Abstract: Previous research on the allocation of scarce resources shows that when people are assigned labels of leader or follower in their group, leaders allocate more of the scarce resources to themselves than followers do. In three laboratory studies, we examine the idea that how people are selected for the leader role (i.e. election or appointment) determines whether leaders take more or equal shares (relative to followers) from a common resource. In a first experiment, we show that participants were more accepting of norm violating behavior by an appointed versus elected leader. In a second experiment, we show that when participants were assigned to a leader or follower role, allocations of appointed leaders differed significantly from those of elected leaders and followers, whereas there was no difference between the two latter conditions. Moreover, elected leaders were shown to feel more social responsibility than both appointed leaders and followers. In a final experiment, we show that when participants were primed with the concept of social responsibility (relative to a neutral condition) no difference in allocations between appointed and elected leaders emerged.

Abstract: Abstract  Here we investigate the counting ability in honeybees by training them to receive a food reward after they have passed a specific number of landmarks. The distance to the food reward is varied frequently and randomly, whilst keeping the number of intervening landmarks constant. Thus, the bees cannot identify the food reward in terms of its distance from the hive. We find that bees can count up to four objects, when they are encountered sequentially during flight. Furthermore, bees trained in this way are able count novel objects, which they have never previously encountered, thus demonstrating that they are capable of object-independent counting. A further experiment reveals that the counting ability that the bees display in our experiments is primarily sequential in nature. It appears that bees can navigate to food sources by maintaining a running count of prominent landmarks that are passed en route, provided this number does not exceed four.

Abstract: Social network analysis is used widely in the social sciences to study interactions among people, groups, and organizations, yet until now there has been no book that shows behavioral biologists how to apply it to their work on animal populations. Exploring Animal Social Networks provides a practical guide for researchers, undergraduates, and graduate students in ecology, evolutionary biology, animal behavior, and zoology.
Existing methods for studying animal social structure focus either on one animal and its interactions or on the average properties of a whole population. This book enables researchers to probe animal social structure at all levels, from the individual to the population. No prior knowledge of network theory is assumed. The authors give a step-by-step introduction to the different procedures and offer ideas for designing studies, collecting data, and interpreting results. They examine some of today's most sophisticated statistical tools for social network analysis and show how they can be used to study social interactions in animals, including cetaceans, ungulates, primates, insects, and fish. Drawing from an array of techniques, the authors explore how network structures influence individual behavior and how this in turn influences, and is influenced by, behavior at the population level. Throughout, the authors use two software packages--UCINET and NETDRAW--to illustrate how these powerful analytical tools can be applied to different animal social organizations.
Darren P. Croft is lecturer in animal behavior at the University of Wales, Bangor. Richard James is senior lecturer in physics at the University of Bath. Jens Krause is professor of behavioral ecology at the University of Leeds.
Reviews:
“Exploring Animal Social Networks shows behavioral biologists how to apply social network theory to animal populations. In doing so, Croft, James, and Krause illustrate the connections between an animal's individual behaviors and how these, in turn, influence and are influenced by behavior at the population level. . . . Valuable for readers interested in using quantitative analyses to study animal social behaviors.”--Choice
“[T]his volume provides an engaging, accessible, and timely introduction to the use of network theory methods for examining the social behavior of animals.”--Noa Pinter-Wollman, Quarterly Review of Biology
“The book is a useful 'handbook' providing detailed, stepwise procedures sufficient to allow the reader to address a broad range of questions about social interactions. . . . The book includes numerous examples of the kind of research questions one might ask, and, thus, it allows the reader to find the analysis that best fits the data set to be analyzed. Thus, even readers with minimal prior knowledge of social network analysis will be able to apply this approach. And if further assistance is needed, the authors provide numerous references to specific procedures that have been used by others.”--Thomas R. Zentall, PsycCRITIQUES
Endorsements:
“An important and timely addition to the literature. This book should be readily accessible to researchers who are interested in animal social organization but who have little or no experience in conducting network analysis. The book is well-written in an engaging style and contains a good number of examples drawn from a range of taxonomic groups.”--Paul R. Moorcroft, Harvard University
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Table of Contents:
Preface vii
Chapter 1: Introduction to Social Networks 1
Chapter 2: Data Collection 19
Chapter 3: Visual Exploration 42
Chapter 4: Node-Based Measures 64
Chapter 5: Statistical Tests of Node-Based Measures 88
Chapter 6: Searching for Substructures 117
Chapter 7: Comparing Networks 141
Chapter 8: Conclusions 163
Glossary of Frequently Used Terms 173
References 175
Index 187
Subject Area:
* Biological Sciences

Abstract: The article by Zucca and Sovrano (2008, this issue) represents part of a new wave of studies of lateralization in nonhuman species. This work is often in conflict with earlier studies of human cerebral asymmetry and handedness, and the associated claim that these asymmetries are uniquely human, and perhaps even a result of the “speciation event” that led to modern humans. It is now apparent that there are close parallels between human and nonhuman asymmetries, suggesting that they have ancient roots. I argue that asymmetries must be seen in the context of a bilaterally symmetrical body plan, and that there is a balance to be struck between the adaptive advantages of symmetry and asymmetry. In human evolution, systematic asymmetries were incorporated into activities that probably are unique to our species, but the precursors of these asymmetries are increasingly evident in other species, including frogs, fish, birds, and mammals – especially primates.

Abstract: Habituation to frightening stimuli plays an important role in horse training. To investigate the extent to which horses generalise between different visual objects, 2-year-old stallions were habituated to feeding from a container placed inside a test arena and assigned as TEST (n=12) or REFERENCE horses (n=12). In Experiment 1, TEST horses were habituated to six objects (ball, barrel, board, box, cone, cylinder) presented in sequence in a balanced order. The objects were of similar size but different colour. Each object was placed 0.5m in front of the feed container, forcing the horses to pass the object to get to the food. TEST horses received as many 2min exposures to each object as required to meet a habituation criterion. We recorded behavioural reactions to the object, latency to feed, total eating time, and heart rate (HR) during all exposures. There was no significant decrease in initial responses towards a novel object with increasing object number, indicating that habituation was stimulus-specific. REFERENCE horses were exposed to the test arena without objects in the same period, and reactions of TEST and REFERENCE horses were subsequently compared in a fear-test (2m2.5m rubber mat placed under the feed container, forcing the horses to step on the mat to get food). There were no significant differences between the treatment groups, i.e. previous habituation of TEST horses to six visual objects did not reduce responses in a fear-test involving visual and tactile stimulation. Due to the lack of generalisation in Experiment 1, we designed a supplemental experiment (Experiment 2), in which REFERENCE horses were exposed to the same six objects except that object colour was kept constant. We found a significant reduction in response (behaviour and HR) with increasing object number, indicating that horses generalise between similarly coloured objects of varying shape. We conclude that a high degree of object similarity, e.g. identical colouring, appears to be crucial for object generalisation in horses.