Rogers, L. J. (2000). Evolution of hemispheric specialization: advantages and disadvantages. Brain Lang, 73(2), 236–253.
Abstract: Lateralization of the brain appeared early in evolution and many of its features appear to have been retained, possibly even in humans. We now have a considerable amount of information on the different forms of lateralization in a number of species, and the commonalities of these are discussed, but there has been relatively little investigation of the advantages of being lateralized. This article reports new findings on the differences between lateralized and nonlateralized chicks. The lateralized chicks were exposed to light for 24 h on day 19 of incubation, a treatment known to lead to lateralization of a number of visually guided responses, and the nonlateralized chicks were incubated in the dark. When they were feeding, the lateralized chicks were found to detect a stimulus resembling a raptor with shorter latency than nonlateralized chicks. This difference was not a nonspecific effect caused by the light-exposed chicks being more distressed by the stimulus. Instead, it appears to be a genuine advantage conferred by having a lateralized brain. It is suggested that having a lateralized brain allows dual attention to the tasks of feeding (right eye and left hemisphere) and vigilance for predators (left eye and right hemisphere). Nonlateralized chicks appear to perform these dual tasks less efficiently than lateralized ones. Reference is made to other species in discussing these results.
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Lyn, H., & Savage-Rumbaugh, E. S. (2000). Observational word learning in two bonobos (Pan paniscus): ostensive and non-ostensive contexts. Language & Communication, 20(3), 255–273.
Abstract: Word learning has been extensively studied in humans. Children seem to be able to map new words onto objects with only one exposure to the referent. This ability has been called “fast mapping”(Carey, 1978 and Carey). Using a modified human paradigm, this paper explores two language-competent bonobos' (Pan paniscus) abilities to map new words to objects in realistic surroundings with few exposures to the referents. This paper also investigates the necessity of the apes maintaining visual contact (ostensive context) with the item to map the novel name onto the novel object. The bonobos tested in this experiment were able to map new words onto objects and could do so without visual contact with the items.
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Mech L.D. (2000). Leadership in Wolf, Canis lupus, Packs. Can Field Nat, 114(2), 259–263.
Abstract: I examine leadership in Wolf (Canis lupus) packs based on published observations and data gathered during summers from 1986 to 1998 studying a free-ranging pack of Wolves on Ellesmere Island that were habituated to my presence. The breeding male tended to initiate activities associated with foraging and travel, and the breeding female to initiate, and predominate in, pup care and protection. However, there was considerable overlap and interaction during these activities such that leadership could be considered a joint function. In packs with multiple breeders, quantitative information about leadership is needed.
Keywords: Wolf, Canis lupus, leadership, behavior, foraging, movements, pup care, provisioning, sociality, reproduction, breeding, Northwest Territories.
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Beauchamp, G. (2000). Individual Differences In Activity And Exploration Influence Leadership In Pairs Of Foraging Zebra Finches. Behaviour, 137, 301–314.
Abstract: This study investigated the role of dominance and level of activity and exploration on leadership in zebra finches (Taenopygia guttata) searching for food. In pairs of zebra finches fairly matched in size and that experienced the same level of food deprivation, the same bird consistently reached first one foraging patch over several trials. The same pattern of arrival to food occurred when resources were provided in two distant patches available concurrently, a situation that would potentially allow subordinates a greater access to resources. In further testing, the formation of new pairs with the same birds led to several changes in leadership, indicating that leadership is not an absolute feature. The member of a pair that proved to be the most active and exploratory during independent, solitary trials became the leader in nearly all pairs tested. The same pattern held true in newly rearranged pairs where individuals often experienced changes in dominance status. Dominance failed to be associated with leadership in all tests. The results suggest that in a relatively egalitarian species, level of activity and exploration may be a stronger predictor of leadership than dominance.
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Wilson O. E.,. (2000). Sociobiology: The new Synthesis (Vol. 25th edition). Cambridge: Belknap Press.
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Mandal, M. K., Bulman-Fleming, M. B., & Tiwari, G. (Eds.). (2000). Side Bias: A Neuropsychological Perspective. Netherlands: Springer.
Abstract: The beginnings of the idea about a book on “side bias” began in the year
1994 during the senior editor"s research association with late Professor M.P.
Bryden and colleagues at the University of Waterloo, Canada. Over many
discussions with Professor Bryden, it was clear that the concept of “side bias”
encompasses all aspects of motor behaviour within the context of human
(and non-human animal) laterality. The tendency to favour one side or limb
over the other is important not only from the perspective of understanding
the functional asymmetries of the cerebral hemispheres, but also to an
understanding of a myriad of aspects of human behaviour, as the
contributions to this volume will attest.
By side bias, most people would think of bias in terms of hand
preference or performance. The phenomenon of side bias, however, is more
general and influences motor behaviour of all kinds, ranging from simple
hand movement to complex behaviours like facial expression and attention.
Therefore, the concept has been operationalized in terms of bias reflected in
the motor expression of paired (such as hands, feet, eyes, or ears) or
nonpaired organs (such as the face) as a function of preference, performance
or attentional/intentional factors. ....
More see: http://www.springerlink.com/content/gr1726/front-matter.pdf
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Jezierski T., G. A. (2000). Changes in the horses heart rate during different levels of social isolation. Anim. Sci. Pap. Rep., 18(1), 33–41.
Abstract: Social isolation in horses may be regarded as a stress factor which implies welfare problems. The aim of the experiment was to examine the effect of different levels of transient social isolation and human presence on the heart rate (HR) in horses. Seven horses were used and the experiment was conducted in a tether-stable without boxes. The HR was recorded electronically, continuously for 40 min during the following test situations: all horses in the stable; experimenter approaches the tested horse, other horses being untied and leaving the stable; tested horse staying alone or in the company of one or two stable-mates; the experimenter attempts to calm the isolated horse; outdoor auditory stimuli from other horses. The HR was significantly higher during the whole period of isolation, and depended on how many horses were left as company for the one tested. The highest HR was observed while other horses were leaving the stable and during perception of outdoor auditory stimuli from others. When in the company of two stable mates, the HR was elevated only while other horses were leaving the stable and during auditory stimuli from outdoors. Human presence evoked a significant increase in HR, probably due to conditioning of horses (expecting to be untied and allowed to join the others), irrespectively whether the tested horse was left alone or with one or two stable-mates.
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Houpt, K., & Kusunose, R. (2000). Genetics of behaviour. In A. Ruvinsky A. T. Bowling (Ed.), The Genetics of the Horse (pp. 281–306). New York: CABI Publishing.
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Seyfarth, R. M., & Cheney, D. L. (2000). Social Awareness in Monkeys. Amer. Zool., 40(6), 902–909.
Abstract: Tests of self-awareness in nonhuman primates have to date been concerned almost entirely with the recognition of an animal's reflection in a mirror. By contrast, we know much less about non-human primates' perception of their place within a social network, or of their understanding of themselves as individuals with unique sets of social relationships. Here we review evidence that monkeys who fail the mirror test may nonetheless behave as if they recognize themselves as distinct individuals, each of whom occupies a unique place in society and has a specific set of relations with others. A free-ranging vervet monkey, baboon, or macaque recognizes other members of his group as individuals. He also recognizes matrilineal kin groups, linear dominance rank orders, and behaves as if he recognizes his own unique place within them. This sense of “social self” in monkeys, however, is markedly different from self-awareness in humans. Although monkeys may behave in ways that accurately place themselves within a social network, they are unaware of the knowledge that allows them to do so: they do not know what they know, cannot reflect on what they know, and cannot become the object of their own attention.
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Foster, K. R., & Ratnieks, F. L. W. (2000). Social insects: Facultative worker policing in a wasp. Nature, 407(6805), 692–693.
Abstract: Kin-selection theory predicts that in social-insect colonies where the queen has mated multiple times, the workers will enforce cooperation by policing each other's reproduction1, 2, 3, 4. We have discovered a species, the wasp Dolichovespula saxonica, in which some queens mate once and others mate many times, and in which workers frequently attempt reproduction, allowing this prediction to be tested directly. We find that multiple mating by the queen leads to mutual policing by workers, whereas single mating does not.
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