Caroline Schuppli

How to explain the unusually late age at skill competence among humans

Humans stand out among primates and other mammals in reaching adult-level foraging skills very late in development, well after the onset of reproduction. The aim of this paper is to place this unusual human skill development into a broader comparative context. Among birds and mammals in general, duration of immaturity, indexed by age at first reproduction (AFR), and adult brain size have undergone correlated evolution. This pattern is consistent with two causal processes: AFR is either limited by the time needed to learn adult-level skills (needing to learn) or by the energy needed to grow brain and body to full size (energetic constraints). We tested predictions arising from these two hypotheses with data retrieved from the published literature for 57 mammal and bird species. First, most mammals reach adult-level foraging skills well before the developmental period is completed, implying that energy constraints determine the age at first reproduction, whereas most birds reach adult-level foraging skills around the time of maturity, suggesting time needed for skill acquisition determines the onset of reproduction. Second, within mammals we found that with increasing niche complexity, the age of adult-level skill competence moves closer to the age at first reproduction. Third, when looking at how adult-level skills can be reached later, we found that gregariousness, slow conservative development and post-weaning provisioning allow mammals to reach their skills later. Finally, in species with intense sharing of resources (such as cooperative hunters) competence in foraging skills may even reach peak values after age of first reproduction. We conclude that the human pattern of skill acquisition could arise because our hominin ancestors added cooperative breeding and hunting to the slow development they had as great apes with increasingly complex niches. This result provides a broad biological foundation for the embodied capital model.

Effects of blood products on inflammatory response in endothelial cells in vitro.

Background Transfusing blood products may induce inflammatory reactions within the vascular compartment potentially leading to a systemic inflammatory response. Experiments were designed to assess the inflammatory potential of different blood products in an endothelial cell-based in vitro model and to compare baseline levels of potentially activating substances in transfusion products. Methods The inflammatory response from pre-activated (endotoxin-stimulated) and non-activated endothelial cells as well as neutrophil endothelial transmigration in response to packed red blood cells (PRBC), platelet concentrates (PC) and fresh frozen plasma (FFP) was determined. Baseline inflammatory mediator and lipid concentrations in blood products were evaluated. Results Following incubation with all blood products, an increased inflammatory mediator release from endothelial cells was observed. Platelet concentrates, and to a lesser extent also FFP, caused the most pronounced response, which was accentuated in already pre-stimulated endothelial cells. Inflammatory response of endothelial cells as well as blood product-induced migration of neutrophils through the endothelium was in good agreement with the lipid content of the according blood product. Conclusion Within the group of different blood transfusion products both PC and FFP have a high inflammatory potential with regard to activation of endothelial cells. Inflammation upon blood product exposure is strongly accentuated when endothelial cells are pre-injured. High lipid contents in the respective blood products goes along with an accentuated inflammatory reaction from endothelial cells.

The reluctant innovator: orangutans and the phylogeny of creativity

Young orangutans are highly neophobic, avoid independent exploration and show a preference for social learning. Accordingly, they acquire virtually all their learned skills through exploration that is socially induced. Adult exploration rates are also low. Comparisons strongly suggest that major innovations, i.e. behaviours that have originally been brought into the population through individual invention, are made where ecological opportunities to do so are propitious. Most populations nonetheless have large innovation repertoires, because innovations, once made, are retained well through social transmission. Wild orangutans are therefore not innovative. In striking contrast, zoo-living orangutans actively seek novelty and are highly exploratory and innovative, probably because of positive reinforcement, active encouragement by human role models, increased sociality and an expectation of safety. The explanation for this contrast most relevant to hominin evolution is that captive apes generally have a highly reduced cognitive load, in particular owing to the absence of predation risk, which strongly reduces the costs of exploration. If the orangutan results generalize to other great apes, this suggests that our ancestors could have become more curious once they had achieved near-immunity to predation on the eve of the explosive increase in creativity characterizing the Upper Palaeolithic Revolution.

Contrasting responses to novelty by wild and captive orangutans

Several studies have suggested that wild primates tend to behave with caution toward novelty, whereas captive primates are thought to be less neophobic, more exploratory, and more innovative. However, few studies have systematically compared captive and wild individuals of the same species to document this “captivity effect” in greater detail. Here we report the responses of both wild and captive orangutans to the same novel items. Novel objects were presented to wild orangutans on multiple platforms placed in the canopy and equipped with motion‐triggered video cameras. The same and different novel objects were also presented to orangutans in two different zoos. The results demonstrate extreme conservatism in both Bornean and Sumatran wild orangutans, who gradually approached the novel objects more closely as they became familiar, but avoided contact with them over many encounters spanning several months. Their zoo‐living conspecifics, in contrast, showed an immediate neophilic response. Our results thus confirm the “captivity effect.” To the various ecological explanations proposed before (reduced risk and increased time and energy balance for captive individuals relative to wild ones), we add the social information hypothesis, which claims that individuals confronted with novel items preferentially rely on social cues whenever possible. This caution toward novelty disappears when human caretakers become additional role models and can also be eroded when all experience with novelty is positive. Am. J. Primatol. 77:1109–1121, 2015.

Observational social learning and socially induced practice of routine skills in immature wild orang-utans

Experiments have shown that captive great apes are capable of observational learning, and patterns of cultural variation between populations suggest that they use this capacity in the wild. So far, the contexts and extent of observational forms of social learning in the wild remain unclear. Social learning is expected to be most pronounced during the skill acquisition of immature individuals. We therefore examined peering (attentive close range watching) by immatures in two populations of wild orang-utans, Pongo spp. We found, first, that peering was most frequent in contexts in which learning is expected, namely feeding and nest building. Second, peering in the feeding context was significantly positively correlated with complexity of food processing and negatively with an items frequency in the mothers diet. Food peering was also followed by significantly increased rates of exploratory behaviours targeting the same food items, indicating that it leads to selective practice. Food peering also decreased with age and increasing feeding competence of the immatures. Third, the age of peak peering in the nesting context coincided with the onset of nest practice behaviour, and peering events were followed by significantly increased rates of this behaviour. Fourth, the proportion of peering directed at other individuals rather than the mother increased with age. These findings are consistent with the prediction that immature orang-utans learn by observing others in a variety of contexts and that peering is followed by selective practice of the observed behaviour. We conclude that observational social learning in combination with socially induced practice over a period of several years is a critical component of the acquisition of learned subsistence skills in orang-utans.

Development of foraging skills in two orangutan populations: needing to learn or needing to grow?

BackgroundOrangutans have one of the slowest-paced life histories of all mammals. Whereas life-history theory suggests that the time to reach adulthood is constrained by the time needed to reach adult body size, the needing-to-learn hypothesis instead suggests that it is limited by the time needed to acquire adult-level skills.To test between these two hypotheses, we compared the development of foraging skills and growth trajectories of immature wild orangutans in two populations: at Tuanan (Pongo pygmaeus wurmbii), Borneo, and Suaq Balimbing (Pongo abelii), Sumatra. We collected behavioral data on diet repertoire, feeding rates and ranging competence during focal follows, and estimated growth through non-invasive laser photogrammetry.ResultsWe found that adult-like diet repertoires are attained around the age of weaning and that female immatures increase their repertoire size faster than their male peers. Adult-level feeding rates of easy techniques are reached just after weaning, but several years later for more difficult techniques, albeit always before adulthood (i.e. age at first reproduction). Independent immatures had faster feeding rates for easy to process items than their mothers, with male immatures achieving faster feeding rates earlier in development relative to females. Sumatran immatures reach adult-level feeding rates 2–3 years later than their Bornean peers, in line with their higher dietary complexity and later weaning. The range-use competence of independently ranging and weaned immatures is similar to that of adult females. Body size measurements showed, immatures grow until female age of first reproduction.ConclusionsIn conclusion, unlike in humans, orangutan foraging skills are in place prior to reproduction. Growth trajectories suggest that energetic constraints, rather than skills, best explain the length of immaturity. However, skill competence for dietary independence is reached later where the adult niche is more complex, which is consistent with the relatively later weaning age with increasing brain size found generally in primates, and apes in particular.

Life history, cognition and the evolution of complex foraging niches.

Animal species that live in complex foraging niches have, in general, improved access to energy-rich and seasonally stable food sources. Because human food procurement is uniquely complex, we ask here which conditions may have allowed species to evolve into such complex foraging niches, and also how niche complexity is related to relative brain size. To do so, we divided niche complexity into a knowledge-learning and a motor-learning dimension. Using a sample of 78 primate and 65 carnivoran species, we found that two life-history features are consistently correlated with complex niches: slow, conservative development or provisioning of offspring over extended periods of time. Both act to buffer low energy yields during periods of learning, and may thus act as limiting factors for the evolution of complex niches. Our results further showed that the knowledge and motor dimensions of niche complexity were correlated with pace of development in primates only, and with the length of provisioning in only carnivorans. Accordingly, in primates, but not carnivorans, living in a complex foraging niche requires enhanced cognitive abilities, i.e., a large brain. The patterns in these two groups of mammals show that selection favors evolution into complex niches (in either the knowledge or motor dimension) in species that either develop more slowly or provision their young for an extended period of time. These findings help to explain how humans constructed by far the most complex niche: our ancestors managed to combine slow development (as in other primates) with systematic provisioning of immatures and even adults (as in carnivorans). This study also provides strong support for the importance of ecological factors in brain size evolution.

Primate archaeology evolves

Since its inception, archaeology has traditionally focused exclusively on humans and our direct ancestors. However, recent years have seen archaeological techniques applied to material evidence left behind by non-human animals. Here, we review advances made by the most prominent field investigating past non-human tool use: primate archaeology. This field combines survey of wild primate activity areas with ethological observations, excavations and analyses that allow the reconstruction of past primate behaviour. Because the order Primates includes humans, new insights into the behavioural evolution of apes and monkeys also can be used to better interrogate the record of early tool use in our own, hominin, lineage. This work has recently doubled the set of primate lineages with an excavated archaeological record, adding Old World macaques and New World capuchin monkeys to chimpanzees and humans, and it has shown that tool selection and transport, and discrete site formation, are universal among wild stone-tool-using primates. It has also revealed that wild capuchins regularly break stone tools in a way that can make them difficult to distinguish from simple early hominin tools. Ultimately, this research opens up opportunities for the development of a broader animal archaeology, marking the end of archaeology’s anthropocentric era.Nearly ten years after the field of primate archaeology was first proposed, the status of the field is reported on, including recent discoveries as well as future directions and challenges, marking the end of archaeology’s ‘anthropocentric era’.

The Ecology of Social Learning in Animals and its Link with Intelligence

Classical ethology and behavioral ecology did not pay much attention to learning. However, studies of social learning in nature reviewed here reveal the near-ubiquity of reliance on social information for skill acquisition by developing birds and mammals. This conclusion strengthens the plausibility of the cultural intelligence hypothesis for the evolution of intelligence, which assumes that selection on social learning abilities automatically improves individual learning ability. Thus, intelligent species will generally be cultural species. Direct tests of the cultural intelligence hypothesis require good estimates of the amount and kind of social learning taking place in nature in a broad variety of species. These estimates are lacking so far. Here, we start the process of developing a functional classification of social learning, in the form of the social learning spectrum, which should help to predict the mechanisms of social learning involved. Once validated, the categories can be used to estimate the cognitive demands of social learning in the wild.

Transfusion practice in anemic, non-bleeding patients: Cross-sectional survey of physicians working in general internal medicine teaching hospitals in Switzerland

Background Transfusion practice might significantly influence patient morbidity and mortality. Between European countries, transfusion practice of red blood cells (RBC) greatly differs. Only sparse data are available on transfusion practice of general internal medicine physicians in Switzerland. Methods In this cross-sectional survey, physicians working in general medicine teaching hospitals in Switzerland were investigated regarding their self-reported transfusion practice in anemic patients without acute bleeding. The definition of anemia, transfusion triggers, knowledge on RBC transfusion, and implementation of guidelines were assessed. Results 560 physicians of 71 hospitals (64%) responded to the survey. Anemia was defined at very diverging hemoglobin values (by 38% at a hemoglobin <130 g/L for men and by 57% at <120 g/L in non-pregnant women). 62% and 43% respectively, did not define anemia in men and in women according to the World Health Organization. Fifty percent reported not to transfuse RBC according to international guidelines. Following factors were indicated to influence the decision to transfuse: educational background of the physicians, geographical region of employment, severity of anemia, and presence of known coronary artery disease. 60% indicated that their knowledge on Transfusion-related Acute Lung Injury (TRALI) did not influence transfusion practice. 50% of physicians stated that no local transfusion guidelines exist and 84% supported the development of national recommendations on transfusion in non-acutely bleeding, anemic patients. Conclusion This study highlights the lack of adherence to current transfusion guidelines in Switzerland. Identifying and subsequently correcting this deficit in knowledge translation may have a significant impact on patient care.