The social cognition of social foraging: partner selection by underlying valuation

Humans and other animals have a variety of psychological abilities tailored to the demands of asocial foraging, that is, foraging without coordination or competition with other conspecifics. Human foraging, however, also includes a unique element: the creation of resource pooling systems. In this type of social foraging, people contribute when they have excess resources and receive provisioning when in need. Is this behavior produced by the same psychology as asocial foraging? If so, foraging partners should be judged by the same criteria used to judge asocial patches of resources: the net energetic benefits they provide. The logic of resource pooling speaks against this. Maintaining such a system requires the ability to judge others not on their short-term returns, but on the psychological variables that guide their behavior over the long term. We test this idea in a series of five studies using an implicit measure of categorization. Results showed that (a) others are judged by the costs they incur (a variable not relevant to asocial foraging), whereas (b) others are not judged by the benefits they provide when benefits provided are unrevealing of underlying psychological variables (despite this variable being relevant to asocial foraging). These results are suggestive of a complex psychology designed for both social and asocial foraging.     

Partner choice creates competitive altruism in humans

Reciprocal altruism has been the backbone of research on the evolution of altruistic behaviour towards non-kin, but recent research has begun to apply costly signalling theory to this problem. In addition to signalling resources or abilities, public generosity could function as a costly signal of cooperative intent, benefiting altruists in terms of (i) better access to cooperative relationships and (ii) greater cooperation within those relationships. When future interaction partners can choose with whom they wish to interact, this could lead to competition to be more generous than others. Little empirical work has tested for the possible existence of this 'competitive altruism'. Using a cooperative monetary game with and without opportunities for partner choice and signalling cooperative intent, we show here that people actively compete to be more generous than others when they can benefit from being chosen for cooperative partnerships, and the most generous people are correspondingly chosen more often as cooperative partners. We also found evidence for increased scepticism of altruistic signals when the potential reputational benefits for dishonest signalling were high. Thus, this work supports the hypothesis that public generosity can be a signal of cooperative intent, which people sometimes 'fake' when conditions permit it.     

Economic Profits Enhance Trust,Perceived Integrity and Memory of Fairness in Interpersonal Judgment

Does money lead to trust in personality and intention of others? Humans have a strong tendency to judge the intention of others from their sequent behaviors. In general, people trust others who behave fairly, but not always. Here we show that judgments of both intentional aspects and memory of intentional behavior are automatically influenced by unintentional benefits from the behaviors of others. We conducted a reward-manipulated and repeated trust game by using real participants interacting with moving image partners on a computer screen. The participants assessed likability, trustworthiness, and perceived integrity of the partners in pre- and post-game questionnaires. The results of judgments of all three dimensions and the memory of frequency of each partner''s fair behavior (sharing) were strongly influenced by profitability in the trust game, even though all partners shared 75% of the profit and participants were told that profitability was randomly assigned to each partner. Furthermore, these effects were moderated by the gender of the participants: males were more sensitive to monetary profits than were females. The results reveal that humans automatically trust, approve the integrity of, and recall well the fair behavior of others who provide affectively positive outcomes such as monetary profits. We call this phenomenon the “affect ripple effect”.     

Socio-sexual behavior of female northern muriquis (Brachyteles hypoxanthus)

Female northern muriquis (Brachyteles hypoxanthus) are known to engage in frequent copulations with multiple partners, a pattern that in other primates has been attributed to various functions such as confusing paternity, reducing male aggression, or ensuring fertilization. However, in some female primates, promiscuity is restricted to times when conceptions are unlikely. We investigated whether female northern muriquis might exhibit a similarly mixed strategy by examining their mating, social, and activity patterns during their conception cycles versus other times. Systematic behavioral data were collected during an 18-month period between August 2001 and February 2003 on 13 adult females in a well-studied group at the RPPN-Feliciano Miguel Abdala, Minas Gerais, Brazil. Females mated on an average of 12.5+/-7.9 days during the study period, and spent significantly less time resting and engaging in non-sexual social behaviors, and significantly more time in sexual behaviors on days that they copulated than on days they did not. Three of the eight females for which sufficient data were available copulated significantly more often with their spatially closest non-kin associates, and four of five females that could be analyzed copulated significantly more often with their most frequent non-kin embrace partners. Comparisons between conception and non-conception periods revealed no differences in female activity budgets or in either the number of copulations or the number of different mating partners per female. Our results suggest that some females mate preferentially with close associates and social partners, but there is no indication that females alter their behavior during the cycles in which they conceive.     

Fitness-related benefits of dominance in primates

Dominance hierarchies are thought to provide various fitness-related benefits to dominant individuals (e.g., preferential access to food or mating partners). Remarkably, however, different studies on this topic have produced contradictory results, with some showing strong positive association between rank and fitness (i.e., dominants gain benefits over subordinates), others weak associations, and some others even revealing negative associations. Here, we investigate dominance-related benefits across primate species while controlling for phylogenetic effects. We extracted data from 94 published studies, representing 25 primate species (2 lemur species, 4 New World monkeys, 16 Old World monkeys, and 3 apes), to assess how dominance affects life-history and behavior. We used standard and phylogenetic meta-analyses to analyze the benefits of dominance in primates. Dominant females had higher infant survival to first year, although we found no significant effect of dominance on female feeding success. Results for female fecundity differed between the two meta-analytical approaches, with no effect of dominance on female fecundity after controlling for phylogeny. Dominant males had a higher fecundity and mating success than subordinate males. Finally, the benefits of dominance for female fecundity were stronger in species with a longer lifespan. Our study supports the view that dominance hierarchies are a key aspect of primate societies as they indeed provide a number of fitness-related benefits to individuals.     

Research Ethics and Intellectual Disability: Broadening the Debates

This article examines the ethical issues surrounding the inclusion of people with intellectual disabilities as research subjects. It explores subject selection, competence, risk and benefits, and authority through three tensions that emerge when considering these concepts in the context of the Disability Rights Movement and critical disability scholarship. These tensions are defined as the double dangers of inclusion and exclusion; the challenges of defining competence and risk in terms of individuals vs. groups; and the conflicts that arise when pursuing the dual goals of amelioration and elimination of disabilities. Though these tensions are not resolved, they underscore the importance of researchers engaging with critical disability perspectives in order to navigate these complex ethical questions.     

Gypsies and health care.

Gypsies in the United States are not a healthy group. They have a high incidence of heart disease, diabetes mellitus, and hypertension. When they seek medical care, Gypsies often come into conflict with medical personnel who find their behavior confusing, demanding, and chaotic. For their part, Gypsies are often suspicious of non-Gypsy people and institutions, viewing them as a source of disease and uncleanliness. Gypsy ideas about health and illness are closely related to notions of good and bad fortune, purity and impurity, and inclusion and exclusion from the group. These basic concepts affect everyday life, including the way Gypsies deal with eating and washing, physicians and hospitals, the diagnosis of illness, shopping around for cures, and coping with birth and death.     

Benefits of aggregation in woodlice: a factor in the terrestrialization process?

In the animal kingdom, living in group is driven by a tradeoff between the costs and the benefits of this way of life. This review focuses especially on the benefits of aggregation and crowding in woodlice (Crustacea: Isopoda: Oniscidea). Indeed, woodlice are well known to live in groups. Their aggregation behavior, as described in the early works of Allee, is regarded as a mechanism to prevent desiccation to which woodlice are extremely sensitive. However, it is now clear that there are additional benefits to aggregation in woodlice. Hence, this review addresses not only the limitation of water loss as the main factor explaining aggregation patterns, but also alternative explanations as reduction of oxygen consumption, increase in body growth, biotic stimuli for reproduction, better access to mates, possible shared defenses against predators, promotion of coprophagy as a secondary food source, sheltering behavior and the acquisition of internal symbionts. In addition, we place woodlice in the context of a terrestrialization process and propose that woodlice—the only suborder of Crustacea almost entirely composed of strictly terrestrial species—are a model taxon for studying the evolution of sociality through the transition from water to land. Further, we discuss other ultimate causes of aggregation preserved in terrestrial isopods in light of those explained in aquatic isopods and under the concept of exaptation. This knowledge could help understand, in this and other taxa, how the spatial closeness between conspecifics may promote the colonization of new environments and nonphysiological responses to climatic constraints.     

Altruism may arise from individual selection

The fact that humans cooperate with non-kin in large groups, or with people they will never meet again, is a long-standing evolutionary puzzle. Altruism, the capacity to perform costly acts that confer benefits on others, is at the core of cooperative behavior. Behavioral experiments show that humans have a predisposition to cooperate with others and to punish non-cooperators at personal cost (so-called strong reciprocity) which, according to standard evolutionary game theory arguments, cannot arise from selection acting on individuals. This has led to the suggestion of group and cultural selection as the only mechanisms that can explain the evolutionary origin of human altruism. We introduce an agent-based model inspired on the Ultimatum Game, that allows us to go beyond the limitations of standard evolutionary game theory and show that individual selection can indeed give rise to strong reciprocity. Our results are consistent with the existence of neural correlates of fairness and in good agreement with observations on humans and monkeys.     

A BIOLOGICAL MARKET ANALYSIS OF THE PLANT‐MYCORRHIZAL SYMBIOSIS

It has been argued that cooperative behavior in the plant‐mycorrhizal mutualism resembles trade in a market economy and can be understood using economic tools. Here, we assess the validity of this “biological market” analogy by investigating whether a market mechanism—that is, competition between partners over the price at which they provide goods—could be the outcome of natural selection. Then, we consider the conditions under which this market mechanism is sufficient to maintain mutualistic trade. We find that: (i) as in a market, individuals are favored to divide resources among trading partners in direct relation to the relative amount of resources received, termed linear proportional discrimination; (ii) mutualistic trade is more likely to be favored when individuals are able to interact with more partners of both species, and when there is a greater relative difference between the species in their ability to directly acquire different resources; (iii) if trade is favored, then either one or both species is favored to give up acquiring one resource directly, and vice versa. We then formulate testable predictions as to how environmental changes and coevolved responses of plants and mycorrhizal fungi will influence plant fitness (crop yields) in agricultural ecosystems.     

Social rejection,exclusion, and shunning among the Gombe chimpanzees

From the observations at Gombe over the past 23 years it appears that group punishment of deviant behavior through ostracism, as practiced in human groups, has not yet evolved in a truly sophisticated way in chimpanzee society. However, cases of “social rejection or exclusion” have been observed in three different behavioral contexts. Most frequently, a chimpanzee is the target of hostility as the result of competitive interaction within the community; in such cases, social cohesion counterbalances rejection, typically leading to integration within a relatively stable pattern of dominance and social interaction. The occasional departure of an individual who has been the target of aggression —like the withdrawal of Evered after repeated attacks by Figan and Faban—seems due to persistent hostility by a few males rather than general “ostracism” by the group as a whole. A second form of exclusion concerns outsiders found in the home range of the group: in these cases, hostility is more generalized, particularly in response to the attempt of an adult female with offspring to join the community. Finally, there are the rarely observed instances of shunning a group member whose behavior seems abnormal the social rejection of Pepe and Old Mr. McGregor after they suffered from polio.     

Short term,long term: An unexpected confound in human-mating research

Here I report that, when partnered people judge the facial attractiveness of potential mates for a short- and a long-term relationship, the order in which the two conditions are presented biases responses in a systematic manner. Women and men display symmetrical biases. Women find men less attractive as new long-term partners if they have first imagined them as one-night stands. Men find women less attractive as one-night stands if they have first imagined them as new long-term partners. On a total sample of over 3000 individuals from different studies, I show that both biases are robust and replicable in partnered people and neither is found in singles. Alas, so far no study has statistically controlled the effect of the order in which participants consider the two types of relationships. Whatever their interpretation, these biases are capable of producing spurious or inconsistent associations and mislead us when we compare studies that on the surface appear similar—most notably, direct and conceptual replications.     

Reputational benefits for altruistic punishment

Many studies show that people act cooperatively and are willing to punish free riders (i.e., people who are less cooperative than others). However, nonpunishers benefit when free riders are punished, making punishment a group-beneficial act. Presented here are four studies investigating whether punishers gain social benefits from punishing. Undergraduate participants played public goods games (PGGs) (cooperative group games involving money) in which there were free riders, and in which they were given the opportunity to impose monetary penalties on free riders. Participants rated punishers as being more trustworthy, group focused, and worthy of respect than nonpunishers. In dyadic trust games following PGGs, punishers did not receive monetary benefits from punishing free riders in a single-round PGG, but did benefit monetarily from punishing free riders in iterated PGGs. Punishment that was not directed at free riders brought no monetary benefits, suggesting that people distinguish between justified and unjustified punishment and only respond to punishment with enhanced trust when the punishment is justified.     

Do marmosets care to share? Oxytocin treatment reduces prosocial behavior toward strangers

Cooperatively-breeding and socially-monogamous primates, like marmosets and humans, exhibit high levels of social tolerance and prosociality toward others. Oxytocin (OXT) generally facilitates prosocial behavior, but there is growing recognition that OXT modulation of prosocial behavior is shaped by the context of social interactions and by other motivational states such as arousal or anxiety. To determine whether prosociality varies based on social context, we evaluated whether marmoset donors (Callithrix penicillata) preferentially rewarded pairmates versus opposite-sex strangers in a prosocial food-sharing task. To examine potential links among OXT, stress systems, and prosociality, we evaluated whether pretrial cortisol levels in marmosets altered the impact of OXT on prosocial responses. Marmosets exhibited spontaneous prosociality toward others, but they did so preferentially toward strangers compared to their pairmates. When donor marmosets were treated with marmoset-specific Pro⁸-OXT, they exhibited reduced prosociality toward strangers compared to marmosets treated with saline or consensus-mammalian Leu⁸-OXT. When pretrial cortisol levels were lower, marmosets exhibited higher prosociality toward strangers. These findings demonstrate that while marmosets show spontaneous prosocial responses toward others, they do so preferentially toward opposite-sex strangers. Cooperative breeding may be associated with the expression of prosociality, but the existence of a pair-bond between marmoset partners appears to be neither necessary nor sufficient for the expression of spontaneous prosocial responses. Furthermore, high prosociality toward strangers is significantly reduced in marmosets treated with Pro⁸-OXT, suggesting that OXT does not universally enhance prosociality, but, rather OXT modulation of prosocial behavior varies depending on social context.     

Post-conflict affiliation by chimpanzees with aggressors: other-oriented versus selfish political strategy

Consolation, i.e., post-conflict affiliation directed from bystanders to recent victims of aggression, has recently acquired an important role in the debate about empathy in great apes. Although similar contacts have been also described for aggressors, i.e., appeasement, they have received far less attention and their function and underlying mechanisms remain largely unknown. An exceptionally large database of spontaneous conflict and post-conflict interactions in two outdoor-housed groups of chimpanzees lends support to the notion that affiliation toward aggressors reduces the latter's aggressive tendencies in that further aggression was less frequent after the occurrence of the affiliation. However, bystander affiliation toward aggressors occurred disproportionally between individuals that were socially close (i.e., affiliation partners) which suggest that it did not function to protect the actor itself against redirected aggression. Contrary to consolation behavior, it was provided most often by adult males and directed toward high ranking males, whereas females engaged less often in this behavior both as actors and recipients, suggesting that affiliation with aggressors is unlikely to be a reaction to the distress of others. We propose that bystander affiliation toward aggressors may function to strengthen bonds between valuable partners, probably as part of political strategies. Our findings also suggest that this post-conflict behavior may act as an alternative to reconciliation, i.e., post-conflict affiliation between opponents, in that it is more common when opponents fail to reconcile.     

History of the enzyme nomenclature system

Naming things is essential for people to understand one another, no matter what language or field of interest is involved. This is as true for enzymes, genes and chemicals as it is for birds, food, flowers, etc. Effective communication requires a lack of ambiguity, but, in practice, ambiguities abound even between people who use the same language in different parts of the world, or even within the same country. Whereas ambiguities in the words used for common objects or actions have been the basis for many, more-or-less memorable jokes, they can also cause a great deal of confusion. Such linguistic chaos is welcomed by many as being a part of a diverse heritage that should be preserved at all costs to prevent us from descending into Orwellian 'newspeak'. However, in the sciences, there are distinct advantages in others being able to understand what one is doing. Many groups have stressed the need for standardized, universally accepted systems of nomenclature in chemistry, genetics, enzymology, etc. However, it is the universal acceptance that usually causes the problem. It is rare to find people who will admit that they find nomenclature to be an interesting subject, but many who profess contempt for it will get very excited if it is suggested that their pet nomenclature should be changed in the interest of clarity or uniformity. This account will consider the development of the enzyme nomenclature system, its benefits, shortcomings and future prospects.     

Charitable giving as a signal of trustworthiness: Disentangling the signaling benefits of altruistic acts

It has been shown that psychological predispositions to benefit others can motivate human cooperation and the evolution of such social preferences can be explained with kin or multi-level selection models. It has also been shown that cooperation can evolve as a costly signal of an unobservable quality that makes a person more attractive with regard to other types of social interactions. Here we show that if a proportion of individuals with social preferences is maintained in the population through kin or multi-level selection, cooperative acts that are truly altruistic can be a costly signal of social preferences and make altruistic individuals more trustworthy interaction partners in social exchange. In a computerized laboratory experiment, we test whether altruistic behavior in the form of charitable giving is indeed correlated with trustworthiness and whether a charitable donation increases the observing agents' trust in the donor. Our results support these hypotheses and show that, apart from trust, responses to altruistic acts can have a rewarding or outcome-equalizing purpose. Our findings corroborate that the signaling benefits of altruistic acts that accrue in social exchange can ease the conditions for the evolution of social preferences.     

Ravens reconcile after aggressive conflicts with valuable partners

Reconciliation, a post-conflict affiliative interaction between former opponents, is an important mechanism for reducing the costs of aggressive conflict in primates and some other mammals as it may repair the opponents' relationship and reduce post-conflict distress. Opponents who share a valuable relationship are expected to be more likely to reconcile as for such partners the benefits of relationship repair should outweigh the risk of renewed aggression. In birds, however, post-conflict behavior has thus far been marked by an apparent absence of reconciliation, suggested to result either from differing avian and mammalian strategies or because birds may not share valuable relationships with partners with whom they engage in aggressive conflict. Here, we demonstrate the occurrence of reconciliation in a group of captive subadult ravens (Corvus corax) and show that it is more likely to occur after conflicts between partners who share a valuable relationship. Furthermore, former opponents were less likely to engage in renewed aggression following reconciliation, suggesting that reconciliation repairs damage caused to their relationship by the preceding conflict. Our findings suggest not only that primate-like valuable relationships exist outside the pair bond in birds, but that such partners may employ the same mechanisms in birds as in primates to ensure that the benefits afforded by their relationships are maintained even when conflicts of interest escalate into aggression. These results provide further support for a convergent evolution of social strategies in avian and mammalian species.     

PATHWAYS TO SOCIAL EVOLUTION: RECIPROCITY,RELATEDNESS, AND SYNERGY

Many organisms live in populations structured by space and by class, exhibit plastic responses to their social partners, and are subject to nonadditive ecological and fitness effects. Social evolution theory has long recognized that all of these factors can lead to different selection pressures but has only recently attempted to synthesize how these factors interact. Using models for both discrete and continuous phenotypes, we show that analyzing these factors in a consistent framework reveals that they interact with one another in ways previously overlooked. Specifically, behavioral responses (reciprocity), genetic relatedness, and synergy interact in nontrivial ways that cannot be easily captured by simple summary indices of assortment. We demonstrate the importance of these interactions by showing how they have been neglected in previous synthetic models of social behavior both within and between species. These interactions also affect the level of behavioral responses that can evolve in the long run; proximate biological mechanisms are evolutionarily stable when they generate enough responsiveness relative to the level of responsiveness that exactly balances the ecological costs and benefits. Given the richness of social behavior across taxa, these interactions should be a boon for empirical research as they are likely crucial for describing the complex relationship linking ecology, demography, and social behavior.     

Altruism towards strangers in need: costly signaling in an industrial society

In the present study, the costly signaling theory (CST) is used to examine the effect of an offer of charity on social recognition. On behalf of a charitable organization, 186 students enrolled in 16 different courses were asked to offer support to unfamiliar persons in need. In accordance with our predictions, the results show that significantly more subjects are willing to give assistance if they make charity offers in the presence of their group members than when the offers are made in secret. In accordance with CST—but not with the prevailing explanations in social psychology—the likelihood of charity service was strongly influenced by the expected cost of altruistic behavior. Publicly demonstrated altruistic intentions yielded long-term benefits: Subjects who were willing to participate in a particular charity activity gained significantly higher sociometry scores (as a sign of social recognition) than did others. The cost of volunteerism correlated with social recognition in the case of a charity act judged as the most expensive (giving assistance to mentally retarded children), but not for the other categories of charity offer. Our results suggest that public generosity towards strangers as a costly signal may convey reliable information about subjects' personality traits, such as cooperativeness, but our data do not support the hypothesis that the signaling mechanism is related to sexual selection and mate choice.