The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Sam G. B. Roberts - One of the best experts on this subject based on the ideXlab platform.
-
Social and ecological complexity is associated with Gestural repertoire size of wild chimpanzees.
Integrative zoology, 2020Co-Authors: Sam G. B. Roberts, Anna Ilona RobertsAbstract:Increasing our understanding of primate Gestural Communication can provide new insights into language evolution. A key question in primate Communication is the association between the social relationships of primates and their repertoire of gestures. Such analyses can reveal how primates use their repertoire of Gestural Communication to maintain their networks of family and friends, much as humans use language to maintain their social networks. In this study we examined the association between the repertoire of gestures (overall, manual and bodily gestures, and gestures of different modalities) and social bonds (presence of reciprocated grooming), coordinated behaviors (travel, resting, co-feeding), and the complexity of ecology (e.g. noise, illumination) and sociality (party size, audience), in wild East African chimpanzees (Pan troglodytes schweinfurthii). A larger repertoire size of manual, visual gestures was associated with the presence of a relationship based on reciprocated grooming and increases in social complexity. A smaller repertoire of manual tactile gestures occurred when the relationship was based on reciprocated grooming. A smaller repertoire of bodily gestures occurred between partners who jointly traveled for longer. Whereas gesture repertoire size was associated with social complexity, complex ecology also influenced repertoire size. The evolution of a large repertoire of manual, visual gestures may have been a key factor that enabled larger social groups to emerge during evolution. Thus, the evolution of the larger brains in hominins may have co-occurred with an increase in the cognitive complexity underpinning Gestural Communication and this, in turn, may have enabled hominins to live in more complex social groups.
-
Persistence in Gestural Communication predicts sociality in wild chimpanzees
Animal Cognition, 2019Co-Authors: Anna Ilona Roberts, Sam G. B. RobertsAbstract:A key challenge for primates is coordinating behaviour with conspecifics in large, complex social groups. Gestures play a key role in this process and chimpanzees show considerable flexibility communicating through single gestures, sequences of gestures interspersed with periods of response waiting (persistence), and rapid sequences where gestures are made in quick succession, too rapid for the response waiting to have occurred. The previous studies examined behavioural reactions to single gestures and sequences, but whether this complexity is associated with more complex sociality at the level of the dyad partner and the group as a whole is not well understood. We used social network analysis to examine how the production of single gestures and sequences of gestures was related to the duration of time spent in proximity and individual differences in proximity in wild East African chimpanzees ( Pan troglodytes schweinfurthii ). Pairs of chimpanzees that spent a longer duration of time in proximity had higher rates of persistence sequences, but not a higher rate of single gestures or rapid sequences. The duration of time spent in proximity was also related to the rate of responding to gestures, and response to gesture by activity change. These results suggest that communicative persistence and the type of response to gestures may play an important role in regulating social interactions in primate societies.
-
Social bonding, Gestural complexity and displacement behaviour of wild chimpanzee
bioRxiv, 2019Co-Authors: Anna Ilona Roberts, Sam G. B. RobertsAbstract:Abstract Kinship and demography affect social affiliation in many different contexts such as co-feeding, resting, travel, grooming, visual attention and proximity. Chimpanzees may coordinate these social interactions by using Gestural Communication to make signaller’s goal transparent to the recipient and also by increasing commitment of the recipient through including rewarding property in Communication. The rewards of gesturing can be measured through the rates of displacement behaviour made in response to these gestures by the recipient. We tested hypothesis that Gestural Communication affects social affiliation after controlling for kinship and demography in wild, adult chimpanzees living in Budongo Forest, Uganda. We found that affiliative but not antagonistic gestures positively predicted social affiliation. Contexts differed in their association with gestures according to complexity and association with displacement behaviour. More complex, less intense gestures predicted mutual grooming, travel, visual attention whereas less complex, more intense gestures predicted unidirectional grooming. Mirroring these patterns, reduced displacement activity occurred in response to gestures associated with unidirectional grooming but not other contexts. We highlight that these tactical decisions that wild chimpanzees make in their use of Gestural Communication may be driven by complexity of social environment that influences effectiveness with which signalers can influence the recipient.
-
visual attention indicative gestures and calls accompanying Gestural Communication are associated with sociality in wild chimpanzees pan troglodytes schweinfurthii
Journal of Comparative Psychology, 2019Co-Authors: Sam G. B. Roberts, Anna Ilona RobertsAbstract:The challenges of life in complex social groups may select for complex Communication to regulate interactions among conspecifics. Whereas the association between social living and vocalizations has been explored in nonhuman primates, great apes also have a rich repertoire of gestures, and how the complexity of Gestural Communication relates to sociality is still unclear. We used social network analysis to examine the relationship between the duration of time pairs of chimpanzees spent in proximity (within 10 m) and the rates of Gestural Communication accompanied by visual attention of the signaler, one-to-one calls, indicative gestures (collectively self-relevance cues), and synchronized pant-hoot calls. Pairs of chimpanzees that spent a longer duration of time in proximity had a higher rate of visual gestures accompanied by these behaviors. Further, individual chimpanzees that had a greater number of proximity bonds had a larger social network maintained through gestures accompanied by synchronized pant-hoot calls. In contrast, gestures unaccompanied by these behaviors were not positively associated with either proximity bonds in pairs of chimpanzees or individual differences in sociality. These results suggest that self-relevance cues and synchronized pant-hoot calls accompanying gestures may increase the efficiency of Gestural Communication in social bonding and that multimodal Communication may have played a key role in language evolution. © 2018 American Psychological Association.
-
Gestural repertoire size is associated with social proximity measures in wild chimpanzees.
American Journal of Primatology, 2019Co-Authors: Anna Ilona Roberts, Anwesha Chakrabarti, Sam G. B. RobertsAbstract:Studying the Communication systems of primates can provide insights into the evolutionary origins of human language. Some theories propose that language evolved to help meet the demands of managing complex social relationships. Examining the associations between sociality and Communication in the great apes can help to identify the specific selection pressures that may have been important for language evolution. In particular, Gestural Communication is believed to be important because it is a relatively recent trait seen only in primates and particularly in the great apes. However, the extent to which more complex Gestural Communication plays a role in managing social relationships, as compared to less complex Gestural Communication, is not well understood. Using social network analysis, we examined the association between complex gesturing (indexed as repertoire size) and complexity of social relationships indexed as proximity (the duration of time spent within 10 m, per hour spent in same party) in wild chimpanzees (Pan troglodytes schweinfurthii). Repertoire size (the total number of gesture types a focal subject produced toward other individuals) and dyadic repertoire size (the number of gesture types produced toward the dyad partner, per hour spent within 10 meters) were positively associated with proximity at the level of the group (centrality in the proximity network) and the dyad (proximity duration between dyads), respectively. Further, the repertoire size of visual and auditory short-range gestures was positively associated with proximity, while the repertoire size of tactile gesture was negatively associated with proximity. Overall these results suggest that Gestural repertoire size has important implications for maintaining social relationships in wild chimpanzees and more broadly that Gestural Communication may have played an important role in language evolution.
Anna Ilona Roberts - One of the best experts on this subject based on the ideXlab platform.
-
Social and ecological complexity is associated with Gestural repertoire size of wild chimpanzees.
Integrative zoology, 2020Co-Authors: Sam G. B. Roberts, Anna Ilona RobertsAbstract:Increasing our understanding of primate Gestural Communication can provide new insights into language evolution. A key question in primate Communication is the association between the social relationships of primates and their repertoire of gestures. Such analyses can reveal how primates use their repertoire of Gestural Communication to maintain their networks of family and friends, much as humans use language to maintain their social networks. In this study we examined the association between the repertoire of gestures (overall, manual and bodily gestures, and gestures of different modalities) and social bonds (presence of reciprocated grooming), coordinated behaviors (travel, resting, co-feeding), and the complexity of ecology (e.g. noise, illumination) and sociality (party size, audience), in wild East African chimpanzees (Pan troglodytes schweinfurthii). A larger repertoire size of manual, visual gestures was associated with the presence of a relationship based on reciprocated grooming and increases in social complexity. A smaller repertoire of manual tactile gestures occurred when the relationship was based on reciprocated grooming. A smaller repertoire of bodily gestures occurred between partners who jointly traveled for longer. Whereas gesture repertoire size was associated with social complexity, complex ecology also influenced repertoire size. The evolution of a large repertoire of manual, visual gestures may have been a key factor that enabled larger social groups to emerge during evolution. Thus, the evolution of the larger brains in hominins may have co-occurred with an increase in the cognitive complexity underpinning Gestural Communication and this, in turn, may have enabled hominins to live in more complex social groups.
-
Persistence in Gestural Communication predicts sociality in wild chimpanzees
Animal Cognition, 2019Co-Authors: Anna Ilona Roberts, Sam G. B. RobertsAbstract:A key challenge for primates is coordinating behaviour with conspecifics in large, complex social groups. Gestures play a key role in this process and chimpanzees show considerable flexibility communicating through single gestures, sequences of gestures interspersed with periods of response waiting (persistence), and rapid sequences where gestures are made in quick succession, too rapid for the response waiting to have occurred. The previous studies examined behavioural reactions to single gestures and sequences, but whether this complexity is associated with more complex sociality at the level of the dyad partner and the group as a whole is not well understood. We used social network analysis to examine how the production of single gestures and sequences of gestures was related to the duration of time spent in proximity and individual differences in proximity in wild East African chimpanzees ( Pan troglodytes schweinfurthii ). Pairs of chimpanzees that spent a longer duration of time in proximity had higher rates of persistence sequences, but not a higher rate of single gestures or rapid sequences. The duration of time spent in proximity was also related to the rate of responding to gestures, and response to gesture by activity change. These results suggest that communicative persistence and the type of response to gestures may play an important role in regulating social interactions in primate societies.
-
Social bonding, Gestural complexity and displacement behaviour of wild chimpanzee
bioRxiv, 2019Co-Authors: Anna Ilona Roberts, Sam G. B. RobertsAbstract:Abstract Kinship and demography affect social affiliation in many different contexts such as co-feeding, resting, travel, grooming, visual attention and proximity. Chimpanzees may coordinate these social interactions by using Gestural Communication to make signaller’s goal transparent to the recipient and also by increasing commitment of the recipient through including rewarding property in Communication. The rewards of gesturing can be measured through the rates of displacement behaviour made in response to these gestures by the recipient. We tested hypothesis that Gestural Communication affects social affiliation after controlling for kinship and demography in wild, adult chimpanzees living in Budongo Forest, Uganda. We found that affiliative but not antagonistic gestures positively predicted social affiliation. Contexts differed in their association with gestures according to complexity and association with displacement behaviour. More complex, less intense gestures predicted mutual grooming, travel, visual attention whereas less complex, more intense gestures predicted unidirectional grooming. Mirroring these patterns, reduced displacement activity occurred in response to gestures associated with unidirectional grooming but not other contexts. We highlight that these tactical decisions that wild chimpanzees make in their use of Gestural Communication may be driven by complexity of social environment that influences effectiveness with which signalers can influence the recipient.
-
visual attention indicative gestures and calls accompanying Gestural Communication are associated with sociality in wild chimpanzees pan troglodytes schweinfurthii
Journal of Comparative Psychology, 2019Co-Authors: Sam G. B. Roberts, Anna Ilona RobertsAbstract:The challenges of life in complex social groups may select for complex Communication to regulate interactions among conspecifics. Whereas the association between social living and vocalizations has been explored in nonhuman primates, great apes also have a rich repertoire of gestures, and how the complexity of Gestural Communication relates to sociality is still unclear. We used social network analysis to examine the relationship between the duration of time pairs of chimpanzees spent in proximity (within 10 m) and the rates of Gestural Communication accompanied by visual attention of the signaler, one-to-one calls, indicative gestures (collectively self-relevance cues), and synchronized pant-hoot calls. Pairs of chimpanzees that spent a longer duration of time in proximity had a higher rate of visual gestures accompanied by these behaviors. Further, individual chimpanzees that had a greater number of proximity bonds had a larger social network maintained through gestures accompanied by synchronized pant-hoot calls. In contrast, gestures unaccompanied by these behaviors were not positively associated with either proximity bonds in pairs of chimpanzees or individual differences in sociality. These results suggest that self-relevance cues and synchronized pant-hoot calls accompanying gestures may increase the efficiency of Gestural Communication in social bonding and that multimodal Communication may have played a key role in language evolution. © 2018 American Psychological Association.
-
Gestural repertoire size is associated with social proximity measures in wild chimpanzees.
American Journal of Primatology, 2019Co-Authors: Anna Ilona Roberts, Anwesha Chakrabarti, Sam G. B. RobertsAbstract:Studying the Communication systems of primates can provide insights into the evolutionary origins of human language. Some theories propose that language evolved to help meet the demands of managing complex social relationships. Examining the associations between sociality and Communication in the great apes can help to identify the specific selection pressures that may have been important for language evolution. In particular, Gestural Communication is believed to be important because it is a relatively recent trait seen only in primates and particularly in the great apes. However, the extent to which more complex Gestural Communication plays a role in managing social relationships, as compared to less complex Gestural Communication, is not well understood. Using social network analysis, we examined the association between complex gesturing (indexed as repertoire size) and complexity of social relationships indexed as proximity (the duration of time spent within 10 m, per hour spent in same party) in wild chimpanzees (Pan troglodytes schweinfurthii). Repertoire size (the total number of gesture types a focal subject produced toward other individuals) and dyadic repertoire size (the number of gesture types produced toward the dyad partner, per hour spent within 10 meters) were positively associated with proximity at the level of the group (centrality in the proximity network) and the dyad (proximity duration between dyads), respectively. Further, the repertoire size of visual and auditory short-range gestures was positively associated with proximity, while the repertoire size of tactile gesture was negatively associated with proximity. Overall these results suggest that Gestural repertoire size has important implications for maintaining social relationships in wild chimpanzees and more broadly that Gestural Communication may have played an important role in language evolution.
Alban Lemasson - One of the best experts on this subject based on the ideXlab platform.
-
Red-capped mangabeys (Cercocebus torquatus) adapt their interspecific Gestural Communication to the recipient’s behaviour
Scientific reports, 2020Co-Authors: Juliette Aychet, Catherine Blois-heulin, Pablo Pezzino, Arnaud Rossard, Philippe Bec, Alban LemassonAbstract:Sensitivity to recipient’s attention and responsiveness are critical markers of intentional Communication. Although previous research showed that ape gestures can be intentional, few studies have yet addressed this question concerning monkeys. Here, we characterise the effect of a recipient’s presence, attentional state and responsiveness on the interspecific Gestural Communication of captive red-capped mangabeys (Cercocebus torquatus). Previous reports showed that they produced learnt begging gestures towards a human recipient preferentially when the latter was facing them. We used here a novel setup that allows subjects to move around an experimenter and to use different modalities (visual and acoustic) to communicate. We found that when the recipient was not facing them, mangabeys moved to a position in the visual field of their recipient rather than using attention-getters. Interestingly, unlike apes, they did not elaborate their Communication visually or acoustically when the experimenter did not respond favourably to their begging. However, our results may suggest that begging gestures were goal-directed, since mangabeys inhibited them when the experimenter was not available to answer immediately (i.e. give a reward). Overall, red-capped mangabeys’ interspecific visual Communication presented intentionality features, but their use of begging gestures was less flexible than that of great apes in similar situations.
-
red capped mangabeys cercocebus torquatus adapt their interspecific Gestural Communication to the recipient s behaviour
Scientific Reports, 2020Co-Authors: Juliette Aychet, Pablo Pezzino, Arnaud Rossard, Philippe Bec, Catherine Bloisheulin, Alban LemassonAbstract:Sensitivity to recipient’s attention and responsiveness are critical markers of intentional Communication. Although previous research showed that ape gestures can be intentional, few studies have yet addressed this question concerning monkeys. Here, we characterise the effect of a recipient’s presence, attentional state and responsiveness on the interspecific Gestural Communication of captive red-capped mangabeys (Cercocebus torquatus). Previous reports showed that they produced learnt begging gestures towards a human recipient preferentially when the latter was facing them. We used here a novel setup that allows subjects to move around an experimenter and to use different modalities (visual and acoustic) to communicate. We found that when the recipient was not facing them, mangabeys moved to a position in the visual field of their recipient rather than using attention-getters. Interestingly, unlike apes, they did not elaborate their Communication visually or acoustically when the experimenter did not respond favourably to their begging. However, our results may suggest that begging gestures were goal-directed, since mangabeys inhibited them when the experimenter was not available to answer immediately (i.e. give a reward). Overall, red-capped mangabeys’ interspecific visual Communication presented intentionality features, but their use of begging gestures was less flexible than that of great apes in similar situations.
William D. Hopkins - One of the best experts on this subject based on the ideXlab platform.
-
on the origins of human handedness and language a comparative review of hand preferences for bimanual coordinated actions and Gestural Communication in nonhuman primates
Developmental Psychobiology, 2013Co-Authors: Adrien Meguerditchian, William D. HopkinsAbstract:Within the evolutionary framework about the origin of human handedness and hemispheric specialization for language, the question of expres- sion of population-level manual biases in nonhuman primates and their potential continuities with humans remains controversial. Nevertheless, there is a growing body of evidence showing consistent population-level handedness particularly for complex manual behaviors in both monkeys and apes. In the present article, within a large comparative approach among primates, we will review our contribution to the field and the handedness literature related to two particular sophisticated manual behaviors regarding their potential and specific implications for the origins of hemispheric specialization in humans: bimanual coordinated actions and Gestural Communication. Whereas bimanual coordinated actions seem to elicit predominance of left-handedness in arboreal primates and of right- handedness in terrestrial primates, all handedness studies that have investigated Gestural Communication in several primate species have reported stronger degree of population-level right-handedness compared to noncommunicative actions. Communicative gestures and bimanual actions seem to affect differently manual asymmetries in both human and nonhuman primates and to be related to different lateralized brain substrates. We will discuss (1) how the data of hand preferences for bimanual coordinated actions highlight the role of ecological factors in the evolution of handedness and provide additional support the postural origin theory of handedness proposed by MacNeilage (MacNeilage (2007). Present status of the postural origins theory. In W. D. Hopkins (Ed.), The evolution of hemispheric specialization in primates (pp. 59-91). London: Elsevier/Academic Press) and (2) the hypothesis that the emergence of Gestural Communication might have affected lateralization in our ancestor and may constitute the precursors of the hemispheric specialization for language. 2013 Wiley Periodicals, Inc. Dev Psychobiol 55: 637-650, 2013.
-
Handedness for manual gestures in great apes
Gesture Studies, 2012Co-Authors: William D. Hopkins, Katja Liebal, Simone Pika, Adrien Meguerditchian, Amanda E. Bania, Molly Gardner, Steven J. SchapiroAbstract:We describe the Gestural Communication of wild chimpanzees in the evolutionarily urgent context of consortship. Consortship represented the dominant context for the use of Gestural Communication by adult males in the Sonso community. Gesturing provided consorting males with the opportunity to communicate their intentions to the female, while avoiding the risk of also advertising these to other community males. The extensive use of gesturing by adult males differs from the low frequency reported in captivity, and emphasises the importance of studying behaviour in a natural population.Postprin
-
From hand to mouth in the evolution of language: the influence of vocal behavior on lateralized hand use in manual gestures by chimpanzees ( Pan troglodytes )
Developmental Science, 2003Co-Authors: William D. Hopkins, Monica CanteroAbstract:Studies in human subjects indicate that manual gestures accompanied by speech are produced more often by the right compared to the left hand. Additional studies indicate that the production of sign language is controlled by the same brain areas as speech, suggesting similar neurobiological substrates for language that are not modality specific. We report evidence that chimpanzees exhibit preferential use of the right hand in Gestural Communication. Moreover, use of the right hand in Gestural Communication is significantly enhanced when accompanied by a vocalization, particularly among human-reared chimpanzees. Taken together, the data suggest that the lateralization of manual and speech systems of Communication may date back as far as 5 million years ago.
-
Gestural Communication in chimpanzees pan troglodytes the influence of experimenter position on gesture type and hand preference
Laterality, 2002Co-Authors: William D. Hopkins, Michael J WesleyAbstract:This study examined the influence of experimenter position on hand use in Gestural Communication in a sample of 127 captive chimpanzees. Hand use in Gestural Communication was recorded while an experimenter was positioned either left, right, or directly in front of the subject. The type of gesture was also recorded as either a food beg or whole hand point. Both hand use and gesture were consistent across experimenter positions. Overall, a significant population-level right hand bias was found, particularly for food beg gestures. These results are consistent with previous findings in chimpanzees and suggest that lateralisation in Gestural Communication is left hemisphere dominant.
-
differential use of vocal and Gestural Communication by chimpanzees pan troglodytes in response to the attentional status of a human homo sapiens
Journal of Comparative Psychology, 2001Co-Authors: Autumn B Hostetter, Monica Cantero, William D. HopkinsAbstract:This study examined the communicative behavior of 49 captive chimpanzees (Pan troglodytes), particularly their use of vocalizations, manual gestures, and other auditory- or tactile-based behaviors as a means of gaining an inattentive audience’s attention. A human (Homo sapiens) experimenter held a banana while oriented either toward or away from the chimpanzee. The chimpanzees’ behavior was recorded for 60 s. Chimpanzees emitted vocalizations faster and were more likely to produce vocalizations as their 1st communicative behavior when a human was oriented away from them. Chimpanzees used manual gestures more frequently and faster when the human was oriented toward them. These results replicate the findings of earlier studies on chimpanzee Gestural Communication and provide new information about the intentional and functional use of their vocalizations.
Juliette Aychet - One of the best experts on this subject based on the ideXlab platform.
-
Red-capped mangabeys (Cercocebus torquatus) adapt their interspecific Gestural Communication to the recipient’s behaviour
Scientific reports, 2020Co-Authors: Juliette Aychet, Catherine Blois-heulin, Pablo Pezzino, Arnaud Rossard, Philippe Bec, Alban LemassonAbstract:Sensitivity to recipient’s attention and responsiveness are critical markers of intentional Communication. Although previous research showed that ape gestures can be intentional, few studies have yet addressed this question concerning monkeys. Here, we characterise the effect of a recipient’s presence, attentional state and responsiveness on the interspecific Gestural Communication of captive red-capped mangabeys (Cercocebus torquatus). Previous reports showed that they produced learnt begging gestures towards a human recipient preferentially when the latter was facing them. We used here a novel setup that allows subjects to move around an experimenter and to use different modalities (visual and acoustic) to communicate. We found that when the recipient was not facing them, mangabeys moved to a position in the visual field of their recipient rather than using attention-getters. Interestingly, unlike apes, they did not elaborate their Communication visually or acoustically when the experimenter did not respond favourably to their begging. However, our results may suggest that begging gestures were goal-directed, since mangabeys inhibited them when the experimenter was not available to answer immediately (i.e. give a reward). Overall, red-capped mangabeys’ interspecific visual Communication presented intentionality features, but their use of begging gestures was less flexible than that of great apes in similar situations.
-
red capped mangabeys cercocebus torquatus adapt their interspecific Gestural Communication to the recipient s behaviour
Scientific Reports, 2020Co-Authors: Juliette Aychet, Pablo Pezzino, Arnaud Rossard, Philippe Bec, Catherine Bloisheulin, Alban LemassonAbstract:Sensitivity to recipient’s attention and responsiveness are critical markers of intentional Communication. Although previous research showed that ape gestures can be intentional, few studies have yet addressed this question concerning monkeys. Here, we characterise the effect of a recipient’s presence, attentional state and responsiveness on the interspecific Gestural Communication of captive red-capped mangabeys (Cercocebus torquatus). Previous reports showed that they produced learnt begging gestures towards a human recipient preferentially when the latter was facing them. We used here a novel setup that allows subjects to move around an experimenter and to use different modalities (visual and acoustic) to communicate. We found that when the recipient was not facing them, mangabeys moved to a position in the visual field of their recipient rather than using attention-getters. Interestingly, unlike apes, they did not elaborate their Communication visually or acoustically when the experimenter did not respond favourably to their begging. However, our results may suggest that begging gestures were goal-directed, since mangabeys inhibited them when the experimenter was not available to answer immediately (i.e. give a reward). Overall, red-capped mangabeys’ interspecific visual Communication presented intentionality features, but their use of begging gestures was less flexible than that of great apes in similar situations.