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Huang, S. - P., Yang, S. - Y., & Hsu, Y. (2011). Persistence of Winner and Loser Effects Depends on the Behaviour Measured. Ethology, 117(2), 171–180.
Abstract: Abstract Recent contest experience can influence an individual’s behaviour in subsequent contests. When the probability of winning a subsequent contest is used to quantify experience effects, a loser effect usually lasts longer than a winner effect. This conclusion, however, may be caused by this probability understating the persistence of the influence of a winning experience on contest decisions. Using Kryptolebias marmoratus, a mangrove killifish, as the study organism, we investigated whether different conclusions about the relative persistence of winning and losing experiences would be reached when different aspects of contest behaviour (probability of initiating attacks, probability of winning non-escalated and escalated contests, escalation rate and contest duration) were measured. The results indicated that the apparent persistence of the effect of winning or losing experiences varied with the behaviour studied. When the likelihood to initiate attacks was used, no winner effect was detected while the loser effect lasted for <1 d. When escalation rate was used, the winner effect lasted for 2–4 d, while the loser effect lasted for 1–2 d. When the probability of winning non-escalated contests was used, the winner effect was detectable for <1 d, while the loser effect lasted for 2–4 d. And, when contest duration was used, the winner effect was detectable for 2–4 d, but no loser effect was detectable. These results show that (1) the probability of winning a subsequent contest understated the persistence of the influence of a winning experience on the fish’s contest decisions, (2) the measures most effective at detecting winner effects are different from those most effective at detecting loser effects and (3) in K. marmoratus, both effects can be detected 2 d after the completion of experience training but both dissipate in 4 d.
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Mersmann, D., Tomasello, M., Call, J., Kaminski, J., & Taborsky, M. (2011). Simple Mechanisms Can Explain Social Learning in Domestic Dogs (Canis familiaris). Ethology, 117(8), 675–690.
Abstract: Abstract Recent studies have suggested that domestic dogs (Canis familiaris) engage in highly complex forms of social learning. Here, we critically assess the potential mechanisms underlying social learning in dogs using two problem-solving tasks. In a classical detour task, the test dogs benefited from observing a demonstrator walking around a fence to obtain a reward. However, even inexperienced dogs did not show a preference for passing the fence at the same end as the demonstrator. Furthermore, dogs did not need to observe a complete demonstration by a human demonstrator to pass the task. Instead, they were just as successful in solving the problem after seeing a partial demonstration by an object passing by at the end of the fence. In contrast to earlier findings, our results suggest that stimulus enhancement (or affordance learning) might be a powerful social learning mechanism used by dogs to solve such detour problems. In the second task, we examined whether naïve dogs copy actions to solve an instrumental problem. After controlling for stimulus enhancement and other forms of social influence (e.g. social facilitation and observational conditioning), we found that dogs’ problem solving was not influenced by witnessing a skilful demonstrator (either an unknown human, a conspecific or the dog’s owner). Together, these results add to evidence suggesting that social learning may often be explained by relatively simple (but powerful) mechanisms.
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Noë, R., van Schaik, C. P., & van Hooff, J. A. R. A. M. (1991). The Market Effect: an Explanation for Pay-off Asymmetries among Collaborating Animals. Ethology, 87(1-2), 97–118.
Abstract: Abstract * 1Animals can derive leverage over others from (a) resource holding power, based for instance on fighting ability or dominance, and (b) the possession of commodities, such as special skills and resources that cannot be taken away by force. * 2We contend that power based on the possession of commodities strongly depends on the level of supply and demand for that commodity, a phenomenon we call the ‘market effect’. * 3Several theoretical and empirical examples are given of social systems in which animals belong to two distinct classes that offer two different kinds of commodities. * 4The relative frequency of occurrence of the two classes is shown to determine the relative power of their members. * 5We consider the theoretical properties of bargaining processes by which relative power is converted into corresponding pay-off distributions. * 6We propose coalition games, a class of games with more than two players and in which bargaining is possible, as suitable paradigms for collaboration among members of social units.
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McFarland, R., & Majolo, B. (2011). Reconciliation and the Costs of Aggression in Wild Barbary Macaques (Macaca sylvanus): A Test of the Integrated Hypothesis. Ethology, , no-no.
Abstract: The ‘integrated hypothesis’ predicts that reconciliation (the post-conflict friendly interaction between former opponents observed in various group-living species) functions to reduce anxiety and the risk of aggression from the former opponent or a bystander in the aftermath of a conflict. It also predicts that relationship quality between opponents affects the occurrence of reconciliation and modulates the anxious response of the opponents after a conflict. Because of the asymmetric nature of aggressive interactions, the cost of aggression is likely to differ between the victim and the aggressor. The aim of this study was to test the predictions of the ‘integrated hypothesis’ independently for the victim and the aggressor of a conflict. We collected data on two wild groups of Barbary macaques. This study represents, to our knowledge, the first systematic test of the integrated hypothesis on wild, non-provisioned animals. Victims of aggression were at a greater risk of receiving aggression from the former opponent or a bystander after a conflict and showed elevated anxiety. We found no such costs for the aggressor. Reconciliation reduced anxiety in the victim but did not reduce their risk of receiving aggression. Finally, relationship quality affected the occurrence of reconciliation but did not modulate post-conflict anxiety. The results of our study show that the costs of aggression are asymmetrically distributed between the victim and the aggressor. Such differences are likely to lead to different social tactics used by the victim and the aggressor in the aftermath of a conflict.
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Cain, K. E., Rich, M. S., Ainsworth, K., & Ketterson, E. D. (2011). Two Sides of the Same Coin? Consistency in Aggression to Conspecifics and Predators in a Female Songbird. Ethology, 117(9), 786–795.
Abstract: Different forms of aggression have traditionally been treated separately according to function or context (e.g., aggression towards a conspecific vs. a predator). However, recent work on individual consistency in behavior predicts that different forms of aggression may be correlated across contexts, suggesting a lack of independence. For nesting birds, aggression towards both conspecifics and nest predators can affect reproductive success, yet the relationship between these behaviors, especially in females, is not known. Here, we examine free-living female dark-eyed juncos (Junco hyemalis) and compare their aggressive responses towards three types of simulated intruders near the nest: a same-sex conspecific, an opposite-sex conspecific, and a nest predator. We also examine differences in the strength of response that might relate to the immediacy of the perceived threat the intruder poses for the female or her offspring. We found greater aggression directed towards a predator than a same-sex intruder and towards a same-sex than an opposite-sex intruder, consistent with a predator being a more immediate threat than a same-sex intruder, followed by an opposite-sex intruder. We also found positive relationships across individuals between responses to a same-sex intruder and a simulated predator, and between responses to a same-sex and an opposite-sex intruder, indicating that individual females are consistent in their relative level of aggression across contexts. If correlated behaviors are mediated by related mechanisms, then different forms of aggression may be expressions of the same behavioral tendency and constrained from evolving independently.
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Pays, O., Sirot, E., & Fritz, H. (2011). Collective Vigilance in the Greater Kudu: Towards a Better Understanding of Synchronization Patterns. Ethology, , no-no.
Abstract: Collective detection of predators is one of the main advantages of living in groups in prey species. However, the mechanisms linking individual and collective vigilance remain largely unknown. Here, we investigated individual and collective vigilance in a natural population of greater kudu (Tragelaphus strepsiceros), a gregarious ruminant living under high predation risk. Controlling for environmental, individual and group factors, we show that the proportion of time during which at least one individual was vigilant increased with group size, whereas individual investment in vigilance decreased. We also show that individuals tended to synchronize both vigilance and feeding activities. More generally, and whatever the considered group size, we demonstrate how the independent scanning assumption underestimated both the proportion of time during which no individual was vigilant and the proportion of time during which all individuals were simultaneously vigilant, but overestimated the proportion of time during which one vigilant individual only was present. Our results thus contrast with the point of view that the alternative to independent vigilance is coordinated vigilance and plead for a better description of the processes whereby reciprocal influences between individuals shape collective patterns of vigilance.
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Lancet, Y., & Dukas, R. (2012). Socially Influenced Behaviour and Learning in Locusts. Ethology, 118(3), 302–310.
Abstract: As a part of our research on the evolution of social learning in insects, we examined socially influenced behaviour and social learning in desert locust (Schistocerca gregaria) nymphs and adults. In the nymphs, the only positive effect we documented was an increased tendency to feed while in the company of another locust than alone. The adults, on the other hand, showed significant preference for joining others (local enhancement) in both the contexts of feeding and egg laying. Neither nymphs nor adults, however, showed social learning. Our preliminary analyses pointed to locusts as a likely insect that might possess social learning. Our research, when taken together with research on phase-shifts and swarm/marching behaviour of gregarious locusts, suggests that the behavioural dynamics of gregarious locusts may make local enhancement but not social learning beneficial. The possible difference we documented between the nymphs and adults could enable us to further explore the proximate and ultimate mechanisms that underlie socially influenced behaviour.
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Mettke-Hofmann, C., Winkler, H., & Leisler, B. (2002). The Significance of Ecological Factors for Exploration and Neophobia in Parrots. Ethology, 108(3), 249–272.
Abstract: Exploratory behaviour plays an important role in most animals for gathering information about their environment. If it constitutes an adaptation to different environmental conditions exploratory behaviour should differ between species. This has been tested with several hypotheses. Sixty-one parrot species (Psittacidae) from eight tribes with different diets and habitat preferences were investigated in aviaries. Two tests were carried out. First, a novel object (wooden ring) in the familiar aviary was presented on two test days in the exploration test. Latencies until first contact with the object and the duration of exploration were recorded. Secondly, in the neophobia test, novel objects were placed beside the feeding dish and latencies until first food intake were recorded. The exploration and neophobia data were related to 12 (13) ecological variables using multiple regression analyses. Phylogenetic relationships were considered. Species that inhabit complex habitats, such as forest edges, or that feed on buds or species from islands showed the shortest latencies in the exploration test. In contrast, long latencies were related to a diet including a great amount of seeds and/or flowers. The longest duration of exploration occurred in species eating nuts or originating from islands, whereas short durations were related to feeding on seeds. Neophobia was positively related to a diet consisting of insects, and negatively to a diet of leaves. There was no relationship between measures of exploration and neophobia. Exploration and neophobia seem to be tightly related to the ecology of a species.
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Clucas, B., Marzluff, J. M., Mackovjak, D., & Palmquist, I. (2013). Do American Crows Pay Attention to Human Gaze and Facial Expressions? Ethology, 119(4), 296–302.
Abstract: Interactions between species can lead to the evolution of interspecific communication. Non-verbal communication by humans, both intentional and unintentional, can be interpreted by other species. We tested whether American crows (Corvus brachyrhynchos) were sensitive to human facial features under field conditions by comparing flight initiation distances and urgency of escape behavior to human approaches varying in eye contact and facial expression. We first examined whether crows distinguish between an approaching human who is directly gazing at them and a human approaching them with an averted gaze. In a second experiment, we tested whether crows differentiate a smiling from scowling human approaching them with direct or averted gaze. In the first experiment, we found that crows fled sooner and more urgently when humans were directly gazing at them. Similarly, in the second experiment, crows responded sooner to a direct vs. averted gaze; however, they did not react differently to varying human facial expressions. We suggest that crows use human gaze as a reliable visual cue compared with facial expressions when making decisions about responding to approaching humans. This is the first study to show that a wild corvid species changes its behavior based on human gaze, possibly representing an adaptation to living in human-dominated urban areas and suggesting crows might perceive human intention by this visual cue.
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Briard, L., Dorn, C., & Petit, O. (2015). Personality and Affinities Play a Key Role in the Organisation of Collective Movements in a Group of Domestic Horses. Ethology, 121(9), 888–902.
Abstract: Understanding how groups of individuals with different motives come to daily decisions about the exploitation of their environment is a key question in animal behaviour. While interindividual differences are often seen only as a threat to group cohesion, growing evidence shows that they may to some extent facilitate effective collective action. Recent studies suggest that personality differences influence how individuals are attracted to conspecifics and affect their behaviour as an initiator or a follower. However, most of the existing studies are limited to a few taxa, mainly social fish and arthropods. Horses are social herbivores that live in long-lasting groups and show identifiable personality differences between individuals. We studied a group of 38 individuals living in a 30-ha hilly pasture. Over 200 h, we sought to identify how far individual differences such as personality and affinity distribution affect the dynamic of their collective movements. First, we report that individuals distribute their relationships according to similar personality and hierarchical rank. This is the first study that demonstrates a positive assortment between unrelated individuals according to personality in a mammal species. Second, we measured individual propensity to initiate and found that bold individuals initiated more often than shy individuals. However, their success in terms of number of followers and joining duration did not depend on their individual characteristics. Moreover, joining process is influenced by social network, with preferred partners following each other and bolder individuals being located more often at the front of the movement. Our results illustrate the importance of taking into account interindividual behavioural differences in studies of social behaviours.
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