Forms Of Collective Behavior Research Articles

Mosquito swarms shear harden

Recently Cavagna et al. (Sci Rep 13(1): 8745, 2023) documented the swarming behaviors of laboratory-based Anopheles gambiae mosquitoes. Here key observations from this 3D-video tracking study are reproduced by a minimally structured (maximum entropy) stochastic trajectory model. The modelling shows that in contrast with midge swarms which are a form of collective behavior, unperturbed mosquito swarms are more like collections of individuals that independently circulate around a fixed location. The modelling predicts the observed response Anopheles gambiae mosquitoes in wild swarms to varying wind speeds (Butail et al. in J Med Entomol 50(3): 552–559, 2013). It is shown that this response can be attributed to shear hardening. This is because mosquitoes are found to be attracted to the centre of the swarm by an effective force that increases with increasing flight speed. Mosquitoes can therefore better resist the influence of environmental disturbances by increasing their flight speeds. This contrasts with other emergent mechanical-like properties of swarming which arise accidentally without a change in an individual’s behavior. The new results add to the growing realization that perturbations can drive swarms into more robust states.

Interaction-motif-based classification of self-organizing metabolic cycles

Particles that are catalytically-active and chemotactic can interact through the concentration fields upon which they act, which in turn may lead to wide-scale spatial self-organization. When these active particles interact through several fields, these interactions gain an additional structure, which can result in new forms of collective behavior. Here, we study a mixture of active species which catalyze the conversion of a substrate chemical into a product chemical, and chemotax in concentration gradients of both substrate and product. Such species develop non-reciprocal, specific interactions that we coarse-grain into attractive and repulsive, which can lead to a potentially complex interaction network. We consider the particular case of a metabolic cycle of three species, each of which interacts with itself and both other species in the cycle. We find that the stability of a cycle of species that only chemotax in gradients of their substrate is piloted by a set of two parameter-free conditions, which we use to classify the low number of corresponding interaction networks. In the more general case of substrate- and product-chemotactic species, we can derive a set of two high-dimensional stability conditions, which can be used to classify the stability of all the possible interaction networks based on the self- and pair-interaction motifs they contain. The classification scheme that we introduce can help guide future studies on the dynamics of complex interaction networks and explorations of the corresponding large parameter spaces in such metabolically active complex systems.

On the Issue of Social Movement Definition

The paper is a theoretical review of “social movement” term definitions. Aiming to show differences among definitions within different paradigms and scientific evolution of the term the main approaches of defining social movements are discussed. Initially, social movements were studied by psychologists, who were examining different forms of collective behavior, such as mobs, crowds, protests and etc. Most of them considered social movements as an irrational and destructive form of collective action driven by the instincts of people. During the next decades, the theory of social movements was developed mostly by sociologists who, on the contrary, started to seek social reasons inducing this type of collective action. Different theoretical schools proposed various concepts of explaining the origin of social movements, but all of them agreed on the main characteristics: rational and organized collective action driven by unfulfilled social needs. Different authors linked social movement definitions with other important social phenomena such as norms and values, social conflict, social identity, and social network. Political scientists have also contributed to the study of social movements but in terms of power and state, terrorism and violence. Discussing psychological, sociological, and political science approaches to term definition we came to the conclusion that the most inclusive sociological definition is viewing social movement as a social network through which collective action is performed to achieve total or partial social change. Such kind of definition makes it possible to reveal the main criteria necessary to distinguish social movement as a separate social phenomenon from other types of collective action.

Goals and Limitations of Modeling Collective Behavior in Biological Systems

Local social interactions among individuals in animal groups generate collective behavior, allowing groups to adjust to changing conditions. Historically, scientists from different disciplines have taken different approaches to modeling collective behavior. We describe how each can contribute to the goal of understanding natural systems. Simple bottom-up models that describe individuals and their interactions directly have demonstrated that local interactions far from equilibrium can generate collective states. However, such simple models are not likely to describe accurately the actual mechanisms and interactions in play in any real biological system. Other classes of top-down models that describe group-level behavior directly have been proposed for groups where the function of the collective behavior is understood. Such models cannot necessarily explain why or how such functions emerge from first principles. Because modeling approaches have different strengths and weaknesses and no single approach will always be best, we argue that models of collective behavior that are aimed at understanding real biological systems should be formulated to address specific questions and to allow for validation. As examples, we discuss four forms of collective behavior that differ both in the interactions that produce the collective behavior and in ecological context, and thus require very different modeling frameworks. 1) Harvester ants use local interactions consisting of brief antennal contact, in which one ant assesses the cuticular hydrocarbon profile of another, to regulate foraging activity, which can be modeled as a closed-loop excitable system. 2) Arboreal turtle ants form trail networks in the canopy of the tropical forest, using trail pheromone; one ant detects the volatile chemical that another has recently deposited. The process that maintains and repairs the trail, which can be modeled as a distributed algorithm, is constrained by the physical configuration of the network of vegetation in which they travel. 3) Swarms of midges interact acoustically and non-locally, and can be well described as agents moving in an emergent potential well that is representative of the swarm as a whole rather than individuals. 4) Flocks of jackdaws change their effective interactions depending on ecological context, using topological distance when traveling but metric distance when mobbing. We discuss how different research questions about these systems have led to different modeling approaches.

Body Size and Behavioural Plasticity Interact to Influence the Performance of Free-Foraging Bumble Bee Colonies.

Simple SummaryBehavioural specialisation of individuals may improve the performance of groups, but could also limit the ability to switch tasks (behavioural ‘plasticity’) in response to changing group needs. In bumble bee colonies, body size, which is fixed once the bees reach adulthood, influences the tasks that bees perform, meaning that large and small bees often act as specialists. We found that when we experimentally reduced the body-size variation of colonies, some performed less well than normal. Nonetheless, in other colonies, individuals increased task specialisation or effort, which apparently compensated for the absence of large and small workers. These results suggest that both behavioural specialisation and plasticity can be important in collective group performance.Specialisation and plasticity are important for many forms of collective behaviour, but the interplay between these factors is little understood. In insect societies, workers are often developmentally primed to specialise in different tasks, sometimes with morphological or physiological adaptations, facilitating a division of labour. Workers may also plastically switch between tasks or vary their effort. The degree to which developmentally primed specialisation limits plasticity is not clear and has not been systematically tested in ecologically relevant contexts. We addressed this question in 20 free-foraging bumble bee (Bombus terrestris) colonies by continually manipulating colonies to contain either a typically diverse, or a reduced (“homogeneous”), worker body size distribution while keeping the same mean body size, over two trials. Pooling both trials, diverse colonies produced a larger comb mass, an index of colony performance. The link between body size and task was further corroborated by the finding that foragers were larger than nurses even in homogeneous colonies with a very narrow body size range. However, the overall effect of size diversity stemmed mostly from one trial. In the other trial, homogeneous and diverse colonies showed comparable performance. By comparing behavioural profiles based on several thousand observations of individuals, we found evidence that workers in homogeneous colonies in this trial rescued colony performance by plastically increasing behavioural specialisation and/or individual effort, compared to same-sized individuals in diverse colonies. Our results are consistent with a benefit to colonies of large and small specialists under certain conditions, but also suggest that plasticity or effort can compensate for reduced (size-related) specialisation. Thus, we suggest that an intricate interplay between specialisation and plasticity is functionally adaptive in bumble bee colonies.

Collective behavior in a two-layer neuronal network with time-varying chemical connections that are controlled by a Petri net.

In this paper, we propose and study a two-layer network composed of a Petri net in the first layer and a ring of coupled Hindmarsh-Rose neurons in the second layer. Petri nets are appropriate platforms not only for describing sequential processes but also for modeling information circulation in complex systems. Networks of neurons, on the other hand, are commonly used to study synchronization and other forms of collective behavior. Thus, merging both frameworks into a single model promises fascinating new insights into neuronal collective behavior that is subject to changes in network connectivity. In our case, the Petri net in the first layer manages the existence of excitatory and inhibitory links among the neurons in the second layer, thereby making the chemical connections time-varying. We focus on the emergence of different types of collective behavior in the model, such as synchronization, chimeras, and solitary states, by considering different inhibitory and excitatory tokens in the Petri net. We find that the existence of only inhibitory or excitatory tokens disturbs the synchronization of electrically coupled neurons and leads toward chimera and solitary states.

Collectivity, connectivity and control: reframing mass society in the digital era

ABSTRACT Mass society theory was originally a discourse on crowds, popular culture and revolutionary change. It portrayed the ideological control of the many by the few in situations of close contact without the complexities of mediated connectivity. The notion of social change was premised on analogue forms of collective behaviour within society rather than digital flows in networks. Reviving this theory in the digital era requires a reconsideration of connectivity and control transacted in mediated publics that support virtual gatherings centred on mass- self communication. Smartphones may be considered the iconic connectors that channel such communication. These electronic devices provide a vital understanding not only of the way information and communication technology is reshaping mass society but also the repositioning of the individual in networked relationships. It implies that mass in digitized environments is not simply a concept of nameless uniformity but one stressing the parasitic nature of networked connectivity. At the same time, it also suggests a connectivity made fragile by forms of remote control that are predatory on mass-self communication.

VELOCITY-BASED EGRESS MODEL FOR THE ANALYSIS OF EVACUATION PROCESS ON PASSENGER SHIPS

This study presents a velocity-based egress model, which takes into account different aspects of human behavior in an emergency situation, for the evacuation analysis on passenger ships. It was supposed that the egress model consists of three behaviors: individual, crowd, and emergency behavior. The individual behavior was represented by the body shape, walking speed, walking direction, and rotation of each passenger. The basic walking direction of each passenger was obtained as a solution to the shortest distance route to a destination using a visibility graph. The crowd behavior of the passengers was composed of two components: one is a flock behavior, a form of collective behavior of a large number of interacting passengers with a common group objective, and the other is a leader- following behavior, which causes one or more passengers to follow another moving passenger who is designated as the leader. The emergency behavior of the passengers was represented by a counterflow-avoiding behavior to avoid collision with other passengers walking in the opposite direction. Eleven basic tests and 2 examples specified in International Maritime Organization Maritime Safety Committee/Circulation 1238 were conducted, and it was confirmed that all the requirements of such tests had been met.

Opinion Formation by Social Influence: From Experiments to Modeling.

Predicting different forms of collective behavior in human populations, as the outcome of individual attitudes and their mutual influence, is a question of major interest in social sciences. In particular, processes of opinion formation have been theoretically modeled on the basis of a formal similarity with the dynamics of certain physical systems, giving rise to an extensive collection of mathematical models amenable to numerical simulation or even to exact solution. Empirical ground for these models is however largely missing, which confine them to the level of mere metaphors of the real phenomena they aim at explaining. In this paper we present results of an experiment which quantifies the change in the opinions given by a subject on a set of specific matters under the influence of others. The setup is a variant of a recently proposed experiment, where the subject’s confidence on his or her opinion was evaluated as well. In our realization, which records the quantitative answers of 85 subjects to 20 questions before and after an influence event, the focus is put on characterizing the change in answers and confidence induced by such influence. Similarities and differences with the previous version of the experiment are highlighted. We find that confidence changes are to a large extent independent of any other recorded quantity, while opinion changes are strongly modulated by the original confidence. On the other hand, opinion changes are not influenced by the initial difference with the reference opinion. The typical time scales on which opinion varies are moreover substantially longer than those of confidence change. Experimental results are then used to estimate parameters for a dynamical agent-based model of opinion formation in a large population. In the context of the model, we study the convergence to full consensus and the effect of opinion leaders on the collective distribution of opinions.

Multicellular agency: an organizational view

We argue that the transition from unicellular to multicellular (MC) systems raises important conceptual challenges for understanding agency. We compare several MC systems (from bacterial swarms to colonies and plants, and to lower metazoans) displaying different forms of collective behavior, and we analyze whether these actions can be considered organismically integrated and attributable to the whole. We distinguish between a ‘constitutive’ and an ‘interactive’ dimension of organizational complexity, and we argue that MC agency requires a radical entanglement between the related processes which we call “the constitutive-interactive closure principle”. We explain in detail that this is not possible without a regulatory center functionally integrating the two dimensions, and we also argue that, in turn, this type of regulation would not be possible without a special type of organization between the cells required for the development and maintenance of systems capable of integrated behavior.

Fast, high-throughput measurement of collective behaviour in a bacterial population.

Swimming bacteria explore their environment by performing a random walk, which is biased in response to, for example, chemical stimuli, resulting in a collective drift of bacterial populations towards 'a better life'. This phenomenon, called chemotaxis, is one of the best known forms of collective behaviour in bacteria, crucial for bacterial survival and virulence. Both single-cell and macroscopic assays have investigated bacterial behaviours. However, theories that relate the two scales have previously been difficult to test directly. We present an image analysis method, inspired by light scattering, which measures the average collective motion of thousands of bacteria simultaneously. Using this method, a time-varying collective drift as small as 50 nm s(-1) can be measured. The method, validated using simulations, was applied to chemotactic Escherichia coli bacteria in linear gradients of the attractant α-methylaspartate. This enabled us to test a coarse-grained minimal model of chemotaxis. Our results clearly map the onset of receptor methylation, and the transition from linear to logarithmic sensing in the bacterial response to an external chemoeffector. Our method is broadly applicable to problems involving the measurement of collective drift with high time resolution, such as cell migration and fluid flows measurements, and enables fast screening of tactic behaviours.

Granular matter and networks: three related examples

Granular matter is broadly defined as the class of materials composed of large numbers of discrete solid particles or grains, where the grains are large enough so that they do not suffer thermal fluctuations, and with a cut-off size being approximately one micron. On first viewing granular matter constitutes a simpler class of matter than soft matter, since quantum effects and temperature play no role. This view, however, is misleading. Granular matter displays a rich set of behaviors and serves as a test-bed for an array of complex systems tools with a potentially wide range of applicability that goes well outside the realm of granular materials and can be extended to concentrated emulsions and pastes. It may be argued that some of the mathematical representations of complex systems, such as networks or agent-based representations, are but charicatures of the actual systems. However, it is undeniably true that some representations have the power to transcend disciplines. Consider for example the highly idealized model of segregation in cities by Thomas Schelling, the co-winner of the 2005 Nobel Memorial Prize for Economic Science. In his book Micromotives and Macrobehavior (WW Norton, New York, 2006) Schelling considers many forms of collective behavior. In one of them, dealing with segregation in cities, a city is represented by a square grid and individuals by colors, say red and green. Green individuals have a degree of tolerance towards red, and red towards green. The surprise is that even if individuals are tolerant the result is a macroscopically segregated system with structures representing spinodal decomposition. And that is precisely the point: someone looking at this problem in social sciences with the perspective of material scientist and spinodal decomposition may have anticipated the qualitative aspects of the result. This short article considers three topics in granular physics, connected though a networks approach, starting with small scales and moving progressively towards larger scales. Although these topics can, in principle, be studied from a more traditional perspective, one finds that the networks viewpoint can inspire new analysis techniques, provide new clues as to the underlying phenomena and generate new, broad interpretations of results that might not always be gained from the more traditional viewpoints.

Superconductivity Near Ferromagnetism in MgCNi3

AbstractSuperconductivity and ferromagnetism have been believed to be incompatible over any extended temperature range until certain specific examples - RuSr2GdCu2O8 and UGe2- have arisen in the past 2-3 years. The discovery of superconductivity above 8 K in MgCNi3, which is primarily the ferromagnetic element Ni and is strongly exchange-enhanced, provides a probable new and different example. This compound is shown here to be near ferromagmnetism, requiring only hole-doping by 12% substitution of Mg by Na or Li. This system will provide the means to prode coupling, and possible coexistence, of these two forms of collective behavior without the requirement of pressure.

Reflections on Social Movement Theory: Criticisms and Proposals

The arrival of a new century and a new millennium are attention-grabbing symbolic markers. They provide a convenient opportunity for me to reflect critically on the current status of social movement theory. Because of space limitations, it is impossible to provide a comprehensive review and critique of this burgeoning field. I focus here on what I contend are serious blind spots within current social movement theory. I argue that these theories continue to slight the role that human agency plays in social movements. The slight occurs because assumptions in current theory lead its proponents to gloss over fundamental sources of agency that social movement groups can bring to the mobilization process, cultural framing, tactical problems, movement leadership, protest histories, and transformative events. I address the human agency and these movement phenomena, and offer correctives. By the mid-twentieth century, collective behavior and related theories constituted the dominant paradigm that guided research of social movements. These theories argued that social movements were a form of collective behavior that emerged when significant social and cultural breakdowns occurred. As a form of collective behavior, social movements were considered spontaneous, unorganized, and unstructured phenomena that were discontinuous with institutional and organizational behavior

Wave propagation along interacting fiber-like lattices

A fiber-like lattice with resistively coupled electronic elements mimicking a 1-D discrete reaction-diffusion system is considered. The chosen unit or element in the fiber is the paradigmatic Chua’s circuit, capable of exhibiting bistable, excitable, oscillatory or chaotic behavior. Then the dynamics of a structure of two such interacting parallel active fibers is studied. Suitable conditions for the interaction to yield synchronization and other forms of collective behavior involving both fibers are obtained. They include wave front propagation, pulse reentry and pulse propagation failure, overcoming of propagation failure, and the appearance of a source of synchronized pulses. The possibility of designing controlled dynamic contacts by means of one or a few inter-fiber couplings is also discussed.

How Not to Murder Your Neighbor: Using Synthetic Behavioral Ecology to Study Aggressive Signaling

The scientific account of intraspecific aggressive signaling is incomplete. In part, this is because it is difficult to identify the consequences (for the nature of signaling systems) of the different ecological contexts in which signaling has developed. The goal of our investigation is to complement the ongoing work in the biological sciences on this issue. Using a theoretical framework that we call synthetic behavioral ecology, we perform a series of experiments involving populations of simulated animals (animats) that, in their simulated world, must compete for food. When animats pick up reliable information about the "strength" of other animats within sensory range, a coherent form of collective behavior develops, which we call minimal territoriality. We then introduce the signaling of aggressive intentions. Each individual has a bluffing strategy that is determined by a form of artificial evolution in which there is no explicit fitness function. By varying, in energy terms, the cost of producing aggressive signals, and by analyzing the population dynamics at different costs of signaling, we are able to provide evidence that the handicap principle (according to which higher costs enforce honesty) can apply in multiagent ecologies. We then suggest how variations in the cost of signaling affect the territorial behavior. The article ends with a discussion of the current model and identification of some directions for future research.

Maghrebi Immigration to Europe: Double Insertion or Double Exclusion?

In Europe, Islam became a significant form of collective behavior among migrants from the Maghreb, Turkey, Western Africa, and India during the 1970s, when that group of people decided to settle abroad and raise their children in what they considered, at the beginning, to be a lasting exile. In that way, Islam appeared as an instrument for building new identities and transnational solidarities for the purpose of negotiating with the states and societies of settlement. But that peaceful approach has been taken as an unacceptable challenge by secular societies, which are no longer used to dealing with religious values as a way of collective self-assertion. In a future open Europe that will include 5 to 6 million Muslims, it will be necessary to establish a new doctrinal framework of cultural pluralism that includes Islam.

Italian Sociology and the Study of Social Movements

The article critically assesses the contribution of Italian sociology to the study of social movements in the last twenty years. These years nearly cover the “institutional life-cycle” of the discipline. In order to help the reader place the study of social movements within the mainstream of Italian sociology, some information is provided about its historical development and academic status, even in relation to political and cultural trends in overall society. Tracing the history of social movements studies back to it origins, the author shows how it has diverged from the American tradition, in particular as far as its relation to the study of other forms of collective behavior is concerned. In an extensive review of both theoretical and empirical contributions, the author points out what she sees as the main merits and faults of Italian scholars. The former include attention to theorization in the field of both conventional and collective behavior and preference for multi-factored models of explanation. Among the latter, are unsatisfactory attempts to build general testable theories, and lack of empirical research. Contributions are analysed with regard to different aspects of social movements: formation, mobilization and recruitment, ideology and organization, politics and outcomes. Pointing out achievements and failures of Italian analysts, the author arrives at some general rather optimistic conclusions about future developments, in both theory and research.

Fear of the drunk driver: Analysis of an emergent social problem

This paper analyzes public perceptions of drunk driving with respect to risk of being victimized, seriousness of the offense, and fear of being victimized. This is based on a state‐wide survey of Louisiana driver's license holders. Compared to other crimes, even murder and rape, it was found that drunk driving ranked highest in its fear invoking quality. An argument is made that this phenomenon should be interpreted from a theoretical standpoint viewing the crimi‐nalization process as a form of collective behavior. Implications for understanding fear of crime as a function of perceived risk and seriousness are discussed, and the implications of the findings for understanding of further legislation and policy action against drunk driving is examined.

The Origins of the Civil Rights Movement: Black Communities Organizing for Change.

This important and provocative book reflects a trend in recent scholarship concerning the modern struggles for black advancement. Scholars have increasingly moved from a national to a local perspective in their effort to understand the momentous changes in American racial relations since 1954. The newer scholarship has begun to examine the distinctive qualities of the local black movements that both grew out of and spurred the campaign for national civil rights laws. Earlier studies have told us much about nationally prominent civil rights leaders such as King, but only recently have scholars begun to portray the southern black struggle as a locally based social movement with its own objectives instead of merely as a source of mass enthusiasm to be mobilized and manipulated by the national leaders. In short, what has been called the civil rights movement is now understood as more than an effort to achieve civil rights reforms. Revisionist scholarship such as Morris's has challenged many widely held assumptions regarding black activism of the 1950's and 1960's. In the 1960's, black activism was usually categorized with other forms of collective behavior, which were seen as ephemeral outbursts of emotions. In this view, protest activity was an expression of the yearning of blacks to realize a longstanding civil rights reform agenda and thereby become part of the American mainstream. While recognizing that black protesters were impatient with the pace of racial change and with the caution of NAACP leaders, scholars nevertheless assumed that the political significance of mass militancy was limited. Mass militancy merely gauged integrationist sentiments among blacks and allowed national civil rights leaders to demonstrate the urgency of their concerns. Only such leaders, it was assumed, possessed the political sophistication and access to institutionalized power that was necessary to transform amorphous racial frustrations and resentments into an effective force for social reform. Most early studies of the civil rights movement gave little at-