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Sousa, C., Okamoto, S., & Matsuzawa, T. (2003). Behavioural development in a matching-to-sample task and token use by an infant chimpanzee reared by his mother. Anim. Cogn., 6(4), 259–267.
Abstract: We investigated the behavioural and cognitive development of a captive male infant chimpanzee, Ayumu, raised by his mother, Ai. Here we report Ayumu's achievements up to the age of 2 years and 3 months, in the context of complex computer-controlled tasks. From soon after birth, Ayumu had been present during an experiment performed by his mother. The task consisted of two phases, a matching-to-sample task in which she received token rewards, and the insertion of these tokens into a vending machine to obtain food rewards. Ayumu himself received no reward or encouragement from humans for any of the actions he exhibited during the experiment. At the age of 9 months and 3 weeks, Ayumu performed his first matching-to-sample trial. At around 1 year and 3 months, he began to perform them consistently. Also during this period, he frequently stole food rewards from his mother. At 2 years and 3 months, Ayumu succeeded for the first time in inserting a token into the vending machine. Once he had succeeded in using a token, he performed both phases of the task in sequence 20 times consecutively. The infant's behaviour was not shaped by food rewards but by a strong motivation to copy his mother's behaviour. Our observations of Ayumu thus mirror the learning processes shown by wild chimpanzees.
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Biro, D., Inoue-Nakamura, N., Tonooka, R., Yamakoshi, G., Sousa, C., & Matsuzawa, T. (2003). Cultural innovation and transmission of tool use in wild chimpanzees: evidence from field experiments. Anim. Cogn., 6(4), 213–223.
Abstract: Chimpanzees (Pan troglodytes) are the most proficient and versatile users of tools in the wild. How such skills become integrated into the behavioural repertoire of wild chimpanzee communities is investigated here by drawing together evidence from three complementary approaches in a group of oil-palm nut- ( Elaeis guineensis) cracking chimpanzees at Bossou, Guinea. First, extensive surveys of communities adjacent to Bossou have shown that population-specific details of tool use, such as the selection of species of nuts as targets for cracking, cannot be explained purely on the basis of ecological differences. Second, a 16-year longitudinal record tracing the development of nut-cracking in individual chimpanzees has highlighted the importance of a critical period for learning (3-5 years of age), while the similar learning contexts experienced by siblings have been found to result in near-perfect (13 out of 14 dyads) inter-sibling correspondence in laterality. Third, novel data from field experiments involving the introduction of unfamiliar species of nuts to the Bossou group illuminates key aspects of both cultural innovation and transmission. We show that responses of individuals toward the novel items differ markedly with age, with juveniles being the most likely to explore. Furthermore, subjects are highly specific in their selection of conspecifics as models for observation, attending to the nut-cracking activities of individuals in the same age group or older, but not younger than themselves. Together with the phenomenon of inter-community migration, these results demonstrate a mechanism for the emergence of culture in wild chimpanzees.
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Ray, E. D., & Heyes, C. M. (2002). Do rats in a two-action test encode movement egocentrically or allocentrically? Anim. Cogn., 5(4), 245–252.
Abstract: Two-action tests of imitation compare groups that observe topographically different responses to a common manipulandum. The general aim of the two experiments reported here was to find a demonstrator-consistent responding effect in a procedure that could be elaborated to investigate aspects of what was learned about the demonstrated lever response. Experiment 1 was a pilot study with rats of a variant of the two-action method of investigating social learning about observed responses. Groups of observer rats ( Rattus norvegicus) saw a demonstrator push a lever up or down for a food reward. When these observers were subsequently given access to the lever and rewarded for responses in both directions, their directional preferences were compared with two 'screen control' groups that were unable to see their demonstrators' behaviour. Demonstrator-consistent responding was found to be restricted to observers that were able to see demonstrator performance, suggesting that scent cues alone were insufficient to cue a preference for the demonstrators' response direction and thereby that the rats learned by observation about body movements (imitation) or lever movement (emulation). Experiment 2 assessed responding on two levers, one that had been manipulated by the demonstrator, and a second, transposed lever positioned some distance away. Demonstrator-consistent responding was abolished when actions were observed and performed in different parts of the apparatus, suggesting that observed movement was encoded allocentrically with respect to the apparatus rather than egocentrically with respect to the actor's body. With particular reference to the influence of scent cues, the results are discussed in relation to the strengths and weaknesses of this and other varieties of the two-action procedure as tests of imitation in animals and human infants.
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Caldwell, C. A., & Whiten, A. (2002). Evolutionary perspectives on imitation: is a comparative psychology of social learning possible? Anim. Cogn., 5(4), 193–208.
Abstract: Studies of imitation in animals have become numerous in recent times, but do they contribute to a comparative psychology of social learning? We review this burgeoning field to identify the problems and prospects for such a goal. Difficulties of two main kinds are identified. First, researchers have tackled questions about social learning from at least three very different theoretical perspectives, the “phylogenetic”, “animal model”, and “adaptational”. We examine the conflicts between them and consider the scope for integration. A second difficulty arises in the methodological approaches used in the discipline. In relation to one of these – survey reviews of published studies – we tabulate and compare the contrasting conclusions of nine articles that together review 36 studies. The basis for authors' disagreements, including the matters of perceptual opacity, novelty, sequential structure, and goal representation, are examined. In relation to the other key method, comparative experimentation, we identify 12 studies that have explicitly compared species' imitative ability on similar tasks. We examine the principal problems of comparing like with like in these studies and consider solutions, the most powerful of which we propose to be the use of a systematic range of task designs, rather than any single “gold standard” task.
Keywords: Animals; *Behavior, Animal; Evolution; Humans; *Imitative Behavior; Learning; Models, Animal
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Bjorklund, D. F., Yunger, J. L., Bering, J. M., & Ragan, P. (2002). The generalization of deferred imitation in enculturated chimpanzees (Pan troglodytes). Anim. Cogn., 5(1), 49–58.
Abstract: Deferred imitation of object-related actions and generalization of imitation to similar but not identical tasks was assessed in three human-reared (enculturated) chimpanzees, ranging in age from 5 to 9 years. Each ape displayed high levels of deferred imitation and only slightly lower levels of generalization of imitation. The youngest two chimpanzees were more apt to generalize the model's actions when they had displayed portions of the target behaviors at baseline, consistent with the idea that learning is more likely to occur when working within the “zone of proximal development.” We argue that generalization of imitation is the best evidence to date of imitative learning in chimpanzees.
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Subiaul, F., Cantlon, J. F., Holloway, R. L., & Terrace, H. S. (2004). Cognitive imitation in rhesus macaques. Science, 305(5682), 407–410.
Abstract: Experiments on imitation typically evaluate a student's ability to copy some feature of an expert's motor behavior. Here, we describe a type of observational learning in which a student copies a cognitive rule rather than a specific motor action. Two rhesus macaques were trained to respond, in a prescribed order, to different sets of photographs that were displayed on a touch-sensitive monitor. Because the position of the photographs varied randomly from trial to trial, sequences could not be learned by motor imitation. Both monkeys learned new sequences more rapidly after observing an expert execute those sequences than when they had to learn new sequences entirely by trial and error.
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Nicol, C. J. (2004). Development, direction, and damage limitation: social learning in domestic fowl. Learn Behav, 32(1), 72–81.
Abstract: This review highlights two areas of particular interest in the study of social learning in fowl. First, the role of social learning in the development of feeding and foraging behavior in young chicks and older birds is described. The role of the hen as a demonstrator and possible teacher is considered, and the subsequent social influence of brood mates and other companions on food avoidance and food preference learning is discussed. Second, the way in which work on domestic fowl has contributed to an understanding of the importance of directed social learning is examined. The well-characterized hierarchical social organization of small chicken flocks has been used to design studies which demonstrate that the probability of social transmission is strongly influenced by social relationships between birds. The practical implications of understanding the role of social learning in the spread of injurious behaviors in this economically important species are briefly considered.
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Horner, V., Whiten, A., Flynn, E., & de Waal, F. B. M. (2006). Faithful replication of foraging techniques along cultural transmission chains by chimpanzees and children. Proc. Natl. Acad. Sci. U.S.A., 103(37), 13878–13883.
Abstract: Observational studies of wild chimpanzees (Pan troglodytes) have revealed population-specific differences in behavior, thought to represent cultural variation. Field studies have also reported behaviors indicative of cultural learning, such as close observation of adult skills by infants, and the use of similar foraging techniques within a population over many generations. Although experimental studies have shown that chimpanzees are able to learn complex behaviors by observation, it is unclear how closely these studies simulate the learning environment found in the wild. In the present study we have used a diffusion chain paradigm, whereby a behavior is passed from one individual to the next in a linear sequence in an attempt to simulate intergenerational transmission of a foraging skill. Using a powerful three-group, two-action methodology, we found that alternative methods used to obtain food from a foraging device (“lift door” versus “slide door”) were accurately transmitted along two chains of six and five chimpanzees, respectively, such that the last chimpanzee in the chain used the same method as the original trained model. The fidelity of transmission within each chain is remarkable given that several individuals in the no-model control group were able to discover either method by individual exploration. A comparative study with human children revealed similar results. This study is the first to experimentally demonstrate the linear transmission of alternative foraging techniques by non-human primates. Our results show that chimpanzees have a capacity to sustain local traditions across multiple simulated generations.
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Zentall, T. R. (2006). Imitation: definitions, evidence, and mechanisms. Anim. Cogn., 9(4), 335–353.
Abstract: Imitation can be defined as the copying of behavior. To a biologist, interest in imitation is focused on its adaptive value for the survival of the organism, but to a psychologist, the mechanisms responsible for imitation are the most interesting. For psychologists, the most important cases of imitation are those that involve demonstrated behavior that the imitator cannot see when it performs the behavior (e.g., scratching one's head). Such examples of imitation are sometimes referred to as opaque imitation because they are difficult to account for without positing cognitive mechanisms, such as perspective taking, that most animals have not been acknowledged to have. The present review first identifies various forms of social influence and social learning that do not qualify as opaque imitation, including species-typical mechanisms (e.g., mimicry and contagion), motivational mechanisms (e.g., social facilitation, incentive motivation, transfer of fear), attentional mechanisms (e.g., local enhancement, stimulus enhancement), imprinting, following, observational conditioning, and learning how the environment works (affordance learning). It then presents evidence for different forms of opaque imitation in animals, and identifies characteristics of human imitation that have been proposed to distinguish it from animal imitation. Finally, it examines the role played in opaque imitation by demonstrator reinforcement and observer motivation. Although accounts of imitation have been proposed that vary in their level of analysis from neural to cognitive, at present no theory of imitation appears to be adequate to account for the varied results that have been found.
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Nguyen, N. H., Klein, E. D., & Zentall, T. R. (2005). Imitation of a two-action sequence by pigeons. Psychon Bull Rev, 12(3), 514–518.
Abstract: Developmental psychologists have described imitation as a process that suggests perspective-taking abilities. However, imitative behavior has been found in animals, which are generally not considered capable of taking the perspective of another. Previous studies with birds have demonstrated the imitation of a single response (sometimes referred to as action-level imitation). In the present experiment, we examined the extent to which pigeons would imitate an unfamiliar sequence of two behaviors (sometimes referred to as program-level imitation). Our results indicate that, although there are individual differences, pigeons show a significant tendency to match a demonstrated sequence of behavior involving, first, a response to a treadle (pecking at it or stepping on it) and, second, pushing aside a screen that blocks access to food (a left-vs.-right push).
Keywords: Animals; Behavior, Animal; *Cognition; Columbidae; *Imitative Behavior; *Learning
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