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William D Hopkins - One of the best experts on this subject based on the ideXlab platform.
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Etiology of Triarchic Psychopathy Dimensions in ChimPanzees (Pan Troglodytes).
Clinical psychological science, 2017Co-Authors: Robert D. Latzman, Christopher J. Patrick, Steven J. Schapiro, Hani D. Freeman, William D HopkinsAbstract:The current study undertook analyses of genealogical data from a sample of 178 socially housed chimPanzees (Pan Troglodytes) with well-documented pedigrees to clarify the etiologic bases of triarchic psychopathy dimensions and the influence of early social rearing experiences. Whereas biometric analyses for the full sample indicated significant heritability for the boldness dimension of psychopathy only, heritability estimates varied by early rearing, with all three triarchic dimensions showing significant heritabilities among mother-reared but not nursery-reared apes. For mother-reared apes, both genes and environment contributed to covariance between meanness and disinhibition, whereas environment contributed mainly to covariation between these dimensions and boldness. Results indicate contributions of both genes and environment to psychopathic tendencies, with an important role for early rearing in their relative contributions to distinct phenotypic subdimensions. In conjunction with findings from huma...
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A ChimPanzee (Pan Troglodytes) Model of Triarchic Psychopathy Constructs: Development and Initial Validation
Clinical psychological science, 2015Co-Authors: Robert D. Latzman, Laura E. Drislane, Lisa K. Hecht, Sarah J. Brislin, Christopher J. Patrick, Scott O. Lilienfeld, Hani J. Freeman, Steven J. Schapiro, William D HopkinsAbstract:The current work sought to operationalize constructs of the triarchic model of psychopathy in chimPanzees (Pan Troglodytes), a species well suited for investigations of basic biobehavioral disposit...
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Factors influencing the prevalence and handedness for throwing in captive chimPanzees (Pan Troglodytes).
Journal of Comparative Psychology, 2005Co-Authors: William D Hopkins, Hani Freeman, Claudio Cantalupo, Jamie L. Russell, Steven J. SchapiroAbstract:Humans throw right-handed, and it has been suggested that the neurophysiological demands of aimed throwing may have served as a precursor to the evolution of left hemisphere specialization for linguistic functions. Although there are descriptions of throwing by wild and captive chimPanzees (Pan Troglodytes), systematic observations of aimed throwing and handedness have not been reported. In this article, evidence of population-level right-handedness for throwing is reported in 2 samples of captive chimPanzees. It is further reported that right-handed throwing is more pronounced than other measures of handedness in captive chimPanzees. The implications of these findings are discussed in the context of theories relating throwing to the evolution of lateralization for language functions.
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Asymmetries in the Hippocampus and Amygdala of ChimPanzees (Pan Troglodytes)
Behavioral Neuroscience, 2004Co-Authors: Hani Freeman, Claudio Cantalupo, William D HopkinsAbstract:Magnetic resonance imaging was used to measure the hippocampal and amygdalar volumes of 60 chimPanzees (Pan Troglodytes). An asymmetry quotient (AQ) was then used to calculate the asymmetry for each of the structures. A one-sample t test indicated that there was a population-level right hemisphere asymmetry for the hippocampus. There was no significant population-level asymmetry for the amygdala. An analysis of variance using sex and rearing history as between-group variables showed no significant main effects or interaction effects on the AQ scores; however, males were more strongly lateralized than females. Several of these findings are consistent with results found in the human literature.
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ChimPanzees (Pan Troglodytes) are predominantly right-handed: replication in three populations of apes.
Behavioral Neuroscience, 2004Co-Authors: William D Hopkins, Michelle A Hook, M. Kay Izard, Michael J Wesley, Steven J. SchapiroAbstract:Population-level right-handedness has historically been considered a hallmark of human evolution. Even though recent studies in chimPanzees (Pan Troglodytes) have demonstrated population-level right-handedness for certain behaviors, some have questioned the validity and consistency of these findings by arguing that reported laterality effects are specific to certain colonies of apes and to those chimPanzees reared by humans. The authors report evidence of population-level right-handedness in 3 separate colonies of chimPanzees. Moreover, handedness in the 3 colonies was unrelated to the proportion of subjects that were raised by humans. This is the strongest evidence to date that population-level handedness is evident in chimPanzees and is not an artifact of human rearing.
Kim A. Bard - One of the best experts on this subject based on the ideXlab platform.
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Measurement of eye‐gaze in chimPanzees (Pan Troglodytes)
American Journal of Primatology, 2007Co-Authors: Emily Bethell, Sarah-jane Vick, Kim A. BardAbstract:Gaze cues are used as an index of social cognition in primates, yet the sensitivity to different forms of gaze, and consequently the cues required to test gaze-following abilities remain understudied. Whereas the eye is attributed special signal value in humans, the camouflaged ocular morphology of non-human primates has led to the consensus that head orientation may be a more salient cue. This study presents the first documentation of the surface eye movements of the chimPanzee, Pan Troglodytes, in order to determine the behavioral forms of eye-gaze and their saliency as signals, document their functional variation, and address the signal value of the eyes distinct from head orientation. Movements of the eye were identified as Scan (continuous movement), Glance (a single movement
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Locomotor Adaptation and Leading Limb Asymmetries in Neonatal ChimPanzees (Pan Troglodytes)
International Journal of Primatology, 1997Co-Authors: William D Hopkins, Kim A. Bard, Kristine M. GrinerAbstract:We assessed laterality for leading limb in crawling and leading limb in stepping in 13 chimPanzees (Pan Troglodytes) during the first 3 months of life. Overall, there is a significant populational right-side bias for crawling but not for stepping. There is a significant negative correlation between laterality in stepping and crawling. The females are more right-sided in lateral bias than the males across both measures. These data suggest that asymmetries in postural organization are present early in life and are specific to the inherent locomotor behavior of a given species.
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indexical and referential pointing in chimPanzees Pan Troglodytes
Journal of Comparative Psychology, 1996Co-Authors: David A Leavens, William D Hopkins, Kim A. BardAbstract:The spontaneous index finger and other referential pointing in 3 adult, laboratory chimPanzees (Pan Troglodytes) who have not received language training is reported. Of 256 total observed points, 254 were emitted in the presence of a human to objects in the environment; therefore, the points were communicative. Indicators of intentional communication used by the subjects included attention-getting behaviors, gaze alternation, and persistence until reward. Thus, pointing by these chimPanzees was intentionally communicative. These data imply that perspective-taking and referential communication are generalized hominoid traits, given appropriate eliciting contexts. Index finger pointing was more frequent with the subjects' dominant hands. This study refutes claims that indexical or referential pointing is species-unique to humans or dependent on linguistic competence or explicit training.
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Asymmetries in Spontaneous Head Orientation in Infant ChimPanzees (Pan Troglodytes)
Behavioral Neuroscience, 1995Co-Authors: William D Hopkins, Kim A. BardAbstract:Behavioral laterality in head orientation while sleeping in either a supine or prone posture was examined in 43 chimPanzees (Pan Troglodytes) for the first 3 months of life. An overall significant right-side lateral bias was found for head orientation in the supine posture. A trend toward greater right-side bias in females compared with males was observed but failed to reach significance. These data suggest that asymmetries in head orientation are present early in life in chimPanzees, and they may be correlated with functional asymmetries observed in adulthood.
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Development of Self-Recognition in ChimPanzees (Pan Troglodytes)
Journal of Comparative Psychology, 1992Co-Authors: Kim A. Bard, James R. AndersonAbstract:ChimPanzees (Pan Troglodytes) demonstrate the ability to recognize themselves in mirrors, yet investigations of the development of self-recognition in chimPanzees are sparse. Twelve young chimPanzees, grouped by age, were given mirror exposure and tested for self-recognition and contingent movement. All 6 juveniles, 4 and 5 years old, exhibited mirror-guided, mark-directed behavior and clear evidence of self-recognition. In contrast, among the infants, only the oldest group of 2'/2-year-olds exhibited clear evidence of self-recognition. All chimPanzees exhibited both self-directed behaviors and contingent movements. These results suggest that self-recognition occurs at a slightly older age in chimPanzees than in human infants. In humans, self-recognition is linked with other cognitive abilities. The results conform to the general pattern that great apes exhibit many cognitive skills comparable to those of 2-year-old humans.
Masaki Tomonaga - One of the best experts on this subject based on the ideXlab platform.
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Preference for human direct gaze in infant chimPanzees (Pan Troglodytes).
Cognition, 2020Co-Authors: Masako Myowa-yamakoshi, Masaki Tomonaga, Masayuki Tanaka, Tetsuro MatsuzawaAbstract:We studied gaze perception in three infant chimPanzees (Pan Troglodytes), aged 10-32 weeks, using a two-choice preferential-looking paradigm. The infants were presented with two photographs of a human face: (a) with the eyes open or closed, and (b) with a direct or an averted gaze. We found that the chimPanzees preferred looking at the direct-gaze face. However, in the context of scrambled faces, the infants showed no difference in gaze discrimination between direct and averted gazes. These findings suggest that gaze perception by chimPanzees may be influenced by the surrounding facial context. The relationship between gaze perception, face processing, and the adaptive significance of gaze perception are discussed from an evolutionary perspective.
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REPORT Imitation in neonatal chimPanzees ( Pan Troglodytes )
2020Co-Authors: Masako Myowa-yamakoshi, Masaki Tomonaga, Masayuki Tanaka, Tetsuro MatsuzawaAbstract:This paper provides evidence for imitative abilities in neonatal chimPanzees ( Pan Troglodytes ), our closest relatives. Two chimPanzees were reared from birth by their biological mothers. At less than 7 days of age the chimPanzees could discriminate between, and imitate, human facial gestures (tongue protrusion and mouth opening). By the time they were 2 months old, however, the chimPanzees no longer imitated the gestures. They began to perform mouth opening frequently in response to any of the three facial gestures presented to them. These findings suggest that neonatal facial imitation is most likely an innate ability, developed through natural selection in humans and in chimPanzees. The relationship between the disappearance of neonatal imitation and the development of social communicative behavior is discussed from an evolutionary perspective.
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Visual search for human gaze direction by a ChimPanzee (Pan Troglodytes).
PLOS ONE, 2010Co-Authors: Masaki Tomonaga, Tomoko ImuraAbstract:Background Humans detect faces with direct gazes among those with averted gazes more efficiently than they detect faces with averted gazes among those with direct gazes. We examined whether this “stare-in-the-crowd” effect occurs in chimPanzees (Pan Troglodytes), whose eye morphology differs from that of humans (i.e., low-contrast eyes, dark sclera).
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Faces capture the visuospatial attention of chimPanzees ( Pan Troglodytes ): evidence from a cueing experiment
Frontiers in Zoology, 2009Co-Authors: Masaki Tomonaga, Tomoko ImuraAbstract:Background Faces, as socially relevant stimuli, readily capture human visuospatial attention. Although faces also play important roles in the social lives of chimPanzees, the closest living species to humans, the way in which faces are attentionally processed remains unclear from a comparative-cognitive perspective. In the present study, three young chimPanzees (Pan Troglodytes) were tested with a simple manual response task in which various kinds of photographs, including faces as non-informative cues, were followed by a target.
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An advantage for concavities in shape perception by chimPanzees (Pan Troglodytes).
Behavioural Processes, 2007Co-Authors: Toyomi Matsuno, Masaki TomonagaAbstract:The significance of concavity in object shape perception by chimPanzees (Pan Troglodytes) was investigated in a matching-to-sample procedure. For the task, chimPanzees were required to choose a polygon stimulus that was identical in shape to a sample. The incorrect alternative was defined by the addition or subtraction of a concave or convex apex. ChimPanzees were more sensitive to the concave deformation than to the convex deformation. This tendency conforms to the theories of human visual perception that have treated concave features as important factors in reconstructing three-dimensional structures from two-dimensional images. Our results suggest that shape representation in chimPanzees is similar to that in humans and that chimPanzees visually process two-dimensional images in the same manner as humans.
Erin R Vogel - One of the best experts on this subject based on the ideXlab platform.
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functional ecology and evolution of hominoid molar enamel thickness Pan Troglodytes schweinfurthii and pongo pygmaeus wurmbii
Journal of Human Evolution, 2008Co-Authors: Erin R Vogel, Janneke T Van Woerden, Sri Suci Utami Atmoko, Peter W. Lucas, Carel P Van Schaik, Nathaniel J. DominyAbstract:The divergent molar characteristics of Pan Troglodytes and Pongo pygmaeus provide an instructive paradigm for examining the adaptive form-function relationship between molar enamel thickness and food hardness. Although both species exhibit a categorical preference for ripe fruit over other food objects, the thick enamel and crenulated occlusal surface of Pongo molar teeth predict a diet that is more resistant to deformation (hard) and fracture (tough) than the diet of Pan. We confirm these predictions with behavioral observations of Pan Troglodytes schweinfurthii and Pongo pygmaeus wurmbii in the wild and describe the mechanical properties of foods utilized during periods when preferred foods are scarce. Such fallback foods may have exerted a selective pressure on tooth evolution, particularly molar enamel thinness, which is interpreted as a functional adaptation to seasonal folivory and a derived character trait within the hominoid clade. The thick enamel and crenulated occlusal surface of Pongo molars is interpreted as a functional adaptation to the routine consumption of relatively tough and hard foods. We discuss the implications of these interpretations for inferring the diet of hominin species, which possessed varying degrees of thick molar enamel. These data, which are among the first reported for hominoid primates, fill an important empirical void for evaluating the mechanical plausibility of putative hominin food objects.
Frans B. M. De Waal - One of the best experts on this subject based on the ideXlab platform.
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Visual kin recognition and family resemblance in chimPanzees (Pan Troglodytes)
Journal of Comparative Psychology, 2004Co-Authors: John R. Vokey, Jason M. Tangen, Drew Rendall, Lisa A Parr, Frans B. M. De WaalAbstract:The male-offspring biased visual kin recognition in chimPanzees (Pan Troglodytes) reported by L. A. Parr and F. B. M. de Waal (1999) was replicated with human (Homo sapiens) particiPants and a principal components analysis (PCA) of pixel maps of the chimPanzee face photos. With the same original materials and methods, both humans and the PCA produced the same asymmetry in kin recognition as found with the chimPanzees. The PCA suggested that the asymmetry was a function of differences in the distribution of global characteristics associated with the framing of the faces in the son and daughter test sets. Eliminating potential framing biases, either by cropping the photos tightly to the faces or by rebalancing the recognition foils, eliminated the asymmetry but not human particiPants' ability to recognize chimPanzee kin.
