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Author Janson, C.; Byrne, R. url  doi
openurl 
  Title What wild primates know about resources: opening up the black box Type Journal Article
  Year 2007 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 10 Issue 3 Pages 357-367  
  Keywords Cognitive map – Primate – Foraging – Ecology – Psychology  
  Abstract Abstract  We present the theoretical and practical difficulties of inferring the cognitive processes involved in spatial movement decisions of primates and other animals based on studies of their foraging behavior in the wild. Because the possible cognitive processes involved in foraging are not known a priori for a given species, some observed spatial movements could be consistent with a large number of processes ranging from simple undirected search processes to strategic goal-oriented travel. Two basic approaches can help to reveal the cognitive processes: (1) experiments designed to test specific mechanisms; (2) comparison of observed movements with predicted ones based on models of hypothesized foraging modes (ideally, quantitative ones). We describe how these two approaches have been applied to evidence for spatial knowledge of resources in primates, and for various hypothesized goals of spatial decisions in primates, reviewing what is now established. We conclude with a synthesis emphasizing what kinds of spatial movement data on unmanipulated primate populations in the wild are most useful in deciphering goal-oriented processes from random processes. Basic to all of these is an estimate of the animals ability to detect resources during search. Given knowledge of the animals detection ability, there are several observable patterns of resource use incompatible with a pure search process. These patterns include increasing movement speed when approaching versus leaving a resource, increasingly directed movement toward more valuable resources, and directed travel to distant resources from many starting locations. Thus, it should be possible to assess and compare spatial cognition across a variety of primate species and thus trace its ecological and evolutionary correlates.  
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  Call Number Admin @ knut @ Serial 4214  
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Author Hattori, Y.; Kuroshima, H.; Fujita, K. url  doi
openurl 
  Title I know you are not looking at me: capuchin monkeys` ? (Cebus apella) sensitivity to human attentional states Type Journal Article
  Year 2007 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 10 Issue 2 Pages 141-148  
  Keywords Capuchin monkeys – Attentional state – Gaze – Social cognition  
  Abstract Abstract  The present study asked whether capuchin monkeys recognize human attentional states. The monkeys requested food from the experimenter by extending an arm (pointing) toward the baited one of two transparent cups. On regular trials the experimenter gave the food immediately to the monkeys upon pointing but on randomly inserted test trials she ignored the pointing for 5 s during which she displayed different attentional states. The monkeys looked at the experimenter's face longer when she looked at the monkeys than when she looked at the ceiling in Experiment 1, and longer when she oriented her head midway between the two cups with eyes open than when she did so with eyes closed in Experiment 2. However, the monkeys showed no differential pointing in these conditions. These results suggest that capuchins are sensitive to eye direction but this sensitivity does not lead to differential pointing trained in laboratory experiments. Furthermore, to our knowledge, this is the first firm behavioral evidence that non-human primates attend to the subtle states of eyes in a food requesting task.  
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  Notes Approved no  
  Call Number Admin @ knut @ Serial 4219  
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Author Voelkl, B.; Huber, L. url  doi
openurl 
  Title Common marmosets (Callithrix jacchus) do not utilize social information in three simultaneous social foraging tasks Type Journal Article
  Year 2007 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 10 Issue 2 Pages 149-158  
  Keywords Marmosets – Social foraging – Social information – Food competition  
  Abstract Abstract  Social foraging is suggested to increase foraging efficiency, as individuals might benefit from public information acquired by monitoring the foraging activities of other group members. We conducted a series experiments with captive common marmosets (Callithrix jacchus) to investigate to what extent marmosets utilize social information about food location when foraging simultaneously with conspecifics. Subjects were confronted with dominant and subordinate demonstrators in three experiments which differed in the amount of information about food location available to the demonstrators. In all three experiments, the focal subjects` performance in the social condition was not enhanced in comparison to a non-social control condition. Because we could rule out kleptoparasitism and aggressive displacements as explanations, we argue that the subjects tendency for scramble competition by avoiding others and dispersing over the foraging area seems to inhibit or mask the acquisition of social information about the location of rewarded patches.  
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  Notes Approved no  
  Call Number Admin @ knut @ Serial 4220  
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Author Bryson, J.; Leong, J. url  doi
openurl 
  Title Primate errors in transitive inference: a two-tier learning model Type Journal Article
  Year 2007 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 10 Issue 1 Pages 1-15  
  Keywords Transitive inference, choice or performance – Task learning – Hippocampal learning – Modelling  
  Abstract Abstract  Transitive performance (TP) is a learning-based behaviour exhibited by a wide range of species, where if a subject has been taught to prefer A when presented with the pair AB but to prefer B when presented with the pair BC, then the subject will also prefer A when presented with the novel pair AC. Most explanations of TP assume that subjects recognize and learn an underlying sequence from observing the training pairs. However, data from squirrel monkeys (Saimiri sciureus) and young children contradict this, showing that when three different items (a triad) are drawn from the sequence, subjects`` performance degrades systematically (McGonigle and Chalmers, Nature 267:694-696, 1977; Chalmers and McGonigle, Journal of Experimental Child Psychology 37:355-377, 1984; Harris and McGonigle, The Quarterly Journal of Experimental Psychology 47B:319-348, 1994). We present here the two-tier model, the first learning model of TP which accounts for this systematic performance degradation. Our model assumes primate TP is based on a general-purpose task learning system rather than a special-purpose sequence-learning system. It supports the hypothesis of Heckers et al. (Hippocampus 14:153-162, 2004) that TP is an expression of two separate general learning elements: one for associating actions and contexts, another for prioritising associations when more than one context is present. The two-tier model also provides explanations for why phased training is important for helping subjects learn the initial training pairs and why some subjects fail to do so. It also supports the Harris and McGonigle (The Quarterly Journal of Experimental Psychology 47B:319-348, 1994) explanation of why, once the training pairs have been acquired, subjects perform transitive choice automatically on two-item diads, but not when exposed to triads from the same sequence.  
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  Notes Approved no  
  Call Number Admin @ knut @ Serial 4221  
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Author Adachi, I.; Kuwahata, H.; Fujita, K. url  doi
openurl 
  Title Dogs recall their owner's face upon hearing the owner's voice Type Journal Article
  Year 2007 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 10 Issue 1 Pages 17-21  
  Keywords Cross-modal representation – Natural concepts – Dogs  
  Abstract Abstract  We tested whether dogs have a cross-modal representation of human individuals. We presented domestic dogs with a photo of either the owner's or a stranger's face on the LCD monitor after playing back a voice of one of those persons. A voice and a face matched in half of the trials (Congruent condition) and mismatched in the other half (Incongruent condition). If our subjects activate visual images of the voice, their expectation would be contradicted in Incongruent condition. It would result in the subjects` longer looking times in Incongruent condition than in Congruent condition. Our subject dogs looked longer at the visual stimulus in Incongruent condition than in Congruent condition. This suggests that dogs actively generate their internal representation of the owner's face when they hear the owner calling them. This is the first demonstration that nonhuman animals do not merely associate auditory and visual stimuli but also actively generate a visual image from auditory information. Furthermore, our subject also looked at the visual stimulus longer in Incongruent condition in which the owner's face followed an unfamiliar person's voice than in Congruent condition in which the owner's face followed the owner's voice. Generating a particular visual image in response to an unfamiliar voice should be difficult, and any expected images from the voice ought to be more obscure or less well defined than that of the owners. However, our subjects looked longer at the owner's face in Incongruent condition than in Congruent condition. This may indicate that dogs may have predicted that it should not be the owner when they heard the unfamiliar person's voice.  
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  Call Number Admin @ knut @ Serial 4222  
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Author Leaver, L.; Hopewell, L.; Caldwell, C.; Mallarky, L. url  doi
openurl 
  Title Audience effects on food caching in grey squirrels (Sciurus carolinensis): evidence for pilferage avoidance strategies Type Journal Article
  Year 2007 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 10 Issue 1 Pages 23-27  
  Keywords Caching – Deception – Pilferage – Grey squirrels – Sciurus carolinensis  
  Abstract Abstract  If food pilferage has been a reliable selection pressure on food caching animals, those animals should have evolved the ability to protect their caches from pilferers. Evidence that animals protect their caches would support the argument that pilferage has been an important adaptive challenge. We observed naturally caching Eastern grey squirrels (Sciurus carolinensis) in order to determine whether they used any evasive tactics in order to deter conspecific and heterospecific pilferage. We found that grey squirrels used evasive tactics when they had a conspecific audience, but not when they had a heterospecific (corvid) audience. When other squirrels were present, grey squirrels spaced their caches farther apart and preferentially cached when oriented with their backs to other squirrels, but no such effect was found when birds were present. Our data provide the first evidence that caching mammals are sensitive to the risk of pilferage posed by an audience of conspecifics, and that they utilise evasive tactics that should help to minimise cache loss. We discuss our results in relation to recent theory of reciprocal pilferage and compare them to behaviours shown by caching birds.  
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  Call Number Admin @ knut @ Serial 4223  
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Author Rankin, D.J.; Lopez-Sepulcre, A.; Foster, K.R.; Kokko, H. url  doi
openurl 
  Title Species-level selection reduces selfishness through competitive exclusion Type Journal Article
  Year 2007 Publication Journal of Evolutionary Biology Abbreviated Journal  
  Volume 20 Issue 4 Pages 1459-1468  
  Keywords  
  Abstract Abstract Adaptation does not necessarily lead to traits which are optimal for the population. This is because selection is often the strongest at the individual or gene level. The evolution of selfishness can lead to a .tragedy of the commons., where traits such as aggression or social cheating reduce population size and may lead to extinction. This suggests that species-level selection will result whenever species differ in the incentive to be selfish. We explore this idea in a simple model that combines individual-level selection with ecology in two interacting species. Our model is not influenced by kin or trait-group selection. We find that individual selection in combination with competitive exclusion greatly increases the likelihood that selfish species go extinct. A simple example of this would be a vertebrate species that invests heavily into squabbles over breeding sites, which is then excluded by a species that invests more into direct reproduction. A multispecies simulation shows that these extinctions result in communities containing species that are much less selfish. Our results suggest that species-level selection and community dynamics play an important role in regulating the intensity of conflicts in natural populations.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 4225  
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Author Kokko, H.; Lopez-Sepulcre, A. url  doi
openurl 
  Title The ecogenetic link between demography and evolution: can we bridge the gap between theory and data? Type Journal Article
  Year 2007 Publication Ecology Letters Abbreviated Journal  
  Volume 10 Issue 9 Pages 773-782  
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  Abstract Abstract Calls to understand the links between ecology and evolution have been common for decades. Population dynamics, i.e. the demographic changes in populations, arise from life history decisions of individuals and thus are a product of selection, and selection, on the contrary, can be modified by such dynamical properties of the population as density and stability. It follows that generating predictions and testing them correctly requires considering this ecogenetic feedback loop whenever traits have demographic consequences, mediated via density dependence (or frequency dependence). This is not an easy challenge, and arguably theory has advanced at a greater pace than empirical research. However, theory would benefit from more interaction between related fields, as is evident in the many near-synonymous names that the ecogenetic loop has attracted. We also list encouraging examples where empiricists have shown feasible ways of addressing the question, ranging from advanced data analysis to experiments and comparative analyses of phylogenetic data.  
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  Call Number Equine Behaviour @ team @ Serial 4226  
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Author Fleurance, G.; Duncan, P.; Fritz, H.; Cabaret, J.; Cortet, J.; Gordon, I.J. url  doi
openurl 
  Title Selection of feeding sites by horses at pasture: Testing the anti-parasite theory Type Journal Article
  Year 2007 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.  
  Volume 108 Issue 3-4 Pages 228-301  
  Keywords Foraging strategies; Horses; Parasite risk; Patch choice  
  Abstract Management of grazed grasslands for production and/or conservation objectives requires a thorough understanding of the choices of feeding sites by herbivores, and of the biological processes involved. Most models of the feeding strategies of herbivores are based on the principle that optimising the intake of energy (or some nutrient) is the primary goal of foragers but other selective forces, such as parasitism, could be important. Gastrointestinal parasites (including cyathostome nematodes) have powerful effects on the fitness of herbivores and may act as a major selection pressure favouring host behaviour that reduces the risk of encountering parasites. Among large herbivores, horses have perhaps the most marked tendency to select particular feeding sites within grasslands. We test here: (1) whether horses select feeding patches with relatively low parasite densities and (2) if their choice is affected by their parasite load. We used 10 two-year old saddle-horses and three periods. In the first period, the horses were under natural parasitism which varied strongly among individuals; in the second period they were all dewormed, and in the third, a sub-set of the horses was experimentally infected with cyathostome larvae. Ninety-eight percent of the infective larvae in the pasture were found <1 m from faeces. The main determinant of the choice of feeding patch by horses was the availability of patches of different parasite risk and grass height. Controlling for availability, the horses used tall grasses (>16 cm) less than expected, whether the grass was contaminated or not, and they selected for short patches >1 m from faeces, where the risk of encountering parasites was low. These results suggest that selection of feeding sites by horses is driven by an interaction between their nutritional and anti-parasite strategies: the horses avoid the patches of tall grass which are generally of low quality and areas contaminated by parasite larvae which leads them to prefer the patches of short grass far from faeces. The parasite status of the horses at the time of the experiment had no effect on their feeding choices. However, before concluding that the challenge by cyathostomes has no effect on the selection of feeding sites in horses, it will be necessary to test whether the history of parasitism of the individuals, rather than the current status, is important.  
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  Call Number Equine Behaviour @ team @ Serial 4228  
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Author Silk, J.B. url  doi
openurl 
  Title Social Components of Fitness in Primate Groups Type Journal Article
  Year 2007 Publication Science Abbreviated Journal Science  
  Volume 317 Issue 5843 Pages 1347-1351  
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  Abstract There is much interest in the evolutionary forces that favored the evolution of large brains in the primate order. The social brain hypothesis posits that selection has favored larger brains and more complex cognitive capacities as a means to cope with the challenges of social life. The hypothesis is supported by evidence that shows that group size is linked to various measures of brain size. But it has not been clear how cognitive complexity confers fitness advantages on individuals. Research in the field and laboratory shows that sophisticated social cognition underlies social behavior in primate groups. Moreover, a growing body of evidence suggests that the quality of social relationships has measurable fitness consequences for individuals.  
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  Notes 10.1126/science.1140734 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4239  
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