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Mulcahy, N. J., & Call, J. (2006). How great apes perform on a modified trap-tube task. Anim. Cogn., 9(3), 193–199.
Abstract: To date, neither primates nor birds have shown clear evidence of causal knowledge when attempting to solve the trap tube task. One factor that may have contributed to mask the knowledge that subjects may have about the task is that subjects were only allowed to push the reward away from them, which is a particularly difficult action for primates in certain problem solving situations. We presented five orangutans (Pongo pygmaeus), two chimpanzees (Pan troglodytes), two bonobos (Pan paniscus), and one gorilla (Gorilla gorilla) with a modified trap tube that allowed subjects to push or rake the reward with the tool. In two additional follow-up tests, we inverted the tube 180 degrees rendering the trap nonfunctional and also presented subjects with the original task in which they were required to push the reward out of the tube. Results showed that all but one of the subjects preferred to rake the reward. Two orangutans and one chimpanzee (all of whom preferred to rake the reward), consistently avoided the trap only when it was functional but failed the original task. These findings suggest that some great apes may have some causal knowledge about the trap-tube task. Their success, however, depended on whether they were allowed to choose certain tool-using actions.
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Santos, L. R., Pearson, H. M., Spaepen, G. M., Tsao, F., & Hauser, M. D. (2006). Probing the limits of tool competence: experiments with two non-tool-using species (Cercopithecus aethiops and Saguinus oedipus). Anim. Cogn., 9(2), 94–109.
Abstract: Non-human animals vary in their ability to make and use tools. The goal of the present study was to further explore what, if anything, differs between tool-users and non-tool-users, and whether these differences lie in the conceptual or motor domain. We tested two species that typically do not use tools-cotton top tamarins (Saguinus oedipus) and vervet monkeys (Cercopithecus aethiops)-on problems that mirrored those designed for prolific tool users such as chimpanzees. We trained subjects on a task in which they could choose one of two canes to obtain an out-of-reach food reward. After training, subjects received several variations on the original task, each designed to examine a specific conceptual aspect of the pulling problem previously studied in other tool-using species. Both species recognized that effective pulling tools must be made of rigid materials. Subsequent conditions revealed significant species differences, with vervets outperforming tamarins across many conditions. Vervets, but not tamarins, had some recognition of the relationship between a tool's orientation and the position of the food reward, the relationship between a tool's trajectory and the substance that it moves on, and that tools must be connected in order to work properly. These results provide further evidence that tool-use may derive from domain-general, rather than domain-specific cognitive capacities that evolved for tool use per se.
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Barry, K. L., & Goth, A. (2006). Call recognition in chicks of the Australian brush-turkey (Alectura lathami). Anim. Cogn., 9(1), 47–54.
Abstract: Most birds rely on imprinting and experience with conspecifics to learn species-specific recognition cues. Australian brush-turkeys (Alectura lathami) do not imprint and form no bonds with parents. They hatch asynchronously, disperse widely and meet juvenile conspecifics at an unpredictable age. Nevertheless, in captivity, hatchlings respond to other chicks. A recent study, which involved the use of robotic models, found that chicks prefer to approach robots that emit specific visual cues. Here, we evaluated their response to acoustic cues, which usually play an important role in avian social cognition. However, in simultaneous choice tests, neither 2-day-old nor 9-day-old chicks preferred the choice arm with playback of either chick or adult conspecific calls over the arm containing a silent loudspeaker. Chicks of both age classes, however, scanned their surroundings more during chick playback, and the response was thus consistent in younger and older chicks. We also presented the chicks with robotic models, either with or without playback of chick calls. They did not approach the calling robot more than they did the silent robot, indicating that the combination of visual and acoustic cues does not evoke a stronger response. These results will allow further comparison with species that face similar cognitive demands in the wild, such as brood parasites. Such a comparative approach, which is the focus of cognitive ecology, will enable us to further analyse the evolution and adaptive value of species recognition abilities.
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Virányi, Z., Topál, J., Miklósi, Á., & Csányi, V. (2006). A nonverbal test of knowledge attribution: a comparative study on dogs and children. Anim. Cogn., 9(1), 13–26.
Abstract: The sensitivity of eleven pet dogs and eleven 2.5-year-old children to others' past perceptual access was tested for object-specificity in a playful, nonverbal task in which a human Helper's knowledge state regarding the whereabouts of a hidden toy and a stick (a tool necessary for getting the out-of-reach toy) was systematically manipulated. In the four experimental conditions the Helper either participated or was absent during hiding of the toy and the stick and therefore she knew the place(s) of (1) both the toy and the stick, (2) only the toy, (3) only the stick or (4) neither of them. The subjects observed the hiding processes, but they could not reach the objects, so they had to involve the Helper to retrieve the toy. The dogs were more inclined to signal the place of the toy in each condition and indicated the location of the stick only sporadically. However the children signalled both the location of the toy and that of the stick in those situations when the Helper had similar knowledge regarding the whereabouts of them (i.e. knew or ignored both of them), and in those conditions in which the Helper was ignorant of the whereabouts of only one object the children indicated the place of this object more often than that of the known one. At the same time however, both dogs and children signalled the place of the toy more frequently if the Helper had been absent during toy-hiding compared to those conditions when she had participated in the hiding. Although this behaviour appears to correspond with the Helper's knowledge state, even the subtle distinction made by the children can be interpreted without a casual understanding of knowledge-formation in others.
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Munoz-Sanz, A. (2006). [Christopher Columbus flu. A hypothesis for an ecological catastrophe]. Enferm Infecc Microbiol Clin, 24(5), 326–334.
Abstract: When Christopher Columbus and his men embarked on the second Colombian expedition to the New World (1493), the crew suffered from fever, respiratory symptoms and malaise. It is generally accepted that the disease was influenza. Pigs, horses and hens acquired in Gomera (Canary Islands) traveled in the same ship. The pigs may well have been the origin of the flu and the intermediary hosts for genetic recombination of other viral subtypes. The Caribbean archipelago had a large population of birds, the natural reservoir of the avian influenza virus. In this ecological scenario there was a concurrence of several biological elements that had never before coexisted in the New World: pigs, horses, the influenza virus and humans. We propose that birds are likely to have played an important role in the epidemiology of the flu occurring on the second Colombian trip, which caused a fatal demographic catastrophe, with an estimated mortality of 90% among the natives.
Keywords: Animals; Atlantic Islands; Birds; Chickens; Disease Outbreaks/*history; Disease Reservoirs; Disease Susceptibility; Ecology; Europe/ethnology; History, 15th Century; Horses; Humans; Indians, South American; Influenza A virus/classification/genetics/pathogenicity; Influenza in Birds/epidemiology/history/transmission/virology; Influenza, Human/epidemiology/*history/mortality/transmission; Models, Biological; Orthomyxoviridae Infections/epidemiology/history/veterinary/virology; Poultry Diseases/epidemiology/history/transmission/virology; Reassortant Viruses/genetics/pathogenicity; Species Specificity; Sus scrofa; Swine Diseases/history/transmission/virology; Terminology; West Indies/epidemiology
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Reznikova, Z. I. (2006). [The study of tool use as the way for general estimation of cognitive abilities in animals]. Zh Obshch Biol, 67(1), 3–22.
Abstract: Investigation of tool use is an effective way to determine cognitive abilities of animals. This approach raises hypotheses, which delineate limits of animal's competence in understanding of objects properties and interrelations and the influence of individual and social experience on their behaviour. On the basis of brief review of different models of manipulation with objects and tools manufacturing (detaching, subtracting and reshaping) by various animals (from elephants to ants) in natural conditions the experimental data concerning tool usage was considered. Tool behaviour of anumals could be observed rarely and its distribution among different taxons is rather odd. Recent studies have revealed that some species (for instance, bonobos and tamarins) which didn't manipulate tools in wild life appears to be an advanced tool users and even manufacturers in laboratory. Experimental studies of animals tool use include investigation of their ability to use objects physical properties, to categorize objects involved in tool activity by its functional properties, to take forces affecting objects into account, as well as their capacity of planning their actions. The crucial question is whether animals can abstract general principles of relations between objects regardless of the exact circumstances, or they develop specific associations between concerete things and situations. Effectiveness of laboratory methods is estimated in the review basing on comparative studies of tool behaviour, such as “support problem”, “stick problem”, “tube- and tube-trap problem”, and “reserve tube problem”. Levels of social learning, the role of imprinting, and species-specific predisposition to formation of specific domains are discussed. Experimental investigation of tool use allows estimation of the individuals' intelligence in populations. A hypothesis suggesting that strong predisposition to formation of specific associations can serve as a driving force and at the same time as obstacle to animals' activity is discussed. In several “technically gifted” species (such as woodpecker finches, New Caledonian crows, and chimpanzees) tool use seems to be guided by a rapid process of trial and error learning. Individuals that are predisposed to learn specific connections do this too quickly and thus become enslaved by stereotypic solutions of raising problems.
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Heistermann, M., Palme, R., & Ganswindt, A. (2006). Comparison of different enzyme-immunoassays for assessment of adrenocortical activity in primates based on fecal analysis. Am. J. Primatol., 68(3), 257–273.
Abstract: Most studies published to date that used fecal glucocorticoid measurements to assess adrenocortical activity in primate (and many nonprimate) species applied a specific cortisol or corticosterone assay. However, since these native glucocorticoids are virtually absent in the feces of most vertebrates, including primates, the validity of this approach has recently been questioned. Therefore, the overall aim of the present study was to assess the validity of four enzyme-immunoassays (EIAs) using antibodies raised against cortisol, corticosterone, and reduced cortisol metabolites (two group-specific antibodies) for assessing adrenocortical activity using fecal glucocorticoid metabolite (GCM) measurements in selected primate species (marmoset, long-tailed macaque, Barbary macaque, chimpanzee, and gorilla). Using physiological stimulation of the hypothalamo-pituitary-adrenocortical (HPA) axis by administering exogenous ACTH or anesthesia, we demonstrated that at least two assays detected the predicted increase in fecal GCM levels in response to treatment in each species. However, the magnitude of response varied between assays and species, and no one assay was applicable to all species. While the corticosterone assay generally was of only limited suitability for assessing glucocorticoid output, the specific cortisol assay was valuable for those species that (according to high-performance liquid chromatography (HPLC) analysis data) excreted clearly detectable amounts of authentic cortisol into the feces. In contrast, in species in which cortisol was virtually absent in the feces, group-specific assays provided a much stronger signal, and these assays also performed well in the other primate species tested (except the marmoset). Collectively, the data suggest that the reliability of a given fecal glucocorticoid assay in reflecting activity of the HPA axis in primates clearly depends on the species in question. Although to date there is no single assay system that can be used successfully across species, our data suggest that group-specific assays have a high potential for cross-species application. Nevertheless, regardless of which GC antibody is chosen, our study clearly reinforces the necessity of appropriately validating the respective assay system before it is used.
Keywords: 11-Hydroxycorticosteroids/*analysis; Adrenocorticotropic Hormone/pharmacology; Anesthesia; Animals; Corticosterone/analysis; Feces/*chemistry; Glucocorticoids/*analysis; Haplorhini/*metabolism; Hydrocortisone/analysis; Hypothalamo-Hypophyseal System/drug effects/physiology; Immunoenzyme Techniques/*methods; Pituitary-Adrenal System/drug effects/physiology; Species Specificity
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Hare, B., Plyusnina, I., Ignacio, N., Schepina, O., Stepika, A., Wrangham, R., et al. (2005). Social cognitive evolution in captive foxes is a correlated by-product of experimental domestication. Curr Biol, 15(3), 226–230.
Abstract: Dogs have an unusual ability for reading human communicative gestures (e.g., pointing) in comparison to either nonhuman primates (including chimpanzees) or wolves . Although this unusual communicative ability seems to have evolved during domestication , it is unclear whether this evolution occurred as a result of direct selection for this ability, as previously hypothesized , or as a correlated by-product of selection against fear and aggression toward humans--as is the case with a number of morphological and physiological changes associated with domestication . We show here that fox kits from an experimental population selectively bred over 45 years to approach humans fearlessly and nonaggressively (i.e., experimentally domesticated) are not only as skillful as dog puppies in using human gestures but are also more skilled than fox kits from a second, control population not bred for tame behavior (critically, neither population of foxes was ever bred or tested for their ability to use human gestures) . These results suggest that sociocognitive evolution has occurred in the experimental foxes, and possibly domestic dogs, as a correlated by-product of selection on systems mediating fear and aggression, and it is likely the observed social cognitive evolution did not require direct selection for improved social cognitive ability.
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Horner, V., & Whiten, A. (2005). Causal knowledge and imitation/emulation switching in chimpanzees (Pan troglodytes) and children (Homo sapiens). Anim. Cogn., 8(3), 164–181.
Abstract: This study explored whether the tendency of chimpanzees and children to use emulation or imitation to solve a tool-using task was a response to the availability of causal information. Young wild-born chimpanzees from an African sanctuary and 3- to 4-year-old children observed a human demonstrator use a tool to retrieve a reward from a puzzle-box. The demonstration involved both causally relevant and irrelevant actions, and the box was presented in each of two conditions: opaque and clear. In the opaque condition, causal information about the effect of the tool inside the box was not available, and hence it was impossible to differentiate between the relevant and irrelevant parts of the demonstration. However, in the clear condition causal information was available, and subjects could potentially determine which actions were necessary. When chimpanzees were presented with the opaque box, they reproduced both the relevant and irrelevant actions, thus imitating the overall structure of the task. When the box was presented in the clear condition they instead ignored the irrelevant actions in favour of a more efficient, emulative technique. These results suggest that emulation is the favoured strategy of chimpanzees when sufficient causal information is available. However, if such information is not available, chimpanzees are prone to employ a more comprehensive copy of an observed action. In contrast to the chimpanzees, children employed imitation to solve the task in both conditions, at the expense of efficiency. We suggest that the difference in performance of chimpanzees and children may be due to a greater susceptibility of children to cultural conventions, perhaps combined with a differential focus on the results, actions and goals of the demonstrator.
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Call, J., Carpenter, M., & Tomasello, M. (2005). Copying results and copying actions in the process of social learning: chimpanzees (Pan troglodytes) and human children (Homo sapiens). Anim. Cogn., 8(3), 151–163.
Abstract: There is currently much debate about the nature of social learning in chimpanzees. The main question is whether they can copy others' actions, as opposed to reproducing the environmental effects of these actions using their own preexisting behavioral strategies. In the current study, chimpanzees (Pan troglodytes) and human children (Homo sapiens) were shown different demonstrations of how to open a tube-in both cases by a conspecific. In different experimental conditions, demonstrations consisted of (1) action only (the actions necessary to open the tube without actually opening it); (2) end state only (the open tube, without showing any actions); (3) both of these components (in a full demonstration); or (4) neither of these components (in a baseline condition). In the first three conditions subjects saw one of two different ways that the tube could open (break in middle; caps off ends). Subjects' behavior in each condition was assessed for how often they opened the tube, how often they opened it in the same location as the demonstrator, and how often they copied the demonstrator's actions or style of opening the tube. Whereas chimpanzees reproduced mainly the environmental results of the demonstrations (emulation), human children often reproduced the demonstrator's actions (imitation). Because the procedure used was similar in many ways to the procedure that Meltzoff (Dev Psych 31:1, 1995) used to study the understanding of others' unfulfilled intentions, the implications of these findings with regard to chimpanzees' understanding of others' intentions are also discussed.
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