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Beaugrand, J. P. (1997). Relative importance of initial individual differences, victory and defeat experiences, and assessment accuracy during hierarchy formation: A simulation study (Vol. 41). Elsevier.
Abstract: This simulation study explores some conditions leading to transitivity within dominance orders. Combinations of three parameters were varied to study their consequences upon hierarchy formation and upon the degree of linearity of resultant structures. The factors studied were (i) the importance of initial Resource Holding Potentials (RHPs) , (ii) changes brought in RHPs by successive victories and defeats, and (iii) accuracy of RHP assessment made by opponents. Results show that initial differences in RHP always lead to perfectly transitive chains whose rank order reflects the importance of initial differences. Even when simulated animals make important errors while assessing each other during round robin tournaments, emerging dominance structures are perfectly linear and ranks obtained in the structure are highly correlated with initial values in RHPs. Moreover, accumulated experiences of victory and/or defeat alone always lead to perfectly linear hierarchies. Their combination with initial individual differences in RHP led to the same conclusion. Even when assessment was far from being perfect, not only perfect chains were formed but initial values in RHPs significantly influenced rank order when the contribution of victory and defeat to RHP was relatively unimportant. The higher the importance of victory and defeat to RHP as compared to that of initial RHP values, the lower was the correlation between initial RHP values and the ranks order reached by individuals in the resultant hierarchies. In general also, the lower the variation within initial RHPs, the lower was the correlation between initial RHPs and ranks in the hierarchy. At a given level of initial RHP dispersion, increasing the contribution of victory and defeat to RHP diminished the correlation between initial RHP values and obtained ranks. In addition, inaccurate assessment reduced the overall correlation, especially when dispersion of initial RHP values was low and the contribution of victory and defeat was high. These results shed some light on the controversy about the respective roles of initial individual attributes and that of patterns of resolution in the formation of animal hierarchies. We present the emergence of social order within closed systems as those simulated here as a case of self-organization.
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Valderrabano-Ibarra, C., Brumon, I., & Drummond, H. (2007). Development of a linear dominance hierarchy in nestling birds. Anim. Behav., 74(6), 1705–1714.
Abstract: Theoreticians propose that trained winning and losing are important processes in creating linear animal dominance hierarchies, and experiments have shown that both processes can occur in animals, but their actual roles in creating natural hierarchies are unknown. We described agonism in 18 broods of three blue-footed boobies, Sula nebouxii, a species for which trained winning and losing have been demonstrated, to infer how these processes generate and maintain a natural hierarchy. Ranks in the linear hierarchy that emerged in every brood were initially assigned by asymmetries in age, size and maturity, which led to differences between broodmates in levels of expressed and received aggression and, consequently, to differences in the training of their aggressiveness and submissiveness. Later, ranks appeared to be maintained by the chicks' acquired aggressive and submissive tendencies combined with ongoing effects of persisting differences in size and maturity. Our results suggest that trained winning and trained losing are important in the construction of booby hierarchies but that these two axes of learning are largely independent. Increase in submissiveness occurs over a period of about 10-20 days, and the level of submissiveness reached varies with the amount of aggression received. After training, submissiveness is apparently maintained by a lower level of aggression and increasing use of threats. Threats become increasingly effective as chicks age, but are never as effective as attacks.
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Sato, W., & Aoki, S. (2006). Right hemispheric dominance in processing of unconscious negative emotion. Brain and Cognition, 62(3), 261–266.
Abstract: Right hemispheric dominance in unconscious emotional processing has been suggested, but remains controversial. This issue was investigated using the subliminal affective priming paradigm combined with unilateral visual presentation in 40 normal subjects. In either left or right visual fields, angry facial expressions, happy facial expressions, or plain gray images were briefly presented as negative, positive, and control primes, followed by a mosaic mask. Then nonsense target ideographs were presented, and the subjects evaluated their partiality toward the targets. When the stimuli were presented in the left, but not the right, visual fields, the negative primes reduced the subjects' liking for the targets, relative to the case of the positive or control primes. These results provided behavioral evidence supporting the hypothesis that the right hemisphere is dominant for unconscious negative emotional processing.
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Scordato, E. S., & Drea, C. M. (2007). Scents and sensibility: information content of olfactory signals in the ringtailed lemur, Lemur catta. Anim. Behav., 73(2), 301–314.
Abstract: The function of olfactory signalling in social species is less well understood than in asocial species. Consequently, we examined olfactory communication in the ringtailed lemur, a socially complex primate that retains a functional vomeronasal organ, has well-developed scent glands and shows a suite of scent-marking behaviour. To assess the information content of different types of scent gland secretions, we decoupled olfactory cues from the visual and behavioural modalities with which scent marking is normally associated. We presented male and female subjects (signal receivers) with a series of choice tests between odours derived from conspecific donors (signal senders) varying by sex, age, social status and reproductive condition. We additionally examined the influence of the receivers' reproductive state and familiarity with the signaller. The reproductive condition, social status and familiarity of senders and receivers affected signal transmission; specifically, male receivers attended most to the odours of conspecifics in breeding condition and to the odours of familiar, dominant animals. By contrast, females varied their responses according to both their own reproductive state and that of the sender. Based on male and female patterns of countermarking, we suggest that scent marking serves a function in intergroup spacing and intrasexual competition for both sexes, as might be expected in a female-dominant species. By contrast, minimal female interest in male odours counters a female mate choice function for scent marking in this species. Nevertheless, scent marks are critical to male-male competition and, therefore, may be subject to sexual selection.
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Ostner, J., Heistermann, M., & Schülke, O. (2008). Dominance, aggression and physiological stress in wild male Assamese macaques (Macaca assamensis). Hormones and Behavior, 54(5), 613–619.
Abstract: In group-living animals relative rank positions are often associated with differences in glucocorticoid output. During phases of social stability, when dominance positions are clear and unchallenged, subordinates often face higher costs in terms of social stress than dominant individuals. In this study we test this prediction and examine additional potential correlates of stress, such as reproductive season, age and amount of aggression received in wild, seasonally breeding Assamese macaques (Macaca assamensis). During a mating and a non-mating season we collected 394 h of focal observational data and 440 fecal samples of six adult and six large subadult males living in a multimale-multifemale group in their natural habitat in northeastern Thailand. The mating season was characterized by a general increase in aggressive behavior and glucocorticoid excretion across all males compared to the non-mating season. Among adult males, mating season glucocorticoid levels were significantly negatively related with dominance rank and positively with the amount of aggression received. Both relationships were non-significant among large subadult males. Thus, our results suggest that in adult Assamese macaques a high dominance position is not associated with high costs. Low costs of dominance might be induced by strong social bonds among top-ranking males, which exchange frequent affiliative interactions and serve as allies in coalitionary aggression against potentially rank-challenging subordinate males.
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Hewitt, S. E., Macdonald, D. W., & Dugdale, H. L. (2009). Context-dependent linear dominance hierarchies in social groups of European badgers, Meles meles. Anim. Behav., 77(1), 161–169.
Abstract: A social hierarchy is generally assumed to exist in those mammalian societies in which the costs and benefits of group living are distributed unevenly among group members. We analysed infrared closed-circuit television footage, collected over 3 years in Wytham Woods, Oxfordshire, to test whether social groups of European badgers have dominance hierarchies. Analysis of directed aggression between dyads revealed linear dominance hierarchies in three social-group-years, but patterns within social groups were not consistent across years. Dominance hierarchies were significantly steeper than random in five out of six social-group-years. In those social-group-years where a linear hierarchy was determined, there was an effect of sex on dominance rank, with females gaining significantly higher rank than males in two social-group-years. Overall, rank was not related to age, nor did it appear to affect the likelihood of an individual being wounded, or an individual's breeding status. The latter resulted from nonorthogonality between sex and breeding status, as there were only two breeding males. Overall, hierarchies were primarily dominated by breeding females, and may occur when breeding competition arises. Relatedness, unreciprocated allogrooming and sequential allomarking were not consistently related to levels of directed aggression across social-group-years. We suggest that dominance structures within European badger groups may be context dependent, with future study required to complete our understanding of where, and when, they arise.
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Anderson, W. D., & Summers, C. H. (2007). Neuroendocrine Mechanisms, Stress Coping Strategies, and Social Dominance: Comparative Lessons about Leadership Potential. Ann Am Acad Polit Soc Sci, 614(1), 102–130.
Abstract: The authors examine dominance and subordination in the social psychology, political science, and biology literatures. Using Summers and Winberg (2006) as a guide, the authors suggest that extreme dominance or subordination phenotypes--including social dominance orientation and right-wing authoritarianism--are determined by an organism's genetic predispositions, motivations, stress responses, and long-term hormone release and uptake states. The authors offer hypotheses about the likely neurochemical profiles for each of these extreme dominance and subordination phenotypes and suggest two designs that begin to test these hypotheses.
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Jennings, D. J., Carlin, C. M., & Gammell, M. P. (2009). A winner effect supports third-party intervention behaviour during fallow deer, Dama dama, fights. Anim. Behav., 77(2), 343–348.
Abstract: Male ungulates engage in intense competition for access to females during the breeding season. Although fights are generally dyadic level encounters, they are on occasion disrupted by the intervention of third-party males. We investigated these third-party interventions using predictions derived from Dugatkin's model (Dugatkin 1998, Proceedings of the Royal Society of London, Series B, 265, 433-437) of intervention behaviour. The model argues that when an individual successfully defeats an opponent there is an increase in the probability of winning a subsequent contest: a winner effect. Third-party intervention behaviour is predicted to occur as it serves to prevent either member of a competing dyad from successfully defeating his opponent, achieving a winner effect and subsequently becoming a threat to the intervener. Consistent with model predictions, our results show that intervening males held significantly higher rank than males that did not intervene and were also more likely to be dominant to both of the competing males. Intervening males did not selectively target competitors based on rank, nor did they target males based on overall dyadic rates of aggression between the intervener and competing males. Furthermore, interveners were more likely to have won their interaction immediately prior to intervention and were also likely to win their interaction subsequent to intervention when compared with contest success of the two competing males. Our results are consistent with predictions that support a winner effect for intervention behaviour in fallow deer fights.
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Heitor, F., & Vicente, L. (2010). Dominance relationships and patterns of aggression in a bachelor group of Sorraia horses (Equus caballus). J. Ethol., 28(1), 35–44.
Abstract: Abstract The influence of individual factors on dominance rank and the relationship between rank distance and patterns of aggression predicted by models of evolutionarily stable strategies (ESS) of animal conflict were investigated in a managed bachelor group of Sorraia horses, Equus caballus. The group was composed of four to six stallions 3- to 12-years-old during the study period. The dominance hierarchy was significantly linear and rank was not related to age, weight, height or aggressiveness. Frequency and intensity of agonistic interactions were low, but higher-ranking stallions did not receive lower aggressiveness than lower-ranking stallions. There was some evidence that dominance relationships were more contested among close-ranking stallions, as predicted. Agonistic-related interactions among close-ranking stallions served similar functions to those among distant-ranking stallions, but the latter interacted more frequently than expected for access to resting sites and/or resting partners. Therefore, we found some evidence that agonistic-related interactions among distant-ranking stallions play a larger role in providing access to valuable and defendable resources than those among close-ranking stallions. Nevertheless, the fact that space to escape from aggression was limited and breeding access was independent from dominance rank may have reduced the benefits relative to costs of aggression and therefore limited the occurrence of contests over dominance and resources.
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Heitor, F., & Vicente, L. (2010). Affiliative relationships among Sorraia mares: influence of age, dominance, kinship and reproductive state. J. Ethol., 28(1), 133–140.
Abstract: Abstract Affiliative relationships among mares were examined in a managed group of Sorraia horses, Equus caballus, over a 3-year period. We assessed the influence of age, dominance, kinship and reproductive state on the strength of affiliative relationships and diversity of partners. The herd comprised 9–11 mares that had known each other since birth, their foals and a stallion that remained in the group exclusively during the breeding season. In contrast to a previous study, kinship did not significantly affect bonds. Mares tended to spend more time in proximity to those in the same reproductive state. Affiliative relationships among mares were relatively stable but their strength decreased after foaling, possibly as a function of foal protection and bonding between dam and foal. There was no consistent evidence that mares disengaged from affiliative relationships with increasing age. As expected, dominant mares and barren mares contributed the most to affiliative relationships. Dominance rank increased with age, but dominance relationships were stable and did not change after foaling. Overall, reproductive state was the factor that had the most consistent influence on affiliative relationships among Sorraia mares.
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