Byrne, R. W. (2002). Imitation of novel complex actions: What does the evidence from animals mean? In C. T. Snowdon, T. J. Roper, & J. S. Rosenblatt (Eds.), Advances in the Study of Behavior (Vol. 31, pp. 77–105). San Diego: Academic Press.
Abstract: Summary Underlying the various behaviors that are classified as imitation, there may be several distinct mechanisms, differing in adaptive function, cognitive basis, and computational power. Experiments reporting “true motor imitation” in animals do not as yet give evidence of production learning by imitation; instead, contextual imitation can explain their data, and this can be explained by a simple mechanism (response facilitation) which matches known neural findings. When imitation serves a function in social mimicry, which applies to a wide range of phenomena from neonatal imitation in humans and great apes to pair-bonding in some bird species, the fidelity of the behavioral match is crucial. Learning of novel behavior can potentially be achieved by matching the outcome of a model's action, and it is argued that vocal imitation by birds is a clear example of this method (which is sometimes called emulation). Alternatively, the behavior itself may be perceived in terms of actions that the observer can perform, and thus it may be copied. If the imitation is linear and stringlike (action level), following the surface form rather than the underlying plan, then its utility for learning new instrumental methods is limited. However, the underlying plan of hierarchically organized behavior is visible in output behavior, in subtle but detectable ways, and imitation could instead be based on this organization (program level), extracted automatically by string parsing. Currently, the most likely candidates for such capacities are all great apes. It is argued that this ability to perceive the underlying plan of action, in addition to allowing highly flexible imitation of novel instrumental methods, may have resulted in the competence to understand the intentions (theory of mind) of others.
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Barton, R. A., Byrne, R. W., & Whiten, A. (1996). Ecology, feeding competition and social structure in baboons. Behav. Ecol. Sociobiol., 38(5), 321–329.
Abstract: Predictions of the model of van Schaik (1989) of female-bonding in primates are tested by systematically comparing the ecology, level of within-group contest competition for food (WGC), and patterns of social behaviour found in two contrasting baboon populations. Significant differences were found in food distribution (percentage of the diet from clumped sources), feeding supplant rates and grooming patterns. In accord with the model, the tendencies of females to affiliate and form coalitions with one another, and to be philopatric, were strongest where ecological conditions promoted WGC. Group fission in the population with strong WGC was “horizontal” with respect to female dominance rank, and associated with female-female aggression during a period of elevated feeding competition. In contrast, where WGC was low, females' grooming was focused on adult males rather than other females. Recent evidence suggests that group fission here is initiated by males, tends to result in the formation of one-male groups, and is not related to feeding competition but to male-male competition for mates. An ecological model of baboon social structure is presented which incorporates the effects of female-female competition, male-male competition, and predation pressure. The model potentially accounts for wide variability in group size, group structure and social relationships within the genus Papio. Socio-ecological convergence between common baboons and hamadryas baboons, however, may be limited in some respects by phylogenetic inertia.
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Topál, J., Byrne, R. W., Miklósi, Á., & Csányi, V. (2006). Reproducing human actions and action sequences: “Do as I Do!” in a dog. Anim. Cogn., 9(4), 355–367.
Abstract: We present evidence that a dog (Philip, a 4-year-old tervueren) was able to use different human actions as samples against which to match his own behaviour. First, Philip was trained to repeat nine human-demonstrated actions on command ('Do it!'). When his performance was markedly over chance in response to demonstration by one person, testing with untrained action sequences and other demonstrators showed some ability to generalise his understanding of copying. In a second study, we presented Philip with a sequence of human actions, again using the 'Do as I do' paradigm. All demonstrated actions had basically the same structure: the owner picked up a bottle from one of six places; transferred it to one of the five other places and then commanded the dog ('Do it!'). We found that Philip duplicated the entire sequence of moving a specific object from one particular place to another more often than expected by chance. Although results point to significant limitations in his imitative abilities, it seems that the dog could have recognized the action sequence, on the basis of observation alone, in terms of the initial state, the means, and the goal. This suggests that dogs might acquire abilities by observation that enhance their success in complex socio-behavioural situations.
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Held, S., Baumgartner, J., Kilbride, A., Byrne, R. W., & Mendl, M. (2005). Foraging behaviour in domestic pigs (Sus scrofa): remembering and prioritizing food sites of different value. Anim. Cogn., 8(2), 114–121.
Abstract: This experiment investigated whether domestic pigs can remember the locations of food sites of different relative value, and how a restricted retrieval choice affects their foraging behaviour. Nine juvenile female pigs were trained to relocate two food sites out of a possible eight in a spatial memory task. The two baited sites contained different amounts of food and an obstacle was added to the smaller amount to increase handling time. On each trial, a pig searched for the two baited sites (search visit). Once it had found and eaten the bait, it returned for a second (relocation) visit, in which the two same sites were baited. Baited sites were changed between trials. All subjects learnt the task. When allowed to retrieve both baits, the subjects showed no preference for retrieving a particular one first (experiment 1). When they were allowed to retrieve only one bait, a significant overall preference for retrieving the larger amount emerged across subjects (experiment 2). To test whether this preference reflected an avoidance of the obstacle with the smaller bait, 15 choice-restricted control trials were conducted. In control trials obstacles were present with both baits. Pigs continued to retrieve the larger bait, indicating they had discriminated between the two food sites on the basis of quantity or profitability and adjusted their behaviour accordingly when the relocation choice was restricted. This suggests for the first time that domestic pigs have the ability to discriminate between food sites of different relative value and to remember their respective locations.
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Byrne, R. W. (1999). Imitation without intentionality. Using string parsing to copy the organization of behaviour. Anim. Cogn., 2(2), 63–72.
Abstract: A theory of imitation is proposed, string parsing, which separates the copying of behavioural organization by observation from an understanding of the cause of its effectiveness. In string parsing, recurring patterns in the visible stream of behaviour are detected and used to build a statistical sketch of the underlying hierarchical structure. This statistical sketch may in turn aid the subsequent comprehension of cause and effect. Three cases of social learning of relatively complex skills are examined, as potential cases of imitation by string parsing. Understanding the basic requirements for successful string parsing helps to resolve the conflict between mainly negative reports of imitation in experiments and more positive evidence from natural conditions. Since string parsing does not depend on comprehension of the intentions of other agents or the everyday physics of objects, separate tests of these abilities are needed even in animals shown to learn by imitation.
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Byrne, R. W., Corp, N., & Byrne, J. M. (2001). Manual dexterity in the gorilla: bimanual and digit role differentiation in a natural task. Anim. Cogn., 4(3), 347–361.
Abstract: The manipulative actions of mountain gorillas Gorilla g. beringei were examined in the context of foraging on hard-to-process plant foods in the field, in particular those used in tackling thistle Carduus nyassanus. A repertoire of 72 functionally distinct manipulative actions was recorded. Many of these actions were used in several variants of grip, finger(s) and movement path, both by different individuals and by the same individual at different times. The repertoire appears somewhat greater than that observed in comparable studies of monkeys, but a far more striking difference is found in the use of differentiated actions in concert. Mountain gorillas routinely and frequently deal with problems that involve: (1) bimanual role differentiation, with the two hands taking different roles but synchronized in time and space, and (2) digit role differentiation, with independent control of parts of the same hand used for separate purposes at the same time. The independent control that allows these abilities, so crucial to human manual constructional ability, is apparently general in African great apes. Role differentiation, between and within the hand, is evidently a primitive characteristic in the human arsenal of skills.
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Held, S., Mendl, M., Devereux, C., & Byrne, R. W. (2001). Studies in Social Cognition: From Primates to Pigs. Animal Welfare, 10, 209–217.
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Byrne, R. W. (2007). Culture in great apes: using intricate complexity in feeding skills to trace the evolutionary origin of human technical prowess. Phil. Trans. Biol. Sci., 362(1480), 577–585.
Abstract: Geographical cataloguing of traits, as used in human ethnography, has led to the description of “culture” in some non-human great apes. Culture, in these terms, is detected as a pattern of local ignorance resulting from environmental constraints on knowledge transmission. However, in many cases, the geographical variations may alternatively be explained by ecology. Social transmission of information can reliably be identified in many other animal species, by experiment or distinctive patterns in distribution; but the excitement of detecting culture in great apes derives from the possibility of understanding the evolution of cumulative technological culture in humans. Given this interest, I argue that great ape research should concentrate on technically complex behaviour patterns that are ubiquitous within a local population; in these cases, a wholly non-social ontogeny is highly unlikely. From this perspective, cultural transmission has an important role in the elaborate feeding skills of all species of great ape, in conveying the “gist” or organization of skills. In contrast, social learning is unlikely to be responsible for local stylistic differences, which are apt to reflect sensitive adaptations to ecology.
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Bates, L. A., Sayialel, K. N., Njiraini, N. W., Poole, J. H., Moss, C. J., & Byrne, R. W. (2008). African elephants have expectations about the locations of out-of-sight family members. Biol Lett, 4(1), 34–36.
Abstract: Monitoring the location of conspecifics may be important to social mammals. Here, we use an expectancy-violation paradigm to test the ability of African elephants (Loxodonta africana) to keep track of their social companions from olfactory cues. We presented elephants with samples of earth mixed with urine from female conspecifics that were either kin or unrelated to them, and either unexpected or highly predictable at that location. From behavioural measurements of the elephants' reactions, we show that African elephants can recognize up to 17 females and possibly up to 30 family members from cues present in the urine-earth mix, and that they keep track of the location of these individuals in relation to themselves.
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Byrne, R. W., & Bates, L. A. (2006). Why are animals cognitive? Curr Biol, 16(12), R445–8.
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