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Whiten, A. (1998). Imitation of the sequential structure of actions by chimpanzees. J Comp Psychol, 11.
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Breitenmoser, U. (1998). Large predators in the Alps: the fall and rise of man's competitors. Biol Conserv, 83.
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Gese, E. M., & Ruff, R. L. (1998). Howling by coyotes (Canis latrans): variation among social classes, seasons, and pack sizes. Can J Zool, 76.
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Peters, G., & Tembrock, G. (1998). Subharmonics, biphonation, and deterministic chaos in mammal vocalizations. Bioacoustics, 9.
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(1998). Animal Acoustic Communication: Sound Analysis and Research Methods. Berlin: Springer.
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de VRIES, H. A. N. (1998). Finding a dominance order most consistent with a linear hierarchy: a new procedure and review. Anim. Behav., 55(4), 827–843.
Abstract: A procedure for ordering a set of individuals into a linear or near-linear dominance hierarchy is presented. Two criteria are used in a prioritized way in reorganizing the dominance matrix to find an order that is most consistent with a linear hierarchy: first, minimization of the numbers of inconsistencies and, second, minimization of the total strength of the inconsistencies. The linear ordering procedure, which involves an iterative algorithm based on a generalized swapping rule, is feasible for matrices of up to 80 individuals. The procedure can be applied to any dominance matrix, since it does not make any assumptions about the form of the probabilities of winning and losing. The only assumption is the existence of a linear or near-linear hierarchy which can be verified by means of a linearity test. A review of existing ranking methods is presented and these are compared with the proposed method.
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Lachmann M., & Bergstrom C.T. (1998). Signalling among Relatives II. Beyond the Tower of Babel. Theor. Pop. Biol., 54(2). Retrieved June 3, 2024, from http://www.santafe.edu/~dirk/papers/SigII.pdf
Abstract: Models of costly signalling are commonly employed in evolutionary biology in order to explain how honest communication between individuals with conflicting interests can be stable. These models have focused primarily on a single type of honest signalling equilibrium, the separating equilibrium in which any two different signallers send distinct signals, thereby providing signal receivers with complete information. In this paper, we demonstrate that in signalling among relatives (modelled using the Sir Philip Sidney game), there is not one but a large number of possible signalling equilibria, most of which are pooling equilibria in which different types of signallers may share a common signal. We prove that in a general Sir Philip Sidney game, any partition of signallers into equi-signalling classes can have a stable signalling equilibrium if and only if it is a contiguous partition, and provide examples of such partitions. A similar (but slightly stricter) condition is shown to hold when signals are transmitted through a medium with signalling error. These results suggest a solution to a problem faced by previous signalling theory models: when we consider the separating equilibrium, signal cost is independent of the frequency of individuals sending that signal and, consequently, even very rare signaller types can drastically affect signal cost. Here, we show that by allowing these rare signallers to pool with more common signallers, signal cost can be greatly reduced. Copyright 1998 Academic Press.
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Templeton, J. J. (1998). Learning from others' mistakes: a paradox revisited. Anim. Behav., 55(1), 79–85.
Abstract: Some researchers have reported the paradoxical finding of enhanced social learning when naive observers learn from unskilled rather than skilled demonstrators, particularly in discrimination tasks. In two experiments with starlings,Sturnus vulgaris, I considered whether this enhanced learning is because the observer (1) sees incorrect responses only, (2) sees both correct and incorrect responses or (3) sees an increase in the proportion of correct responses over trials. In experiment 1, individual starlings observed a demonstrator bird perform multiple simultaneous discrimination tasks. In one group, the demonstrator always picked the correct stimulus; in another group, the demonstrator always picked the incorrect stimulus; in a third group, the demonstrator consistently picked the correct stimulus 50% of the time. Those subjects that observed only incorrect choices performed significantly better than the other two groups, but none of the birds achieved the 90% correct performance criterion. Experiment 2 involved a single discrimination task; thus, a fourth group was added to control for individual learning. Again, subjects that observed only incorrect responses learned the discrimination significantly more quickly than the other three groups. Subjects that observed the demonstrator make both correct and incorrect responses were equally likely to select the same (correct) or opposite (incorrect) stimulus when the demonstrator picked the correct stimulus. When the demonstrator picked the incorrect stimulus, however, these subjects were significantly more likely to pick the opposite (correct) stimulus. These findings suggest that when learning a discrimination problem, observing a foraging companion's lack of success is more informative than observing its success.
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Tomasello, M., Call, J., & Hare, B. (1998). Five primate species follow the visual gaze of conspecifics. Anim. Behav., 55(4), 1063–1069.
Abstract: Individuals from five primate species were tested experimentally for their ability to follow the visual gaze of conspecifics to an outside object. Subjects were from captive social groups of chimpanzees,Pan troglodytes, sooty mangabeys,Cercocebus atys torquatus, rhesus macaques,Macaca mulatta, stumptail macaques,M. arctoides, and pigtail macaques,M. nemestrina. Experimental trials consisted of an experimenter inducing one individual to look at food being displayed, and then observing the reaction of another individual (the subject) that was looking at that individual (not the food). Control trials consisted of an experimenter displaying the food in an identical manner when the subject was alone. Individuals from all species reliably followed the gaze of conspecifics, looking to the food about 80% of the time in experimental trials, compared with about 20% of the time in control trials. Results are discussed in terms of both the proximate mechanisms that might be involved and the adaptive functions that might be served by gaze-following.
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Schnall, S., & Gattis, M. (1998). Transitive Inference by Visual Reasoning. Retrieved June 3, 2024, from http://faculty.virginia.edu/schnall/Schnall%20&%20Gattis.pdf
Abstract: Two experiments are reported that investigated the influence
of linear spatial organization on transitive inference
performance. Reward/no-reward relations between
overlapping pairs of elements were presented in a context of
linear spatial order or random spatial order. Participants in
the linear arrangement condition showed evidence for visual
reasoning: They systematically mapped spatial relations to
conceptual relation and used the spatial relations to make
inferences on a reasoning task in a new spatial context. We
suggest that linear ordering may be a “good figure”, by
constituting a parsimonious representation for the integration
of premises, as well as for the inferencing process. The late
emergence of transitive inference in children may be the
result of limited cognitive capacity, which --unless an
external spatial array is available --constrains the
construction of an internal spatial array.
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