Cooperative Group Behavior Research Articles

When multi-group selection meets mystery of cooperation in structured public goods games.

Cooperation is the cornerstone of social stability and human development. In order to promote mutual cooperation among individuals, some researchers analyzed the important factors influencing individual behavior from the perspective of group selection, while others revealed the evolutionary mechanism of cooperative behavior in groups from the perspective of network reciprocity. However, group selection and network reciprocity actually work together and simultaneously drive individuals to cooperate with each other. Analyzing each mechanism in isolation provides an incomplete understanding of the interaction process. Inspired by this, we integrate the coupled effects of both group selection and network reciprocity on the behavior of individuals. We develop a structured public goods game model to study the evolution of individual cooperative behavior in multiple groups, where each individual can interact not only with intra-group individuals but also with inter-group individuals. Based on the fixed probabilities of multi-group selection, including intra-group and inter-group selection, we derive a general condition that promotes cooperation among individuals. Besides, we discuss the effects of the number of neighbors in a group, group size, and group size on the selection of cooperative behavior. Finally, we systematically compare our model with the well-mixed case, and the results show that a structured population enhances cooperation. Increasing the number of populations boosts the fixation probability of cooperation. To the best of our knowledge, this paper is the first to study the cooperative evolutionary dynamics of multi-group selection in structured populations through public goods games.

The influence of experienced guider on cooperative behavior in the Prisoner’s dilemma game

In game theory, it is an essential topic to study the emergence and maintenance of cooperative behavior in groups based on the theories of evolutionary game and complex network. Unfortunately, an in-depth analysis of cooperative behavior on maintenance and development is usually challenged by the diversity of groups in society, which is mainly caused by the single mechanism in traditional networks. More recent studies have shown that multi-layer coupled network based evolutionary game theory is promising in exploiting the transmission of cooperative behavior between individuals in the game. Meanwhile, inspired by the decisive ability of reinforcement learning in overcoming the limitation of replica, in this work, we propose to combine the game strategy of reinforcement learning with the traditional prisoner’s dilemma strategy based on multiple coupled networks. The most advantage of this model is the improved capability of intelligent decision making for group behaviors. With the simulation of game evolution, the influence of individual strategy change, as well as individual ability on cooperative behavior in reinforcement learning, is also explored. Substantial validations have verified that in social dilemmas, the cooperative behavior can be maintained by adjusting the group’s ability with effective guidance.

Cooperative rescue of a juvenile capuchin (Cebus imitator) from a Boa constrictor

The threat of predation by snakes is considered to have played a significant role in the evolution of primate sensory systems and behavior. However, we know relatively little about individual and group responses given the rarity of observed predation events. Here we report an observed (filmed) predation attempt by an adult Boa constrictor (~ 2 m) on a juvenile white-faced capuchin (Cebus imitator) in the Sector Santa Rosa of the Área de Conservación Guanacaste, Costa Rica. The snake caught the juvenile monkey on the ground during a terrestrial play session. When the victim screamed, the alpha male, alpha female, and another adult female ran to the scene, physically attacked the snake (with bites and hits), and pulled the victim to safety. Most group members participated in the vocal mobbing of the snake both during and after the attack. Based on the outcomes of this predation attempt and published reports of other B. constrictor attacks on primates, the coordinated efforts of ≥ 2 group members is needed for a successful rescue. This observation adds to our growing knowledge of cooperative group behavior and its importance in predator defense.

Public Goods Games on Coevolving Social Network Models

Public good games are a metaphor for modeling cooperative behavior in groups in the presence of incentives to free ride. In the model presented here agents play a public good game with their neighbors in a social network structure. Agents' decision rules in our model are inspired by elementary learning observed in laboratory and online behavioral experiments involving human participants with the same amount of information, i.e., when individuals only know their own current contribution and their own cumulated payoff. In addition, agents in the model are allowed to severe links with groups in which their payoff is lower and create links to a new randomly chosen public goods game. Reinforcing the results obtained in network scenarios where agents play Prisoner's Dilemma games, we show that thanks to this relinking possibility, the whole system reaches higher levels of average contribution with respect to the case in which the network cannot change. Our setup opens new frameworks to be investigated, and potentially confirmed, through controlled human experiments.

Microbial biofilms—Development, behaviour and therapeutic significance in oral health

Background: Biofilms are communities of microorganisms that are found attached to a surface. They develop on both biotic and abiotic surfaces and could act as a source of infection. The formation of biofilm involves the population of bacteria in an extracellular matrix exhibiting a cooperative group behavior. It is a dynamic process that involves adhesion, growth mobility, and extracellular matrix production with both cells and the environment contributing to the formation of this matrix material. The biofilm exhibits unique properties of protecting itself from host defenses and desiccation, persistence in the flowing system, heterogeneity, spatial organization, and resistance to antimicrobial agents through its ability to influence gene expression and phenotype. Quorum sensing, a means of a cell to cell communication is closely interconnected to the development of biofilm formation and inhibition. Dental plaque is the most common and well known oral biofilm. The preponderance of biofilm-associated diseases and its resistance in eradication has potentiated the need for further research in this field. Purpose: The purpose of this review is to create an awareness of the dentist on biofilms, its mode of formation, and the effect of biofilms on oral health. A comprehensive search of all literature on biofilms pertaining to oral health using literary search engines like PubMed and PubMed central has been taken into account in reviewing the pathogenesis and significance of biofilms in this article.

Dissimilarity-driven behavior and cooperation in the spatial public goods game

In this paper, we explore the impact of four different types of dissimilarity-driven behavior on the evolution of cooperation in the spatial public goods game. While it is commonly assumed that individuals adapt their strategy by imitating one of their more successful neighbors, in reality only very few will be awarded the highest payoffs. Many have equity or equality preferences, and they have to make do with an average or even with a low payoff. To account for this, we divide the population into two categories. One consists of payoff-driven players, while the other consists of dissimilarity-driven players. The later imitate the minority strategy in their group based on four different dissimilarity-driven behaviors. The rule that most effectively promotes cooperation, and this regardless of the multiplication factor of the public goods game, is when individuals adopt the minority strategy only when their payoff is better than that of their neighbors. If the dissimilarity-driven players adopt the minority strategy regardless of the payoffs of others, or if their payoff is the same, the population typically evolves towards a neutral state where cooperators and defectors are equally common. This may be beneficial when the multiplication factor is low, when defectors would otherwise dominate. However, if the dissimilarity-driven players adopt the minority strategy only when their payoff is worse than that of their neighbors, then cooperation is not promoted at all in comparison to the baseline case in the absence of dissimilarity-driven behavior. We explore the pattern formation behind these results, and we discuss their wider implications for the better understanding of cooperative behavior in social groups.

Cooperative Group Behavior Research Based on Lattice

Cooperative Group Behavior Research Based on Lattice

Social context reveals gender differences in cooperative behavior

A number of previous researches indicate that men prefer competition over cooperation, and it is sometimes suggested that women show the opposite behavioral preference. In the current study the effects of social context on gender differences in cooperation are investigated. For the purpose, we compared men and women behavior under two social conditions: in groups of strangers and in groups with long-term socialization—groups of friends. The differences were found in changes in the level of cooperation, taking into account the effects of mixing social and gender variables. Social interaction and communication made cooperation of group members strength and sustainable. However, men’s and women’s cooperative behavior in groups differed. Women were initially more inclined to cooperate in interaction with strangers. Men showed greater sensitivity to sociality effects. They tended to make cooperative decisions more often if there were friends in the group. Furthermore, men cooperated with previously unknown people after socialization with them significantly more than women.

Steinbeck: Citizen Spy. The Untold Story of John Steinbeck and the CIA

Steinbeck: Citizen Spy. The Untold Story of John Steinbeck and the CIA

Replicator dynamics of reward & reputation in public goods games

Public goods games have become the mathematical metaphor for game theoretical investigations of cooperative behavior in groups of interacting individuals. Cooperation is a conundrum because cooperators make a sacrifice to benefit others at some cost to themselves. Exploiters or defectors reap the benefits and forgo costs. Despite the fact that groups of cooperators outperform groups of defectors, Darwinian selection or utilitarian principles based on rational choice should favor defectors. In order to overcome this social dilemma, much effort has been expended for investigations pertaining to punishment and sanctioning measures against defectors. Interestingly, the complementary approach to create positive incentives and to reward cooperation has received considerably less attention—despite being heavily advocated in education and social sciences for increasing productivity or preventing conflicts. Here we show that rewards can indeed stimulate cooperation in interaction groups of arbitrary size but, in contrast to punishment, fail to stabilize it. In both cases, however, reputation is essential. The combination of reward and reputation result in complex dynamics dominated by unpredictable oscillations.

More than a signal: non-signaling properties of quorum sensing molecules

Quorum sensing in bacteria serves as an example of the adaptation of single-celled organisms to engage in cooperative group behaviors. This phenomenon is much more widespread than originally thought, with many different species 'speaking' through various secreted small molecules. Despite some variation in signaling molecules, the principles of quorum sensing are conserved across a wide range of organisms. Small molecules, secreted into the environment, are detected by neighbors who respond by altering gene expression and, as a consequence, behavior. However, it is not known whether these systems evolved specifically for this purpose, or even if their role is exclusive to information trafficking. Rather, clues exist that many quorum sensing molecules function as more than just signals. Here, we discuss non-signaling roles for quorum sensing molecules in such important processes as nutrient scavenging, ultrastructure modification and competition.

Natural strategies for search

In recent years a considerable amount of natural computing research has been undertaken to exploit the analogy between, say, searching a given problem space for an optimal solution and the natural process of foraging for food. Such analogies have led to useful solutions in areas such as optimisation, prominent examples being ant colony systems and particle swarm optimisation. However, these solutions often rely on well defined fitness landscapes that are not always be available in more general search scenarios. This paper surveys a wide variety of behaviours observed within the natural world, and aims to highlight general cooperative group behaviours, search strategies and communication methods that might be useful within a wider computing context, beyond optimisation, where information from the fitness landscape may be sparse, but new search paradigms could be developed that capitalise on research into biological systems that have developed over millennia within the natural world.

지역적 통신과 인공면역계에 기반한 군집 로봇의 협조 전략과 군 행동

군집 로봇시스템에서 협조 행동을 위기 위해서는 로봇의 센싱과 통신 기능은 필수적이다. 일반적으로 대역적 통신 시스템에서는 로봇의 대수가 증가하면 통신 자원의 제한과 정보의 범람이 발생한다. 따라서 이 경우 지역적 통신방법이 유리하다. 따라서 본 논문에서는 지역적 통신에 의한 정보의 전파 해석을 통하여 최적의 통신 반경을 결정하는 방법을 제안하고, 이를 이용하여 인공면역계에 기반한 군집 로봇시스템의 협조 전략과 군 행동 알고리즘을 제안한다. It is essential for robot to have the sensing and communication abilities in the swarm robot system. In general, as the number of robot goes on increasing, the limitation of communication capacity and information overflow occur in global communication system. Therefore a local communication is more effective than global one. In this paper, we propose the novel method for determining the optimal communication radius through the analyzing of the information propagation based on local communication. And we also propose a method of cooperative strategies and group behavior of swarm robot based on artificial immune system.

A swarm system design based on a modified particle swarm algorithm for a self-organizing scheme

In this paper, an attempt has been made to incorporate some special features in the conventional particle swarm optimization (PSO) technique for decentralized swarm agents. The modified particle swarm algorithm (MPSA) for the self-organization of decentralized swarm agents is proposed and studied. In the MPSA, the update rule of the best agent in a swarm is based on a proportional control concept and the fitness of each agent is evaluated on-line. The virtual zone is developed to avoid conflict among the agents. In this scheme, each agent self-organizes to flock to the best agent in a swarm and migrate to a moving target while avoiding obstacles and collision among agents. Aided by these advantages such as cooperative group behaviors, flexible formation and scalability, the proposed approach enables large-scale swarm agents to distribute themselves optimally for a given task. The simulation results have shown that the proposed scheme effectively constructs a self-organized swarm system with the capability of flocking and migration.

NAROSOT – NANOTECHNOLOGY IN ROBOT SOCCER

Robot soccer is a good opportunity to implement and test the cooperative group behavior of mobile robots. There are several categories based on the size of the robot. In this contribution a robot soccer system in the category of NaroSot (Nano Robosoccer Tournament) will be described. The maximum size of the robot in NaroSot category has to be smaller than 4 x 4 x 5.5 centimeters. It is a big challenge to build a robot in such a small size with two wheels, two DC motors, a microcontroller, a communication module, a battery pack and other parts. The robot should be stable and able to move with a maximum speed of 3.5 m/s and an acceleration 8m/s2. The hardware consists of the robots, the camera and the host computer. Software is necessary for image processing, communication, game strategies and control of the robots.In the paper the hard- as well as the software of the new “naro” robots, a new fast vision system with a digital camera is described. Furthermore an outlook on realized and future industrial applications of such extremely miniaturized robots will be given.

Commentary: On Segalla and Stone & Karterud

What these two papers share are the therapists’ attempts to help their groups overcome therapeutic impasses. Segalla explores two interrelated aspects of dynamic systems, affects and values, especially the therapist’s values, which she considers to be core elements in shaping group culture. One of her theses is that there is a delicate balance between the primacy of individual needs and that of the whole group and she emphasizes that group membership requires a capacity for cooperative group behavior. She cites Lichtenberg’s (1989) idea that the desire to affiliate, as in becoming a group member, entails a temporary relinquishment of the primacy of the self. I agree with her perspective that the balance between the needs of the individual and the whole group is uniquely determined by each group, a view that corresponds to my own ideas about the co–construction of interactional patterns and meaning (Feld, 2004). I think that the ideas of co–construction of interactive dyadic patterns and bi–directional and mutual regulation systems (cf. Beebe & Lachmann, 2002), as well as triadic regulatory systems like the family (cf. Fivaz–Depeursinge & Corboz-Warnery, 1999), can be helpful when applied to the highly complex system of the small group. In group life, there are multiple dyads and triads, all of which can help to regulate affect and provide its members with new and different experiences of relatedness and opportunities for greater flexibility in the capacities for responsiveness and regulation of affect. Each member of the group shapes and is shaped by the others, either as individ-

VISION SYSTEM AND GAME – STRATEGIES FOR ROBOTSOCCER

The game robot soccer provides a good opportunity to implement and test the cooperative group behavior of mobile robots. In this contribution a robot soccer system (Kopacek, 2002; Putz, 2004; Würzl, 2003 and 2005) will be described. The new software mainly consists, as usual, of a vision system, a communication module and a game strategy module. For the new system robots were developed and a vision system with a digital camera was implemented. The strategies for this new Multi Agent System (MAS) will be highlighted in this paper.

Patterns of participation and free riding in territorial conflicts among ringtailed lemurs (Lemur catta)

Cooperation in animal social groups may be limited by the threat of “free riding,” the potential for individuals to reap the benefits of other individuals’ actions without paying their share of the costs. Here we investigate the factors that influence individual contributions to group-level benefits by studying individual participation in territorial defense among female ringtailed lemurs (Lemur catta). To control for potentially confounding factors, particularly group size, we studied two semi-free-ranging groups at the Duke University Primate Center. First, we used a combination of experimental and observational methods to investigate the costs and benefits of territorial defense for individual lemurs. We found three indications of costs: physical contact occurred during inter-group encounters, participation in territorial defense was negatively correlated with ambient temperature, and rates of self-directed behaviors increased during encounters. Benefits were more difficult to quantify, but observational and experimental tests suggested that individuals shared the gains of territorial defense by foraging in defended territories. Thus, during experiments in which one of the groups was prevented from defending its territory, the free-ranging group made more frequent incursions into the other group’s territory. Second, we examined variation in participation in territorial defense. Individuals varied significantly in their rates of aggression and genital marking during inter-group encounters. The extensive variation documented among individuals was partially accounted for by dominance rank, kinship and patterns of parental care. However, we found no evidence to suggest that participation was enforced through punishment (policing) or exchange of benefits involving grooming. In conclusion, this study provides further insights into cooperative behavior in mammalian social groups by revealing how the costs and benefits of territoriality influence patterns of individual participation in the context of shared (collective) goods.

The Residual Effects of Cooperative-Learning Experiences: A Two-Year Follow-Up

The author investigated how training in small-group and interpersonal behaviors affected children's behavior and interactions as they worked in small groups 2 years later. The authors assigned 52 fifth graders, who had been trained 2 years previously in cooperative group behaviors, to the trained condition and 36 fifth graders, who had not previously been trained, to the untrained condition. Both were reconstituted from the pool of students who had participated previously in group activities. The results showed a residual training effect, with the children in the trained groups being more cooperative and helpful than their untrained peers.

The Long‐term Effects of Cooperative Learning on Children's Behaviour and Interactions

This study investigates the long‐term effects of training in small‐group and interpersonal behaviours on children's behaviours and interactions as they worked in small groups two years after they were initially trained. Forty‐eight third grade children, who had been trained two years previously in cooperative group behaviours, were assigned to the Trained condition and 44 third grade children who had not previously been trained were assigned to the Untrained condition. The children in the trained and untrained groups were reconstituted from the pool of students who had participated previously in either trained or untrained group activities. The results showed that there was a long‐term training effect with the children in the Trained groups demonstrating more cooperative behaviour and providing more explanations in response to requests for help than their untrained peers.