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.

Do Lower Minimum Wages for Young Workers Raise their Employment? Evidence from a Danish Discontinuity

Do Lower Minimum Wages for Young Workers Raise their Employment? Evidence from a Danish Discontinuity. Claus Thustrup Kreiner, Daniel Reck, Peer Ebbesen Skov. Centre for Economic Policy Research, June 4, 2017. https://cepr.org/sites/default/files/3564_KREINER%20-%20Do%20Lower%20Minimum%20Wages%20for%20Young%20Workers%20Raise%20their%20Employment_0.pdf

Abstract: This paper estimates the long-run impact of youth minimum wages on youth employment by exploiting a large discontinuity in Danish minimum wage rules at age 18 and using monthly payroll records for the Danish population. We show theoretically how the discontinuity in the minimum wage may be exploited to estimate the casual eect of a change in the minimum wage of youth on their employment. On average, the hourly wage rate jumps up by 40 percent when individuals turn eighteen years old. Employment (extensive margin) falls by 33 percent and total labor input (extensive and intensive margin) decreases by around 45 percent, leaving the aggregate wage payment nearly unchanged. Data on flows into and out of employment show that the drop in employment is driven almost entirely by job loss when individuals turn 18 years old. We estimate that the relevant elasticity for evaluating the eect on youth employment of changes in their minimum wage is about -0.8.

Keywords: Minimum wage policy, employment, regression discontinuity

We observed 584 instances of sociosexual behaviour in chimpanzees in 3 years; all ages and sexes engaged in sociosexual behaviour; most sociosexual behaviour was between adult males

Sociosexual behaviour in wild chimpanzees occurs in variable contexts and is frequent between same-sex partners. Aaron A. Sandel & Rachna B. Reddy. Behaviour, Feb 2 2021, https://doi.org/10.1163/1568539X-bja10062

Rolf Degen's take: Sociosexual behavior, including that between same-sex pairs, is a standard component of chimpanzee behavior

Abstract: Many animals engage in sociosexual behaviour, including that between same-sex pairs. Bonobos (Pan paniscus) are famous for their sociosexual behaviour, but chimpanzees (Pan troglodytes) apparently do not engage in sociosexual behaviour frequently. However, sociosexual behaviour in chimpanzees may have been overlooked. We observed 584 instances of sociosexual behaviour in chimpanzees at Ngogo, Kibale National Park, Uganda during three years of study. All ages and sexes engaged in sociosexual behaviour, which included mounting, touching of genitals, and pressing genitals together. Most sociosexual behaviour was between adult males. Sociosexual behaviour was often during tense contexts, such as subgroup reunions and during territorial behaviour. Among males, grooming and dominance rank relationships do not explain patterns of sociosexual behaviour. Although sociosexual behaviour may be less frequent in chimpanzees than in bonobos, and bonobos remain distinct in their genito-genital rubbing, our findings suggest that sociosexual behaviour is a regular part of chimpanzee behaviour.

Keywords: genital contact; Pan troglodytes; mounting; same-sex sexual behaviour

Lay comments: Same-Sex Sexual Behavior in Chimpanzees Challenge Our Gendered Biases About Evolution. Michelle Rodrigues, 2021. https://thisviewoflife.com/same-sex-sexual-behavior-in-chimpanzees-challenge-our-gendered-biases-about-evolution/

4. Discussion Sociosexual behaviour, including same-sex sexual behaviour, occurred in every sex- and age-class combination among chimpanzees at Ngogo. The most common type of sociosexual behaviour was mounting. Chimpanzees would also reach their hand to touch the rump or genitals of others and on rare occasions touch rumps or engage in genito-genital touching. Sociosexual behaviour occurred in multiple contexts. In nearly all cases for which we recorded the context, the context represented cases of tension, often due to aggression or the threat of aggression, including during food sharing, upon hearing neighbouring groups of chimpanzees, or prior to or after joining another subgroup within the community (Table 2). Sociosexual behaviour was variable among the Ngogo chimpanzees. It appeared to be most common between adult males. This may be due to the cooperative nature of male chimpanzees, and the tension involved during certain activities, such as reunions that involve the reestablishment of dominance relationships. Adolescent and young adult male chimpanzees were the A.A. Sandel, R.B. Reddy / Behaviour (2021) 19 focus of our research, so they may be overrepresented in the sample. Indeed, we have considerably more observation time on them than any other agesex class. However we frequently observed sociosexual behaviour between adult male pairs that were not the focus of our research. Despite our focus on adolescent and adult males, we recorded individuals in all possible age-sex class pairings engage in sociosexual behaviour including between sexually mature adult females (Table 1). Nevertheless, given our sampling procedure, females and infants are likely underrepresented. In fact, we likely underestimated the frequency of sociosexual behaviour in general, as such behaviours often occurred quickly and during somewhat chaotic events, including during aggression or just prior to the chimpanzees running toward a neighbouring group of chimpanzees, making it difficult to record. Some individuals appeared to engage in sociosexual behaviour more than others. Several adult males accounted for a large proportion of sociosexual behaviours. One young adult male, somewhat low-ranking but rising in the male hierarchy (Evans), mounted others 30 times, and only twice was mounted by others. Another adult male, middle-aged and relatively lowranking (Mulligan) was mounted nine times, and never mounted others. In fact, these two males engaged in one of the instances of genito-genital rubbing (Video 1 at 10.6084/m9.figshare.13546526). One of these males, Mulligan, was also involved in an unusual case of mounting in which he presented his rump to another male, and while the other male (Dexter) mounted him, Mulligan crouched down on the ground in a posture resembling that of females during a copulation. Other males that were over-represented in our sample included high-ranking adult males. It is possible that status and personality play a role in the frequency of sociosexual behaviour. High-ranking males may encounter tense situations frequently — competing for mating opportunities, sharing meat, participating in border patrols — instigating sociosexual behaviour as well as other forms of relationship regulation, such as grooming. In addition, some males may be more ‘nervous’ in general, and thus seek out reassurance from others. With regard to the prevalence of sociosexual behaviour in chimpanzees, it is possible that it is more common at Ngogo than other chimpanzee sites. There are more males at Ngogo than any other community that has been studied. At Ngogo, chimpanzees, especially adult males, engage in frequent cooperative behaviour, group hunts, and border patrols (Mitani et al., 2000; Mitani & Watts, 2001; Watts & Mitani, 2001; Mitani, 2009b; Langergraber et al., 2017). Being surrounded on all sides by other chimpanzee communities, they regularly have intergroup encounters. As a result, there may be heightened need for regulating tension. However, we consider it unlikely that Ngogo stands out with regard to the nature and prevalence of sociosexual behaviour as similar behaviours have been described at multiple other sites (van Lawick-Goodall, 1968; Bygott, 1974; Nishida et al., 1999). For example, a study at Gombe found that 50% of all touching between male chimpanzees (N = 194 total touches) involved touching of genitals, and 70% of all touching between female chimpanzees (N = 56 total touches) involved touching genitals (Bygott, 1974). There also appeared to be variation among individuals in the frequency and patterning of sociosexual behaviour, including with some individuals being distinct in their sociosexual behaviour. Bygott (1974, p. 63) noted that “the adult male Faben often presented to other males, and when they held out a hand to him he would bounce his scrotum up and down against their hand. No other male was seen to do this.” Further research is required to test hypotheses for the function of sociosexual behaviour in wild chimpanzees. Our findings suggest that sociosexual behaviour is unlikely related to dominance given that combinations of all age and sex classes engaged in these behaviours. Importantly, in cases of mounting between males, the mounter was not higher ranking; if anything, the mounter tended to be lower ranking than the mountee, although mounters were also frequently higher ranking than the mountee (Figure 5). Sociosexual behaviour may relate to other behaviours, such as affiliative bonds, but grooming was not a strong predictor of sociosexual behaviour (Figure 4). Some pairs that groomed frequently also engaged in sociosexual behaviour more than did other pairs, but sociosexual behaviour also occurred between males who associated less frequently because they occupied different social neighbourhoods within the community. Thus, at least for males, sociosexual behaviour may be a way to reduce tension among pairs who meet infrequently. The function of sociosexual behaviour likely varies by age and sex. For example, we observed infant females rubbing their genitals on others, and this may have been for a pleasurable sensation alone (Vasey & Duckworth, 2006). Further study of sociosexual behaviour is required in chimpanzees, particularly focused on females, and how the function of sociosexual behaviour changes with development, which will in turn inform its possible functions. Although we focused on genital contact, much of the behaviour that we observed resembled what other researchers have A.A. Sandel, R.B. Reddy / Behaviour (2021) 21 considered ‘reassurance’ behaviour (Goodall, 1986; Nishida et al., 1999). Prior studies seem to have lumped sociosexual behaviour within reassurance behaviour, and indeed, they may serve the same function. Future studies should analyse sociosexual behaviour along with other forms of touch, including mouth-to-mouth, hand-to-mouth, hand-to-hand, hand-to-body, and embraces without genital contact. Given that much of sociosexual behaviour across mammals has been linked to cooperation and tension reduction in fission-fusion species, it is no surprise that chimpanzees do it. Indeed, this finding is not new. Some of the earliest studies of chimpanzees reported behaviours involving mounting and genital contact, both in captivity (Crawford, 1942) and the wild (Nishida, 1968; van Lawick-Goodall, 1968; Sugiyama, 1969). However, the ensuing decades have focused on such behaviours in bonobos, framing them as key for tolerance and female power (Hohmann & Fruth, 2000; Hohmann et al., 2009), and this seems to have downplayed its significance in chimpanzee life. For example, Hohmann et al. (2009) considered genital contact to be ‘habitual’ in bonobos, but not in other apes, and Grueter & Stoinski (2016) considered same-sex sexual behaviour “rare or absent among chimpanzees” in their study of such behaviours in wild gorillas. Similarly, sociosexual behaviour is considered “weak or infrequent” in East African chimpanzees (Pan troglodytes schweinfurthii) compared to hunting, which is “strong or highly frequent,” and infanticide, which is “moderate or frequent” (Gruber & Clay, 2016). In our study, sociosexual behaviour occurred considerably more frequently than did infanticides and was closer to the frequency of hunts, thus we would not consider it as “weak or infrequent”. Although we were not able to calculate a rate of sociosexual behaviour for most of our subjects, sociosexual behaviour was only one third as frequent as mating behaviour. And adolescent and young adult males tended to exhibit sociosexual behaviour approximately once every two months, which is likely an underestimate. It may have been that the study by Gruber and Clay (2016) considered a more limited array of behaviours as sociosexual, which could also account for its apparent absence between young chimpanzees compared to bonobos in an experimental feeding context (Woods & Hare, 2011). When analysing chimpanzee behaviour, scientists seem to classify mounts or genital contact within other functional behaviours, such as gestures or reassurance. We do not dispute that genital contact may serve conciliatory or communicative purposes in chimpanzees, but we also suggest that it deserves attention in studies investigating sociosexual behaviour explicitly. Doing so will allow proper comparisons to bonobos, and may elucidate the evolution and function of sociosexual behaviour in primates more generally. Although we found chimpanzees to engage in a range of sociosexual behaviours, bonobos remain distinct. Bonobos exhibit frequent genito-genital rubbing, especially between adult females (Hohmann & Fruth, 2000), whereas, we recorded only three instances of face-to-face, genito-genital rubbing in chimpanzees, and it was only observed between adult males. However, different species of primates manifest different forms of sociosexual behaviour, such as ‘ritualized’ touching of the penis in some baboons species (Smuts & Watanabe, 1990; Dal Pesco & Fischer, 2018). For chimpanzees, mounting and touching genitals may be their species-typical manifestation of sociosexual behaviour. That behaviours involving gential contact have not been conceptualized as ‘sociosexual’ in chimpanzees may also be due to cultural biases against homosexuality, as has been seen in the literature on other primates (Vasey, 1995). “Never, however, have we seen anything that could be regarded as homosexuality in chimpanzees,” Jane Goodall writes in her 1971 book, In the Shadow of Man. “Admittedly a male may mount another in moments of stress or excitement, clasping the other around the waist, and he may even make thrusting movements of the pelvis, but there is no intromission. It is true, also, that a male may try to calm himself or another male by reaching out to touch or pat the other’s genitals; while we still have much to learn about this type of behaviour, it certainly does not imply homosexuality. He only does this in moments of stress, and he will touch or pat a female on her genitals in exactly the same contexts” (Goodall, 2010, pp. 183–184). We agree that this does not indicate ‘homosexuality’ in the sense of a sexual orientation, but it does potentially represent sexual behaviour broadly defined, including that between members of the same sex. Our findings reveal that sociosexual behaviour is a standard component of chimpanzee behaviour. Although sociosexual behaviour is, no doubt, more salient and frequent in bonobos, especially with their characteristic side-toside genital rubbing, the range and type of sociosexual behaviour is similar in chimpanzees. Thus, there should not be such a distinction made between the two species. In addition, given the evidence of sociosexual behaviour in gorillas and a range of monkey species (e.g., Yamagiwa, 1987; Grueter & Stoinski, 2016), sociosexual behaviour is likely a common trait to haplorrhine primates. In some primate species, sociosexual behaviour has become key to negotiating relationships, as is the case in bonobos, some baboon A.A. Sandel, R.B. Reddy / Behaviour (2021) 23 species, and some populations of spider monkeys. Given its prevalence across taxa, sociosexual behaviour, including between members of the same sex, may be an important component of relationships that arose early on in primate evolution.