Familiar Opponents Research Articles

Male Pagurus minutus hermit crabs use multiple types of information in decisions to give up male–male contests

Organisms use information to make adaptive decisions in various contexts, including aggression. Potentially weaker, but better-informed, contestants should give up earlier to reduce fighting costs by using information related to their own lower success such as their size relative to their opponent and past contest outcomes to make this choice. Here, we examined whether intruders of the hermit crab Pagurus minutus could use information about their (1) smaller size, (2) past contest defeats, (3) opponent’s past wins, or (4) relationship in the dominance hierarchy to their opponent when making a decision to give up during male–male contests for a female. In all trials, we randomly matched a smaller intruder with a larger opponent that was guarding a female. Our analyses suggest that P. minutus intruders can use all four types of information to decide whether to give up a contest without escalation or decrease its duration after escalation; it is the first species of Pagurus reported to do so, and the second reported to be able to distinguish familiar opponents from others in the context of male–male contests. These findings demonstrate the importance of cognitive abilities in minimizing costs when competing for vital resources.

Socio-cognitive correlates of primary school children's deceptive behavior toward peers in competitive settings

Competing for limited resources with peers is common among children from an early age, illustrating their propensity to use deceptive strategies to win. We focused on how primary school-age (6–8 years old) children's strategic deception toward peers is associated with their socio-cognitive development (theory of mind and executive functions). In a novel computerized competitive hide-and-seek game, we manipulated the peer opponents' familiarity (familiar vs. unfamiliar) and actions (following vs. not following children's indications), as well as the stimuli likability (liked vs. disliked cards). Our findings demonstrated that children deceived the familiar opponent less than the unfamiliar one, indicating their determination to preserve positive peer interactions. We showed that theory of mind and executive functions significantly predicted children's willingness to deceive. Notably, second-order false belief understanding and visuospatial working memory positively predicted children's use of truths to deceive, whereas inhibitory control and cognitive flexibility efficacy scores were negatively related to their deceptive performance when using the same strategy. Implications for children's competitive behavior toward peers involving lie-telling are discussed.

Journal of Cancer Discovery: we are a part of the battlefield

The world has witnessed the tremendous development of anticancer therapies over the past decades. Our tools to fight against this ancient enemy have evolved from traditional chemotherapy to targeted therapy, and then to immunotherapy now. Especially with the great success of immune checkpoint blockade therapies such as anti-PD-1 antibodies, we have taken a giant leap towards the future in which cancer will no longer be seen as an irreparable tragedy of life. However, we are still far from winning the battle against cancer. The current therapeutic strategies are not close to the final answer of cancer treatment, with limited PFS and OS with almost all the treatments in the majority of the patients and types of cancer. The game is still in the hard mode. That is how I feel when I see the clinical trial results reporting a few more weeks’ prolonged survival time, and doctors all over the world excited about it. Fundamentally, our understanding of the biological processes of cancer is still limited, and new discoveries and ideas are urgently needed to make breakthroughs. The age of the universe is about 13.7 billion years. The Earth was born roughly 4.5 billion years ago. The first life on Earth appeared about 3.8 billion years ago. The first cancer was found on the fossil of a turtle living nearly 230 million years ago. The first human found to have cancer lived about 1.7 million years ago. The first anticancer drug, nitrogen mustard, was approved 65 years ago. I feel lucky that I live in an era with rapid progress in cancer research and clinical practice, and act as both a doctor in medical oncology and a scientific worker in the field of cancer research to play a part in the fight against this familiar opponent. That’s why we launched the Journal of Cancer Discovery (JCD): we want to be a part of the battlefield, and do our best to provide some new ideas for the human beings to win this billion-year-old battle. JCD is an open-access, peer-reviewed and bilingual journal. Like other Luminescience journals, in addition to publishing in English, our professional editing team will also provide the readers with abstracts in Chinese, and the full text of some selected manuscripts will be published in both English and Chinese. We also welcome authors to provide us with the abstract in their native language after the article is accepted. Our aim is to enhance global communication in cancer research, and to let different voices from all over the world be heard. We hope and believe that JCD will be an outstanding journal in cancer research in the near future.

Vocalizations during post-conflict affiliations from victims toward aggressors based on uncertainty in Japanese macaques.

We investigated the use of vocalizations called “grunts,” “girneys,” and “coos” accompanied by post-conflict affiliative interaction between former opponents (reconciliation) in Japanese macaques (Macaca fuscata). Although reconciliation functions to repair bonds, such interactions sometimes entail risks of receiving further aggression. Vocalizations can be used at a distance from the former opponent; thus, we predict that vocalizations are used particularly by victims of a conflict, and are frequently used in situations of uncertainty when it is difficult for them to estimate whether the former opponent will resume aggression. In addition, we predict that vocalizations are effective in preventing further aggression. To test these hypotheses, we conducted observations of post-conflict and matched-control situations in female Japanese macaques living in a free-ranging group. We found that former opponents tended to be attracted to each other within the first minute following a conflict, thus demonstrating reconciliation behavior. Vocalizations were more frequently used by the victims in post-conflict interactions than under control situations; however, this tendency was not found in aggressors. When affiliation with the former opponent occurred, victims were more likely to use vocalizations towards less familiar opponents. These findings suggest that Japanese macaques used vocalizations more often when interacting with less predictable former opponents. Victims were more likely to receive aggression from former aggressors when engaged in affiliations with them than under no such affiliations. No significant differences were found in the probability of the victims receiving aggression, regardless of whether they used vocalizations; thus, whether the victim benefits from using vocalizations in these contexts remains unclear. Japanese macaques form despotic societies and therefore, further aggression was inevitable, to some degree, after a conflict. The use of vocalizations by a victim was found to depend on the nature of their relationship with the aggressor; however, the effectiveness of this behavior requires further investigation.

Social play in juvenile hamsters alters dendritic morphology in the medial prefrontal cortex and attenuates effects of social stress in adulthood.

Social play is a fundamental aspect of behavioral development in many species. Social play deprivation in rats alters dendritic morphology in the ventromedial prefrontal cortex (vmPFC) and we have shown that this brain region regulates responses to social defeat stress in Syrian hamsters. In this study, we tested whether play deprivation during the juvenile period disrupts dendritic morphology in the prefrontal cortex and potentiates the effects of social defeat stress. At weaning, male hamsters were either group-housed with peers or pair-housed with their mother, with whom they do not play. In adulthood, animals received acute social defeat stress or no-defeat control treatment. The hamsters were then tested for a conditioned defeat response in a social interaction test with a novel intruder, and were also tested for social avoidance of a familiar opponent. Brains were collected for Golgi-Cox staining and analysis of dendritic morphology in the infralimbic (IL), prelimbic (PL), and orbitofrontal cortex (OFC). Play-deprived animals showed an increased conditioned defeat response and elevated avoidance of a familiar opponent compared with play-exposed animals. Furthermore, play-deprived animals showed increased total length and branch points in apical dendrites of pyramidal neurons in the IL and PL cortices, but not in the OFC. These findings suggest that social play deprivation in juvenile hamsters disrupts neuronal development in the vmPFC and increases vulnerability to the effects of social stress in adulthood. Overall, these results suggest that social play is necessary for the natural dendritic pruning process during adolescence and promotes coping with stress in adulthood. (PsycINFO Database Record

Competing against a familiar friend: Interactive mechanism of the temporo-parietal junction with the reward-related regions during episodic encoding

Competition enhances learning under certain circumstances. However, little is known about how the neural mechanisms involved in a competition during the episodic encoding are modulated by the social distance of personal relationships with opponents. To investigate this issue, using functional magnetic resonance imaging (fMRI), we scanned healthy young adults during a competition with their familiar friends and unfamiliar others in the episodic encoding. Three major findings emerged from this study. First, activations in the right temporo-parietal junction (rTPJ) were significantly greater in the competition with familiar friends than with unfamiliar others, and the activations in this region were significantly correlated with the subjective ratings of motivation. Second, striatum and amygdala activations increased by the competition with familiar friends were significantly correlated with the increased ratings of pleasantness, which reflected emotionally positive feelings in victory for the competition with familiar opponents. Third, the functional connectivity between the rTPJ and reward-related regions, including the striatum and substantia nigra, was higher in the competition with familiar friends than with unfamiliar others. Taken together with our behavioral findings, in which memories encoded by competing with familiar friends were remembered more accurately than those with unfamiliar others, the interacting mechanisms between the rTPJ that is involved in social motivation and the reward-related regions that are involved in social reward could contribute to the enhancement of memories encoded in the competition with familiar others.

Toward an ethics of professional understanding

In this paper, we advance a novel conception of normative ethics and draw out its implications within the domain of professional ethics. We argue that all moral agents, and thus professionals, share a fundamental and constitutive normative interest in correctly conceiving of their ends. All professionals, we claim, by virtue of their positions of social power, have special role responsibilities in cultivating and sustaining societies oriented by this shared ideal of practically oriented ethical understanding. We defend this conception against a familiar opponent of a philosophical approach to professional ethics: the morally skeptical student (or university administrator). By taking the skeptic’s challenge seriously, we clarify the conditions for a sound account of normative ethics and then provide a response that meets this test. Against this type of skeptic, we claim that a fundamental commitment to the ideal of understanding our ends ought to be included within any curriculum of professional ethics that reflects moral reality. We argue that endorsing such a curriculum would make a significant difference in our sense of professional advocacy and in conceiving of who, what, and how we teach.

Hermit crab, Pagurus middendorffii, males avoid the escalation of contests with familiar winners

Prior contest outcomes often affect subsequent contest behaviour (winner/loser effects). If contestants discriminate between familiar and unfamiliar opponents, individual recognition may alter the strength and/or manner of winner/loser effects. We examined whether hermit crabs, Pagurus middendorffii, changed their contest behaviour based on winner/loser effects, whether they distinguished a familiar opponent from an unfamiliar opponent, and how the familiarity with the opponent related to the winner/loser effects in male–male contests. Males of this species show precopulatory guarding behaviour, and male–male contests often occur between a guarding male and an intruder. In contests between unfamiliar males, intruders use self-assessment during the initial contact phase and mutual assessment during the physical combat phase to determine their behaviours. Precopulatory guarding males and females collected in the field were used in two consecutive trials of male–male contests. Losers in the first trial were used as focal intruders in the second trial with (1) a familiar opponent that had won the first trial, (2) an unfamiliar opponent that had won the first trial with another intruder, or (3) a naive opponent with no trial experience. Focal intruders did not alter their aggressiveness against either unfamiliar or naive opponents in the second trial. However, they rarely initiated physical combat against familiar opponents in the second trial. When they initiated combat, they gave up sooner against familiar opponents than against unfamiliar opponents. These results suggest that intruders are able to distinguish familiar opponents from others and decrease their aggressiveness only when they encounter familiar opponents. Our study therefore shows loser effects in P. middendorffii related to the familiarity with the opponent and suggests intruders can obtain information about their opponents during the initial encounter.

Response of red deer stags (Cervus elaphus) to playback of harsh versus common roars.

Red deer stags (Cervus elaphus) give two distinct types of roars during the breeding season, the "common roar" and the "harsh roar." Harsh roars are more frequent during contexts of intense competition, and characterized by a set of features that increase their perceptual salience, suggesting that they signal heightened arousal. While common roars have been shown to encode size information and mediate both male competition and female choice, to our knowledge, the specific function of harsh roars during male competition has not yet been studied. Here, we investigate the hypothesis that the specific structure of male harsh roars signals high arousal to competitors. We contrast the behavioral responses of free ranging, harem-holding stags to the playback of harsh roars from an unfamiliar competitor with their response to the playback of common roars from the same animal. We show that males react less strongly to sequences of harsh roars than to sequences of common roars, possibly because they are reluctant to escalate conflicts with highly motivated and threatening unfamiliar males in the absence of visual information. While future work should investigate the response of stags to harsh roars from familiar opponents, our observations remain consistent with the hypothesis that harsh roars may signal motivation during male competition, and illustrate how intrasexual selection can contribute to the diversification of male vocal signals.

5-HT1A receptor activation reduces fear-related behavior following social defeat in Syrian hamsters

Social defeat leads to selective avoidance of familiar opponents as well as general avoidance of novel, non-threatening intruders. Avoidance of familiar opponents represents a fear-related memory whereas generalized social avoidance indicates anxiety-like behavior. We have previously shown that serotonin signaling alters responses to social defeat in Syrian hamsters, although it is unclear whether serotonin modulates defeat-induced fear, anxiety, or both. In this study we focus on 5-HT1A receptors, in part, because their activation had been linked to the acquisition of conditioned fear. We hypothesized that pharmacological activation of 5-HT1A receptors prior to social defeat would reduce avoidance of familiar opponents and impair Arc expression in the basolateral amygdala (BLA), but not alter anxiety-like behavior. We administered 8-OH-DPAT, a 5-HT1A receptor agonist, prior to 3, 5-minute social defeats and 24h later exposed hamsters to a social interaction test to measure the conditioned defeat response immediately followed by either a Y-maze test or an open field test. In a separate experiment, we administered 8-OH-DPAT prior to 3, 5-minute social defeats and later removed the brains for Arc immunohistochemistry. Social defeat increased the number of Arc immunopositive cells in the central amygdala (CeA), prelimbic cortex (PL), and BLA, and 8-OH-DPAT treatment reduced Arc immunoreactivity in the PL. These results suggest that 5-HT1A receptor activation impairs the fear memory associated with social defeat, but does not alter defeat-induced anxiety. Overall, 5-HT1A receptor activation may impair Arc expression in select brain regions such as the PL and thereby disrupt the development of a fear memory essential for the conditioned defeat response.

Lokpal: Anti Corruption Agency to Be Built on Existing Practical Experience

The all too shrill 'civil society' discourse on corruption, led by Anna Hazare's team, has rekindled public debate on the need for a Lokpal. Corruption and maladministration have become an integral part of our ‘celebrated democracy’. Corruption is one of the prime causes of poverty in India. India’s shining economic growth keeps ironically the largest number of impoverished people in the world. The debate on policy choices and the institutional design for a new anti-corruption agency at the Union and State levels has pervaded every public fora. The ubiquitous debate is characterized by passionate disagreement between familiar opponents who never tire of restating and rehashing their adopted positions informed by their moral or political commitments. Despite the polarized debate there is agreement on the core moral imperative to tackle corruption seriously. However, the debate has quickly moved from this agreed premise to the questionable conclusion that we need a powerful national institution to prosecute and convict the corrupt under the criminal law. In this working paper we hope to bring new insights to this debate by engaging with law in action. While my final analysis and conclusions will follow shortly, I hope to contribute to the present debates with our preliminary findings through this working paper. My analysis suggests that the policy debate on the Lokpal has focused on issues that have been anticipated and largely resolved by existing legislation and institutional design of the Lokayukta in, say, Karnataka and has ignored critical issues that may have little or nothing to do with the design of the Lokpal itself but affect its performance. I conclude that a bill that does not assimilate the experience of existing anti-corruption agencies in states is doomed to fail. Rest of the discussion is organized around discrete themes that have been highlighted in the current Lokpal debate.

Opponent familiarity influences the audience effect in male–male interactions in Siamese fighting fish

It is well established that communication in social organisms often occurs within a network of individuals rather than within signaller–receiver dyads. Most of these investigations, however, have not assessed how other social factors might influence communication. In the present study, we investigated whether previous exposure to an opponent influences audience effects on male–male interactions in Siamese fighting fish, Betta splendens. Males interacted with an unfamiliar opponent or a familiar opponent in the presence of a male, a female or no audience. Opponent-directed gill flaring was greatest when opponents were unfamiliar with one another and a male audience was present. In contrast, opponent-directed tail beats were most frequent when a female audience was present, especially when opponents were unfamiliar. Opponent familiarity appears to have a greater effect on opponent-directed gill flaring than on tail beats. This may reflect the difference in the function of these behaviours as tail beats are commonly used in courtship as well as during aggressive encounters. Our findings suggest that audience type and the social history of the opponents work together to influence aggressive interactions in this species.

The effect of escapable versus inescapable social defeat on conditioned defeat and social recognition in Syrian hamsters

Male Syrian hamsters are naturally aggressive animals that reliably defend their home territory against intruding conspecifics. Hamsters that lose agonistic encounters subsequently exhibit a striking change in their agonistic behavior, however, expressing no aggression and instead becoming highly submissive, a behavioral change that we have termed conditioned defeat. We have generally employed an inescapable defeat training protocol when studying conditioned defeat. The purpose of the present study was to determine if conditioned defeat is an epiphenomenon of the inescapable defeat experience by comparing the behavior of hamsters exposed to inescapable versus escapable defeat. In the conditioned defeat model, defeated hamsters subsequently generalize their submission and social avoidance to a novel, non-aggressive opponent, suggesting that hamsters subjected to inescapable defeat may not form a specific memory of their aggressive opponent. Thus, a secondary purpose of the present study was to determine whether hamsters subjected to our defeat protocol have the ability to recognize a familiar opponent following defeat. Our results provide evidence that conditioned defeat is not solely a by-product of inescapable defeat because all experimental animals, regardless of the type of defeat, expressed conditioned defeat during testing. We also found that animals experiencing an inescapable defeat avoided a familiar aggressor significantly more than they did an unfamiliar aggressor, demonstrating that these animals have the ability to recognize their previous attacker. Thus, we maintain that a variety of social defeat models, and conditioned defeat in particular, represent generalizable and ethologically valid models with which to study the effects of social stress on physiology and behavior.

Probing the Limits of Rights Discourse in the Obama Era: A Crossroads for Labor and Liberalism

In the August 8, 2008, edition of the Wall Street Journal, an editorial denounced the Employee Free Choice Act (EFCA), organized labor's most recent effort to reform US labor law, as a measure that would lead to worker intimidation and the end of free and fair workplace representation elections. That the nation's leading business journal carried an editorial outlining the familiar EFCA opponent's trope of worker intimidation by unions was not surprising. That the author's identity was former South Dakota senator George McGovern—that aging icon of American liberalism and a self-described “longtime friend of labor unions”—foreshadowed the uphill battle and ultimate defeat labor and its allies would face in enacting the measure.

Visual recognition of conspecifics in the American lobster, Homarus americanus

For years, individual recognition has been the subject of many studies but, owing to the intrinsic complexity of the phenomenon, it has also been the source of much controversy. The sensory channel(s) used for recognition has also been much discussed. In aquatic invertebrates, vision has been one of the least understood media. We carried out two laboratory experiments using 49 pairs of adult male American lobsters. The first experiment was aimed at investigating the sensory channel/s (smell, sight or the two combined) used by lobsters to get information about the opponent, whereas in the second experiment we tested whether visual experience might allow lobsters to recognize the familiar opponent. Previous exposure to the sight of a conspecific induced lobsters either to avoid the opponent or to skip preliminaries (approaches and threats) and escalate the interaction. However, such changes in the dynamics of fighting were shown only when the opponent was the individual that the experimental lobster had previously seen rather than a generic lobster. This is the first study to provide evidence that lobsters can identify familiar conspecifics by sight, although this does not necessarily mean that they recognize them as individuals. Further studies are needed to clarify this issue.

Opponent recognition and social status differentiate rapid neuroendocrine responses to social challenge

Individual social status discriminates rapid neuroendocrine responses to non-social stress in male Anolis carolinensis, but whether such status-influenced reactions are retained in response to subsequent social stress is unknown. Dominant and subordinate males modify their behavioral responses to social challenge according to familiarity of the opponent, suggesting that accompanying neuroendocrine responses may differ according to opponent recognition despite social rank. We examined endocrine and neurochemical correlates of prior social status and opponent recognition during the opening stages of social challenge. Male pairs interacted and established dominant/subordinate status, followed by 3 days separation. Subsequently, subjects were paired with either the same opponent or an unfamiliar male according to rank (dominant with subordinate). After 90 s of social exposure, subjects were caught and brains and plasma collected for measurement of circulating corticosterone and limbic monoamines. Controls included pairs experiencing just one 90 s encounter plus a group of non-interacting subjects. Opponent recognition differentiated status-influenced responses, such that dominant lizards paired with familiar subordinate opponents had increased hippocampal dopamine and epinephrine, but showed increased plasma corticosterone and ventral tegmental area (VTA) norepinephrine when challenged with an unfamiliar opponent. Subordinate lizards encountering familiar opponents also had increased corticosterone, along with decreased hippocampal dopamine and increased VTA epinephrine, but showed no changes in response to an unfamiliar opponent. Such plasticity in status-influenced rapid neuroendocrine responses according to opponent recognition may be necessary for facilitating production of behavioral responses adaptive for particular social contexts, such as encountering a novel versus familiar opponent.

The Effect of Social and Situational Factors on the Intended Response to Aggression Among Adolescents

ABSTRACT In this study, I explored intended response to aggression among adolescents. I drew hypotheses from social identity theory, cost/benefit considerations, and social information processing model. I asked 217 Jewish and Muslim male adolescents in this study to assess their intended use of aggression in 12 hypothetical conflict situations (vignettes), in which I manipulated the opponent's religion, gender, acquaintance, and severity of aggression. I mainly found that male adolescents respond to aggression by same-religion opponents more moderately than to cross-religion aggression; their response is more moderate to cross-gender aggression than to same-gender aggression; response is more moderate to the aggression of familiar opponents than to that of unfamiliar ones; and response is less severe toward moderate than toward severe aggression.

Crustacean Social Behavioral Changes in Response to Isolation

Periods of isolation during which animals have no social contact are common in the design of behavioral experiments. They are used, for example, to test memory and recognition responses, or to ensure a baseline condition before experimental manipulations commence. We investigated the effect of isolation periods on the aggressive behavior of matched pairs of the crayfish Cherax destructor in two contexts. The first experiment tested the effects of a period of isolation between two encounters. The second experiment tested the effects of isolation before an encounter by pairing one crayfish from a communal living environment with another crayfish from an isolated one. Fight outcome and aggression levels were analyzed, resulting in three conclusions about the social biology of C. destructor. First, encounters between familiar opponents are influenced by the outcome of the familiarization fight for about 2 weeks. Second, the level of aggression and the outcome of an encounter are affected over different time frames. Third, individuals that are isolated before an encounter can be disadvantaged. These data suggest that isolation, or events that occur during periods of isolation, affect multiple elements of social behavior in C. destructor. This suggestion has implications for the interpretation of previous results and future studies in crustaceans and other taxa.

Familiarity and threat of opponents determine variation in Thomas langur (Presbytis thomasi) male behaviour during between-group encounters

Abstract During between-group encounters in primates, males often defend mates, food or infants against other males. Males, however, show variation in contests between opponents. In other taxa, such variation has been attributed to variation in familiarity with or threat of opponents. Here we present the results of analyses of between-group encounter intensity variation in Thomas langurs while controlling for threat when evaluating familiarity and vice versa. Encounter intensity was measured by the proportion of encounters with chases and the number of loud calls per minute during the encounter given by the focal male. The results indicate that both familiarity and threat influence encounter intensity. Less familiar opponents had more intense encounters and opponents that differed in the threat level to each other also had more intense encounters. Thus, Thomas langur males seem to incorporate information on both the level of threat and familiarity of other males to make a decision on how to react during a between-group encounter.

Dominant–subordinate relationships in hamsters: Sex differences in reactions to familiar opponents

In the majority of mammalian species, males are dominant over and more aggressive than females. In contrast, some reports suggest that female golden hamsters are more aggressive than males but systematic comparisons using the same methods for both sexes are rare. We observed same-sexed pairs of hamsters over repeated trials to assess whether sex differences existed in the level of agonistic behavior and in the development and maintenance of dominant–subordinate relationships with familiar partners. There were no sex differences in measures of agonistic behavior or fear responses (fleeing) during the initial series of three trials on the first day of testing. Following a four-day interval, males that had lost in session 1 showed fearful responses to a familiar dominant male and were not likely to engage in a fight with him. In contrast, females that lost the initial fights were not fearful and fought vigorously with the familiar winner in subsequent encounters. Although the amount of agonistic behavior engaged in by females did decrease over the course of the three sessions, females that lost did not demonstrate an increase in fear, as measured by the latency to flee. Males that lost fights did show increased fear during later trials and sessions. These results suggest that female hamsters are less affected by losing fights than males are and thus that females are less likely than males to develop highly polarized dominant–subordinate relationships. Further work is needed to understand the mechanisms underlying these sex differences.