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Earley, R. L., Druen, M., & Alan Dugatkin, L. (2005). Watching fights does not alter a bystander's response towards naive conspecifics in male green swordtail fish, Xiphophorus helleri. Anim. Behav., 69(5), 1139–1145.
Abstract: Bystanders are capable of extracting cues from signalling interactions between others and appear to use information gained via eavesdropping when confronted with the watched individuals. A question that has gained little attention is whether observing fights affects bystander behaviour outside the context of interacting with the watched individuals. Our aim was to determine whether watching fights elicits general changes in bystander aggression levels in Xiphophorus helleri. We manipulated the bystanders' ability to witness encounters using clear, one-way-mirror and opaque partitions. After watching (or not watching) an initial contest, the bystanders were pitted against naive conspecifics instead of the animals they had seen fight. Observing fights did not alter the bystanders' propensity to initiate aggression, escalate, or win against naive individuals, indicating that bystanders do not experience general changes in aggressive behaviour after watching a fight. Earlier work in this species, however, has shown that bystanders respond in predictable ways to individuals they have witnessed winning or losing a fight. Taken together, these data support the notion that bystanders consistently modify their behaviour towards previously watched winners or losers in response to information gained via eavesdropping. We discuss our results in light of some recent work on the behavioural and endocrinological responses triggered by watching fights and suggest that comparative approaches to understanding networking phenomena may be productive.
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Judge, P. G., & Mullen, S. H. (2005). Quadratic postconflict affiliation among bystanders in a hamadryas baboon group. Anim. Behav., 69(6), 1345–1355.
Abstract: The tendency in primate groups for two opponents to affiliate shortly after a fight has been described as dyadic reconciliation. The response has been shown to restore disrupted relationships and curtail ongoing aggression. Rates of self-directed behaviour (e.g. scratching) are positively correlated with anxiety in primates and the rates decline after reconciliation, indicating that the response also functions to reduce postconflict tension. Third parties not involved in an aggressive interaction are also likely to affiliate with one of the combatants subsequent to a fight. Such `triadic' interactions may also promote conflict resolution when, for instance, the relatives of a victim affiliate with their relative's aggressor. Because aggression in a group influences a bystander's behaviour with combatants, we hypothesized that aggression between two animals would also influence a bystander's behaviour with other bystanders. Such `quadratic' postconflict interactions might also function to reduce postconflict tension or occur in patterns among kin subgroups to resolve conflict. We tested for quadratic interactions in an 18-member group of captive hamadryas baboons, Papio hamadryas hamadryas. Immediately following a fight, an uninvolved bystander was randomly selected for observation and its affiliative interactions with other bystanders and its displacement activities were recorded for 3 min. Rates of behaviour during these postconflict periods were compared to rates during 3-min baseline periods not preceded by aggression. Bystanders engaged in quadratic interactions by increasing affiliation with other bystanders following aggression. Bystanders directed affiliation to nonkin bystanders that were their preferred social partners. Displacement activities of bystanders were significantly higher during postconflict intervals compared to baseline intervals, and bystander displacement activity levels before affiliative contact with other bystanders were significantly higher than after contact. Apparently, bystanders become tense or anxious after witnessing aggression and affiliate with preferred partners to reduce the arousal.
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Huebener, E. (2005). Der Natur abgelauschte Erkenntnisse: Der Weg zum Balancesitz und zum Begreifen des Timers für Signale an das Pferd;. Tierärztl. Umschau, 2, 90–99.
Abstract: Zusammenfassung
Mit dem Beitrag “Die Bewegungen von Pferderumpf und -rücken aus der Sicht des Reiters” (TU 59, 327-334, 2004) wurde um universitäre Forschung zur Ermittlung gemessener Werte für diese Begleiter der Fortbewegung geworben.
Die Entdeckung des Ranges der Rumpf-Rücken-Bewegungen für pferdgerechtes und kultiviertes, feinfühliges Reiten ist mit der Entwicklung des Balancesitzes und der Technik des vom Pferd Zeitvorgaben Empfangens und ihm Signale Sendens (Reiter sagen: des Fühlens und Einwirkens) eng verbunden. Ihre Geschichte läßt sich über viereinhalb Jahrhunderte verfolgen. Ein kurzer Abriß wird hier nachgeliefert.
Er mündet erneut in ein Plädoyer für interdisziplinäres universitäres Forschen, weil auch bei Sitz und Hilfengebung, weiteren Grundlagen des Reitens – im Interesse effektiveren Unterrichts an der Basis unseres “Sports” – dringender Klärungsbedarf besteht.
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Huebener, E. (2005). Listening to Nature: Ways to A Balanced Seat and Understanding the Correct Timing for the Rider's Aids. Tierärztl. Umschau, 2, 90–99.
Abstract: In the publication “Movements of trunk and back of the horse from a riders view” in the TU 59, 327-334, 2004 the author suggested that academic research is necessary to determine measurable parameters for these agents of the horse's movement.
The discovery of the importance of the trunk-back-movements for a sensitive and horse-oriented riding style is closely connected to the development of the balanced seat and the technique of receiving signals from and sending signals to the horse at the right time (riders would say: “the feel and the impact”). The history of this interaction between horse and rider can be traced for four and a half centuries. A short digest will be published here later. Again the studies result in a demand for interdisciplinary academic research.
There is an urgent need to clarify the impact of the riders's seat and aids (two more pillars in the art of riding) in the interest teaching riding correctly and more efficiently at the so-called 'basis' of our sport.
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Huebener, E. (2005). Hilfen für Übergänge von einer Gangart in eine andere ? Die Bewegungen von Pferderumpf und -rücken als Zeitgeber für reiterliche Einwirkung. Trakehner Hefte,, 5-11.
Abstract: Übergänge von einer Gangart in eine andere sind nach Ludwig Koch jeweils nur aus einer ganz bestimmten Phase einer Bewegungsfolge (oder Bewegungsfolgen-Hälfte) der einen in eine ganz bestimmte Bewegungsfolge (oder Bewegungsfolgen-Hälfte) der anderen Gangart möglich.
Diese Phasen dauern nur Bruchteile einer Sekunde an. In diesen Momenten muß die Hilfe nach europäischer klassischer Lehre gegeben, nur in diesen Momenten kann sie vom Pferd blitzartig-automatisch umgesetzt werden. Um die Hilfe im “passenden” Moment geben zu können, braucht der Reiter einen Zeitgeber. Den einzigen verfügbaren, zuverlässigen Timer bilden die Bewegungen des Pferderückens und des Pferderumpfes.
Die Zusammenhänge zwischen den Bewegungsphasen in den Grundgangarten, dem mit frei beweglichem Beckenring allen Bewegungen des Pferderückens folgendem Sitz des Reiters, und dem Schenkel, der von Schritt zu Schritt, von Tritt zu Tritt, von Galoppsprung zu Galoppsprung an den wegschwingenden Pferderumpf fallen möchte bis er das im rechten Augenblick – vom Reiter gesteuert – dann auch darf, sind erstmals in piktogrammartigen Miniaturbild-Folgen leicht verständlich dargestellt.
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Huebener, E. (2005). Rider's Aids for Transitions Between Different Gaits ? The Movements of the Horse's Trunk and Back as Timers for the Rider's Influence. Trakehner Hefte, 5-11.
Abstract: Abstract
According to Ludwig Koch, the horse's transition from one gait to another is only possible during a particular phase in its' movement cycle (respectively in a half of it's movement cycle) in one gait to a particular phase in its' movement cycle (respectively in a half of it's movement cycle) in the other gait.
It only takes a fraction of a second for these movements to occur. It is precisely in these moments that according to the European classical riding school principles the rider has to give the appropriate aids, because only then the horse can execute them in a flash. In order to give the aids in the “fitting” moment, the rider needs a timer. The only available and reliable indicators of the right timing are the movements of the horse's trunk and back.
The connections between the different phases of the movements during the basic gaits, the rider's seat which follows all the movements of the horse's back with a freely rotating pelvis, and the rider's leg which – from step to step, from footfall to footfall, from canter beat to canter beat – wants to follow the horse's swinging trunk (until it is finally – controlled by the rider – free to do so, at the right moment), are being shown for the first time in easy to follow miniature picture sequences.
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Hemelrijk, C. K., & Wantia, J. (2005). Individual variation by self-organisation. Neurosci Biobehav Rev, 29(1), 125–136.
Abstract: In this paper, we show that differences in dominance and spatial centrality of individuals in a group may arise through self-organisation. Our instrument is a model, called DomWorld, that represents two traits that are often found in animals, namely grouping and competing. In this model individual differences grow under the following conditions: (1) when the intensity of aggression increases and grouping becomes denser, (2) when the degree of sexual dimorphism in fighting power increases. In this case the differences among females compared to males grow too, (3) when, upon encountering another individual, the tendency to attack is 'obligate' and not conditional, namely 'sensitive to risks'. Results resemble phenomena described for societies of primates, mice, birds and pigs.
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Hemelrijk, C. K., Wantia, J., & Gygax, L. (2005). The construction of dominance order: comparing performance of five methods using an individual-based model. Behaviour, 142(8), 1043–1064.
Abstract: In studies of animal behaviour investigators correlate dominance with all kinds of behavioural
variables, such as reproductive success and foraging success. Many methods are used to
produce a dominance hierarchy from a matrix reflecting the frequency of winning dominance
interactions. These different methods produce different hierarchies. However, it is difficult to
decide which ranking method is best. In this paper, we offer a new procedure for this decision:
we use an individual-based model, called DomWorld, as a test-environment. We choose this
model, because it provides access to both the internal dominance values of artificial agents
(which reflects their fighting power) and the matrix of winning and losing among them and,
in addition, because its behavioural rules are biologically inspired and its group-level patterns
resemble those of real primates. We compare statistically the dominance hierarchy based on
the internal dominance values of the artificial agents with the dominance hierarchy produced
by ranking individuals by (a) their total frequency of winning, (b) their average dominance
index, (c) a refined dominance index, the David`s score, (d) the number of subordinates each
individual has and (e) a ranking method based on maximizing the linear order of the hierarchy.
Because dominance hierarchies may differ depending on group size, type of society, and the
interval of study, we compare these ranking methods for these conditions.We study complete
samples as well as samples randomly chosen to resemble the limitations of observing real
animals. It appears that two methods of medium complexity (the average dominance index
and David`s score) lead to hierarchical orders that come closest to the hierarchy based on
internal dominance values of the agents. We advocate usage of the average dominance index,
because of its computational simplicity.
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Adams, E. S. (2005). Bayesian analysis of linear dominance hierarchies. Anim. Behav., 69(5), 1191–1201.
Abstract: Studies on social animals often seek to identify dominance hierarchies, in which individuals are ranked according to competitive abilities based on counts of wins and losses in pairwise encounters. I illustrate Bayesian approaches, based on the method of paired comparisons, for determining ranks and for estimating relationships between dominance ability and other attributes. Bayesian inference combines prior probability distributions for each unknown parameter with likelihood functions to produce the joint posterior probability distribution for the quantities of interest. In contrast to nonparametric techniques for inferring ranks, Bayesian models yield measures of certainty for each inference and allow rigorous estimates of correlations between ranks and covariates even when there is considerable uncertainty as to the ranks themselves. A possible objection to the Bayesian approach is that it appears to entail more restrictive assumptions than do simpler methods. However, simulations show that Bayesian inferences are more robust to deviations from these assumptions than are the results of nonparametric methods.
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Hanggi, E. B. (2005). The Thinking Horse: Cognition and Perception. In International Veterinary Information Service (Vol. 51).
Abstract: Cognition and perception in horses has often been misunderstood. Not only in the past but even today, people proclaim that horses react only by instinct, that they are just conditioned-response animals, that they lack advanced cognitive ability, and that they have poor visual capabilities (e.g., acuity, color vision, depth perception). Until relatively recently, there was little scientific evidence to address such beliefs. Change, however, is underway as scientific and public interest in all aspects of equine learning and perception intensifies. A review of the scientific literature, as well as practical experience, shows that horses excel at simpler forms of learning such as classical and operant conditioning, which is not surprising considering their trainability when these principles and practices are applied. Furthermore, horses have shown ease in stimulus generalization and discrimination learning. Most recently and unexpected by many, horses have solved advanced cognitive challenges involving categorization learning and some degree of concept formation. A comprehensive understanding of the cognitive and perceptual abilities of horses is necessary to ensure that this species receives proper training, handling, management, and care.
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