Papers by Elisabetta Visalberghi
The abstract concept of equivalence is considered one of the bases of higher-order cognition, and... more The abstract concept of equivalence is considered one of the bases of higher-order cognition, and it has been the subject of considerable research in comparative cognition. This study examined the conditions under which tufted capuchin monkeys (Cebus apella) are able to acquire an identity concept. Six capuchin monkeys were trained to solve a visual matching-to-sample (MTS) task on the basis of perceptual identity. The acquisition of the identity rule was inferred from the subject’s ability to solve transfer tests with novel stimuli. We evaluated the ability of the capuchin monkeys to match the shape of novel stimuli after training with both several small stimulus sets (Experiment 1) and a large stimulus set (Experiment 2). Moreover, we examined the ability of capuchins to transfer the concept to novel visual dimensions, such as colour and size and to transfer to novel spatial arrangements of the stimuli (Experiment 2). We demonstrated that the ability of capuchins to match novel stimuli was improved by increasing the number of stimuli used during training (Experiments 1 and 2) and that after a widely applicable identity concept based on the stimulus shape was acquired, the capuchins were able to match stimuli according to an identity rule based on both the colour and size of the stimuli and when the spatial arrangement of the stimuli was varied (Experiment 2). This study is the first to demonstrate that the size of the training set affects the acquisition of an abstract identity concept in an MTS task in non-human primates.
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Folia Primatologica, 1990
This paper summarizes early anecdotal information and systematic studies of tool use in capuchin ... more This paper summarizes early anecdotal information and systematic studies of tool use in capuchin monkeys (Cebus spp.). Tool use in capuchins is neither context specific nor stereotyped. The success of capuchins in using tools and in exploiting a variety of food resources in the wild derives from several factors: their manipulative abilities, interest in external objects and a tendency to explore the environment. In using tools, capuchins are similar to apes and more proficient than other monkey species. A cognitive approach indicates, however, that (in contrast with chimpanzees) they never develop an understanding of the requirements of the tool tasks presented.
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International Journal of Primatology, 1986
The case of a captive Cebus apella,capable of utilizing detached objects as true hammering tools ... more The case of a captive Cebus apella,capable of utilizing detached objects as true hammering tools in cracking nuts open, is investigated. In the experimental task administered, the monkey was offered nuts of two different sizes, hazelnuts and walnuts, and a choice among three “hammers” of different percussional efficacy. Its performance was compared to that of one of its cagemates that did not use tools and to its own performance in the absence of tools. Results show that there was a consistent choice of the most efficient tool, that tool use greatly reduces the amount of time needed to crack a nut open (in comparison with either the action of the teeth or pounding the nut against a hard substrate), and that the efficacy of tool use is not conditioned by the relative hardness or size of the nut. In the light of these results, the role of tool use in the exploitation of food resouces is discussed.
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Proceedings of The Royal Society B: Biological Sciences, 2006
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Conservation Biology, 2003
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Journal of Comparative Psychology, 1994
... In addition, the finding that Rb was successful both with the opaque trap Page 6. 20 ELISABET... more ... In addition, the finding that Rb was successful both with the opaque trap Page 6. 20 ELISABETTA VISALBERGHI AND LUCA LIMONGELLI ... This is strikingly different from what 3-year-old children do in the trap-tube task (Li-mongelli, 1993). ...
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Journal of Comparative Psychology, 1995
Five chimpanzees (Pan troglodytes) were tested to assess their understanding of causality in a to... more Five chimpanzees (Pan troglodytes) were tested to assess their understanding of causality in a tool task. The task consisted of a transparent tube with a trap-hole drilled in its middle. A reward was randomly placed on either side of the hole. Depending on which side the chimpanzee inserted the stick into, the candy was either pushed out of the tube or into the trap. In Experiment 1, the success rate of 2 chimpanzees rose highly above chance, but that of the other subjects did not. Results show that the 2 successful chimpanzees selected the correct side for insertion beforehand. Experiment 2 ruled out the possibility that their success was due to a distance-based associative rule, and the results favor an alternative hypothesis that relates success to an understanding of the causal relation between the tool-using action and its outcome.
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Animal Behaviour, 1997
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Animal Behaviour, 1997
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American Journal of Physical Anthropology, 2007
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Behavioural Processes, 1998
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American Journal of Primatology, 1988
The responses of two social groups of Cebus apella to novel or familiar objects were examined, bo... more The responses of two social groups of Cebus apella to novel or familiar objects were examined, both in scarce and in abundant conditions. The aim was to obtain a description of capuchins' general norms of behavior toward objects, focusing on the variability across sex/age classes. Plain wooden blocks were presented to each group of monkeys in four phases. In phase I, the blocks were scarce and novel; in the following phases the blocks were abundant and increasingly more familiar. Several categories of behaviors directed toward the blocks were scored. The blocks elicited high levels of responsiveness throughout the experiment. In both sexes, responsiveness tended to decrease across phases. In all phases, males interacted with the blocks more than did females. Age was a significant determinant of responsiveness. Furthermore, age-classes showed different trends in level of responsiveness across phases. Sex and age significantly affected the behavioral pattern of interaction with the blocks. Dominance did not seem to constrain monkeys' responsiveness. The high and sustained responsiveness toward objects by Cebus apella is consistent with their manipulative skills and their varied habitat exploitation.
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American Journal of Primatology, 1998
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Appetite, 2005
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American Journal of Primatology, 2004
We conducted an exploratory investigation in an area where nut-cracking by wild capuchin monkeys ... more We conducted an exploratory investigation in an area where nut-cracking by wild capuchin monkeys is common knowledge among local residents. In addition to observing male and female capuchin monkeys using stones to pound open nuts on stone “anvils,” we surveyed the surrounding area and found physical evidence that monkeys cracked nuts on rock outcrops, boulders, and logs (collectively termed anvils). Anvils, which were identified by numerous shallow depressions on the upper surface, the presence of palm shells and debris, and the presence of loose stones of an appropriate size to pound nuts, were present even on the tops of mesas. The stones used to crack nuts can weigh >1 kg, and are remarkably heavy for monkeys that weigh <4 kg. The abundance of shell remains and depressions in the anvil surface at numerous anvil sites indicate that nut-cracking activity is common and long-enduring. Many of the stones found on anvils (presumably used to pound nuts) are river pebbles that are not present in the local area we surveyed (except on or near the anvils); therefore, we surmise that they were transported to the anvil sites. Ecologically and behaviorally, nut-cracking by capuchins appears to have strong parallels to nut-cracking by wild chimpanzees. The presence of abundant anvil sites, limited alternative food resources, abundance of palms, and the habit of the palms in this region to produce fruit at ground level all likely contribute to the monkeys' routine exploitation of palm nuts via cracking them with stones. This discovery provides a new reference point for discussions regarding the evolution of tool use and material culture in primates. Routine tool use to exploit keystone food resources is not restricted to living great apes and ancestral hominids. Am. J. Primatol. 64:359–366, 2004. © 2004 Wiley-Liss, Inc.
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Current Biology, 2009
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Animal Behaviour, 1995
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Animal Behaviour, 2003
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Animal Behaviour, 2000
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Papers by Elisabetta Visalberghi