Divergent personality structures of brown (Sapajus apella) and white-faced capuchins (Cebus capucinus)

One way to gain insights into personality evolution is by comparing the personality structures of related species. We compared the personality structure of 240 wild white-faced capuchin monkeys to the personality structure of 100 captive brown capuchin monkeys. An ancillary goal was to test the degree to which different personality questionnaires yielded similar personality dimensions. Both species were rated on a common set of 26 antonym pairs. The brown capuchin monkeys were also rated on the 54-item Hominoid Personality Questionnaire. Our cross-species comparisons revealed three personality dimensions---Assertiveness, Openness, and Neuroticism---shared by brown and white-faced capuchins, suggesting that these dimensions were present in the common ancestor of these species. Our comparison of the dimensions derived from the antonym pairs and the Hominoid Personality Questionnaire revealed that three common dimensions were identified by both questionnaires. In addition, the dimension Attentiveness was only identified using the Hominoid Personality Questionnaire. These results indicate that major features of capuchin personality are conserved and that the structure of some traits, such as those related to focus, persistence, and attention, diverged. Further work is needed to identify the evolutionary bases that led to the conservation of some dimensions but not others

Chimpanzee identification and social network construction through an online citizen science platform

Abstract Citizen science has grown rapidly in popularity in recent years due to its potential to educate and engage the public while providing a means to address a myriad of scientific questions. However, the rise in popularity of citizen science has also been accompanied by concerns about the quality of data emerging from citizen science research projects. We assessed data quality in the online citizen scientist platform Chimp&See, which hosts camera trap videos of chimpanzees (Pan troglodytes) and other species across Equatorial Africa. In particular, we compared detection and identification of individual chimpanzees by citizen scientists with that of experts with years of experience studying those chimpanzees. We found that citizen scientists typically detected the same number of individual chimpanzees as experts, but assigned far fewer identifications (IDs) to those individuals. Those IDs assigned, however, were nearly always in agreement with the IDs provided by experts. We applied the data sets of citizen scientists and experts by constructing social networks from each. We found that both social networks were relatively robust and shared a similar structure, as well as having positively correlated individual network positions. Our findings demonstrate that, although citizen scientists produced a smaller data set based on fewer confirmed IDs, the data strongly reflect expert classifications and can be used for meaningful assessments of group structure and dynamics. This approach expands opportunities for social research and conservation monitoring in great apes and many other individually identifiable species

Personality structure in brown capuchin monkeys (Sapajus apella): Comparisons with chimpanzees (Pan troglodytes), orangutans (Pongo spp.), and rhesus macaques (Macaca mulatta)

Species comparisons of personality structure (i.e. how many personality dimensions and the characteristics of those dimensions) can facilitate questions about the adaptive function of personality in nonhuman primates. Here we investigate personality structure in the brown capuchin monkey (Sapajus apella), a New World primate species, and compare this structure to those of chimpanzees (Pan troglodytes), orangutans (Pongo spp.), and rhesus macaques (Macaca mulatta). Brown capuchins evolved behavioral and cognitive traits that are qualitatively similar to those of great apes, and individual differences in behavior and cognition are closely associated with differences in personality. Thus, we hypothesized that brown capuchin personality structure would overlap more with great apes than with rhesus macaques. We obtained personality ratings from seven sites on 127 brown capuchin monkeys. Principal-components analysis identified five personality dimensions (Assertiveness, Openness, Neuroticism, Sociability, and Attentiveness), which were reliable across raters and, in a subset of subjects, significantly correlated with relevant behaviors up to a year later. Comparisons between species revealed that brown capuchins and great apes overlapped in personality structure, particularly chimpanzees in the case of Neuroticism. However, in some respects (i.e. capuchin Sociability and Openness) the similarities between capuchins and great apes were not significantly greater than those between capuchins and rhesus macaques. We discuss the relevance of our results to brown capuchin behavior, and the evolution of personality structure in primates

Nocturnal activity in wild chimpanzees (Pan troglodytes): evidence for flexible sleeping patterns and insights into human evolution

Objectives – We investigated occurrences and patterns of terrestrial nocturnal activity in wild chimpanzees (Pan troglodytes) and modelled the influence of various ecological predictors on nocturnal activity. Methods – Data were extracted from terrestrial camera-trap footage and ecological surveys from 22 chimpanzee study sites participating in the Pan African Programme: The Cultured Chimpanzee. We described videos demonstrating nocturnal activity, and we tested the effects of the percentage of forest, abundance of predators (lions, leopards and hyenas), abundance of large mammals (buffalos and elephants), average daily temperature, rainfall, human activity, and percent illumination on the probability of nocturnal activity. Results – We found terrestrial nocturnal activity to occur at 18 of the 22 study sites, at an overall average proportion of 1.80% of total chimpanzee activity, and to occur during all hours of the night, but more frequently during twilight hours. We found a higher probability of nocturnal activity with lower levels of human activity, higher average daily temperature, and at sites with a larger percentage of forest. We found no effect of the abundance of predators and large mammals, rainfall, or moon illumination. Discussion – Chimpanzee terrestrial nocturnal activity appears widespread yet infrequent, which suggests a consolidated sleeping pattern. Nocturnal activity may be driven by the stress of high daily temperatures and may be enabled at low levels of human activity. Human activity may exert a relatively greater influence on chimpanzee nocturnal behavior than predator presence. We suggest that chimpanzee nocturnal activity is flexible, enabling them to respond to changing environmental factors

Higher or Lower Hemoglobin Transfusion Thresholds for Preterm Infants

Background: Limited data suggest that higher hemoglobin thresholds for red-cell transfusions may reduce the risk of cognitive delay among extremely-low-birth-weight infants with anemia. Methods: We performed an open, multicenter trial in which infants with a birth weight of 1000 g or less and a gestational age between 22 weeks 0 days and 28 weeks 6 days were randomly assigned within 48 hours after delivery to receive red-cell transfusions at higher or lower hemoglobin thresholds until 36 weeks of postmenstrual age or discharge, whichever occurred first. The primary outcome was a composite of death or neurodevelopmental impairment (cognitive delay, cerebral palsy, or hearing or vision loss) at 22 to 26 months of age, corrected for prematurity. Results: A total of 1824 infants (mean birth weight, 756 g; mean gestational age, 25.9 weeks) underwent randomization. There was a between-group difference of 1.9 g per deciliter (19 g per liter) in the pretransfusion mean hemoglobin levels throughout the treatment period. Primary outcome data were available for 1692 infants (92.8%). Of 845 infants in the higher-threshold group, 423 (50.1%) died or survived with neurodevelopmental impairment, as compared with 422 of 847 infants (49.8%) in the lower-threshold group (relative risk adjusted for birth-weight stratum and center, 1.00; 95% confidence interval [CI], 0.92 to 1.10; P = 0.93). At 2 years, the higher- and lower-threshold groups had similar incidences of death (16.2% and 15.0%, respectively) and neurodevelopmental impairment (39.6% and 40.3%, respectively). At discharge from the hospital, the incidences of survival without severe complications were 28.5% and 30.9%, respectively. Serious adverse events occurred in 22.7% and 21.7%, respectively. Conclusions: In extremely-low-birth-weight infants, a higher hemoglobin threshold for red-cell transfusion did not improve survival without neurodevelopmental impairment at 22 to 26 months of age, corrected for prematurity

Nocturnal activity in wild chimpanzees (Pan troglodytes): evidence for flexible sleeping patterns and insights into human evolution

Objectives – We investigated occurrences and patterns of terrestrial nocturnal activity in wild chimpanzees (Pan troglodytes) and modelled the influence of various ecological predictors on nocturnal activity. Methods – Data were extracted from terrestrial camera-trap footage and ecological surveys from 22 chimpanzee study sites participating in the Pan African Programme: The Cultured Chimpanzee. We described videos demonstrating nocturnal activity, and we tested the effects of the percentage of forest, abundance of predators (lions, leopards and hyenas), abundance of large mammals (buffalos and elephants), average daily temperature, rainfall, human activity, and percent illumination on the probability of nocturnal activity. Results – We found terrestrial nocturnal activity to occur at 18 of the 22 study sites, at an overall average proportion of 1.80% of total chimpanzee activity, and to occur during all hours of the night, but more frequently during twilight hours. We found a higher probability of nocturnal activity with lower levels of human activity, higher average daily temperature, and at sites with a larger percentage of forest. We found no effect of the abundance of predators and large mammals, rainfall, or moon illumination. Discussion – Chimpanzee terrestrial nocturnal activity appears widespread yet infrequent, which suggests a consolidated sleeping pattern. Nocturnal activity may be driven by the stress of high daily temperatures and may be enabled at low levels of human activity. Human activity may exert a relatively greater influence on chimpanzee nocturnal behavior than predator presence. We suggest that chimpanzee nocturnal activity is flexible, enabling them to respond to changing environmental factors

A systematic review of the reporting of Data Monitoring Committees' roles, interim analysis and early termination in pediatric clinical trials

<p>Abstract</p> <p>Background</p> <p>Decisions about interim analysis and early stopping of clinical trials, as based on recommendations of Data Monitoring Committees (DMCs), have far reaching consequences for the scientific validity and clinical impact of a trial. Our aim was to evaluate the frequency and quality of the reporting on DMC composition and roles, interim analysis and early termination in pediatric trials.</p> <p>Methods</p> <p>We conducted a systematic review of randomized controlled clinical trials published from 2005 to 2007 in a sample of four general and four pediatric journals. We used full-text databases to identify trials which reported on DMCs, interim analysis or early termination, and included children or adolescents. Information was extracted on general trial characteristics, risk of bias, and a set of parameters regarding DMC composition and roles, interim analysis and early termination.</p> <p>Results</p> <p>110 of the 648 pediatric trials in this sample (17%) reported on DMC or interim analysis or early stopping, and were included; 68 from general and 42 from pediatric journals. The presence of DMCs was reported in 89 of the 110 included trials (81%); 62 papers, including 46 of the 89 that reported on DMCs (52%), also presented information about interim analysis. No paper adequately reported all DMC parameters, and nine (15%) reported all interim analysis details. Of 32 trials which terminated early, 22 (69%) did not report predefined stopping guidelines and 15 (47%) did not provide information on statistical monitoring methods.</p> <p>Conclusions</p> <p>Reporting on DMC composition and roles, on interim analysis results and on early termination of pediatric trials is incomplete and heterogeneous. We propose a minimal set of reporting parameters that will allow the reader to assess the validity of trial results.</p

The evolution of self-control

This work was supported by the National Evolutionary Synthesis Center (NESCent) through support of a working group led by C.L.N. and B.H. NESCent is supported by the National Science Foundation (NSF) EF-0905606. For training in phylogenetic comparative methods, we thank the AnthroTree Workshop (supported by NSF BCS-0923791). Y.S. thanks the National Natural Science Foundation of China (Project 31170995) and National Basic Research Program (973 Program: 2010CB833904). E.E.B. thanks the Duke Vertical Integration Program and the Duke Undergraduate Research Support Office. J.M.P. was supported by a Newton International Fellowship from the Royal Society and the British Academy. L.R.S. thanks the James S. McDonnell Foundation for Award 220020242. L.J.N.B. and M.L.P. acknowledge the National Institutes of Mental Health (R01-MH096875 and R01-MH089484), a Duke Institute for Brain Sciences Incubator Award (to M.L.P.), and a Duke Center for Interdisciplinary Decision Sciences Fellowship (to L.J.N.B.). E.V. and E.A. thank the Programma Nazionale per la Ricerca–Consiglio Nazionale delle Ricerche (CNR) Aging Program 2012–2014 for financial support, Roma Capitale–Museo Civico di Zoologia and Fondazione Bioparco for hosting the Istituto di Scienze e Tecnologie della Cognizione–CNR Unit of Cognitive Primatology and Primate Centre, and Massimiliano Bianchi and Simone Catarinacci for assistance with capuchin monkeys. K.F. thanks the Japan Society for the Promotion of Science (JSPS) for Grant-in-Aid for Scientific Research 20220004. F. Aureli thanks the Stages in the Evolution and Development of Sign Use project (Contract 012-984 NESTPathfinder) and the Integrating Cooperation Research Across Europe project (Contract 043318), both funded by the European Community’s Sixth Framework Programme (FP6/2002–2006). F. Amici was supported by Humboldt Research Fellowship for Postdoctoral Researchers (Humboldt ID 1138999). L.F.J. and M.M.D. acknowledge NSF Electrical, Communications, and Cyber Systems Grant 1028319 (to L.F.J.) and an NSF Graduate Fellowship (to M.M.D.). C.H. thanks Grant-in-Aid for JSPS Fellows (10J04395). A.T. thanks Research Fellowships of the JSPS for Young Scientists (21264). F.R. and Z.V. acknowledge Austrian Science Fund (FWF) Project P21244-B17, the European Research Council (ERC) under the European Union’s Seventh Framework Programme (FP/2007–2013)/ERC Grant Agreement 311870 (to F.R.), Vienna Science and Technology Fund Project CS11-026 (to Z.V.), and many private sponsors, including Royal Canin for financial support and the Game Park Ernstbrunn for hosting the Wolf Science Center. S.M.R. thanks the Natural Sciences and Engineering Research Council (Canada). J.K.Y. thanks the US Department of Agriculture–Wildlife Services–National Wildlife Research Center. J.F.C. thanks the James S. McDonnell Foundation and Alfred P. Sloan Foundation. E.L.M. and B.H. thank the Duke Lemur Center and acknowledge National Institutes of Health Grant 5 R03 HD070649-02 and NSF Grants DGE-1106401, NSF-BCS-27552, and NSF-BCS-25172. This is Publication 1265 of the Duke Lemur Center.Cognition presents evolutionary research with one of its greatest challenges. Cognitive evolution has been explained at the proximate level by shifts in absolute and relative brain volume and at the ultimate level by differences in social and dietary complexity. However, no study has integrated the experimental and phylogenetic approach at the scale required to rigorously test these explanations. Instead, previous research has largely relied on various measures of brain size as proxies for cognitive abilities. We experimentally evaluated these major evolutionary explanations by quantitatively comparing the cognitive performance of 567 individuals representing 36 species on two problem-solving tasks measuring self-control. Phylogenetic analysis revealed that absolute brain volume best predicted performance across species and accounted for considerably more variance than brain volume controlling for body mass. This result corroborates recent advances in evolutionary neurobiology and illustrates the cognitive consequences of cortical reorganization through increases in brain volume. Within primates, dietary breadth but not social group size was a strong predictor of species differences in self-control. Our results implicate robust evolutionary relationships between dietary breadth, absolute brain volume, and self-control. These findings provide a significant first step toward quantifying the primate cognitive phenome and explaining the process of cognitive evolution.PostprintPeer reviewe