Group-level Traits Research Articles

The Big Five and Collaborative Problem Solving: A Narrative Systematic Review

The current study integrates available findings on the relationship between the Big Five personality traits and collaborative problem solving (CPS), as a specific type of teamwork. Based on a systematic search and screening of the literature, 47 papers were reviewed. Having separately analyzed how individual and group-level traits relate to the processes and outcomes of CPS, we found several meaningful associations. Both individual-level and group-level Conscientiousness and Agreeableness were positively related to the quality of CPS. The former trait contributed more to the enactment of task roles/behaviors in CPS, to task-related team processes and team performance; the latter was dominantly related to the enactment of social roles/behaviors, and to relationship-related team processes and emergent states. The role of the remaining traits in CPS depended on the level of analysis, with individual Extraversion being particularly important for within-group positioning, and group Emotional Stability affecting team cohesion. Unsurprisingly, the effects of group-level traits on CPS also depended on the method of aggregating individual trait scores. The hypothesis that some traits would relate more to CPS processes and others to its outcomes was partially confirmed, while the assumption that team processes would mediate the effects of group-level traits on CPS outcomes received substantial support.

Influence of behavioural and morphological group composition on pigeon flocking dynamics.

Animals rely on movement to explore and exploit resources in their environment. While movement can provide energetic benefits, it also comes with energetic costs. This study examines how group phenotypic composition individual speed and energy expenditure during group travel in homing pigeons. We manipulated the composition of pigeon groups based on body mass and leadership rank. Our findings indicate that groups of leader phenotypes show faster speeds and greater cohesion than follower phenotype groups. Additionally, we show that groups of homogenous mass composition, whether all heavy or all light, were faster and expended less energy over the course of a whole flight than flocks composed of a mixture of heavy and light individuals. We highlight the importance of considering individual-level variation in social-level studies, and the interaction between individual and group-level traits in governing speed and the cost of travel.

Multi-group analysis of grooming network position in a highly social primate.

Individual variation in complex social behavioral traits, like primate grooming, can be influenced by the characteristics of the individual and those of its social group. To better grasp this complexity, social network analysis can be used to quantify direct and indirect grooming relationships. However, multi-group social network studies remain rare, despite their importance to disentangle individual from group-level trait effects on grooming strategies. We applied social network analysis to grooming data of 22 groups of zoo-housed bonobos and investigated the impact of three individual (sex, age, and rearing-history) and two group-level traits (group size and sex ratio) on five social network measures (out-strength, in-strength, disparity, affinity, and eigenvector centrality). Our results showed age-effects on all investigated measures: for females, all measures except for affinity showed quadratic relationships with age, while in males, the effects of age were more variable depending on the network measure. Bonobos with atypical rearing histories showed lower out-strength and eigenvector centrality, while in-strength was only impacted by rearing history in males. Group size showed a negative association with disparity and eigenvector centrality, while sex ratio did not influence any of the investigated measures. Standardization for group size did not impact the effects of sex and age, indicating the robustness of these findings. Our study provides comprehensive insights into the complexity of grooming behavior in zoo-housed bonobos, and underlines the importance of multi-group analyses for the generalizability of social network analysis results for species as a whole.

Organizational Development as Generative Entrenchment.

A critical task for organizations is how to best structure themselves to efficiently allocate information and resources to individuals tasked with solving sub-components of the organization’s central problems. Despite this criticality, the processes by which organizational structures form remain largely opaque within organizational theory, with most approaches focused on how structure is influenced by individual managerial heuristics, normative cultural perceptions, and trial-and-error. Here, we propose that a broad understanding of organizational formation can be aided by appealing to generative entrenchment, a theory from developmental biology that helps explain why phylogenetically diverse animals appear similar as embryos. Drawing inferences from generative entrenchment and applying it to organizational differentiation, we argue that the reason many organizations appear structurally similar is due to core informational restraints on individual actors beginning at the top and descending to the bottom of these informational hierarchies, which reinforces these structures via feedback between separate levels. We further argue that such processes can lead to the emergence of a variety of group-level traits, an important but undertheorized class of phenomena in cultural evolution.

Exploring Evolved Multicellular Life Histories in a Open-Ended Digital Evolution System

Evolutionary transitions occur when previously-independent replicating entities unite to form more complex individuals. Such transitions have profoundly shaped natural evolutionary history and occur in two forms: fraternal transitions involve lower-level entities that are kin (e.g., transitions to multicellularity or to eusocial colonies), while egalitarian transitions involve unrelated individuals (e.g., the origins of mitochondria). The necessary conditions and evolutionary mechanisms for these transitions to arise continue to be fruitful targets of scientific interest. Here, we examine a range of fraternal transitions in populations of open-ended self-replicating computer programs. These digital cells were allowed to form and replicate kin groups by selectively adjoining or expelling daughter cells. The capability to recognize kin-group membership enabled preferential communication and cooperation between cells. We repeatedly observed group-level traits that are characteristic of a fraternal transition. These included reproductive division of labor, resource sharing within kin groups, resource investment in offspring groups, asymmetrical behaviors mediated by messaging, morphological patterning, and adaptive apoptosis. We report eight case studies from replicates where transitions occurred and explore the diverse range of adaptive evolved multicellular strategies.

What Are Group Level Traits and How Do They Evolve?

Cultural traits are seldom atomic, are distributed over multiple social domains, and undergo differential selection. This makes it important to study the nature and evolution of these traits from a global viewpoint. This paper considers group level cultural traits-what sort of traits are there, how do they evolve, and what is the relationship between cultural traits and their representation in individual worldviews. While not providing a concise theory, important aspects of cultural traits are elaborated and directions of further research indicated. Group level traits arising from individual biological traits are distinguished from those that are intrinsic to a group. The latter are formative of individual worldviews and are emotionally salient for group members. Children are saturated with culture from birth, it provides the scaffolding for their developing worldviews. Affective links between cultural ideas, social behavior, and material elements of culture develop so that the affordances in perceived situations carry biases influencing behavior toward culturally acceptable responses. Intrinsic traits are not, however, acted on directly by group level selection; rather, this selection acts on the behavior of group members and only indirectly on intrinsic cultural ideas through social exchange processes between group members.

The Collective Behavior of Ant Groups Depends on Group Genotypic Composition.

Recently, researchers have documented variation between groups in collective behavior. However, how genetic variation within and between groups contributes to population-level variation for collective behavior remains unclear. Understanding how genetic variation of group members relates to group-level phenotypes is evolutionarily important because there is increasing evidence that group-level behavioral variation influences fitness and that the genetic architecture of group-level traits can affect the evolutionary dynamics of traits. Social insects are ideal for studying the complex relationship between individual and group-level variation because they exhibit behavioral variation at multiple scales of organization. To explore how the genetic composition of groups affects collective behavior, we constructed groups of pharaoh ants (Monomorium pharaonis) from 33 genetically distinct colonies of known pedigree. The groups consisted of either all workers from the same single colony or workers from two genetically different colonies, and we assayed the exploration and aggression of the groups. We found that collective exploration, but not aggression, depended on the specific genotypic combination of group members, i.e., we found evidence for genotype-by-genotype epistasis for exploration. Group collective behavior did not depend on the pedigree relatedness between genotypes within groups. Overall, this study highlights that specific combinations of genotypes influence group-level phenotypes, emphasizing the importance of considering nonadditive effects of genotypic interactions between group members.

Why don't cockatoos have war songs?

We suggest that the accounts offered by the target articles could be strengthened by acknowledging the role of group selection and cultural niche construction in shaping the evolutionary trajectory of human music. We argue that group level traits and highly variable cultural niches can explain the diversity of human song, but the target articles' accounts are insufficient to explain such diversity.

Explanatory goals and explanatory means in multilevel selection theory.

It has become customary in multilevel selection theory to use the same terms (namely "multilevel selection 1" and "multilevel selection 2") to denote both two explanatory goals (explaining why certain individual- and, respectively, group-level traits spread) and two explanatory means (namely, two kinds of group selection we may appeal to in such explanations). This paper spells out some of the benefits that derive from avoiding this terminological conflation. I argue that keeping explanatory means and goals well apart allows us to see that, contrary to a popular recent idea, Price's equation and contextual analysis-the statistical methods most extensively used for measuring the effects of certain evolutionary factors (like individual selection, group selection etc.) on the change in the focal individual trait in multilevel selection scenarios-do not come with built-in notions of group selection and, therefore, the efficacy of these methods at analyzing various kinds of cases does not constitute a basis for deciding how group selection should best be defined. Moreover, contrary to another widely accepted idea, I argue that more than one type of group selection may serve as explanatory means when one's goal is that of explaining the evolution of individual traits in multilevel selection scenarios and I spell out how this explanatory role should be understood.

Manipulation of worker size diversity does not affect colony fitness under natural conditions in the ant Temnothorax nylanderi

In social insects, within-colony worker diversity has long been thought to improve colony fitness. Recent studies start to question this assertion in species with moderate diversity. However, demonstrating an absence of effect is difficult as this absence could be due to the measurement of only few life history traits or to artificial conditions. In order to circumvent these limitations, we experimentally decreased worker size diversity within colonies of the ant Temnothorax nylanderi, with or without affecting mean worker size and we reintroduced them in the field for 4 months (spring and early summer). We then thoroughly measured their fitness based on survival, growth, and reproductive success. Our results show that our manipulation did not affect colony fitness. In addition, colonies did not restore diversity to its initial level, further suggesting that worker size diversity is not a key parameter to them. We found the classically observed positive relationship between colony size, colony growth, and reproductive success. Overall, our results confirm that worker size diversity within colony is not necessarily adaptive in species where it is moderate. We discuss the alternative mechanisms that could explain the evolutionary persistence of moderate worker size diversity. Organisms that live in groups can greatly benefit from the emergence of novel group-level traits. For instance, social insects show significant variability in worker size within colonies. This size diversity increases the division of labor among workers and improves colony fitness. However, in species where size diversity is moderate, this relationship may not always be verified. Here, we manipulated both worker size diversity and mean worker size within colonies of the ant Temnothorax nylanderi, we reintroduced them in the field, and we extensively measured colony fitness after 4 months. We found no impact on colony survival, growth, and reproduction. We discuss how social life and its associated cooperation and conflicts could cause variation in worker size, without any positive effect on colony fitness.

Male social plasticity influences transient dynamics in the emergence of alternative mating systems in water striders

AbstractAnimal mating systems are often studied with the goal of understanding why species, populations, or groups vary from one another in the system they display. Although these differences are often treated as basically stable, it is also known that mating systems may shift over time (e.g., from one breeding season to the next). There has been some study of how ecological factors correlate with these changes; however, few, if any, studies have investigated how the phenotypic composition of a group governs the timing and probability of these mating system transitions. Groups of stream water striders (Aquarius remigis) can experience rapid changes in mating system dynamics, with small groups often transitioning into a system in which a single, large male monopolizes mating opportunities. We asked if variation in individual- and group-level traits associated with morphology and behavior (e.g., size of the largest individual, average activity behavioral type in the group) could partially explain the variability in how rapidly groups make this transition, if they make it at all. We show that groups with males that exhibit higher social plasticity tended to take longer to transition to a mating system dominated by a single male. Our results, therefore, suggest that groups in identical ecological conditions can diverge in their mating systems based on how much individuals in the group change their behavior in response to the behavior of other members of the group.

The use of identity primes to explain behavioral differences between groups: A methodological note

Although economists are increasingly using behavioral experiments to study variation in preferences among human groups (e.g., males vs. females), relatively little attention has been paid to the inferential limitations of such experiments. Focusing on group identity primes, this methodological note considers the conditions under which researchers are able to identify causes and explain differences in behavior or preferences between groups. Main concern is that group identity priming (or other approaches to strengthening causal inference in such experiments) are not a panacea and that a persistent omitted variables problem continues to hamper identification of specific causes of group differences in preferences. This note develops a framework for thinking systematically about the treatment effects of priming individuals’ group identity and possible approaches to clean identification of specific group-level traits explaining differences in preferences between groups. Unpacking observed effects of group membership on preferences and identifying specific causes of group differences is paramount from the perspective of policy implications and I clarify the framework's usefulness using concrete examples.

Trust and signals in workplace organization: evidence from job autonomy differentials between immigrant groups

Trust involves a willingness to be vulnerable to other agents’ actions as well as an assessment of these agents’ trustworthiness. This paper seeks to unpack the relationship between trust and workplace organization, focusing on signals of (un)trustworthiness guiding employers’ trust decisions. While much research finds that societal trust norms affect workplace organization, particularly the granting of autonomy to employees, the underlying process remains essentially a black box. Integrating extant literatures, I posit that employers use group-level traits to infer (un)trustworthiness and decide on how much job autonomy to grant to specific employees. I test this prediction in a large cross-national sample comprising migrant employees originating from home countries that differ in the degree to which corruption has been institutionalized in society. Confirming my prediction, empirical results reveal a strong negative relationship between homecountry corruption and job autonomy. Results are robust to controlling for a range of potential confounders, including personal income and home-country level of economic development as proxies for unobserved skill differentials. Key contribution of the paper is to reveal important real-world features of trust governing exchange in the context of workplace organization.

Low Income Consumers Stigma Discrimination and the Stress Response in Services

Marketplace discrimination, which involves a differential treatment of customers in the marketplace based on perceived group-level traits, is common in service encounters.In this study, we attempt to answer a basic question: How low income customer’s deal with stigma and what are the major coping strategies utilized during a service encounter. In order to create and evaluate strategies for dealing with the destructive effects of stigma we must understand its nature and impacts on marketing activities.Drawing the study under Social Identification Theory (Tafjel and Turner, 1979), the research was design with a qualitative approach with 210 interviews with low-income customers, done in the South of Brazil, using Critical Incident Technique (CIT) for the interviews. The data transcriptions was analyze with Content Analysis N-VIVO software, to evaluate the stigma impact during service encounters and also, what kind of coping strategies were used by low income customers. Coping differences may explain some consumers' decisions not to complain. These findings give some directions and managerial implications for those companies who intend to deal with low-income consumers.

Evolutionary transitions of complex labile traits: Silk weaving and arboreal nesting in Polyrhachis ants

Understanding the maintenance and evolution of complex group behavioural systems has broad significance to our understanding of social evolution, yet we have little insight into how these systems have evolved. Nest-weaving, a rare group behaviour considered a pinnacle of cooperative action in social insects, involves the coordination of workers and larvae by incorporating larval silk into the nest structure. To investigate the evolution of this complex behaviour in the ant genus Polyrhachis, we used comparative analysis and an inferred molecular phylogeny based on three mitochondrial genes COI, COII and CytB, and three nuclear genes EF1 a-F2, Wg and Tf. Our results showed that arboreality and nest-weaving are closely associated, but in contrast to the previous hypotheses, represent the ancestral state in the monophyletic genus. Nest-weaving within the genus, moreover, is remarkably labile. Arboreality and nest-weaving have been lost and partially regained on at least two occasions: two non-weaving subterranean species (sister taxa likely reflecting a single evolutionary event) have reverted to arboreal nesting habits without regaining the use of silk nests, while a third subterranean species has transitioned to nesting in silk nests on the sides of rocks, obtaining silk from spiders and not their own larvae. The loss of larval cocoons, which is correlated with the most complex form of nest-weaving behavior as typified in Oecophylla, has occurred independently on at least two occasions within Polyrhachis. The repeated loss of nest-weaving behaviour and its partial regaining within the genus provides the first example of a complex group-level trait that did not arise through behavioural progression from simple to complex states. The evolution and loss of complex group-level traits may be more evolutionarily labile than previously appreciated.

The genetical theory of multilevel selection.

The theory of multilevel selection (MLS) is beset with conceptual difficulties. Although it is widely agreed that covariance between group trait and group fitness may arise in the natural world and drive a response to ‘group selection’, ambiguity exists over the precise meaning of group trait and group fitness and as to whether group selection should be defined according to changes in frequencies of different types of individual or different types of group. Moreover, the theory of MLS has failed to properly engage with the problem of class structure, which greatly limits its empirical application to, for example, social insects whose colonies are structured into separate age, sex, caste and ploidy classes. Here, I develop a genetical theory of MLS, to address these problems. I show that taking a genetical approach facilitates a decomposition of group-level traits – including reproductive success – into the separate contributions made by each constituent individual, even in the context of so-called emergence. However, I uncover a novel problem with the group-oriented approach: in many scenarios, it may not be possible to express a meaningful covariance between trait and fitness at the level of the social group, because the group's constituents belong to separate, irreconcilable classes.

Evolutionary applications research highlight for issue 1.

As we highlight each month in this section, the application of evolutionary theory to issues affecting the health and well-being of human, agricultural, and natural populations is gaining increasing momentum. In a recent review article written for Science, Scott Carroll et al. take on the now monumental task of synthesizing the many ways that evolutionary biology can be used to address global challenges (Carroll et al. 2014). They comprehensively explore the main problems being tackled with an evolutionary approach, ranging from populations evolving too quickly (such as emerging pathogens or pests evolving resistance to treatment) to populations not evolving quickly enough (for example those being negatively affected by human-mediated change). The authors begin by identifying what they see as the two key paradigms of applied evolutionary biology: (i) managing contemporary evolution (i.e., manipulating the rapid evolutionary response of short-lived organisms with large population sizes, such as bacterial pathogens) and (ii) altering the phenotype–environment mismatch (i.e., responding to populations of long-lived organisms such as trees that are no longer well adapted to their local environment due to shifts in climatic conditions or changes in biotic interactions). As a great example of such a mismatch, the authors highlight the increasing rates of obesity, diabetes, and heart disease in the human populations as a result of a more sedentary lifestyle with diets rich in sugars and fat. They then identify a number of promising research avenues that either have addressed or have the potential to address current global challenges, covering a wide range of approaches including the use of genetic engineering to more appropriately match genomes to their environment, the use of ‘refuges’ in agriculture and combination treatments against pests and pathogens to hinder the evolution of resistance, and introducing nonlocal genotypes which are predicted to perform better under given environmental conditions into natural populations to increase local adaptation. The article nicely separates these conceptual approaches into strategies for slowing unwanted evolution or directly influencing fitness of pests and pathogens, strategies for reducing the mismatch between phenotype and the local environment, and strategies for increasing group performance by selecting on group-level traits. For example, the authors discuss the success of artificially selecting for group yield in agricultural plots rather than individual fitness as a means for decreasing competition among plants. Critically, the piece also emphasizes the need to take a unified approach in meeting international objectives for sustainable development and suggests a need for stricter enforcement of guidelines in order to ensure best practice is achieved despite temptation to put profit or immediate success ahead of sustainable solutions. Overall, the review acts as a unique and remarkable resource both for researchers and students who are new to the field of applied evolution and those who actively contribute to the field.

Evolutionary biology: Survival of the fittest group.

Experiments with social spiders find that colony size and composition affect colony survival in a site-specific manner, indicating that natural selection on group-level traits contributes to local adaptation. See Letter p.359 Evolutionary theory predicts that group selection could drive the evolution of traits in individuals that promote the success of their group which, in turn, will promote the long-term fitness interests of group constituents. However, there is scant experimental evidence in support of group selection. This study uses colonies of the social spider Anelosimus studiosus to investigate the evolution of a group-level trait, the ratio of docile to aggressive individuals in a colony. Wild colonies display characteristic, site-specific docile-to-aggressive ratios. Jonathan Pruitt and Charles Goodnight generated experimental colonies with varying docile-to-aggressive ratios, and established them in the wild. Colonies with ratios closer to the native ratio were more successful, and experimental colonies adjusted their ratio over two generations to what would have been favoured at their native site. This experimental evidence suggests that group-level selection is acting in the wild.

Explaining group-level traits requires distinguishing process from product.

Smaldino is right to argue that we need a richer theory of group-level traits. He is wrong, however, in limiting group-level traits to units of cultural selection, which require explanations based on group selection. Traits are best understood when explanations focus on both process (i.e., selection) and product (i.e., adaptation). This approach can distinguish group-level traits that arise through within-group processes from those that arise through between-group processes.

Coordination, cooperation, and the ontogeny of group-level traits.

Group-level traits (GLTs) clarify the necessity of cultural multilevel selection theory. We propose a revised definition of the GLT concept. We also highlight the need to better understand the interplay between the dimensions of cooperation and coordination in the ontogeny of GLTs.