Learning from communication versus observation in great apes

This research was supported by the European Research Council (ERC) under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant 609819 (SOMICS project).When human infants are intentionally addressed by others, they tend to interpret the information communicated as being relevant to them and worth acquiring. For humans, this attribution of relevance leads to a preference to learn from communication, making it possible to accumulate knowledge over generations. Great apes are sensitive to communicative cues, but do these cues also activate an expectation of relevance? In an observational learning paradigm, we demonstrated to a sample of nonhuman great apes (bonobos, chimpanzees, orangutans; N = 24) how to operate on a food dispenser device. When apes had the opportunity to choose between an effective and an ineffective method in the baseline conditions, the majority of them chose the effective method. However, when the ineffective method was demonstrated in a communicative way, they failed to prioritize efficiency, even though they were equally attentive in both conditions. This suggests that the ostensive demonstration elicited an expectation of relevance that modified apes’ interpretation of the situation, potentially leading to a preference to learn from communication, as human children do.Publisher PDFPeer reviewe

Chimpanzees flexibly update working memory contents and show susceptibility to distraction in the self-ordered search task

This project has received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 639072).Working memory (WM) is a core executive function that allows individuals to hold, process, and manipulate information. WM capacity has been repeatedly nominated as a key factor in human cognitive evolution; nevertheless, little is known about the WM abilities of our closest primate relatives. In this study, we examined signatures of WM ability in chimpanzees (Pan troglodytes). Standard WM tasks for humans (Homo sapiens) often require participants to continuously update their WM. In Experiment 1, we implemented this updating requirement in a foraging situation:zoo-housed chimpanzees (N=13) searched for food in an array of containers. To avoid redundant searches, they needed to continuously update which containers they had already visited (similar to WM paradigms for human children) with 15-sretention intervals in between each choice. We examined chimpanzees’ WM capacity and to what extent they used spatial cues and object features to memorize their previous choices. In Experiment 2, we investigated how susceptible their WM was to attentional interference, an important signature, setting WM in humans apart from long-term memory. We found large individual differences with some individuals remembering at least their last four choices. Chimpanzees used a combination of spatial cues and object features to remember which boxes they had chosen already. Moreover, their performance decreased specifically when competing memory information was introduced. Finally, we found that individual differences in task performance were highly reliable over time. Together, these findings show remarkable similarities between human and chimpanzee WM abilities despite evolutionary and life history differences.PostprintPostprintPeer reviewe

Chimpanzees use observed temporal directionality to learn novel causal relations

We investigated whether chimpanzees use the temporal sequence of external events to determine causation. Seventeen chimpanzees (Pan troglodytes) witnessed a human experimenter press a button in two different conditions. When she pressed the “causal button” the delivery of juice and a sound immediately followed (cause-then-effect). In contrast, she pressed the “non-causal button” only after the delivery of juice and sound (effect-then-cause). When given the opportunity to produce the desired juice delivery themselves, the chimpanzees preferentially pressed the causal button, i.e., the one that preceded the effect. Importantly, they did so in their first test trial and even though both buttons were equally associated with juice delivery. This outcome suggests that chimpanzees, like human children, do not rely solely on their own actions to make use of novel causal relations, but they can learn causal sequences based on observation alone. We discuss these findings in relation to the literature on causal inferences as well as associative learning.Publisher PDFPeer reviewe

Bargaining in chimpanzees (Pan troglodytes) : the effect of cost, amount of gift, reciprocity and communication

Authors thank the two funding institutions which supported the present study: FPU12/00409 grant provided by the Spanish Ministry of Education and held by NBG and La Caixa grant held by AD.Humans routinely incur costs when allocating resources and reject distributions judged to be below/over an expected threshold. The Dictator/Ultimatum Games (DG/UG) are two-player games that quantify prosociality and inequity aversion by measuring allocated distributions and rejection thresholds. Although the UG has been administered to chimpanzees and bonobos, no study has used both games to pinpoint their motivational substrate. We administered a DG/UG using pre-assigned distributions to four chimpanzee dyads controlling for factors that could explain why proposers’ behavior varied substantially across previous studies: game order, cost for proposers and amount for recipients. Moreover, players exchanged their roles (proposer/recipient) to test reciprocity. Our results show that proposers offered more in the DG than in the non-social baseline, particularly when they incurred no cost. In UG, recipients accepted all above-zero offers, suggesting absence of inequity aversion. Proposers preferentially chose options that gave larger amounts to the partner. However, they also decreased their offers across sessions, probably being inclined to punish their partner’s rejections. Therefore, chimpanzees were not strategically motivated towards offering more generously to achieve ulterior acceptance from their partner. We found no evidence of reciprocity. We conclude that chimpanzees are generous rational maximizers that may not engage in strategic behavior.PostprintPeer reviewe

German S3 guideline "actinic keratosis and cutaneous squamous cell carcinoma" – long version of the update 2023

Actinic keratosis (AK) are common lesions in light-skinned individuals that can potentially progress to cutaneous squamous cell carcinoma (cSCC). Both conditions may be associated with significant morbidity and constitute a major disease burden, especially among the elderly. To establish an evidence-based framework for clinical decision making, the guideline “actinic keratosis and cutaneous squamous cell carcinoma” was updated and expanded by the topics cutanepus squamous cell carcinoma in situ (Bowen’s disease) and actinic cheilitis. This guideline was developed at the highest evidence level (S3) and is aimed at dermatologists, general practitioners, ear nose and throat specialists, surgeons, oncologists, radiologists and radiation oncologists in hospitals and office-based settings, as well as other medical specialties, policy makers and insurance funds involved in the diagnosis and treatment of patients with AK and cSCC

Establishing an infrastructure for collaboration in primate cognition research

Inferring the evolutionary history of cognitive abilities requires large and diverse samples. However, such samples are often beyond the reach of individual researchers or institutions, and studies are often limited to small numbers of species. Consequently, methodological and site-specific-differences across studies can limit comparisons between species. Here we introduce the ManyPrimates project, which addresses these challenges by providing a large-scale collaborative framework for comparative studies in primate cognition. To demonstrate the viability of the project we conducted a case study of short-term memory. In this initial study, we were able to include 176 individuals from 12 primate species housed at 11 sites across Africa, Asia, North America and Europe. All subjects were tested in a delayed-response task using consistent methodology across sites. Individuals could access food rewards by remembering the position of the hidden reward after a 0, 15, or 30-second delay. Overall, individuals performed better with shorter delays, as predicted by previous studies. Phylogenetic analysis revealed a strong phylogenetic signal for short-term memory. Although, with only 12 species, the validity of this analysis is limited, our initial results demonstrate the feasibility of a large, collaborative open-science project. We present the ManyPrimates project as an exciting opportunity to address open questions in primate cognition and behaviour with large, diverse datasets

Establishing an infrastructure for collaboration in primate cognition research

Inferring the evolutionary history of cognitive abilities requires large and diverse samples. However, such samples are often beyond the reach of individual researchers or institutions, and studies are often limited to small numbers of species. Consequently, methodological and site-specific-differences across studies can limit comparisons between species. Here we introduce the ManyPrimates project, which addresses these challenges by providing a large-scale collaborative framework for comparative studies in primate cognition. To demonstrate the viability of the project we conducted a case study of short-term memory. In this initial study, we were able to include 176 individuals from 12 primate species housed at 11 sites across Africa, Asia, North America and Europe. All subjects were tested in a delayed-response task using consistent methodology across sites. Individuals could access food rewards by remembering the position of the hidden reward after a 0, 15, or 30-second delay. Overall, individuals performed better with shorter delays, as predicted by previous studies. Phylogenetic analysis revealed a strong phylogenetic signal for short-term memory. Although, with only 12 species, the validity of this analysis is limited, our initial results demonstrate the feasibility of a large, collaborative open-science project. We present the ManyPrimates project as an exciting opportunity to address open questions in primate cognition and behaviour with large, diverse datasets

Strategie Antibiotikaresistenzen. Umsichtiger Einsatz von Antibiotika bei Hunden und Katzen. Therapieleitfaden für Tierärztinnen und Tierärzte

Neu gibt es einen Therapieleitfaden für Hunde und Katzen. Dieser gibt Tierärztinnen und Tierärzten Empfehlungen für die Antibiotika-Behandlung ab. Er soll bei der Entscheidung helfen, ob Antibiotika nötig sind und wenn ja, welche verwendet werden sollen. Die Vetsuisse Fakultät, die Gesellschaft Schweizer Tierärztinnen und Tierärzte (GST) und die Schweizerische Vereinigung für Kleintiermedizin (SVK) haben unter Koordination des BLV den Therapieleitfaden gemeinsam erarbeitet