The Experts below are selected from a list of 5322 Experts worldwide ranked by ideXlab platform
Josep Call - One of the best experts on this subject based on the ideXlab platform.
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gravity and solidity in four great ape species gorilla gorilla Pongo Pygmaeus pan troglodytes pan paniscus vertical and horizontal variations of the table task
Journal of Comparative Psychology, 2009Co-Authors: T Cacchione, Josep Call, R ZinggAbstract:Three experiments modeled after infant studies were run on four great ape species (Gorilla gorilla, Pongo Pygmaeus, Pan troglodytes, Pan paniscus) to investigate their reasoning about solidity and gravity constraints. The aims were: (a) to find out if great apes are subject to gravity biased search or display sensitivity for object solidity, (b) to check for species differences, and (c) to assess if a gravity hypothesis or more parsimonious explanations best account for failures observed. Results indicate that great apes, unlike monkeys, show no reliable gravity bias, that ape species slightly differ in terms of their performance, and that the errors made are best explained by a gravity account.
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gorillas gorilla gorilla and orangutans Pongo Pygmaeus encode relevant problem features in a tool using task
Journal of Comparative Psychology, 2005Co-Authors: Nicholas J Mulcahy, Josep Call, R I M DunbarAbstract:wo important elements in problem solving are the abilities to encode relevant task features and to combine multiple actions to achieve the goal. The authors investigated these 2 elements in a task in which gorillas (Gorilla gorilla) and orangutans (Pongo Pygmaeus) had to use a tool to retrieve an out-of-reach reward. Subjects were able to select tools of an appropriate length to reach the reward even when the position of the reward and tools were not simultaneously visible. When presented with tools that were too short to retrieve the reward, subjects were more likely to refuse to use them than when tools were the appropriate length. Subjects were proficient at using tools in sequence to retrieve the reward.
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piagetian liquid conservation in the great apes pan paniscus pan troglodytes and Pongo Pygmaeus
Journal of Comparative Psychology, 2004Co-Authors: Chikako Suda, Josep CallAbstract:An understanding of Piagetian liquid conservation was investigated in 4 bonobos (Pan paniscus), 5 chimpanzees (Pan troglodytes), and 5 orangutans (Pongo Pygmaeus). The apes were tested in the ability to track the larger of 2 quantities of juice that had undergone various kinds of transformations. The accuracy of the apes' judgment depended on the shape or number of containers into which the larger quantity was transferred. The apes made their choice mainly on the basis of visual estimation but showed modest success when the quantities were occluded. The results suggest that the apes rely to a greater extent on visual information, although they might have some appreciation of the constancy of liquid quantities.
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object permanence in orangutans Pongo Pygmaeus chimpanzees pan troglodytes and children homo sapiens
Journal of Comparative Psychology, 2001Co-Authors: Josep CallAbstract:Juvenile and adult orangutans (n = 5; Pongo Pygmaeus), chimpanzees (n = 7; Pan troglodytes), and 19- and 26-month-old children (n = 24; Homo sapiens) received visible and invisible displacements. Three containers were presented forming a straight line, and a small box was used to displace a reward under them. Subjects received 3 types of displacement: single (the box visited 1 container), double adjacent (the box visited 2 contiguous containers), and double nonadjacent (the box visited 2 noncontiguous containers). All species performed at comparable levels, solving all problems except the invisible nonadjacent displacements. Visible displacements were easier than invisible, and single were easier than double displacements. In a 2nd experiment, subjects saw the baiting of either 2 adjacent or 2 nonadjacent containers with no displacements. All species selected the empty container more often when the baited containers were nonadjacent than when they were adjacent. It is hypothesized that a response bias and inhibition problem were responsible for the poor performance in nonadjacent displacements.
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Estimating and operating on discrete quantities in orangutans (Pongo Pygmaeus).
Journal of Comparative Psychology, 2000Co-Authors: Josep CallAbstract:This study investigated the ability of 3 male orangutans (Pongo Pygmaeus; 1 subadult, 2 adults) to estimate, compare, and operate on 2 sets of small quantities (1-6 cereal bits). Experiment 1 investigated the orangutans' ability to choose the larger of 2 quantities when they were presented successively as opposed to simultaneously, thus being perceptually unavailable at the time of choice. Experiment 2 investigated the orangutans' ability to select the larger quantity after the original quantities were augmented or reduced. Orangutans were capable of selecting the larger of 2 quantities in Experiment 1. There was also some evidence from Experiment 2, albeit weaker, that orangutans may mentally combine quantities (but not dissociate) to obtain the larger of 2 quantities. This study suggests that orangutans use a representational mechanism (especially when comparing quantities) to select the larger of 2 sets of items.
Benoit Goossens - One of the best experts on this subject based on the ideXlab platform.
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riverine effects on mitochondrial structure of bornean orang utans Pongo Pygmaeus at two spatial scales
Molecular Ecology, 2008Co-Authors: Mohd Fairuz Jalil, Joanne Cable, J Sinyor, Isabelle Lackmanancrenaz, Marc Ancrenaz, Michael William Bruford, Benoit GoossensAbstract:We examined mitochondrial DNA control region sequences of 73 Kinabatangan orang-utans to test the hypothesis that the phylogeographical structure of the Bornean orang-utan is influenced by riverine barriers. The Lower Kinabatangan Wildlife Sanctuary contains one of the most northern populations of orang-utans (Pongo Pygmaeus) on Borneo and is bisected by the Kinabatangan River, the longest river in Sabah. Orang-utan samples on either side of the river were strongly differentiated with a high ΦST value of 0.404 (P < 0.001). Results also suggest an east–west gradient of genetic diversity and evidence for population expansion along the river, possibly reflecting a postglacial colonization of the Kinabatangan floodplain. We compared our data with previously published sequences of Bornean orang-utans in the context of river catchment structure on the island and evaluated the general relevance of rivers as barriers to gene flow in this long-lived, solitary arboreal ape.
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Riverine effects on mitochondrial structure of Bornean orang‐utans (Pongo Pygmaeus) at two spatial scales
Molecular ecology, 2008Co-Authors: Mohd Fairuz Jalil, Joanne Cable, J Sinyor, Marc Ancrenaz, Michael William Bruford, Isabelle Lackman-ancrenaz, Benoit GoossensAbstract:We examined mitochondrial DNA control region sequences of 73 Kinabatangan orang-utans to test the hypothesis that the phylogeographical structure of the Bornean orang-utan is influenced by riverine barriers. The Lower Kinabatangan Wildlife Sanctuary contains one of the most northern populations of orang-utans (Pongo Pygmaeus) on Borneo and is bisected by the Kinabatangan River, the longest river in Sabah. Orang-utan samples on either side of the river were strongly differentiated with a high ΦST value of 0.404 (P < 0.001). Results also suggest an east–west gradient of genetic diversity and evidence for population expansion along the river, possibly reflecting a postglacial colonization of the Kinabatangan floodplain. We compared our data with previously published sequences of Bornean orang-utans in the context of river catchment structure on the island and evaluated the general relevance of rivers as barriers to gene flow in this long-lived, solitary arboreal ape.
R Zingg - One of the best experts on this subject based on the ideXlab platform.
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gravity and solidity in four great ape species gorilla gorilla Pongo Pygmaeus pan troglodytes pan paniscus vertical and horizontal variations of the table task
Journal of Comparative Psychology, 2009Co-Authors: T Cacchione, Josep Call, R ZinggAbstract:Three experiments modeled after infant studies were run on four great ape species (Gorilla gorilla, Pongo Pygmaeus, Pan troglodytes, Pan paniscus) to investigate their reasoning about solidity and gravity constraints. The aims were: (a) to find out if great apes are subject to gravity biased search or display sensitivity for object solidity, (b) to check for species differences, and (c) to assess if a gravity hypothesis or more parsimonious explanations best account for failures observed. Results indicate that great apes, unlike monkeys, show no reliable gravity bias, that ape species slightly differ in terms of their performance, and that the errors made are best explained by a gravity account.
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Gravity and solidity in four greatape species (Gorilla gorilla, Pongo Pygmaeus, Pan troglodytes, Pan paniscus): Vertical and horizontal variations of the table task
2009Co-Authors: T Cacchione, J Call, R ZinggAbstract:Three experiments modeled after infant studies were run on four great ape species (Gorilla gorilla, Pongo Pygmaeus, Pan troglodytes, Pan paniscus) to investigate their reasoning about solidity and gravity constraints. The aims were: (a) to find out if great apes are subject to gravity biased search or display sensitivity for object solidity, (b) to check for species differences, and (c) to assess if a gravity hypothesis or more parsimonious explanations best account for failures observed. Results indicate that great apes, unlike monkeys, show no reliable gravity bias, that ape species slightly differ in terms of their performance, and that the errors made are best explained by a gravity account.
William D. Hopkins - One of the best experts on this subject based on the ideXlab platform.
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Comparative assessment of handedness for a coordinated bimanual task in chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla) and orangutans (Pongo Pygmaeus).
Journal of Comparative Psychology, 2003Co-Authors: William D. Hopkins, Tara S. Stoinski, Kristen E. Lukas, Stephen R. Ross, Michael J WesleyAbstract:Hand preferences for a coordinated bimanual task were assessed in a sample of 31 captive gorillas (Gorilla gorilla) and 19 captive orangutans (Pongo Pygmaeus) and were compared with chimpanzee (Pan troglodytes) hand preferences in subjects that were matched on the basis of age, sex, and rearing history. The task required that the apes remove food from the inside edges of a symmetrical polyvinyl chloride pipe presented to them in their home cages. The results indicate significant species differences with chimpanzees showing population-level right-handedness and orangutans showing population-level left-handedness. The gorillas showed a nonsignificant trend toward right-handedness. The results are discussed in terms of possible ecological or biomechanical factors that may influence hand preferences in different ape species.
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posture and reaching in chimpanzees pan troglodytes and orangutans Pongo Pygmaeus
Journal of Comparative Psychology, 1993Co-Authors: William D. HopkinsAbstract:Hand preference in reaching was assessed under 2 postural adjustment conditions in 40 chimpanzees (Pan troglodytes) and 9 orangutans (Pongo Pygmaeus). The postural conditions were quadrupedal and upright, during which reaching for food was scored on a minimum of 50 trials. Results indicated no population preference during quadrupedal reaching but a right-hand population preference was found during upright reaching. There were no significant effects of age or sex on either the direction or strength of hand preference. Early rearing history affected the strength of hand preference but not direction. The results suggest that posture is an important factor in the assessment of hand preference in great apes and may have important evolutionary consequences
Tara S. Stoinski - One of the best experts on this subject based on the ideXlab platform.
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Relative numerousness judgment and summation in young, middle-aged, and older adult orangutans (Pongo Pygmaeus abelii and Pongo Pygmaeus Pygmaeus).
Journal of Comparative Psychology, 2007Co-Authors: Ursula S. Anderson, Tara S. Stoinski, Mollie A. Bloomsmith, Terry L. MapleAbstract:The ability to select the larger of two quantities ranging from 1 to 5 (relative numerousness judgment [RNJ[) and the ability to select the larger of two pairs of quantities with each pair ranging from 1 to 8 (summation) were evaluated in young, middle-aged, and older adult orangutans (7 Pongo Pygmaeus abelii and 2 Pongo Pygmaeus Pygmaeus). Summation accuracy and RNJ were similar to those of previous reports in apes; however, the pattern of age-related differences with regard to these tasks was different from that previously reported in gorillas. Older orangutans were less accurate than the young and middle-aged for RNJ, and summation accuracy was equivalent among age groups. Evidence was found to suggest that the young and middle-aged based their selection of the largest quantity pair on both quantities within each pair during the summation task. These results show a relationship between subject age and the quantitative abilities of adult orangutans.
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Social learning by orangutans (Pongo abelii and Pongo Pygmaeus) in a simulated food-processing task.
Journal of Comparative Psychology, 2003Co-Authors: Tara S. Stoinski, Andrew WhitenAbstract:Increasing evidence for behavioral differences between populations of primates has created a resurgence of interest in examining mechanisms of information transfer between individuals. The authors examined the social transmission of information in 15 captive orangutans (Pongo abelii and Pongo Pygmaeus) using a simulated food-processing task. Experimental subjects were shown 1 of 2 methods for removing a suite of defenses on an "artificial fruit." Control subjects were given no prior exposure before interacting with the fruit. Observing a model provided a functional advantage in the task, as significantly more experimental than control subjects opened the fruit. Within the experimental groups, the authors found a trend toward differences in the actual behaviors used to remove 1 of the defenses. Results support observations from the wild implying horizontal transfer of information in orangutans and show that a number of social learning processes are likely to be involved in the transfer of knowledge in this species.
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Comparative assessment of handedness for a coordinated bimanual task in chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla) and orangutans (Pongo Pygmaeus).
Journal of Comparative Psychology, 2003Co-Authors: William D. Hopkins, Tara S. Stoinski, Kristen E. Lukas, Stephen R. Ross, Michael J WesleyAbstract:Hand preferences for a coordinated bimanual task were assessed in a sample of 31 captive gorillas (Gorilla gorilla) and 19 captive orangutans (Pongo Pygmaeus) and were compared with chimpanzee (Pan troglodytes) hand preferences in subjects that were matched on the basis of age, sex, and rearing history. The task required that the apes remove food from the inside edges of a symmetrical polyvinyl chloride pipe presented to them in their home cages. The results indicate significant species differences with chimpanzees showing population-level right-handedness and orangutans showing population-level left-handedness. The gorillas showed a nonsignificant trend toward right-handedness. The results are discussed in terms of possible ecological or biomechanical factors that may influence hand preferences in different ape species.