1,721,033 research outputs found
Social enhancement can create adaptive, arbitrary and maladaptive cultural traditions
No full textMany animals are known to learn socially, i.e. they are able to acquire new behaviours by using information from other individuals. Researchers distinguish between a number of different social-learning mechanisms such as imitation and social enhancement. Social enhancement is a simple form of social learning that is among the most widespread in animals. However, unlike imitation, it is debated whether social enhancement can create cultural traditions. Based on a recent study on capuchin monkeys, we developed an agent-based model to test the hypotheses that (i) social enhancement can create and maintain stable traditions and (ii) social enhancement can create cultural conformity. Our results supported both hypotheses. A key factor that led to the creation of cultural conformity and traditions was the repeated interaction of individual reinforcement and social enhancement learning. This result emphasizes that the emergence of cultural conformity does not necessarily require cognitively complex mechanisms such as ‘copying the majority’ or group norms. In addition, we observed that social enhancement can create learning dynamics similar to a ‘copy when uncertain’ learning strategy. Results from additional analyses also point to situations that should favour the evolution of learning mechanisms more sophisticated than social enhancement.</jats:p
Socioecology, but not cognition, predicts male coalitions across primates
No full textHumans form agonistic coalitions and alliances in many contexts, but this behavior is thought to be rare in other species. A prominent hypothesis states that coalitions may be under cognitive constraints, but this idea is debated and remains to be tested empirically. In this study, we evaluate the cognitive constraint hypothesis against 3 alternative hypotheses that stress the role of demography, substrate use, and resource competition, for the evolution of male coalitions. A comparative analysis of a unique data set of 86 multimale multifemale groups of 38 nonhuman primate species from all major radiations revealed no evolutionary association of male coalition frequency with cognitive capacity (as indexed by neocortex ratio and endocranial volume). The observed variation was best explained by demography and resource competition in that male coalitions were more likely to occur in species characterized by larger male groups and reduced levels of contest competition (after controlling for phylogeny). These findings suggest that constraints imposed by the socioecological setting, rather than cognition, explain best why some primate species evolved customary coalitionary behavior while others did not. This study presents the first empirical evidence against the long-standing view that cognitive abilities may impose a limit on the use of coalitions in animals
Stable heterosexual associations in a promiscuous primate
No full textClose associations between adult males and females are rare among group-living, nonmonogamous mammals but may mark the transition from life in promiscuous bisexual groups to groups of pairs or pair living. Although heterosexual friendships have been described in baboons, these are short-term affairs serving as protection against infanticide and thus tightly linked to the presence of vulnerable infants. Long-term association may be adaptive in situations of low male monopolization potential where it pays to invest in a particular female partner instead of spreading the effort among many females. Using long-term data, we investigated male–female and male–infant associations in wild Assamese macaques, Macaca assamensis. Group-wide and individual male–female associations were stable for at least 2 or 3 years. Association during the mating season but not before the mating season predicted male mating success, lending support to the ‘friends with benefits’ but not the ‘mating effort’ hypothesis. Mating success in turn predicted male–female association at birth as well as male–infant association before weaning. In support of the ‘paternal care hypothesis’ paternity was an independent predictor of male–infant association beyond weaning age, creating potential for true paternal care. We thus postulate that particular demographic and life history circumstances may favour male–female friendships by creating a positive feedback between male–female–infant associations driven by paternal care and male–female associations promoted by increased mating access to drive the evolution of long-term male–female bonds
Rapid evolution of cooperation in group-living animals
Full text linkBackgroundIt is often assumed that evolution takes place on very large timescales. Countering this assumption, rapid evolutionary dynamics are increasingly documented in biological systems, e.g. in the context of predator–prey interactions, species coexistence and invasion. It has also been shown that rapid evolution can facilitate the evolution of cooperation. In this context often evolutionary dynamics influence population dynamics, but in spatial models rapid evolutionary dynamics also emerge with constant population sizes. Currently it is not clear how well these spatial models apply to species in which individuals are not embedded in fixed spatial structures. To address this issue we employ an agent-based model of group living individuals. We investigate how positive assortment between cooperators and defectors and pay-off differences between cooperators and defectors depend on the occurrence of evolutionary dynamics.ResultsWe find that positive assortment and pay-off differences between cooperators and defectors differ when comparing scenarios with and without selection, which indicates that rapid evolutionary dynamics are occurring in the selection scenarios. Specifically, rapid evolution occurs because changes in positive assortment feed back on evolutionary dynamics, which crucially impacts the evolution of cooperation. At high frequencies of cooperators these feedback dynamics increase positive assortment facilitating the evolution of cooperation. In contrast, at low frequencies of cooperators rapid evolutionary dynamics lead to a decrease in assortment, which acts against the evolution of cooperation. The contrasting dynamics at low and high frequencies of cooperators create positive frequency-dependent selection.ConclusionsRapid evolutionary dynamics can influence the evolution of cooperation in group-living species and lead to positive frequency-dependent selection even if population size and maximum group-size are not affected by evolutionary dynamics. Rapid evolutionary dynamics can emerge in this case because sufficiently strong selective pressures allow evolutionary and demographic dynamics, and consequently also feedback between assortment and evolution, to occur on the same timescale. In particular, emerging positive frequency-dependent selection could be an important explanation for differences in cooperative behaviors among different species with similar population structures such as humans and chimpanzees
Investigating the Impact of Observation Errors on the Statistical Performance of Network-based Diffusion Analysis
Full text linkExperiments in captivity have provided evidence for social learning, but it remains challenging to demon- strate social learning in the wild. Recently, we developed network-based diffusion analysis (NBDA; 2009) as a new approach to inferring social learning from observational data. NBDA fits alternative models of asocial and social learning to the diffusion of a behavior through time, where the potential for social learning is related to a social network. Here, we investigate the performance of NBDA in relation to variation in group size, network heterogeneity, observer sampling errors, and duration of trait diffusion. We find that observation errors, when severe enough, can lead to increased Type I error rates in detecting social learning. However, elevated Type I error rates can be prevented by coding the observed times of trait acquisition into larger time units. Collectively, our results provide further guidance to applying NBDA and demonstrate that the method is more robust to sampling error than initially expected. Supplemental materials for this article may be downloaded from http:// lb.psychonomic-journals.org/content/supplemental.Human Evolutionary BiologyAccepted Manuscrip
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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