Inter-individual Interactions Research Articles

Regimes of collective logic

PurposeThe study aims to reveal regularities of collective decision in groups of varying cooperativity and to investigate the influence of individualism–collectivism cultural dimension on the emergence of collective behavioral entities.Design/methodology/approachAn agent-based model of group behavior is used to simulate the logic of collective binary decisions defined by reaching a consensus threshold. The key parameter of the model is the cooperativity of interaction between individuals which locates the group in individualism–collectivism cultural dimension. The probabilities of collective decisions are measured as a function of individual preferences and the strength of cooperation between agents.FindingsStrong, weak and middle point cooperativities of inter-individual interaction define three distinct regimes of collective decision logic, namely, individualism, conformism and criticality. The critical organization allows the group to generate coherent non-predetermined collective behavior in statistical agreement with individual preferences.Research limitations/implicationsEmergent collective behavior with coherent and nondeterministic decision-making can be modeled in an agent-based approach with local interaction between individuals tuned to a critical point. Variation of a single cooperativity parameter accounts for a continuous transition between organizations of the group inherent to inert matter and living systems.Social implicationsA new organization of social systems distinguished by internally relaxed relations and large-scale freedom is found beyond the traditional individualism–collectivism contraposition. This state is reached by tuning behavioral logic of individuals to a critical balance of individual and collective values.Originality/valueIndividualist, conformist and critical regimes of collective organization distinct in terms of integrity, complexity and determinism are recognized as universal organizational classes of nature spanning both inert and living systems. In particular, individualist and conformist regimes produce simple deterministic behavior typical for gases and solid bodies, whereas the critical organization generates complex nondeterministic behavior inherent to living organisms.

Individual and group characteristics affecting nest building in sea lamprey (Petromyzon marinusL. 1758)

Nest building relates to reproductive effort, sexual selection, intersexual conflict and cooperation and may be linked to individual phenotype and interindividual interactions. In particular, larger individuals having more energy reserves are expected to build more, larger nests, without having to trade intrasexual competition for cooperative nest building. Capture-mark-recapture and nest survey of sea lamprey (Petromyzon marinus L. 1758) were combined to assess the relationship between individuals and nesting activity on a spawning ground, throughout a breeding season, during which 202 nests were observed and 114 individuals were captured. On average, males and females stayed 8.33 ± 1.02 and 3.57 ± 1.04 days on the spawning ground, visited 2.26 ± 1.72 and 1.67 ± 1.17 nests and encountered 2.33 ± 2.13 mates for males and 2.29 ± 1.32 mates for females, respectively, and the number of mates encountered increased with the number of nests visited. Body size had no effect on the duration of presence on spawning ground, number of nests visited, number of individuals per nest and sex ratio on nest or nest volume. Bigger nests were found at the end of the season and were not necessarily built by more individuals. This work brings insights on the mating system and cooperative nest building in sea lamprey and may inform managers who want to estimate sea lamprey populations via nest surveys.

Behavioral Teleporting of Individual Ethograms onto Inanimate Robots: Experiments on Social Interactions in Live Zebrafish.

SummarySocial behavior is widespread in the animal kingdom, and it remarkably influences human personal and professional lives. However, a thorough understanding of the mechanisms underlying social behavior is elusive. Integrating the seemingly different fields of robotics and preclinical research could bring new insight on social behavior. Toward this aim, we established “behavioral teleporting” as an experimental solution to independently manipulate multiple factors underpinning social interactions. Behavioral teleporting consists of real-time transfer of the complete ethogram of a live zebrafish onto a remotely-located robotic replica. Through parallel and simultaneous behavioral teleporting, we studied the interaction between two live fish swimming in remotely-located tanks: each live fish interacted with an inanimate robot that mirrored the behavior of the other fish, and the morphology of each robot was independently tailored. Our results indicate that behavioral teleporting can preserve natural interaction between two live animals, while allowing fine control over morphological features that modulate social behavior.

High-resolution behavioral time series of Japanese quail within their social environment

The behavioral dynamics within a social group not only could depend on individual traits and social-experience of each member, but more importantly, emerges from inter-individual interactions over time. Herein, we first present a dataset, as well as the corresponding original video recordings, of the results of 4 behavioral tests associated with fear and aggressive response performed on 106 Japanese quail. In a second stage, birds were housed with conspecifics that performed similarly in the behavioral tests in groups of 2 females and 1 male. By continuously monitoring each bird in these small social groups, we obtained time series of social and reproductive behavior, and high-resolution locomotor time series. This approach provides the opportunity to perform precise quantification of the temporal dynamics of behavior at an individual level within different social scenarios including when an individual showing continued aggressive behaviors is present. These unique datasets and videos are publicly available in Figshare and can be used in further analysis, or for comparison with existing or future data sets or mathematical models across different taxa.

THE CULTURAL FACTORS IN INTERGROUP RELATIONS IN THE MODERN WORLD (ON THE EXAMPLE OF RELIGIOUS AND ETHNIC GROUPS)

The problem of intergroup relations becomes very important nowadays. The cultural interactions of ethnic and religious groups are influenced by the processes of globalization and migration. Considering this problem philosophically is connected with the question of how a person determines his cultural identity. There is an opinion that the world develops on the basis of contradictions. However, globalization, along with positive functions, can generate new social conflicts and aggravate old ones. Cultural conflict as a type of social interaction can perform both positive and negative functions. Relations between religious groups deserve special attention. This type of intergroup relations is often characterized with conflicts. Many local religious conflicts have political reasons. A conflict may also arise between the state and a religious group. More than that, many new religious movements (NRMs) appear, and there is an open confrontation between the traditional religious confessions and the NRMs. The ethnic aspect of intergroup relations is also very topical. In this regard, the following paradox can be noted: the weakening of the ethnic properties of culture occurs simultaneously with the strengthening of ethnic self-consciousness. The number of ethnic groups, religions, and worldviews is rapidly increasing, and there is a transition from a homogeneous population to a pluralistic society. It can be concluded that the philosophical understanding of the processes of interaction between ethnic and religious groups is largely connected with the phenomenon of cultural self-identification. The way an individual identifies himself with this or that culture is determined by the context of intercultural interaction carried out between individuals. Depending on the situation of interindividual interaction, one or another person’s knowledge about him- or herself is actualized.

Propagating wave based on transition of interaction within animal group

Propagating waves, information transfers of direction of travel in collective groups, have been observed in animal groups of insects, birds, fish, and mammals. Nevertheless, although many previously proposed models of group behaviors have elucidated various aspects of collective motion, none has directly shown the propagating wave constructively. These models consisted of flocking algorithms in which individuals modify their positions or velocities through average responses to their neighbors. The algorithms involve the function of diluting local fluctuations, individual motions, or social cues that initiate coherent decision-making of where to travel and which spread through a group in the form of a wave. The present study challenged physics-inspired models based solely on average interaction and instead proposed a combination with pair interaction: the ‘copy’ mechanism. By the mechanism, individuals specially attend and mimic the motion of the largest turning neighbor. The model comprises three modes (base, copy, and align modes) that sequentially switch among themselves, depending on the degree of variance in direction. The model therefore involves propagating waves that produce rapid collective responses and quick turning motions of a group. This proposal is an attempt to uncover the mechanisms of self-organized waves in simulation studies of coordinated groups, without explicit signals such as alarm calls. Understanding such mechanisms is expected to contribute to the ‘collective mind’ metaphor, answering the question of how animal groups obtain higher-order computational capabilities from local inter-individual interactions.

Le traitement arthroscopique de l’epicondylalgie chronique préserve la proprioception du coude

Study designRetrospective cohort study. IntroductionA new method of accurately assessing the compromised elbow's proprioception was developed for this post-surgical population using information from previous neurophysiologic proprioception studies of healthy elbows. HypothesisThis retrospective cohort study investigated the patterns and the degree of proprioceptive impairment and recovery following arthroscopic surgery for chronic lateral epicondylitis. Material and methodsParticipants had undergone arthroscopic elbow surgery two years prior to this study (n=15). Healthy, non-injured volunteers with similar demographics (n=15) served as controls. Both groups were evaluated using quantitative measures of joint position sense for proprioceptive functioning. In order to obtain the most accurate proprioceptive measurements, inter-individual interaction and visual input biases were eliminated. Retrospective chart reviews were performed to compare qualitative self-reported measures of proprioceptive function in arthroscopic surgery patients before surgery and two years post-surgery. ResultsActive and passive joint repositioning outcome measurements were similar between groups (p>0.05). No significant differences were found among any angles except one: passive joint position sense at 120° of flexion (p<0.05). At this angle, the arthroscopy group showed greater deviation from target angles than the control group. The novel proprioceptive testing method we developed was found to be accurate and reliable. DiscussionOutcomes of arthroscopic treatment of chronic lateral epicondylitis with no decortication yielded outcomes measure similar to those of healthy controls. The sole significant difference was at 120° flexion passive joint repositioning, with a higher negative angular deviation from the target point. We propose that our study results and specific proprioception method may have implications for improving accuracy of future elbow arthroscopy and proprioceptive recovery in this population. Level of evidenceII, low-powered prospective randomized trial.

Numerical ability and improvement through interindividual cooperation varied between two cyprinid fish species, qingbo and crucian carp.

We used qingbo (Spinibarbus sinensis) and Chinese crucian carp (Carassius auratus) to test whether numerical discrimination could be improved by the coexistence and possible cooperation of conspecies or heterospecies. We conducted a spontaneous shoal choice test of singletons, conspecific dyads and heterospecific dyads under different numerical comparisons (8 vs. 12, 9 vs. 12 and 10 vs. 12). Singletons of qingbo could discriminate only 8 vs. 12, whereas the dyads of qingbo showed better numerical acuity, as they could discriminate 10 vs. 12. Crucian carp may have poor numerical ability, as both singleton and dyads showed no significant preference for larger stimulus shoals, even at the ‘easier’ numerical discrimination, that is, 8 vs. 12. Furthermore, heterospecific dyads of crucian carp and qingbo did not show significant preference for larger shoals at any numerical comparison in the present study. It is suggested that both the numerical ability and the possibility for improvement by interindividual interaction and hence cooperation might vary among fish species, and the interaction between heterospecies in the present study showed negative effect on numerical ability possibly due to the different behavioural and cognitive traits which make the information transfer and consensus difficult to reach.

Arthroscopic chronic tennis elbow surgery preserves elbow proprioception

Study designRetrospective cohort study. IntroductionA new method of accurately assessing the compromised elbow's proprioception was developed for this postsurgical population using information from previous neurophysiologic proprioception studies of healthy elbows. HypothesisThis retrospective cohort study investigated the patterns and the degree of proprioceptive impairment and recovery following arthroscopic surgery for chronic lateral epicondylitis. Material and methodsParticipants had undergone arthroscopic elbow surgery two years prior to this study (n=15). Healthy, non-injured volunteers with similar demographics (n=15) served as controls. Both groups were evaluated using quantitative measures of joint position sense for proprioceptive functioning. In order to obtain the most accurate proprioceptive measurements, interindividual interaction and visual input biases were eliminated. Retrospective chart reviews were performed to compare qualitative self-reported measures of proprioceptive function in arthroscopic surgery patients before surgery and two years post-surgery. ResultsActive and passive joint repositioning outcome measurements were similar between groups (p>0.05). No significant differences were found among any angles except one: passive joint position sense at 120° of flexion (p<0.05). At this angle, the arthroscopy group showed greater deviation from target angles than the control group. The novel proprioceptive testing method we developed was found to be accurate and reliable. DiscussionOutcomes of arthroscopic treatment of chronic lateral epicondylitis with no decortication yielded outcomes measure similar to those of healthy controls. The sole significant difference was at 120° flexion passive joint repositioning, with a higher negative angular deviation from the target point. We propose that our study results and specific proprioception method may have implications for improving accuracy of future elbow arthroscopy and proprioceptive recovery in this population. Level of evidenceII, low-powered prospective randomized trial.

Infrastructure construction without information exchange: the trail clearing mechanism in Atta leafcutter ants.

A wide range of group-living animals construct tangible infrastructure networks, often of remarkable size and complexity. In ant colonies, infrastructure construction may require tens of thousands of work hours distributed among many thousand individuals. What are the individual behaviours involved in the construction and what level of complexity in inter-individual interaction is required to organize this effort? We investigate this question in one of the most sophisticated trail builders in the animal world: the leafcutter ants, which remove leaf litter, cut through overhangs and shift soil to level the path of trail networks that may cumulatively extend for kilometres. Based on obstruction experiments in the field and the laboratory, we identify and quantify different individual trail clearing behaviours. Via a computational model, we further investigate the presence of recruitment, which-through direct or indirect information transfer between individuals-is one of the main organizing mechanisms of many collective behaviours in ants. We show that large-scale transport networks can emerge purely from the stochastic process of workers encountering obstructions and subsequently engaging in removal behaviour with a fixed probability. In addition to such incidental removal, we describe a dedicated clearing behaviour in which workers remove additional obstructions independent of chance encounters. We show that to explain the dynamics observed in the experiments, no information exchange (e.g. via recruitment) is required, and propose that large-scale infrastructure construction of this type can be achieved without coordination between individuals.

Are groups more competitive, more selfish-rational or more prosocial bargainers?

Often, it is rather groups than individuals that make decisions. In previous experiments, groups have frequently been shown to act differently from individuals in several ways. It has been claimed that inter-group interactions may be (1) more competitive, (2) more selfish-rational, or (3) more prosocial than inter-individual interactions. While some of these observed differences may be due to differences in the experimental setups, it is still not clear which of the three kinds of behavior is prevailing as they have hardly been distinguishable in previous experiments. We use Rubinstein’s alternating offers bargaining game to compare inter-individual with inter-group behavior since it allows separating the predictions of competitive, selfish-rational, and prosocial behavior. We find that groups are, on average, more selfish-rational bargainers than individuals, in particular when being in a weak as opposed to a strong position.

Individual-Level and Population-Level Lateralization: Two Sides of the Same Coin

Lateralization, i.e., the different functional roles played by the left and right sides of the brain, is expressed in two main ways: (1) in single individuals, regardless of a common direction (bias) in the population (aka individual-level lateralization); or (2) in single individuals and in the same direction in most of them, so that the population is biased (aka population-level lateralization). Indeed, lateralization often occurs at the population-level, with 60–90% of individuals showing the same direction (right or left) of bias, depending on species and tasks. It is usually maintained that lateralization can increase the brain’s efficiency. However, this may explain individual-level lateralization, but not population-level lateralization, for individual brain efficiency is unrelated to the direction of the asymmetry in other individuals. From a theoretical point of view, a possible explanation for population-level lateralization is that it may reflect an evolutionarily stable strategy (ESS) that can develop when individually asymmetrical organisms are under specific selective pressures to coordinate their behavior with that of other asymmetrical organisms. This prediction has been sometimes misunderstood as it is equated with the idea that population-level lateralization should only be present in social species. However, population-level asymmetries have been observed in aggressive and mating displays in so-called “solitary” insects, suggesting that engagement in specific inter-individual interactions rather than “sociality” per se may promote population-level lateralization. Here, we clarify that the nature of inter-individuals interaction can generate evolutionarily stable strategies of lateralization at the individual- or population-level, depending on ecological contexts, showing that individual-level and population-level lateralization should be considered as two aspects of the same continuum.

Complex interactions underpin social behaviour in Dictyostelium giganteum

In the wild, social groups of the cellular slime mould amoeba Dictyostelium giganteum are genetically heterogeneous more often than not. When studied as 1:1 binary mixes, amoebae of one strain almost always form more spores than the other, an observation that leads one to wonder what might be responsible for the long-term persistence of different strains in nature. We have monitored a number of individual and collective traits bearing on reproductive fitness in chimaeras of Dictyostelium giganteum obtained by mixing pairs of starved amoebae belonging to distinct wild-type strains in proportions ranging from 1:9 to 9:1. The main findings are that intercellular interactions take place at more than one stage of the life cycle and that generalisations drawn after mixing cells only in a 1:1 ratio can be misleading. A strain that does better than another in respect of some component of fitness (for example, spore formation) may do worse in respect of a different component (for example, growth rate). Also, a strain that is a more efficient sporulator than a second strain in one context may be less efficient in another context. In addition to such trade-offs, spore formation in chimaeras can exhibit negative frequency dependence, which too can lead to stable co-existence. Humans live in social groups whose members perform different but equally important tasks. When they do so freely, the long-term stability of the group depends on give and take (‘trade-offs’) between individuals who are generally unrelated. In contrast, studies of cooperation in non-human animals have focussed on relatedness through common descent as responsible for the maintenance of group cohesion. But animal groups too contain unrelated individuals. Using the example of a social amoeba, we show that this need not rule out a high level of cooperation including so-called altruism, as long as inter-individual interactions permit it. In both genetically homogeneous and heterogeneous groups, interactions can result in trade-offs between different traits. In genetically heterogeneous groups, they can also lead to a negative correlation between the efficiency with which cells of a genotype reproduce and the proportion of cells belonging to that genotype.

A lipocalin protein, Neural Lazarillo, is key to social interactions that promote termite soldier differentiation.

Social communication among castes is a crucial component of insect societies. However, the genes involved in soldier determination through the regulation of inter-individual interactions are largely unknown. In an incipient colony of the damp-wood termite Zootermopsis nevadensis, the first larva to develop into a third instar always differentiates into a soldier via frequent trophallactic feeding from the reproductives. Here, by performing RNA-seq analysis of third instar larvae, a homologue of Neural Lazarillo (named ZnNLaz1) was found to be the most differentially expressed gene in these soldier-destined larvae, compared with worker-destined larvae. This gene encodes a lipocalin protein related to the transport of small hydrophobic molecules. RNAi-induced knockdown of ZnNLaz1 significantly inhibited trophallactic interactions with the queen and decreased the soldier differentiation rates. This protein is localized in the gut, particularly in the internal wall, of soldier-destined larvae, suggesting that it is involved in the integration of social signals from the queen through frequent trophallactic behaviours. Based on molecular phylogenetic analysis, we suggest that a novel function of termite NLaz1 has contributed to social evolution from the cockroach ancestors of termites. These results indicated that a high larval NLaz1 expression is crucial for soldier determination through social communication in termites.

Groups clapping in unison undergo size-dependent error-induced frequency increase

Humans clapping together in unison is a familiar and robust example of emergent synchrony. We find that in experiments, such groups (from two to a few hundred) always increase clapping frequency, and larger groups increase more quickly. Based on single-person experiments and modeling, an individual tendency to rush is ruled out as an explanation. Instead, an asymmetric sensitivity in aural interactions explains the frequency increase, whereby individuals correct more strongly to match neighbour claps that precede their own clap, than those that follow it. A simple conceptual coupled oscillator model based on this interaction recovers the main features observed in experiments, and shows that the collective frequency increase is driven by the small timing errors in individuals, and the resulting inter-individual interactions that occur to maintain unison.

Schools as Acculturative and Developmental Contexts for Youth of Immigrant and Refugee Background

Abstract. Schools are important for the academic and socio-emotional development, as well as acculturation of immigrant- and refugee-background youth. We highlight individual differences which shape their unique experiences, while considering three levels of the school context in terms of how they may affect adaptation outcomes: (1) interindividual interactions in the classroom (such as peer relations, student-teacher relations, teacher beliefs, and teaching practices), (2) characteristics of the classroom or school (such as ethnic composition and diversity climate), and (3) relevant school- and nation-level policies (such as diversity policies and school tracking). Given the complexity of the topic, there is a need for more research taking an integrated and interdisciplinary perspective to address migration related issues in the school context. Teacher beliefs and the normative climate in schools seem particularly promising points for intervention, which may be easier to change than structural aspects of the school context. More inclusive schools are also an important step toward more peaceful interethnic relations in diverse societies.

Understanding interactions between populations: Individual based modelling and quantification using pair correlation functions

Understanding the underlying mechanisms that produce the huge variety of swarming and aggregation patterns in animals and cells is fundamental in ecology, developmental biology, and regenerative medicine, to name but a few examples. Depending upon the nature of the interactions between individuals (cells or animals), a variety of different large-scale spatial patterns can be observed in their distribution; examples include cell aggregates, stripes of different coloured skin cells, etc. For the case where all individuals are of the same type (i.e., all interactions are alike), a considerable literature already exists on how the collective organisation depends on the inter-individual interactions. Here, we focus on the less studied case where there are two different types of individuals present. Whilst a number of continuum models of this scenario exist, it can be difficult to compare these models to experimental data, since real cells and animals are discrete. In order to overcome this problem, we develop an agent-based model to simulate some archetypal mechanisms involving attraction and repulsion. However, with this approach (as with experiments), each realisation of the model is different, due to stochastic effects. In order to make useful comparisons between simulations and experimental data, we need to identify the robust features of the spatial distributions of the two species which persist over many realisations of the model (for example, the size of aggregates, degree of segregation or intermixing of the two species). In some cases, it is possible to do this by simple visual inspection. In others, the features of the pattern are not so clear to the unaided eye. In this paper, we introduce a pair correlation function (PCF), which allows us to analyse multi-species spatial distributions quantitatively. We show how the differing strengths of inter-individual attraction and repulsion between species give rise to different spatial patterns, and how the PCF can be used to quantify these differences, even when it might be impossible to recognise them visually.

Plasticity of Root Architecture Under Mixed Culture and Tiller Regulation in Sugarcane

It is important for the effective use of soil resource and sustainable sugarcane production to study the root architecture and plasticity because soil resources are distributed unevenly. However, information on sugarcane root architecture and plasticity is limited because of its larger plant size and longer growth period. The mechanism of root formation is divided into internal (main stem and tillers) and inter-individual (sole and mixture) interactions. Our study attempted to reveal the effect of tiller regulation (internal interaction) and mixed cultivars (inter-individual interaction) on root formation in sugarcane. Tiller regulation decreased the total root biomass but distributed the roots in deeper soil, indicating that high-tillering characteristics may not necessarily contribute to a deeper root system and drought tolerance, at least during the early growth stages of tillers. Our results also revealed that the total shoot biomass, including the main stem and tillers, was not influenced by tiller regulation, suggesting a plasticity of shoot growth under tiller regulation. Roots under mixed cultivars grew well in the middle soil layer (20–50 cm depth) and were thoroughly distributed in each soil layer. These facts suggested that root habitat segregation of each cultivar may have occurred. Such root densification did not increase shoot biomass in the present study; however, it has the potential for improving lodging resistance and resource use efficiency under some abiotic stress conditions.

Anisotropic interaction rules in circular motions of pigeon flocks: An empirical study based on sparse Bayesian learning.

Coordination shall be deemed to the result of interindividual interaction among natural gregarious animal groups. However, revealing the underlying interaction rules and decision-making strategies governing highly coordinated motion in bird flocks is still a long-standing challenge. Based on analysis of high spatial-temporal resolution GPS data of three pigeon flocks, we extract the hidden interaction principle by using a newly emerging machine learning method, namely the sparse Bayesian learning. It is observed that the interaction probability has an inflection point at pairwise distance of 3-4 m closer than the average maximum interindividual distance, after which it decays strictly with rising pairwise metric distances. Significantly, the density of spatial neighbor distribution is strongly anisotropic, with an evident lack of interactions along individual velocity. Thus, it is found that in small-sized bird flocks, individuals reciprocally cooperate with a variational number of neighbors in metric space and tend to interact with closer time-varying neighbors, rather than interacting with a fixed number of topological ones. Finally, extensive numerical investigation is conducted to verify both the revealed interaction and decision-making principle during circular flights of pigeon flocks.

Coping with noise in social dilemmas: Group representatives fare worse than individuals because they lack trust in others’ benign intentions

Research on interindividual–intergroup discontinuity has illuminated distinct patterns of cognition, motivation, and behavior in interindividual versus intergroup contexts. However, it has examined these processes in laboratory environments with perfect transparency, whereas real-life interactions are often characterized by noise (i.e., misperceptions and unintended errors). This research compared interindividual and intergroup interactions in the presence or absence of noise. In a laboratory experiment, participants played 35 rounds of a dyadic give-some dilemma, in which they acted as individuals or group representatives. Noise was manipulated, such that players’ intentions either were perfectly translated into behavior or could deviate from their intentions in certain rounds (resulting in less cooperative behavior). Noise was more detrimental to cooperation in intergroup contexts than in interindividual contexts, because (a) participants who formed benign impressions of the other player coped better with noise, and (b) participants were less likely to form such benign impressions in intergroup than interindividual interactions.