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Journal of Human Evolution Jan 2022The analysis of patterns of integration is crucial for the reconstruction and understanding of how morphological changes occur in a taxonomic group throughout evolution....
The analysis of patterns of integration is crucial for the reconstruction and understanding of how morphological changes occur in a taxonomic group throughout evolution. These patterns are relatively constant; however, both patterns and the magnitudes of integration may vary across species. These differences may indicate morphological diversification, in some cases related to functional adaptations to the biomechanics of organisms. In this study, we analyze patterns of integration between two functional and developmental structures, the cranium and the cervical spine in hominids, and we quantify the amount of divergence of each anatomical element through phylogeny. We applied these methods to three-dimensional data from 168 adult hominid individuals, summing a total of more than 1000 cervical vertebrae. We found the atlas (C1) and axis (C2) display the lowest covariation with the cranium in hominids (Homo sapiens, Pan troglodytes, Pan paniscus, Gorilla gorilla, Gorilla beringei, Pongo pygmaeus). H. sapiens show a relatively different pattern of craniocervical correlation compared with chimpanzees and gorillas, especially in variables implicated in maintaining the balance of the head. Finally, the atlas and axis show lower magnitude of shape change during evolution than the rest of the cervical vertebrae, especially those located in the middle of the subaxial cervical spine. Overall, results suggest that differences in the pattern of craniocervical correlation between humans and gorillas and chimpanzees could reflect the postural differences between these groups. Also, the stronger craniocervical integration and larger magnitude of shape change during evolution shown by the middle cervical vertebrae suggests that they have been selected to play an active role in maintaining head balance.
Topics: Adult; Animals; Cervical Vertebrae; Gorilla gorilla; Hominidae; Humans; Pan paniscus; Pan troglodytes; Pongo pygmaeus; Skull
PubMed: 34894608
DOI: 10.1016/j.jhevol.2021.103112 -
American Journal of Primatology Jan 2021Despite the large body of literature on ape conservation, much of the data needed for evidence-based conservation decision-making is still not readily accessible and...
Despite the large body of literature on ape conservation, much of the data needed for evidence-based conservation decision-making is still not readily accessible and standardized, rendering cross-site comparison difficult. To support knowledge synthesis and to complement the IUCN SSC Ape Populations, Environments and Surveys database, we created the A.P.E.S. Wiki (https://apeswiki.eva.mpg.de), an open-access platform providing site-level information on ape conservation status and context. The aim of this Wiki is to provide information and data about geographical ape locations, to curate information on individuals and organizations active in ape research and conservation, and to act as a tool to support collaboration between conservation practitioners, scientists, and other stakeholders. To illustrate the process and benefits of knowledge synthesis, we used the momentum of the update of the conservation action plan for western chimpanzees (Pan troglodytes verus) and began with this critically endangered taxon. First, we gathered information on 59 sites in West Africa from scientific publications, reports, and online sources. Information was compiled in a standardized format and can thus be summarized using a web scraping approach. We then asked experts working at those sites to review and complement the information (20 sites have been reviewed to date). We demonstrate the utility of the information available through the Wiki, for example, for studying species distribution. Importantly, as an open-access platform and based on the well-known wiki layout, the A.P.E.S. Wiki can contribute to direct and interactive information sharing and promote the efforts invested by the ape research and conservation community. The Section on Great Apes and the Section on Small Apes of the IUCN SSC Primate Specialist Group will guide and support the expansion of the platform to all small and great ape taxa. Similar collaborative efforts can contribute to extending knowledge synthesis to all nonhuman primate species.
Topics: Africa, Western; Animals; Conservation of Natural Resources; Endangered Species; Pan troglodytes
PubMed: 33169878
DOI: 10.1002/ajp.23213 -
Journal of Comparative Psychology... May 2021Comparative studies can help identify selective pressures that contributed to species differences in the number and composition of personality domains. Despite being...
Comparative studies can help identify selective pressures that contributed to species differences in the number and composition of personality domains. Despite being adapted to an aquatic lifestyle and last sharing a common ancestor with primates some 95 million years ago, bottlenose dolphins (Tursiops truncatus) resemble nonhuman primate species in several behavioral and cognitive traits. For example, like chimpanzees (Pan troglodytes), dolphins live in fission-fusion societies, use tools, and have relatively large brains. To determine the extent to which these and other factors contribute to the evolution of dolphin personality, we examined personality structure in 134 bottlenose dolphins. Personality was measured in 49 dolphins using a 42-item questionnaire, and in 85 dolphins using a version of the questionnaire that included 7 additional items. We found four domains. Three-Openness, Sociability, and Disagreeableness-resembled personality domains found in nonhuman primates and other species. The fourth, Directedness, was a blend of high Conscientiousness and low Neuroticism and was unique to dolphins. Unlike other species, but like humans, dolphins did not appear to have a strong Dominance domain. The overlap in personality structure between dolphins and other species suggests that selective pressures, such as those related to group structure, terrestrial lifestyles, morphology, and social learning or tool use are not necessary for particular domains to evolve within a species. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
Topics: Animals; Bottle-Nosed Dolphin; Pan troglodytes; Personality
PubMed: 33464108
DOI: 10.1037/com0000259 -
Philosophical Transactions of the Royal... Feb 2021Involuntary autobiographical memories are memories of personal events that come to mind spontaneously-that is, with no conscious initiation of the retrieval process.... (Review)
Review
Involuntary autobiographical memories are memories of personal events that come to mind spontaneously-that is, with no conscious initiation of the retrieval process. Such spontaneously arising memories were long ignored in cognitive psychology, which generally has focused on controlled and strategic forms of remembering, studied in laboratory settings. Recent evidence shows that involuntary memories of past events are highly frequent in daily life, and that they represent a context-sensitive, and associative way of recollecting past events that involves little executive control. They operate by constraints that favour recent events and events with a distinct feature overlap to the current situation, which optimizes the probability of functional relevance to the ongoing situation. In addition to adults, they are documented in young children and great apes and may be an ontogenetic and evolutionary forerunner of strategic retrieval of past events. Findings suggest that intrusive involuntary memories observed clinically after traumatic events should be viewed as a dysfunctional subclass of otherwise functional involuntary autobiographical memories. Because of their highly constrained, situation-dependent and automatic nature, involuntary autobiographical memories form a distinct category of spontaneous thought that cannot be equated with mind wandering. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.
Topics: Adult; Aged; Animals; Attention; Child; Child, Preschool; Executive Function; Humans; Memory, Episodic; Mental Recall; Middle Aged; Pan paniscus; Pan troglodytes; Pongo abelii; Young Adult
PubMed: 33308074
DOI: 10.1098/rstb.2019.0693 -
Developmental Science Sep 2022Cognitive flexibility is a core component of executive function, a suite of cognitive capacities that enables individuals to update their behavior in dynamic...
Cognitive flexibility is a core component of executive function, a suite of cognitive capacities that enables individuals to update their behavior in dynamic environments. Human executive functions are proposed to be enhanced compared to other species, but this inference is based primarily on neuroanatomical studies. To address this, we examined the nature and origins of cognitive flexibility in chimpanzees, our closest living relatives. Across three studies, we examined different components of cognitive flexibility using reversal learning tasks where individuals first learned one contingency and then had to shift responses when contingencies flipped. In Study 1, we tested n = 82 chimpanzees ranging from juvenility to adulthood on a spatial reversal task, to characterize the development of basic shifting skills. In Study 2, we tested how n = 24 chimpanzees use spatial versus arbitrary perceptual information to shift, a proposed difference between human and nonhuman cognition. In Study 3, we tested n = 40 chimpanzees on a probabilistic reversal task. We found an extended developmental trajectory for basic shifting and shifting in response to probabilistic feedback-chimpanzees did not reach mature performance until late in ontogeny. Additionally, females were faster to shift than males were. We also found that chimpanzees were much more successful when using spatial versus perceptual cues, and highly perseverative when faced with probabilistic versus consistent outcomes. These results identify both core features of chimpanzee cognitive flexibility that are shared with humans, as well as constraints on chimpanzee cognitive flexibility that may represent evolutionary changes in human cognitive development.
Topics: Adult; Animals; Cognition; Cues; Executive Function; Female; Humans; Male; Pan troglodytes
PubMed: 35397187
DOI: 10.1111/desc.13266 -
American Journal of Primatology Jan 2023Inequity aversion (IA), the affective, cognitive, and behavioral response to inequitable outcomes, allows individuals to avoid exploitation and therefore stabilizes...
Inequity aversion (IA), the affective, cognitive, and behavioral response to inequitable outcomes, allows individuals to avoid exploitation and therefore stabilizes cooperation. The presence of IA varies across animal species, which has stimulated research to investigate factors that might explain this variation, and to investigate underlying affective responses. Among great apes, IA is most often studied in chimpanzees. Here, we investigate IA in bonobos, a reputedly tolerant and cooperative species for which few IA studies are available. We describe how bonobos respond to receiving less preferred rewards than a partner in a token exchange task. We show that bonobos respond to receiving less preferred rewards by refusing tokens and rewards, and by leaving the experimental area. Bonobos never refused a trial when receiving preferred rewards, and thus showed no advantageous IA. We also investigate the variability in the disadvantageous IA response on a dyadic level, because the level of IA is expected to vary, depending on characteristics of the dyad. Like in humans and chimpanzees, we show that the tolerance towards inequity was higher in bonobo dyads with more valuable relationships. To study the affective component of IA, we included behavioral and physiological measures of arousal: a displacement behavior (rough self-scratching) and changes in salivary cortisol levels. Both measures of arousal showed large variability, and while analyses on rough self-scratching showed no significant effects, salivary cortisol levels seemed to be lower in subjects that received less than their partner, but higher in subjects that received more than their partner, albeit that both were not significantly different from the equity condition. This suggests that although overcompensated bonobos showed no behavioral response, they might be more aroused. Our data support the cooperation hypothesis on an interspecific and intraspecific level. They show inequity aversion in bonobos, a reputedly cooperative species, and suggest that the variability in IA in bonobos can be explained by their socioecology. Most successful cooperative interactions happen between mothers and their sons and among closely bonded females. The limited need to monitor the partners' investment within these dyads can result in a higher tolerance towards inequity. We therefore suggest future studies to consider relevant socioecological characteristics of the species when designing and analyzing IA studies.
Topics: Humans; Female; Animals; Pan paniscus; Social Behavior; Pan troglodytes; Hydrocortisone; Hominidae
PubMed: 36419405
DOI: 10.1002/ajp.23455 -
The Veterinary Record Nov 2023Georgina Mills discusses new research that investigates if the hormonal changes seen in women in later life are reflected in chimpanzees.
Georgina Mills discusses new research that investigates if the hormonal changes seen in women in later life are reflected in chimpanzees.
Topics: Female; Animals; Pan troglodytes; Menopause
PubMed: 37975459
DOI: 10.1002/vetr.3683 -
American Journal of Biological... Feb 2022Craniofacial fluctuating asymmetry (FA) refers to the random deviations from symmetry exhibited across the craniofacial complex and can be used as a measure of...
OBJECTIVES
Craniofacial fluctuating asymmetry (FA) refers to the random deviations from symmetry exhibited across the craniofacial complex and can be used as a measure of developmental instability for organisms with bilateral symmetry. This article addresses the lack of data on craniofacial FA in nonhuman primates by analyzing FA magnitude and variation in chimpanzees, gorillas, and macaques. We offer a preliminary investigation into how FA, as a proxy for developmental instability, varies within and among nonhuman primates.
MATERIALS AND METHODS
We generated 3D surface models of 121 crania from Pan troglodytes troglodytes, Gorilla gorilla gorilla, and Macaca fascicularis fascicularis. Using geometric morphometric techniques, the magnitude of observed FA was calculated and compared for each individual, sex, and taxon, along with the variation of FA across cranial regions and for each bilateral landmark.
RESULTS
Gorillas and macaques exhibited higher and more similar magnitudes of FA to each other than either taxon did to chimpanzees; variation in magnitude of FA followed this same trend. No significant differences were detected between sexes using pooled data across species, but sex did influence FA magnitude within taxa in gorillas. Further, variation in FA variance across cranial regions and by landmark was not distributed in any particular pattern.
CONCLUSION
Possible environmentally induced causes for these patterns of FA magnitude include differences in growth rate and physiological stress experienced during life. Developmental stability may be greatest in chimpanzees in this sample. Additionally, these results point to appropriate landmarks for future FA analyses and may help suggest more urgent candidate taxa for conservation efforts.
Topics: Animals; Gorilla gorilla; Pan troglodytes; Macaca; Hominidae; Skull; Facial Asymmetry
PubMed: 36790754
DOI: 10.1002/ajpa.24432 -
American Journal of Primatology Jul 2021Primate foraging is influenced by the spatial and temporal distribution of foods, which may facilitate or constrain optimal nutrient intakes. Chimpanzees are frugivorous...
Primate foraging is influenced by the spatial and temporal distribution of foods, which may facilitate or constrain optimal nutrient intakes. Chimpanzees are frugivorous primates that mainly subsist on ripe fruit that is typically low in available protein (AP) and high in easily digestible carbohydrates. Because chimpanzees prefer ripe fruit and often eat it in large quantities compared with other foods, we hypothesized that protein intake would be tightly regulated while non-protein energy (NPE) would vary with fruit intake. To test this hypothesis, we conducted all-day follows on female chimpanzees, recorded all types of food consumed (i.e., drupes, figs, and non-fruit foods), estimated the nutritional contributions of these foods to daily NPE and AP intake and investigated how the ratio of NPE to AP varied due to changes in the types of foods consumed. Although the proportions of drupes, figs, and non-fruit foods varied in their diets, female chimpanzees maintained a relatively stable intake of AP while intake of NPE varied depending on the daily diet, demonstrating that like other frugivorous primates studied to date, chimpanzees prioritize protein. The mean daily ratio of NPE to AP was 7:1, which is similar to that of other frugivorous primates studied. Our results support the hypothesis that frugivorous animals may generally prioritize AP, while maximizing NPE intake within that constraint, and could shed light on aspects of human dietary evolution.
Topics: Animals; Diet; Energy Intake; Fruit; Pan troglodytes
PubMed: 34002861
DOI: 10.1002/ajp.23269 -
Biology Letters Jun 2023When facing uncertainty, humans often build mental models of alternative outcomes. Considering diverging scenarios allows agents to respond adaptively to different...
When facing uncertainty, humans often build mental models of alternative outcomes. Considering diverging scenarios allows agents to respond adaptively to different actual worlds by developing contingency plans (covering one's bases). In a pre-registered experiment, we tested whether chimpanzees () prepare for two mutually exclusive possibilities. Chimpanzees could access two pieces of food, but only if they successfully protected them from a human competitor. In one condition, chimpanzees could be certain about which piece of food the human experimenter would attempt to steal. In a second condition, either one of the food rewards was a potential target of the competitor. We found that chimpanzees were significantly more likely to protect both pieces of food in the second relative to the first condition, raising the possibility that chimpanzees represent and prepare effectively for different possible worlds.
Topics: Animals; Humans; Pan troglodytes; Reward; Uncertainty; Food
PubMed: 37340809
DOI: 10.1098/rsbl.2023.0179