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Author |
Weir, A.A.S.; Kacelnik, A. |
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Title |
A New Caledonian crow (Corvus moneduloides) creatively re-designs tools by bending or unbending aluminium strips |
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Journal Article |
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Year |
2006 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
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9 |
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4 |
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317-334 |
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Animals; *Comprehension; *Crows; Female; Learning; *Motor Skills; *Problem Solving; *Tool Use Behavior |
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Abstract |
Previous observations of a New Caledonian crow (Corvus moneduloides) spontaneously bending wire and using it as a hook [Weir et al. (2002) Science 297:981] have prompted questions about the extent to which these animals 'understand' the physical causality involved in how hooks work and how to make them. To approach this issue we examine how the same subject (“Betty”) performed in three experiments with novel material, which needed to be either bent or unbent in order to function to retrieve food. These tasks exclude the possibility of success by repetition of patterns of movement similar to those employed before. Betty quickly developed novel techniques to bend the material, and appropriately modified it on four of five trials when unbending was required. She did not mechanically apply a previously learned set of movements to the new situations, and instead sought new solutions to each problem. However, the details of her behaviour preclude concluding definitely that she understood and planned her actions: in some cases she probed with the unmodified tools before modifying them, or attempted to use the unmodified (unsuitable) end of the tool after modification. Gauging New Caledonian crows' level of understanding is not yet possible, but the observed behaviour is consistent with a partial understanding of physical tasks at a level that exceeds that previously attained by any other non-human subject, including apes. |
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Department of Zoology, South Parks Road, Oxford, OX1 3PS, UK. alex.weir@magdalen.oxon.org |
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1435-9448 |
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PMID:17024509 |
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Equine Behaviour @ team @ |
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2436 |
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Kacelnik, A.; Todd, I.A. |
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Title |
Psychological mechanisms and the Marginal Value Theorem: effect of variability in travel time on patch exploitation |
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Journal Article |
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Year |
1992 |
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Animal Behaviour. |
Abbreviated Journal |
Anim. Behav. |
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43 |
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2 |
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313-322 |
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The Marginal Value Theorem (MVT) describes the behaviour that maximizes the ratio of expected gain over expected foraging time in a patchy environment. When travel time is variable, the MVT rationale and its predictions are sensitive only to the mean travel time and not to the spread or skew of the distribution. Two mechanistic arguments contradict these predictions. First, tests of the MVT have previously shown that there is a disproportionate influence of the last travel time, and second, psychological models of information processing suggest that memory for time intervals is strongly dependent on the scatter of the distribution experienced. These mechanistic concepts, combined with Jensen's inequality, suggest that patch exploitation should decrease as the scatter of the travel distribution increases. In a Skinner box experiment with pigeons, Columba livia, the problem was examined by simulating three environments with identical patches and the same mean travel time, but different travel time variability. Patch exploitation decreased with increasing variance in travel time. The results are used to argue in favour of the inclusion of realistic psychological properties as constraints in functional models of behaviour. Although both the MVT and the mechanistic models account for some features of the results, none of them can explain all the findings. |
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2114 |
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Beauchamp, G.; Kacelnik, A. |
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Title |
Effects of the knowledge of partners on learning rates in zebra finches Taeniopygia guttata |
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Year |
1991 |
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Animal Behaviour. |
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Anim. Behav. |
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41 |
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2 |
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247-253 |
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Many interpretations of the adaptive value of group living involve tranfer of knowledge. However, according to learning theory, being in a pair with a knowledgeable partner can have paradoxical consequences. Obtaining food by following a skilled companion may reduce the ability of naive individuals to learn about clues that signal the occurrence of food. This study examined the relation between learning and following in paris of zebra finches. Knowledgeable partners were trained to obtain food from a computer-controlled dispenser by using the information provided by a signal. For non-knowledgeable partners, the signal was irrelevant and could not be used to predict foraging opportunities. The rate of learning about the signal by naive birds that shared the experience of either knowledgeable or nonknowledgeable tutors was then examined. Naive birds learned more slowly as a result of being in a pair with a knowledgeable than a non-knowledgeable partner. Well-informed mates acted as a reliable cue to predict foraging opportunities, and thus overshadowed the independent signal. The knowledge of a partner influences learning rates in naive individuals, but in the opposite direction to that predicted by earlier accounts of learning in social contexts. |
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2115 |
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Kacelnik, A.; Marsh, B. |
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Title |
Cost can increase preference in starlings |
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Journal Article |
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Year |
2002 |
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Animal Behaviour. |
Abbreviated Journal |
Anim. Behav. |
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63 |
Issue |
2 |
Pages |
245-250 |
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We used European starlings, Sturnus vulgaris, to investigate the relationship between the cost paid to obtain food rewards and preference between stimuli associated with the resulting rewards. In no-choice trials either 16 1-m flights (high effort) or four 1-m flights (low effort) gave access to differently coloured keys. Pecking at these keys resulted in identical food rewards. When subjects were given choices between the coloured keys in choice trials without having paid any effort, the majority preferred the coloured key that was paired with the higher level of work in no-choice trials. We relate our findings to results in animal behaviour, psychology and economics, and give a theoretical account that has implications for phenomena variously recognized as the `sunk cost fallacy' (the tendency to invest more in something after much has already been invested), `work ethics' (valuing an option more as a result of physical effort), `cognitive dissonance' (making mental effort to overlook or re-evaluate information that does not accord with a dominant internal representation) and the `Concorde Fallacy' (the readiness to forego more fitness for something that has been responsible for greater fitness compromise in the past). |
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2107 |
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Author |
Kacelnik, A. |
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Title |
The foraging efficiency of great tits (Parus major L.) in relation to light intensity |
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Journal Article |
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Year |
1979 |
Publication |
Animal Behaviour. |
Abbreviated Journal |
Anim. Behav. |
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Volume |
27 |
Issue |
Part 1 |
Pages |
237-241 |
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I report an experiment aimed at testing whether foraging efficiency of great tits is limited by light intensity at the time of the dawn chorus. Captive great tits hunting for prey under different luminance conditions were less successful in finding prey when foraging, hunted for a lower proportion of their time, and handled individual prey items for longer when luminance was under approximately 7 cd/m2. This luminance is not reached in the field until after the time of the dawn chorus, suggesting that in the early morning foraging is limited by light intensity. I suggest that a satisfactory functional explanation of the dawn chorus must take into account the comparatively low foraging opportunity early in the morning, as well as the factors affecting the opportunity for singing and other territorial activities. |
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2125 |
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Chappell, J.; Kacelnik, A. |
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Title |
Selection of tool diameter by New Caledonian crows Corvus moneduloides |
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Journal Article |
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2004 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
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7 |
Issue |
2 |
Pages |
121-127 |
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Animals; Behavior, Animal; *Choice Behavior; Discrimination Learning; *Feeding Behavior; Female; Functional Laterality; *Manufactured Materials; *Plant Leaves; *Problem Solving; *Songbirds; Technology |
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One important element of complex and flexible tool use, particularly where tool manufacture is involved, is the ability to select or manufacture appropriate tools anticipating the needs of any given task-an ability that has been rarely tested in non-primates. We examine aspects of this ability in New Caledonian crows-a species known to be extraordinary tool users and manufacturers. In a 2002 study, Chappell and Kacelnik showed that these crows were able to select a tool of the appropriate length for a task among a set of different lengths, and in 2002, Weir, Chappell and Kacelnik showed that New Caledonian crows were able to shape unfamiliar materials to create a usable tool for a specific task. Here we examine their handling of tool diameter. In experiment 1, we show that when facing three loose sticks that were usable as tools, they preferred the thinnest one. When the three sticks were presented so that one was loose and the other two in a bundle, they only disassembled the bundle when their preferred tool was tied. In experiment 2, we show that they manufacture, and modify during use, a tool of a suitable diameter from a tree branch, according to the diameter of the hole through which the tool will have to be inserted. These results add to the developing picture of New Caledonian crows as sophisticated tool users and manufacturers, having an advanced level of folk physics. |
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Department of Zoology, South Parks Road, OX1 3PS, Oxford, UK. jackie.chappell@zoo.ox.ac.uk |
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1435-9448 |
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PMID:15069612 |
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Equine Behaviour @ team @ |
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2528 |
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Astié, A.A.; Kacelnik, A.; Reboreda, J.C. |
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Title |
Sexual differences in memory in shiny cowbirds |
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Journal Article |
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1998 |
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Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
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1 |
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2 |
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77-82 |
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Avian brood parasites depend on other species, the hosts, to raise their offspring. During the breeding season, parasitic cowbirds (Molothrus sp.) search for potential host nests to which they return for laying a few days after first locating them. Parasitic cowbirds have a larger hippocampus/telencephalon volume than non-parasitic species; this volume is larger in the sex involved in nest searching (females) and it is also larger in the breeding than in the non-breeding season. In nature, female shiny cowbirds Molothrus bonariensis search for nests without the male's assistance. Here we test whether, in association with these neuroanatomical and behavioural differences, shiny cowbirds display sexual differences in a memory task in the laboratory. We used a task consisting of finding food whose location was indicated either by the appearance or the location of a covering disk. Females learnt to retrieve food faster than males when food was associated with appearance cues, but we found no sexual differences when food was associated with a specific location. Our results are consistent with the view that parasitism and its neuroanatomical correlates affect performance in memory tasks, but the effects we found were not in the expected direction, emphasising that the nature of avian hippocampal function and its sexual differences are not yet understood. |
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Equine Behaviour @ team @ |
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3158 |
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Author |
Chappell, J.; Kacelnik, A. |
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Title |
Tool selectivity in a non-primate, the New Caledonian crow (Corvus moneduloides) |
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Journal Article |
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2002 |
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Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
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5 |
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2 |
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71-78 |
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Adaptation, Psychological; Animals; *Cognition; Female; *Learning; Male; Perception; *Songbirds |
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We present an experiment showing that New Caledonian crows are able to choose tools of the appropriate size for a novel task, without trial-and-error learning. This species is almost unique amongst all animal species (together with a few primates) in the degree of use and manufacture of polymorphic tools in the wild. However, until now, the flexibility of their tool use has not been tested. Flexibility, including the ability to select an appropriate tool for a task, is considered to be a hallmark of complex cognitive adaptations for tool use. In experiment 1, we tested the ability of two captive birds (one male, one female), to select a stick (from a range of lengths provided) matching the distance to food placed in a horizontal transparent pipe. Both birds chose tools matching the distance to their target significantly more often than would be expected by chance. In experiment 2, we used a similar task, but with the tools placed out of sight of the food pipe, such that the birds had to remember the distance of the food before selecting a tool. The task was completed only by the male, who chose a tool of sufficient length significantly more often than chance but did not show a preference for a matching length. |
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Department of Zoology, University of Oxford, South Parks Road, Oxford OXI 3PS, UK. jackie.chappell@zoo.ox.ac.uk |
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1435-9448 |
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PMID:12150038 |
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Equine Behaviour @ team @ |
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2606 |
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