Intelligent tool use in wild Sumatran orangutans

Fox, Elizabeth; Sitompul, Arnold F.; Schaik, Carel P. van

doi:10.1017/cbo9780511542305.005

Cited by 185 publications

(177 citation statements)

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“…The cerebellum appears to enhance and sharpen precise timing of neural events and to promote the smooth control of rapid, stereotyped neural responses, regardless of whether it is processing sensory, motor, or cognitive signals (33)(34)(35)(36)(37). Neocortical regions with reciprocal cerebellar circuitry are summarized in Table 1.…”

Section: Discussionmentioning

confidence: 99%

Reciprocal evolution of the cerebellum and neocortex in fossil humans

Weaver

2005

Proc. Natl. Acad. Sci. U.S.A.

177

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Human brain evolution involved both neurological reorganization and an increase in overall brain volume relative to body mass. It is generally difficult to draw functional inferences about the timing and nature of brain reorganization, given that superficial brain morphology recorded on fossil endocasts is functionally ambiguous. However, the cerebellum, housed in the clearly delineated posterior cranial fossa, is functionally and ontologically discrete. The cerebellum is reciprocally connected to each of 14 neocortical regions important to human cognitive evolution. Cerebellar volume varies significantly relative to overall brain volume among mammalian orders, as well as within the primate order. There is also significant diachronic variation among fossil human taxa. In the australopithecines and early members of the genus Homo, the cerebral hemispheres were large in proportion to the cerebellum, compared with other hominoids. This trend continued in Middle and Late Pleistocene humans, including Neandertals and CroMagnon 1, who have the largest cerebral hemispheres relative to cerebellum volume of any primates, including earlier and Holocene humans. In recent humans, however, the pattern is reversed; the cerebellum is larger with respect to the rest of the brain (and, conversely, the cerebral hemispheres are smaller with respect to the cerebellum) than in Late Pleistocene humans. The cerebellum and cerebral hemispheres appear to have evolved reciprocally. Cerebellar development in Holocene humans may have provided greater computational efficiency for coping with an increasingly complex cultural and conceptual environment.human evolution ͉ Plio-Pleistocene hominins ͉ Upper Paleolithic transition P aleoneurologists agree that increased encephalization is an important dynamic of human brain evolution. However, brain evolution involved more than brain expansion. It also involved reorganization to support specific, uniquely human cognitive tasks, including those involved in linguistic processing and a highly developed facility for manufacturing and manipulating tools. Nevertheless, despite more than a century of effort, there is little consensus about how and when such reorganization occurred.One approach to exploring functional reorganization of the brain in humans has been the analysis of impressions of the brain's surface convolutions (sulci and gyri) on the inner table of the endocranium. However, endocranial markings are notoriously difficult to identify reliably (1, 2). Even where the impressions are fairly clear, taphonomic processes may distort the evidence. In addition, the functional correlates of the brain's surface convolutions, especially in fossils, are literally superficial. Cognitive functions occur through internal connections among brain regions, as well as through the distribution of neuroreceptors that cannot be detected by examining the surface of the brain, let alone from endocranial markings. Therefore, functional inferences based on sulcal patterns are problematic.Another approach to endocran...

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Section: Discussionmentioning

confidence: 99%

Reciprocal evolution of the cerebellum and neocortex in fossil humans

Weaver

2005

Proc. Natl. Acad. Sci. U.S.A.

177

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“…Fox et al [25] proposed three non-mutually exclusive hypotheses to explain differences in the expression of tool use among great ape populations. The 'necessity hypothesis' suggests tool use is a response to resource scarcity, which enables its practitioners to exploit novel food items during times when resource abundance is low.…”

Section: Introductionmentioning

confidence: 99%

“…In effect, the relative profitability hypothesis encompasses the previously mentioned ecological hypotheses (see also §4). Fox et al's [25] third hypothesis focuses on the social factors driving tool use. The 'invention hypothesis' (also referred to as the 'limited invention hypothesis' in Fox et al [25]) proposes that 'behaviours such as tool use are rarely invented, and that the spread and maintenance of such behaviour requires sufficient opportunities for observational learning via social proximity to conspecifics' [29, p. 163].…”

Section: Introductionmentioning

confidence: 99%

“…Fox et al's [25] third hypothesis focuses on the social factors driving tool use. The 'invention hypothesis' (also referred to as the 'limited invention hypothesis' in Fox et al [25]) proposes that 'behaviours such as tool use are rarely invented, and that the spread and maintenance of such behaviour requires sufficient opportunities for observational learning via social proximity to conspecifics' [29, p. 163]. As described in the following sections, previous field studies of tool using animals have provided mixed results in the evaluation of these hypotheses (table 1).…”

Section: Introductionmentioning

confidence: 99%

“…The final explanation for the emergence of tool use is the invention hypothesis, which states that tool behaviour is invented rarely and/or may have difficulty spreading and being maintained [25]. One can predict that, because social learning requires some type of direct or indirect contact between individuals, it may be more common in high density or highly social animal populations.…”

Section: Introductionmentioning

confidence: 99%

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Ecological and social correlates of chimpanzee tool use

Sanz

Morgan

2013

Phil. Trans. R. Soc. B

146

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The emergence of technology has been suggested to coincide with scarcity of staple resources that led to innovations in the form of tool-assisted strategies to diversify or augment typical diets. We examined seasonal patterns of several types of tool use exhibited by a chimpanzee ( Pan troglodytes ) population residing in central Africa, to determine whether their technical skills provided access to fallback resources when preferred food items were scarce. Chimpanzees in the Goualougo Triangle exhibit a diverse repertoire of tool behaviours, many of which are exhibited throughout the year. Further, they have developed specific tool sets to overcome the issues of accessibility to particular food items. Our conclusion is that these chimpanzees use a sophisticated tool technology to cope with seasonal changes in relative food abundance and gain access to high-quality foods. Subgroup sizes were smaller in tool using contexts than other foraging contexts, suggesting that the size of the social group may not be as important in promoting complex tool traditions as the frequency and type of social interactions. Further, reports from other populations and species showed that tool use may occur more often in response to ecological opportunities and relative profitability of foraging techniques than scarcity of resources.

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