Emery, N. J. (2000). The eyes have it: the neuroethology, function and evolution of social gaze. Neurosci Biobehav Rev, 24(6), 581–604.
Abstract: Gaze is an important component of social interaction. The function, evolution and neurobiology of gaze processing are therefore of interest to a number of researchers. This review discusses the evolutionary role of social gaze in vertebrates (focusing on primates), and a hypothesis that this role has changed substantially for primates compared to other animals. This change may have been driven by morphological changes to the face and eyes of primates, limitations in the facial anatomy of other vertebrates, changes in the ecology of the environment in which primates live, and a necessity to communicate information about the environment, emotional and mental states. The eyes represent different levels of signal value depending on the status, disposition and emotional state of the sender and receiver of such signals. There are regions in the monkey and human brain which contain neurons that respond selectively to faces, bodies and eye gaze. The ability to follow another individual's gaze direction is affected in individuals with autism and other psychopathological disorders, and after particular localized brain lesions. The hypothesis that gaze following is “hard-wired” in the brain, and may be localized within a circuit linking the superior temporal sulcus, amygdala and orbitofrontal cortex is discussed.
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Rudran, R. (1973). Adult male replacement in one-male troops of purple-faced langurs (Presbytis senex senex) and its effect on population structure. Folia Primatol (Basel), 19(2), 166–192.
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Harcourt, J. L., Ang, T. Z., Sweetman, G., Johnstone, R. A., & Manica, A. (2009). Social feedback and the emergence of leaders and followers. Curr Biol, 19(3), 248–252.
Abstract: In many animal groups, certain individuals consistently appear at the forefront of coordinated movements [1-4]. How such leaders emerge is poorly understood [5, 6]. Here, we show that in pairs of sticklebacks, Gasterosteus aculeatus, leadership arises from individual differences in the way that fish respond to their partner's movements. Having first established that individuals differed in their propensity to leave cover in order to look for food, we randomly paired fish of varying boldness, and we used a Markov Chain model to infer the individual rules underlying their joint behavior. Both fish in a pair responded to each other's movements-each was more likely to leave cover if the other was already out and to return if the other had already returned. However, we found that bolder individuals displayed greater initiative and were less responsive to their partners, whereas shyer individuals displayed less initiative but followed their partners more faithfully; they also, as followers, elicited greater leadership tendencies in their bold partners. We conclude that leadership in this case is reinforced by positive social feedback.
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Biro, D., Sumpter, D. J. T., Meade, J., & Guilford, T. (2006). From Compromise to Leadership in Pigeon Homing. Curr Biol, 16(21), 2123–2128.
Abstract: Summary A central problem faced by animals traveling in groups is how navigational decisions by group members are integrated, especially when members cannot assess which individuals are best informed or have conflicting information or interests , , , and . Pigeons are now known to recapitulate faithfully their individually distinct habitual routes home , and , and this provides a novel paradigm for investigating collective decisions during flight under varying levels of interindividual conflict. Using high-precision GPS tracking of pairs of pigeons, we found that if conflict between two birds' directional preferences was small, individuals averaged their routes, whereas if conflict rose over a critical threshold, either the pair split or one of the birds became the leader. Modeling such paired decision-making showed that both outcomes--compromise and leadership--could emerge from the same set of simple behavioral rules. Pairs also navigated more efficiently than did the individuals of which they were composed, even though leadership was not necessarily assumed by the more efficient bird. In the context of mass migration of birds and other animals, our results imply that simple self-organizing rules can produce behaviors that improve accuracy in decision-making and thus benefit individuals traveling in groups , and .
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Mori, U. (1979). Ecological and sociological studies of gelada baboons. Individual relationships within a unit. Contrib Primatol, 16, 93–124.
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Mori, U. (1979). Ecological and sociological studies of gelada baboons. Inter-unit relationships. Contrib Primatol, 16, 83–92.
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Mori, U. (1979). Ecological and sociological studies of gelada baboons. Unit formation and the emergence of a new leader. Contrib Primatol, 16, 155–181.
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Bernstein, I. S., & Dobrofsky, M. (1981). Compensatory social responses of older pigtailed monkeys to maternal separation. Dev Psychobiol, 14(2), 163–168.
Abstract: Thirteen 3-5-year-old pigtailed monkeys were subjected to five 2-hr maternal separations while remaining in their normal social group. Significant changes in activity profiles were noted during separation and reunion phases. This suggests the continued social dependence of older offspring upon the matriarch. The shift in social activities reflected attempts by the juvenile and adolescent subjects to compensate for maternal absence by intensification of other affiliative social behavior and avoidance of potentially socially disruptive situation. The subjects oriented more towards kin in the absence of the matriarch, but actual time with kin decreased. Upon the return of the matriarch, the intensified some responses depressed during her absence and returned to preseparation social relationships. Play and aggressive responses declined whereas social approaches increased during maternal absences. Submissive responses declined upon the return of the matriarch, and play increased. The subjects also showed a marked, temporary increase of direct interaction, largely sniffing and grooming, with the matriarch upon her return.
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Larose, C., Richard-Yris, M. - A., Hausberger, M., & Rogers, L. J. (2006). Laterality of horses associated with emotionality in novel situations. Laterality, 11(4), 355–367.
Abstract: We have established that lateral biases are characteristic of visual behaviour in 65 horses. Two breeds, Trotters and French Saddlebreds aged 2 to 3, were tested on a novel object test. The main finding was a significant correlation between emotionality index and the eye preferred to view the novel stimulus: the higher the emotionality, the more likely that the horse looked with its left eye. The less emotive French Saddlebreds, however, tended to glance at the object using the right eye, a tendency that was not found in the Trotters, although the emotive index was the same for both breeds. The youngest French Saddlebreds did not show this trend. These results are discussed in relation to the different training practices for the breeds and broader findings on lateralisation in different species.
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Lynch, J. J., Fregin, G. F., Mackie, J. B., & Monroe, R. R. J. (1974). Heart rate changes in the horse to human contact. Psychophysiology, 11(4), 472–478.
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