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Seyfarth, R. M., & Cheney, D. L. (2003). The Structure of Social Knowledge in Monkeys. In F. B. M. de Waal, & P. L. Tyack (Eds.), Animal Social Complexity: Intelligence, Culture, and Individualized Societies. Cambridge, Massachusetts: Harvard University Press.
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Sighieri, C., Tedeschi, D., De Andreis, C., Petri, L., & Baragli, P. (2003). Behaviour patterns of horses can be used to establish a dominantsubordinate relationship between man and horse. Animal Welfare, 12, 705–708.
Abstract: This paper describes how man can enter the social hierarchy of the horse by mimicking the behaviour and stance it uses to establish dominance. A herd is organised according to a dominance hierarchy established by means of ritualised conflict. Dominance relationships are formed through these confrontations: one horse gains the dominant role and others identify themselves as subordinates. This study was conducted using five females of the Haflinger breed, totally unaccustomed to human contact, from a free-range breeding farm. The study methods were based on the three elements fundamental to the equilibrium of the herd: flight, herd instinct and hierarchy. The trainer-horse relationship was established in three phases: retreat, approach and association. At the end of the training sessions, all of the horses were able to respond correctly to the trainer. These observations suggest that it is possible to manage unhandled horses without coercion by mimicking their behaviour patterns.
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Plotnik, J., Nelson, P. A., & de Waal, F. B. M. (2003). Visual field information in the face perception of chimpanzees (Pan troglodytes). Ann N Y Acad Sci, 1000, 94–98.
Abstract: Evidence for a visual field advantage (VFA) in the face perception of chimpanzees was investigated using a modification of a free-vision task. Four of six chimpanzee subjects previously trained on a computer joystick match-to-sample paradigm were able to distinguish between images of neutral face chimeras consisting of two left sides (LL) or right sides (RR) of the face. While an individual's ability to make this distinction would be unlikely to determine their suitability for the VFA tests, it was important to establish that distinctive information was available in test images. Data were then recorded on their choice of the LL vs. RR chimera as a match to the true, neutral image; a bias for one of these options would indicate an hemispatial visual field advantage. Results suggest that chimpanzees, unlike humans, do not exhibit a left visual field advantage. These results have important implications for studies on laterality and asymmetry in facial signals and their perception in primates.
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de Waal, F. B. M. (2003). Animal communication: panel discussion. Ann N Y Acad Sci, 1000, 79–87.
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de Waal, F. B. M. (2003). Darwin's legacy and the study of primate visual communication. Ann N Y Acad Sci, 1000, 7–31.
Abstract: After Charles Darwin's The Expression of the Emotions in Man and Animals, published in 1872, we had to wait 60 years before the theme of animal expressions was picked up by another astute observer. In 1935, Nadezhda Ladygina-Kohts published a detailed comparison of the expressive behavior of a juvenile chimpanzee and of her own child. After Kohts, we had to wait until the 1960s for modern ethological analyses of primate facial and gestural communication. Again, the focus was on the chimpanzee, but ethograms on other primates appeared as well. Our understanding of the range of expressions in other primates is at present far more advanced than that in Darwin's time. A strong social component has been added: instead of focusing on the expressions per se, they are now often classified according to the social situations in which they typically occur. Initially, quantitative analyses were sequential (i.e., concerned with temporal associations between behavior patterns), and they avoided the language of emotions. I will discuss some of this early work, including my own on the communicative repertoire of the bonobo, a close relative of the chimpanzee (and ourselves). I will provide concrete examples to make the point that there is a much richer matrix of contexts possible than the common behavioral categories of aggression, sex, fear, play, and so on. Primate signaling is a form of negotiation, and previous classifications have ignored the specifics of what animals try to achieve with their exchanges. There is also increasing evidence for signal conventionalization in primates, especially the apes, in both captivity and the field. This process results in group-specific or “cultural” communication patterns.
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Seyfarth, R. M., & Cheney, D. L. (2003). Meaning and emotion in animal vocalizations. Ann N Y Acad Sci, 1000, 32–55.
Abstract: Historically, a dichotomy has been drawn between the semantic communication of human language and the apparently emotional calls of animals. Current research paints a more complicated picture. Just as scientists have identified elements of human speech that reflect a speaker's emotions, field experiments have shown that the calls of many animals provide listeners with information about objects and events in the environment. Like human speech, therefore, animal vocalizations simultaneously provide others with information that is both semantic and emotional. In support of this conclusion, we review the results of field experiments on the natural vocalizations of African vervet monkeys, diana monkeys, baboons, and suricates (a South African mongoose). Vervet and diana monkeys give acoustically distinct alarm calls in response to the presence of leopards, eagles, and snakes. Each alarm call type elicits a different, adaptive response from others nearby. Field experiments demonstrate that listeners compare these vocalizations not just according to their acoustic properties but also according to the information they convey. Like monkeys, suricates give acoustically distinct alarm calls in response to different predators. Within each predator class, the calls also differ acoustically according to the signaler's perception of urgency. Like speech, therefore, suricate alarm calls convey both semantic and emotional information. The vocalizations of baboons, like those of many birds and mammals, are individually distinctive. As a result, when one baboon hears a sequence of calls exchanged between two or more individuals, the listener acquires information about social events in its group. Baboons, moreover, are skilled “eavesdroppers:” their response to different call sequences provides evidence of the sophisticated information they acquire from other individuals' vocalizations. Baboon males give loud “wahoo” calls during competitive displays. Like other vocalizations, these highly emotional calls provide listeners with information about the caller's dominance rank, age, and competitive ability. Although animal vocalizations, like human speech, simultaneously encode both semantic and emotional information, they differ from language in at least one fundamental respect. Although listeners acquire rich information from a caller's vocalization, callers do not, in the human sense, intend to provide it. Listeners acquire information as an inadvertent consequence of signaler behavior.
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Kalin, N. H., & Shelton, S. E. (2003). Nonhuman primate models to study anxiety, emotion regulation, and psychopathology. Ann N Y Acad Sci, 1008, 189–200.
Abstract: This paper demonstrates that the rhesus monkey provides an excellent model to study mechanisms underlying human anxiety and fear and emotion regulation. In previous studies with rhesus monkeys, stable, brain, endocrine, and behavioral characteristics related to individual differences in anxiety were found. It was suggested that, when extreme, these features characterize an anxious endophenotype and that these findings in the monkey are particularly relevant to understanding adaptive and maladaptive anxiety responses in humans. The monkey model is also relevant to understanding the development of human psychopathology. For example, children with extremely inhibited temperament are at increased risk to develop anxiety disorders, and these children have behavioral and biological alterations that are similar to those described in the monkey anxious endophenotype. It is likely that different aspects of the anxious endophenotype are mediated by the interactions of limbic, brain stem, and cortical regions. To understand the brain mechanisms underlying adaptive anxiety responses and their physiological concomitants, a series of studies in monkeys lesioning components of the neural circuitry (amygdala, central nucleus of the amygdala and orbitofrontal cortex) hypothesized to play a role are currently being performed. Initial findings suggest that the central nucleus of the amygdala modulates the expression of behavioral inhibition, a key feature of the endophenotype. In preliminary FDG positron emission tomography (PET) studies, functional linkages were established between the amygdala and prefrontal cortical regions that are associated with the activation of anxiety.
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Seyfarth, R. M., & Cheney, D. L. (2003). Signalers and receivers in animal communication. Annu Rev Psychol, 54, 145–173.
Abstract: In animal communication natural selection favors callers who vocalize to affect the behavior of listeners and listeners who acquire information from vocalizations, using this information to represent their environment. The acquisition of information in the wild is similar to the learning that occurs in laboratory conditioning experiments. It also has some parallels with language. The dichotomous view that animal signals must be either referential or emotional is false, because they can easily be both: The mechanisms that cause a signaler to vocalize do not limit a listener's ability to extract information from the call. The inability of most animals to recognize the mental states of others distinguishes animal communication most clearly from human language. Whereas signalers may vocalize to change a listener's behavior, they do not call to inform others. Listeners acquire information from signalers who do not, in the human sense, intend to provide it.
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Sondergaard, E., & Halekoh, U. (2003). Young horses' reactions to humans in relation to handling and social environment. Appl. Anim. Behav. Sci., 84(4), 265–280.
Abstract: Forty Danish warmblood colts in two replicates were used to investigate the effect of housing and handling in the rearing period on the reactions to humans. The horses entered the experiment after weaning and were housed either individually (n=16) or in groups of three (n=24). Half of the horses from each housing group were handled three times per week for a period of 10 min. Approach tests were performed in the home environment when the horses were 6, 9, 12, 18, 21, and 24 months old, and an Arena and Human Encounter test was performed in a novel environment when the horses were 12 and 24 months old, respectively. In the home environment, single-housed horses approached sooner and were more easily approached by a human than group-housed horses where no effect of handling was observed. Horses approached sooner and were more easily approached with increasing age. In the Arena and Human Encounter test, single-housed horses expressed less restless behaviour, more explorative behaviour, and less vocalisation than group-housed horses. Handled horses showed lower increase in heart rate during the test than non-handled horses. There was no difference between the number of times single or group-housed horses touched an unfamiliar person in the Arena and Human Encounter test but handled horses approached sooner than non-handled horses. It is concluded that the social environment affected the way horses reacted to humans when tested in the home environment but not in a novel environment. In contrast, handling affected the reactions to humans when tested in the novel environment but not in the home environment. However, handled horses also reacted less to the novel environment in general, thus indicating that handling is a mean of avoiding potential dangerous situations.
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Visser, E. K., Van Reenen, C. G., Engel, B., Schilder, M. B. H., Barneveld, A., & Blokhuis, H. J. (2003). The association between performance in show-jumping and personality traits earlier in life. Appl. Anim. Behav. Sci., 82(4), 279–295.
Abstract: For a horse to succeed in a show-jumping career, the individual has to possess both excellent physical abilities as well as a suitable personality to perform under challenging conditions. Forty-one Dutch Warmblood horses were used to develop personality tests and correlations between test variables and early training performances in jumping were studied. In behavioural tests, during the first 2 years of the horses' lives, personality aspects like emotionality, reactivity to human and learning abilities were quantified. At the age of 3, horses were broken and received early training in show-jumping. The inter-relationship between several performance variables measured during this early training phase were studied using principal component analysis (PCA). Variables measured in the different personality tests (novel-object test, handling test, avoidance-learning test and a reward-learning test) showed no correlations, suggesting that these tests all triggered different aspects of a horse's personality. This study indicates that it is possible to predict a substantial part of the show-jumping performance of an individual horse later in life by personality traits earlier in life.
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