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Author Ward, A.J.W.; Sumpter, D.J.T.; Couzin, I.D.; Hart, P.J.B.; Krause, J. url  doi
openurl 
  Title Quorum decision-making facilitates information transfer in fish shoals Type Journal Article
  Year 2008 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 105 Issue 19 Pages (down) 6948-6953  
  Keywords  
  Abstract Despite the growing interest in collective phenomena such as “swarm intelligence” and “wisdom of the crowds,” little is known about the mechanisms underlying decision-making in vertebrate animal groups. How do animals use the behavior of others to make more accurate decisions, especially when it is not possible to identify which individuals possess pertinent information? One plausible answer is that individuals respond only when they see a threshold number of individuals perform a particular behavior. Here, we investigate the role of such “quorum responses” in the movement decisions of fish (three-spine stickleback, Gasterosteus aculeatus). We show that a quorum response to conspecifics can explain how sticklebacks make collective movement decisions, both in the absence and presence of a potential predation risk. Importantly our experimental work shows that a quorum response can reduce the likelihood of amplification of nonadaptive following behavior. Whereas the traveling direction of solitary fish was strongly influenced by a single replica conspecific, the replica was largely ignored by larger groups of four or eight sticklebacks under risk, and the addition of a second replica was required to exert influence on the movement decisions of such groups. Model simulations further predict that quorum responses by fish improve the accuracy and speed of their decision-making over that of independent decision-makers or those using a weak linear response. This study shows that effective and accurate information transfer in groups may be gained only through nonlinear responses of group members to each other, thus highlighting the importance of quorum decision-making.  
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  Notes 10.1073/pnas.0710344105 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5252  
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Author Bode, N.W.F.; Faria, J.J.; Franks, D.W.; Krause, J.; Wood, A.J. url  doi
openurl 
  Title How perceived threat increases synchronization in collectively moving animal groups Type Journal Article
  Year 2010 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.  
  Volume 277 Issue 1697 Pages (down) 3065-3070  
  Keywords  
  Abstract Nature is rich with many different examples of the cohesive motion of animals. Previous attempts to model collective motion have primarily focused on group behaviours of identical individuals. In contrast, we put our emphasis on modelling the contributions of different individual-level characteristics within such groups by using stochastic asynchronous updating of individual positions and orientations. Our model predicts that higher updating frequency, which we relate to perceived threat, leads to more synchronized group movement, with speed and nearest-neighbour distributions becoming more uniform. Experiments with three-spined sticklebacks (Gasterosteus aculeatus) that were exposed to different threat levels provide strong empirical support for our predictions. Our results suggest that the behaviour of fish (at different states of agitation) can be explained by a single parameter in our model: the updating frequency. We postulate a mechanism for collective behavioural changes in different environment-induced contexts, and explain our findings with reference to confusion and oddity effects.  
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  Notes 10.1098/rspb.2010.0855 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5188  
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Author Krause, S.; Mattner, L.; James, R.; Guttridge, T.; Corcoran, M.; Gruber, S.; Krause, J. doi  openurl
  Title Social network analysis and valid Markov chain Monte Carlo tests of null models Type Journal Article
  Year 2009 Publication Behavioral Ecology and Sociobiology Abbreviated Journal Behav. Ecol. Sociobiol.  
  Volume 63 Issue 7 Pages (down) 1089-1096-1096  
  Keywords Biomedical and Life Sciences  
  Abstract Analyses of animal social networks derived from group-based associations often rely on randomisation methods developed in ecology (Manly, Ecology 76:1109–1115, 1995) and made available to the animal behaviour community through implementation of a pair-wise swapping algorithm by Bejder et al. (Anim Behav 56:719–725, 1998). We report a correctable flaw in this method and point the reader to a wider literature on the subject of null models in the ecology literature. We illustrate the importance of correcting the method using a toy network and use it to make a preliminary analysis of a network of associations among eagle rays.  
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  Publisher Springer Berlin / Heidelberg Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0340-5443 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5208  
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Author James, R.; Croft, D.; Krause, J. doi  openurl
  Title Potential banana skins in animal social network analysis Type Journal Article
  Year 2009 Publication Behavioral Ecology and Sociobiology Abbreviated Journal Behav. Ecol. Sociobiol.  
  Volume 63 Issue 7 Pages (down) 989-997-997  
  Keywords Biomedical and Life Sciences  
  Abstract Social network analysis is an increasingly popular tool for the study of the fine-scale and global social structure of animals. It has attracted particular attention by those attempting to unravel social structure in fission–fusion populations. It is clear that the social network approach offers some exciting opportunities for gaining new insights into social systems. However, some of the practices which are currently being used in the animal social networks literature are at worst questionable and at best over-enthusiastic. We highlight some of the areas of method, analysis and interpretation in which greater care may be needed in order to ensure that the biology we extract from our networks is robust. In particular, we suggest that more attention should be given to whether relational data are representative, the potential effect of observational errors and the choice and use of statistical tests. The importance of replication and manipulation must not be forgotten, and the interpretation of results requires care.  
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  Publisher Springer Berlin / Heidelberg Place of Publication Editor  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0340-5443 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5206  
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Author Krause, J.; Lusseau, D.; James, R. doi  openurl
  Title Animal social networks: an introduction Type Journal Article
  Year 2009 Publication Behavioral Ecology and Sociobiology Abbreviated Journal Behav. Ecol. Sociobiol.  
  Volume 63 Issue 7 Pages (down) 967-973-973  
  Keywords Biomedical and Life Sciences  
  Abstract Network analysis has a long history in the mathematical and social sciences and the aim of this introduction is to provide a brief overview of the potential that it holds for the study of animal behaviour. One of the most attractive features of the network paradigm is that it provides a single conceptual framework with which we can study the social organisation of animals at all levels (individual, dyad, group, population) and for all types of interaction (aggressive, cooperative, sexual etc.). Graphical tools allow a visual inspection of networks which often helps inspire ideas for testable hypotheses. Network analysis itself provides a multitude of novel statistical tools that can be used to characterise social patterns in animal populations. Among the important insights that networks have facilitated is that indirect social connections matter. Interactions between individuals generate a social environment at the population level which in turn selects for behavioural strategies at the individual level. A social network is often a perfect means by which to represent heterogeneous relationships in a population. Probing the biological drivers for these heterogeneities, often as a function of time, forms the basis of many of the current uses of network analysis in the behavioural sciences. This special issue on social networks brings together a diverse group of practitioners whose study systems range from social insects over reptiles to birds, cetaceans, ungulates and primates in order to illustrate the wide-ranging applications of network analysis.  
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  Publisher Springer Berlin / Heidelberg Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0340-5443 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5209  
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Author Faria, J.J.; Dyer, J.R.G.; Tosh, C.R.; Krause, J. url  doi
openurl 
  Title Leadership and social information use in human crowds Type Journal Article
  Year 2010 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 79 Issue 4 Pages (down) 895-901  
  Keywords collective animal behaviour; group; human; inadvertent social cue; information; leadership  
  Abstract One of the big challenges for group-living animals is to find out who in a group has pertinent information (regarding food or predators) at any moment in time, because informed individuals may not be obviously recognizable to other group members. We found that individuals in human groups were capable of identifying those with information, and this identification increased group performance: the speed and accuracy of groups in reaching a target. Using video analysis we found how informed individuals might have been identified by other group members by means of inadvertent social cues (such as starting order, time spent following and group position). Furthermore, we were able to show that at least one of these cues, the group position of informed individuals, was indeed correlated with group performance. Our final experiment confirmed that leadership was even more efficient when the group members were given the identity of the leader. We discuss the effect of information status regarding the presence and identity of leaders on collective animal behaviour.  
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  ISSN 0003-3472 ISBN Medium  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5192  
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Author Dyer, J.R.G.; Johansson, A.; Helbing, D.; Couzin, I.D.; Krause, J. url  doi
openurl 
  Title Leadership, consensus decision making and collective behaviour in humans Type Journal Article
  Year 2009 Publication Philosophical Transactions of the Royal Society B: Biological Sciences Abbreviated Journal Phil. Trans. Biol. Sci.  
  Volume 364 Issue 1518 Pages (down) 781-789  
  Keywords * leadership * consensus decision making * collective behaviour * human group  
  Abstract This paper reviews the literature on leadership in vertebrate groups, including recent work on human groups, before presenting the results of three new experiments looking at leadership and decision making in small and large human groups. In experiment 1, we find that both group size and the presence of uninformed individuals can affect the speed with which small human groups (eight people) decide between two opposing directional preferences and the likelihood of the group splitting. In experiment 2, we show that the spatial positioning of informed individuals within small human groups (10 people) can affect the speed and accuracy of group motion. We find that having a mixture of leaders positioned in the centre and on the edge of a group increases the speed and accuracy with which the group reaches their target. In experiment 3, we use large human crowds (100 and 200 people) to demonstrate that the trends observed from earlier work using small human groups can be applied to larger crowds. We find that only a small minority of informed individuals is needed to guide a large uninformed group. These studies build upon important theoretical and empirical work on leadership and decision making in animal groups.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5122  
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Author Couzin, I.D.; Krause, J.; Franks, N.R.; Levin, S.A. url  doi
openurl 
  Title Effective leadership and decision-making in animal groups on the move Type Journal Article
  Year 2005 Publication Abbreviated Journal Nature  
  Volume 433 Issue 7025 Pages (down) 513-516  
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  Series Volume Series Issue Edition  
  ISSN 0028-0836 ISBN Medium  
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  Notes 10.1038/nature03236 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4827  
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Author Conradt, L.; Krause, J.; Couzin, I. D.; Roper, T. J. url  doi
openurl 
  Title “Leading According to Need” in Self-Organizing Groups Type Journal Article
  Year 2009 Publication The American Naturalist Abbreviated Journal Am Nat  
  Volume 173 Issue 3 Pages (down) 304-312  
  Keywords behavioral synchrony, collective group decisions, democracy and egalitarianism in animals, public goods experiments, sexual segregation, social choice theory  
  Abstract Self‐organizing‐system approaches have shed significant light on the mechanisms underlying synchronized movements by large groups of animals, such as shoals of fish, flocks of birds, or herds of ungulates. However, these approaches rarely consider conflicts of interest between group members, although there is reason to suppose that such conflicts are commonplace. Here, we demonstrate that, where conflicts exist, individual members of self‐organizing groups can, in principle, increase their influence on group movement destination by strategically changing simple behavioral parameters (namely, movement speed, assertiveness, and social attraction range). However, they do so at the expense of an increased risk of group fragmentation and a decrease in movement efficiency. We argue that the resulting trade‐offs faced by each group member render it likely that group movements are led by those members for which reaching a particular destination is most crucial or group cohesion is least important. We term this phenomenon leading according to “need” or “social indifference,” respectively. Both kinds of leading can occur in the absence of knowledge of or communication about the needs of other group members and without the assumption of altruistic cooperation. We discuss our findings in the light of observations on fish and other vertebrates.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5121  
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Author Krause, J.; Bumann, D.; Todt, D. url  doi
openurl 
  Title Relationship between the position preference and nutritional state of individuals in schools of juvenile roach (Rutilus rutilus) Type Journal Article
  Year 1992 Publication Behavioral Ecology and Sociobiology Abbreviated Journal Behav. Ecol. Sociobiol.  
  Volume 30 Issue 3 Pages (down) 177-180  
  Keywords  
  Abstract Position preferences of well-fed and food-deprived juvenile roach were investigated in schools of 2 and 4 fish in the laboratory. Food-deprived fish appeared significantly more often in the front position than their well-fed conspecifics. For fish at the same hunger level, individuals at the front of the school had the highest feeding rate. These results represent the first evidence for a relationship between the nutritional state of individual fish and their positions in a school and suggest a functional advantage of the preference.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5140  
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