chinese and in the Greek cultural contexts. There were differences however, between the two cultural settings. In particular, Chinese participants reported the lack of mating effort to be a more common source of relationship strain, than Greek participants. One possible reason is a wider use of dating applications among young people in China, which could lead them to believe that they can easily substitute their current partner, so they do not spend considerable effort in keeping their relationship (Ding, 2020; Ya & Zhang, 2020). In addition, Greek participants indicated that character issues were a more common source of relationship strain than Chinese participants have indicated. One explanation is that, the Greek culture is more individualistic than the Chinese one (in Hofstede’s index for individualism Greece scored 35 and China 20 see https://clearlycultural.com/geert-hofstede-cultural-dimensions/individualism), so traits, such as being selfish, are more pronounced in the former than in the latter.

Furthermore, there were significant interactions between the sample and the sex. More specifically, the sex difference in the “Not monogamous” factor was less pronounced in the Chinese sample. One likely explanation is that, in the Chinese cultural context, men outnumber women (Liang & Ni, 2018), which turns finding a partner more difficult for them. Such a difficulty may suppress an innate desire for variety in partners, something which is not the case in the Greek context where the sex ratio is balanced. The difference in the sex ratio may also explain why in the pooled sample the sex-difference for the “Not monogamous” factor did not pass the Bonferroni-adjusted significance level. There was a higher number of Chinese than Greek male participants, and if the sex ratio imbalance influenced the former in suppressing their desire for partner variety, then the pooled sex difference would be relatively small. In addition, the sex ratio effect, possibly explains the significant interaction between the sex and the sample for the “Not making compromises” factor. In particular, by being in scarce supply, women in China can be selective, and can afford to make fewer compromises than women in Greece.

One limitation of the present work is that it is far from sufficient for understanding the difficulties that people face in keeping an intimate relationship, and it should thus, be considered as one of the first steps toward this direction. In the same vein, given the complexity of the phenomenon, there are probably more difficulties that people face in keeping an intimate relationship that have been accounted by the present study. For instance, men are expected to earn more than women (Hogue et al., 2010); thus, a situation where a husband earning less than the wife may generate considerable strain to the relationship. Future research needs to identify and account for additional sources of relationship strain.

Moving on, we paid particular attention in developing a theoretical framework that would account for the observed difficulties. Still, this framework may need further development, which could involve incorporating arguments from other schools of thought. Further limitations include that our findings were based on self-report data, and participants may not have had a good understanding or may have been unwilling to be honest about what caused them difficulties in keeping their relationship. In addition, we employed non-probability samples, so our results may not readily generalize to the population. That is, it is possible that the recruited individuals were different from those who opted not to participate in ways that affect the generalizability of the results. Moreover, for the Greek-speaking respondents, the survey link was also forwarded by email to students and colleagues, so there is the possibility that some of those who answered the survey were in a relationship with each other, and thus, their answers were to some degree correlated. We do not think that this limitation had a considerable effect on our findings, because the bulk of the participants were recruited through promoting the link in social media.

Furthermore, our theoretical framework predicted cross-cultural consistency but also variation in the causes of relationship strain. Evidence from more than two different cultures is required for adequately testing these predictions, and future research needs to extend our work by replicating it in different cultural settings. In addition, the current study did not examine how likely each of the identified difficulties would be in leading to the termination of the relationship. Future studies could address this limitation by asking how each of the identified difficulties have actually caused people to terminate an intimate relationship.

In conclusion, we identified thirteen factors causing relationship strain. We have also found that these factors were similar in the Chinese and in the Greek cultural contexts, but there were important differences. Considerable more research is required, however, in order to understand this fascinating and complex phenomenon.