It's the attention that counts: interpersonal attention fosters intimacy and social exchange

Human friendship poses an evolutionary puzzle, since people behave more generously toward their friends than the tit-for-tat strategy stipulates. A possible explanation is that people selectively behave in a generous manner toward their true friends, but not toward fair-weather friends. Social psychological studies have suggested that people use a partner's attentiveness toward them as a cue to distinguish these two types of friends. Accordingly, it was hypothesized that people would increase their intimacy with a partner who was attentive to them. This hypothesis was tested by disentangling the frequent confounding between a partner's attention and the benefits provided by the attentive partner in two scenario experiments (studies 1a and 1b) and three laboratory experiments (studies 2a to 2c). In study 1, a partner's attentiveness was manipulated independently of the benefit provided by the partner. In study 2, the partner's attention was experimentally dissociated from any potential benefit. These studies consistently showed that the participants increased their intimacy with a partner when they received attention from the partner. This result implies that models of the evolution of friendship must incorporate information exchange regarding the valuation of the relationship, as well as the exchange of fitness-related costs and benefits.     

No Evidence That Gratitude Enhances Neural Performance Monitoring or Conflict-Driven Control

It has recently been suggested that gratitude can benefit self-regulation by reducing impulsivity during economic decision making. We tested if comparable benefits of gratitude are observed for neural performance monitoring and conflict-driven self-control. In a pre-post design, 61 participants were randomly assigned to either a gratitude or happiness condition, and then performed a pre-induction flanker task. Subsequently, participants recalled an autobiographical event where they had felt grateful or happy, followed by a post-induction flanker task. Despite closely following existing protocols, participants in the gratitude condition did not report elevated gratefulness compared to the happy group. In regard to self-control, we found no association between gratitude—operationalized by experimental condition or as a continuous predictor—and any control metric, including flanker interference, post-error adjustments, or neural monitoring (the error-related negativity, ERN). Thus, while gratitude might increase economic patience, such benefits may not generalize to conflict-driven control processes.     

Relationships’ Best Friend: Links between Pet Ownership,Empathy, and Romantic Relationship Outcomes

The benefits of pets on individual wellbeing is well established. But can pets also have benefits for romantic relationships? Using mixed methods, three studies explored the link between pet ownership and romantic relationship quality. First, using a grounded theory approach, we qualitatively investigated participants’ personal beliefs of how their pets influence their romantic relationships by coding open-ended responses. Results suggested that pets are seen as having predominantly positive (86.5%) effects, followed by few neutral (8%) and negative (4.5%) effects (study 1). We next compared a community sample of pet owners’ reports of relationship quality with those of non-pet owners. Results suggested that pet ownership was associated with several relationship benefits (greater overall relationship quality, partner responsiveness, adjustment, and relational investment) compared with couples without pets (study 2). Finally, we examined one possible reason for why pets may benefit relationships: A pet might provide the opportunity to practice empathic abilities, which is a crucial ability in the maintenance of positive relationships. Results showed that the number of years an individual owned a pet was positively correlated with empathic concern, which in turn was linked to several relationship benefits (commitment, couple identity, and relationship maintenance behaviors; study 3). In sum, three studies provided initial evidence that there is indeed a positive association between two important relationships in peoples’ lives: their partners and their pets.     

Cooperation: The roles of interpersonal value and gratitude

Here we examine the roles of interpersonal valuation and gratitude in the formation of cooperative relationships. Building on prior work, we draw on the concept of a welfare tradeoff ratio (WTR), an internally computed index of the extent to which one person values another person's welfare relative to his or her own. We test several predictions regarding the effects of benefit delivery on changes in WTR, gratitude, and subsequent cooperation. We show that benefit delivery by a stranger: (i) raises the beneficiary's valuation of the stranger's welfare, (ii) predicts downstream cooperative behavior by the beneficiary toward the stranger, and (iii) is coincident with beneficiaries' expressions of gratitude. We find evidence that cooperation and gratitude, while both sparked via benefit delivery and both underpinned by estimates of welfare valuation, are nevertheless produced in parallel via different paths. Specifically, the updated magnitude—not the initial magnitude or degree of change—of a beneficiary's WTR toward a stranger predicts the beneficiary's downstream cooperative behavior. By contrast, the extent to which the beneficiary's WTR positively changes—and not the initial or updated WTR magnitude—predicts gratitude production, a feature proposed to reinforce the benefactor's actions and foreshadow future cooperative intent on the part of the beneficiary. Taken together, our findings point to the possibility that cooperative behavior might operate via internal estimates of welfare valuation, and that gratitude signals benefit reception and the intent to engage in a cooperative relationship.     

It's not just lunch: extra-pair commensality can trigger sexual jealousy

Do people believe that sharing food might involve sharing more than just food? To investigate this, participants were asked to rate how jealous they (Study 1)--or their best friend (Study 2)--would be if their current romantic partner were contacted by an ex-romantic partner and subsequently engaged in an array of food- and drink-based activities. We consistently find--across both men and women--that meals elicit more jealousy than face-to-face interactions that do not involve eating, such as having coffee. These findings suggest that people generally presume that sharing a meal enhances cooperation. In the context of romantic pairs, we find that participants are attuned to relationship risks that extra-pair commensality can present. For romantic partners left out of a meal, we find a common view that lunch, for example, is not "just lunch."     

Benefit valuation predicts gratitude

Gratitude is an emotion that promotes cooperative relationships and is elicited when an act reveals that an actor values the recipient, especially when the benefit conferred is greater than the recipient expected. But, recipient expectations might vary depending on how much the benefactor is perceived to value the recipient — all else equal, the greater the benefactor is perceived to value the recipient's welfare, the greater the recipient's expectations of benefit delivery. Thus, at a given benefit level, it might be easier to exceed the threshold of expectation in a relationship for which the recipient holds low expectations (e.g., a stranger) as compared to a relationship for which the recipient holds high expectations (e.g., a sibling). This leads to the prediction that cognitive representations of welfare valuation inversely correlate with gratitude: The greater the expected welfare valuation, the more difficult it is to exceed expectations of benefit delivery and, therefore, the less felt gratitude. To test this prediction, we conducted two experiments in which subjects estimated how much they perceived a particular person in their social network to value the subject's welfare. Next, subjects estimated how grateful they would feel if this person provided them with differing levels of benefits. Contrary to our model, we found that gratitude was predicted by the magnitude of the benefit, but not by the recipient's perception of the benefactor's valuation of the recipient.     

Jealousy evocation, partner reassurance, and relationship stability: An exploration of the potential benefits of jealousy

Three studies examined possible effects of jealousy evocation and jealous expression in romantic relationships. In Study 1, we used an indirect method to examine subjects' motivations for evoking jealousy in their romantic partners. Students' attributions for ambiguous interactions suggest that jealousy evocation is goal specific and that it is primarily used for mate retention. A majority of Study 1 participants also reported that they had previously attempted to evoke jealousy in a romantic partner to accomplish relationship goals. In Study 2, we examined the expected effect of jealousy evocation, from the perspective of the jealous partner. Here, results suggest that jealousy evocation is unlikely to produce immediate relationship benefits; in fact, it seems more likely to provoke fighting between romantic partners. Finally, in Study 3, we examined the longitudinal association of jealousy with relationship stability. Although there was a positive lagged correlation between participants' partners' jealousy and relationship stability, this association was not significant when participants' prior relationship commitment was controlled. This suggests that while jealousy itself is not causally related to relationship stability, a person's reactions to their jealous partner may be.     

To nest communally or not to nest communally: a review of rodent communal nesting and nursing

Communal nesting, the sharing of parental responsibilities between multiple individuals in a nest, is common in many rodents. Upon first glance, this behaviour seems to be selectively disadvantageous. Communal care not only involves energetic costs, but may also be subject to cheating behaviour. Despite abundant literature, many questions remain regarding advantages gained by females that form nesting groups. I discuss the communal nesting of eusocial, singular and plural breeding rodents. I first clarify the distinction between communal nesting and thermoregulatory huddling. I then review two major groups of hypotheses ('ecological constraints' and 'benefits of philopatry') that are used to explain the occurrence of communal nesting in rodents. Most likely, these hypotheses are not mutually exclusive. Regardless of the main selective pressure(s) acting on communal nesting, the indirect components of inclusive fitness that result from nest sharing most likely influence the formation and maintenance of communal nests. Communal nesting and nursing (the sharing of milk with nonoffspring) are under different selective regimes and thus, must be evaluated separately. I review adaptive and nonadaptive hypotheses for rodent communal nursing. I argue that communal nursing may not be adaptive as mothers may be forced to share milk with nonoffspring in large communal nests (i.e. communal nursing may be a cost associated with communal nesting). In conclusion, I propose directions for future study that may improve our understanding of communal nesting and nursing in the wild. Copyright 2000 The Association for the Study of Animal Behaviour.     

Cooperation and the common good

In this paper, we draw the attention of biologists to a result from the economic literature, which suggests that when individuals are engaged in a communal activity of benefit to all, selection may favour cooperative sharing of resources even among non-relatives. Provided that group members all invest some resources in the public good, they should refrain from conflict over the division of these resources. The reason is that, given diminishing returns on investment in public and private goods, claiming (or ceding) a greater share of total resources only leads to the actor (or its competitors) investing more in the public good, such that the marginal costs and benefits of investment remain in balance. This cancels out any individual benefits of resource competition. We illustrate how this idea may be applied in the context of biparental care, using a sequential game in which parents first compete with one another over resources, and then choose how to allocate the resources they each obtain to care of their joint young (public good) versus their own survival and future reproductive success (private good). We show that when the two parents both invest in care to some extent, they should refrain from any conflict over the division of resources. The same effect can also support asymmetric outcomes in which one parent competes for resources and invests in care, whereas the other does not invest but refrains from competition. The fact that the caring parent gains higher fitness pay-offs at these equilibria suggests that abandoning a partner is not always to the latter''s detriment, when the potential for resource competition is taken into account, but may instead be of benefit to the ‘abandoned’ mate.     

Benefit Sharing in a Global Context: Working Towards Solutions for Implementation

Due to the state of globalized clinical research, questions have been raised as to what, if any, benefits those who contribute to research should receive. One model for compensating research participants is “benefit sharing,” and the basic premise is that, as a matter of justice, those who contribute to scientific research should share in its benefits. While incorporated into several international documents for over two decades, benefit sharing has only been sparsely implemented. This analysis begins by addressing the concept of benefit sharing, its historical development, and how it has been applied in the context of virus sharing for influenza research. The second portion of this analysis presents recommendations for ensuring benefit sharing. These recommendations are threefold: 1) an emphasis on social pressure, 2) the revision of international documents as means to ensure benefit sharing, and 3) greater collaboration between sponsor IRB and host country IRB. Because clinical research is a globalized industry, a global model will be proposed in the second that focuses on collaboration between the sponsor and host country. This collaboration is vital in order to ensure that proper forms of benefit sharing are accomplished as a matter of justice.     

The influence of kinship and dominance hierarchy on grooming partner choice in free-ranging <Emphasis Type="Italic">Macaca mulatta brevicaudus</Emphasis>

In group-living animals, individuals do not interact uniformly with their conspecifics. Among primates, such heterogeneity in partner choice can be discerned from affiliative grooming patterns. While the preference for selecting close kin as grooming partners is ubiquitous across the primate order, the selection of higher-ranking non-kin individuals as grooming partners is less common. We studied a group of provisioned rhesus macaques (Macaca mulatta brevicaudus) on Hainan Island, China, to examine rank-related benefits of grooming exchanges and the influence of kin relationships. We tested four hypotheses based on Seyfarth’s model: (1) there will be kin preference in grooming relationships; (2) grooming between non-kin individuals will be directed up the dominance rank; (3) grooming between non-kin individuals will reduce aggression from higher-ranking ones; and (4) non-kin individuals will spend more time grooming with adjacent ranked ones. We found that grooming relationships between kin individuals were stronger than those between non-kin individuals. For non-kin relationships, lower-ranking individuals received less aggression from higher-ranking ones through grooming; a benefit they could not derive through grooming exchanges with individuals related by kinship. Individuals spent more time grooming adjacent higher-ranking non-kin individuals and higher-ranking individuals also received more grooming from non-kin individuals. Our results supported Seyfarth’s model for predicting partner choice between non-kin individuals. For relationships between kin individuals, we found results that were not consistent with prediction for the exchanges of aggression and grooming, indicating the importance to control for the influence of kinship in future studies.     

Communal Nesting in Asocial Abert's Squirrels: the Role of Social Thermoregulation and Breeding Strategy

The social thermoregulation hypothesis states that endothermic species will communally nest to reduce energy expenditures on thermoregulation. The hypothesis predicts that the frequency of communal nesting should increase with decreasing ambient temperature. The potential costs of communal nesting (e.g., increased predation risk, resource competition, cuckoldry, parasite/disease transmission, or infanticide) could decrease the frequency of communal nesting especially for asocial breeding females with dependent offspring. We examined the effects of ambient temperature and seasonal reproductive activities on the probability of communal nesting in Abert's squirrels (Sciurus aberti) in the Pinaleño Mountains, Arizona. Most squirrels nested consistently with the same partner in mixed‐sex pairs. The proportion of individuals engaging in communal nesting increased with decreasing ambient temperature as predicted by the social thermoregulation hypothesis. The onset of the breeding season greatly reduced the proportion of individuals communally nesting. The negative relationship between ambient temperature and communal nesting supports the use of communal nesting in Abert's squirrels as a mechanism to reduce thermoregulatory costs during cold conditions. The abrupt drop in the frequency of communal nesting during the breeding season is likely due to female abandonment of this behavior. By avoiding communally nesting during the breeding season, females may prevent males from mating with them outside of mating chases, reduce resource competition, and protect offspring from infanticide, diseases, and parasites. Males may gain additional fitness benefits from nesting with females because familiarity with females increases dominance rank in mating activities.     

A Model of Mutual Tolerance and the Origin of Communal Associations Between Unrelated Females

We use a genetic algorithm model employing game theory to explore the ecological conditions favoring reproductive tolerance between two unrelated females that meet at a nesting site (i.e., breeding resource). Each female adopts one of three strategies: (1) fight for exclusive use of the nest, (2) tolerate the other female and breed communally, but fight back if attacked, or (3) leave in search of new breeding opportunities. Nests vary in the number of offspring they can support and their probability of failure due to discovery by competitors. The model predicts that communal associations are most likely to arise when (1) the benefits of nest sharing to females exceed the losses to individual reproduction, (2) additional nesting sites are rare, (3) females have limited clutch sizes, and (4) dominant females are able to skew reproduction in their favor. The amount of reproductive skew a dominant (larger) female can acquire while maintaining a communal association is predicted to increase when the asymmetry in fighting ability between females increases, and at nests that have a relatively high probability of nesting success for solitary females. When the losers of fights can parasitize the winner's brood, dominant females must reduce reproductive skew to promote a communal relationship. We discuss the ability of our model to predict patterns of facultative communal behavior in burying beetles (Silphidae; Nicrophorus spp.), as well as the absence of communal behavior in dung beetles (Scarabaeidae).     

Realizing benefit sharing - the case of post-study obligations

In 2006, the Indonesian government decided to withhold avian flu samples from the World Health Organization. They argued that even though Indonesian samples were crucial to the development of vaccines, the results of vaccine research would be unaffordable for its citizens. Commentaries on the case varied from alleging blackmail to welcoming this strong stance against alleged exploitation. What is clear is that the concern expressed is related to benefit sharing. Benefit sharing requires resource users to return benefits to resource providers in order to achieve justice. One benefit sharing tool within health research is the duty to provide a health care intervention which has been proven to be beneficial (or alternative benefits) to research participants after a study has been concluded. This duty is generally known as a post-study obligation. It was enshrined in the Declaration of Helsinki in 2000 and re-emphasized in 2008. Yet, there are few, if any, examples of good practice. In this article, we analyse the obstacles to giving more bite to benefit sharing provisions in health research through ethical review. We conclude that the provision of post-study access to healthcare interventions is not a promising mechanism when monitored through research ethics committees. Alternative benefit provision is preferable if one focuses on achieving compliance. However, even the latter faces challenges, which we address in specific recommendations.     

Affect-Laden Imagery and Risk Taking: The Mediating Role of Stress and Risk Perception

This paper investigates how affect-laden imagery that evokes emotional stress influences risk perception and risk taking in real-life scenarios. In a series of three studies, we instructed participants to imagine the consequences of risky scenarios and then rate the intensity of the experienced stress, perceived risk and their willingness to engage in risky behavior. Study 1 showed that people spontaneously imagine negative rather than positive risk consequences, which are directly related to their lower willingness to take risk. Moreover, this relationship was mediated by feelings of stress and risk perception. Study 2 replicated and extended these findings by showing that imagining negative risk consequences evokes psychophysiological stress responses observed in elevated blood pressure. Finally, in Study 3, we once again demonstrated that a higher intensity of mental images of negative risk consequences, as measured by enhanced brain activity in the parieto-occipital lobes, leads to a lower propensity to take risk. Furthermore, individual differences in creating vivid and intense negative images of risk consequences moderated the strength of the relationship between risk perception and risk taking. Participants who created more vivid and intense images of negative risk consequences paid less attention to the assessments of riskiness in rating their likelihood to take risk. To summarize, we showed that feelings of emotional stress and perceived riskiness mediate the relationship between mental imagery and risk taking, whereas individual differences in abilities to create vivid mental images may influence the degree to which more cognitive risk assessments are used in the risk-taking process.     

The thermoregulatory benefits of the communal nest of sociable weavers Philetairus socius are spatially structured within nests

Structures built by animals, such as nests, mounds and burrows, are often the product of cooperative investment by more than one individual. Such structures may be viewed as a public good, since all individuals that occupy them share the benefits they provide. However, access to the benefits generated by the structure may vary among individuals and is likely to be an important determinant of social organisation. Here we use the massive, communal nests of sociable weavers Philetairus socius, to investigate whether their thermoregulatory function varies in relation to the size of communal nests, and the position of individual nest chambers within the communal structure. We then examine whether this spatial variation in thermoregulatory function predicts the social organisation of colonies. First, we show that the sociable weavers’ communal nests buffer variation in ambient temperature, and reduce temperature variability within nest chambers. The extent of this buffering effect depends significantly on the position of nest chambers within the communal structure, and on the depth to which chambers are embedded within the nest mass. We detected no effect of nest volume on thermoregulatory benefits, suggesting that there are likely to be additional, non‐thermoregulatory benefits leading to communal nests. Finally, our results indicate that there may be competition for access to the benefits of the public good, since older birds occupied the chambers with the highest thermoregulatory benefits, where breeding activity was also more common. We discuss how the spatial structure of the benefits of the public good might influence social organisation in the unique communal lifestyle of sociable weavers.     

Relationships among Facial Mimicry,Emotional Experience,and Emotion Recognition

Background

The relationships between facial mimicry and subsequent psychological processes remain unclear. We hypothesized that the congruent facial muscle activity would elicit emotional experiences and that the experienced emotion would induce emotion recognition.

Methodology/Principal Findings

To test this hypothesis, we re-analyzed data collected in two previous studies. We recorded facial electromyography (EMG) from the corrugator supercilii and zygomatic major and obtained ratings on scales of valence and arousal for experienced emotions (Study 1) and for experienced and recognized emotions (Study 2) while participants viewed dynamic and static facial expressions of negative and positive emotions. Path analyses showed that the facial EMG activity consistently predicted the valence ratings for the emotions experienced in response to dynamic facial expressions. The experienced valence ratings in turn predicted the recognized valence ratings in Study 2.

Conclusion

These results suggest that facial mimicry influences the sharing and recognition of emotional valence in response to others'' dynamic facial expressions.     

Vicissitudes of benefit sharing of crop genetic resources: downstream and upstream

In this article, we will first give a historic overview of the concept of benefit sharing and its appearance in official agreements, particularly with respect to crop genetic resources. It will become clear that, at present, benefit sharing is primarily considered as an instrument of compensation or exchange, and thus refers to commutative justice. However, we believe that such a narrow interpretation of benefit sharing disregards, and even undermines, much of its (historical) content and potency, especially where crop genetic resources are concerned. We argue that benefit sharing should not be based merely on commutative justice but rather on a broader model that is also grounded in the concept of distributive justice. This has repercussions for the application of benefit sharing, which we try to clarify by distinguishing between downstream and upstream benefit sharing. Upstream benefit sharing is not so much inspired by compensation for actions done, or the distribution downstream of benefits developed, but by the idea of shared decision-making on the research and development of resources fundamental to human welfare. Going upstream in the research process of crop genetic resources, and determining research agendas and improving crops according to the needs of the poor, benefit sharing may well be a tool to contribute to world food security and global justice. We concretize our ideas on upstream benefit sharing by introducing a set of criteria that determine the success of consultations on agricultural research agenda setting.     

Gift-giving in romantic couples serves as a commitment signal: Relational mobility is associated with more frequent gift-giving

The present study explored why married couples periodically exchange gifts. Based on the commitment signal hypothesis, we tested whether relational mobility, which was operationalized as divorce rate in Study 1 and relational opportunities in Study 2, is positively correlated with the frequency of gift exchanges among married couples. In Study 1, we found that married couples in the U.S., which is associated with a relatively high divorce rate, were more likely to give and receive gifts to and from their partners than those in Japan, which is associated with a relatively low divorce rate. This societal difference, in contrast, was not observed among unmarried couples, who were still developing their relationship (and thus, partner changes could frequently happen regardless of the country-level divorce rate). Study 2, a secondary analysis of extant survey data, revealed that Japanese married couples who have more relational opportunities more frequently engage in gift exchanges than those who do not. Together, these results support our hypothesis that periodical gift exchanges work as commitment signals among married couples.     

Costly signaling and cooperation.

We propose an explanation of cooperation among unrelated members of a social group in which cooperation evolves because it constitutes an honest signal of the member's quality as a mate, coalition partner or competitor, and therefore results in advantageous alliances for those signaling in this manner. Our model is framed as a multi-player public goods game that involves no repeated or assortative interactions, so that non-cooperation would be a dominant strategy if there were no signaling benefits. We show that honest signaling of underlying quality by providing a public good to group members can be evolutionarily stable, and can proliferate in a population in which it is initially rare, provided that certain plausible conditions hold, including a link between group-beneficial signaling and underlying qualities of the signaler that would be of benefit to a potential mate or alliance partner. Our model applies to a range of cooperative interactions, including unconditionally sharing individually consumable resources, participating in group raiding or defense, and punishing free-riding or other violations of social norms.