Chimpanzees Help Each Other upon Request

Background: The evolution of altruism has been explained mainly from ultimate perspectives. However, it remains to be investigated from a proximate point of view how and in which situations such social propensity is achieved. We investigated chimpanzees' targeted helping in a tool transfer paradigm, and discuss the similarities and differences in altruism between humans and chimpanzees. Previously it has been suggested that chimpanzees help human experimenters by retrieving an object which the experimenter is trying to reach. In the present study, we investigated the importance of communicative interactions between chimpanzees themselves and the influence of conspecific partner's request on chimpanzees' targeted helping. Methodology/Principal Findings: We presented two tool-use situations ( a stick-use situation and a straw-use situation) in two adjacent booths, and supplied non-corresponding tools to paired chimpanzees in the two booths. For example, a chimpanzee in the stick-use situation was supplied with a straw, and the partner in the straw-use situation possessed a stick. Spontaneous tool transfer was observed between paired chimpanzees. The tool transfer events occurred predominantly following recipients' request. Even without any hope of reciprocation from the partner, the chimpanzees continued to help the partner as long as the partner required help. Conclusions/Significance: These results provide further evidence for altruistic helping in chimpanzees in the absence of direct personal gain or even immediate reciprocation. Our findings additionally highlight the importance of request as a proximate mechanism motivating prosocial behavior in chimpanzees whether between kin or non-kin individuals and the possible confounding effect of dominance on the symmetry of such interactions. Finally, in contrast to humans, our study suggests that chimpanzees rarely perform acts of voluntary altruism. Voluntary altruism in chimpanzees is not necessarily prompted by simple observation of another's struggle to attain a goal and therefore an accurate understanding of others' desires in the absence of communicative signals

Cooperation in wild Barbary macaques: factors affecting free partner choice

A key aspect of cooperation is partner choice: choosing the best available partner improves the chances of a successful cooperative interaction and decreases the likelihood of being exploited. However, in studies on cooperation subjects are rarely allowed to freely choose their partners. Group-living animals live in a complex social environment where they can choose among several social partners differing in, for example, sex, age, temperament, or dominance status. Our study investigated whether wild Barbary macaques succeed to cooperate using an experimental apparatus, and whether individual and social factors affect their choice of partners and the degree of cooperation. We used the string pulling task that requires two monkeys to manipulate simultaneously a rope in order to receive a food reward. The monkeys were free to interact with the apparatus or not and to choose their partner. The results showed that Barbary macaques are able to pair up with a partner to cooperate using the apparatus. High level of tolerance between monkeys was necessary for the initiation of successful cooperation, while strong social bond positively affected the maintenance of cooperative interactions. Dominance status, sex, age, and temperament of the subjects also affected their choice and performance. These factors thus need to be taken into account in cooperative experiment on animals. Tolerance between social partners is likely to be a prerequisite for the evolution of cooperation

Chimpanzees (Pan troglodytes) do not develop contingent reciprocity in an experimental task

Chimpanzees provide help to unrelated individuals in a broad range of situations. The pattern of helping within pairs suggests that contingent reciprocity may have been an important mechanism in the evolution of altruism in chimpanzees. However, correlational analyses of the cumulative pattern of interactions over time do not demonstrate that helping is contingent upon previous acts of altruism, as required by the theory of reciprocal altruism. Experimental studies provide a controlled approach to examine the importance of contingency in helping interactions. In this study, we evaluated whether chimpanzees would be more likely to provide food to a social partner from their home group if their partner had previously provided food for them. The chimpanzees manipulated a barpull apparatus in which actors could deliver rewards either to themselves and their partners or only to themselves. Our findings indicate that the chimpanzees’ responses were not consistently influenced by the behavior of their partners in previous rounds. Only one of the 11 dyads that we tested demonstrated positive reciprocity. We conclude that contingent reciprocity does not spontaneously arise in experimental settings, despite the fact that patterns of behavior in the field indicate that individuals cooperate preferentially with reciprocating partners

To Each According to His Need? Variability in the Responses to Inequity in Nonhuman Primates

While it is well established that humans respond to inequity, it remains unclear the extent to which this behavior occurs in our nonhuman primate relatives. By comparing a variety of species, spanning from New World and Old World monkeys to great apes, scientists can begin to answer questions about how the response to inequity evolved, what the function of this response is, and why and how different contexts shape it. In particular, research across nonhuman primate species suggests that the response is quite variable across species, contexts and individuals. In this paper, we aim to review these differences in an attempt to identify and better understand the patterns that emerge from the existing data with the goal of developing directions for future research. To begin, we address the importance of considering socio-ecological factors in nonhuman primates in order to better understand and predict expected patterns of cooperation and aversion to inequity in different species, following which we provide a detailed analysis of the patterns uncovered by these comparisons. Ultimately, we use this synthesis to propose new ideas for research to better understand this response and, hence, the evolution of our own responses to inequity

Seed systems smallholder farmers use

Seed can be an important entry point for promoting productivity, nutrition and resilience among smallholder farmers. While investments have primarily focused on strengthening the formal sector, this article documents the degree to which the informal sector remains the core for seed acquisition, especially in Africa. Conclusions drawn from a uniquely comprehensive data set, 9660 observations across six countries and covering 40 crops, show that farmers access 90.2 % of their seed from informal systems with 50.9 % of that deriving from local markets. Further, 55 % of seed is paid for by cash, indicating that smallholders are already making important investments in this arena. Targeted interventions are proposed for rendering formal and informal seed sector more smallholder-responsive and for scaling up positive impacts

Ixazomib, daratumumab and low-dose dexamethasone in intermediate-fit patients with newly diagnosed multiple myeloma:an open-label phase 2 trial

Background: The outcome of non-transplant eligible newly diagnosed multiple myeloma (NDMM) patients is heterogeneous, partly depending on frailty level. The aim of this study was to prospectively investigate the efficacy and safety of Ixazomib-Daratumumab-low-dose dexamethasone (Ixa-Dara-dex) in NDMM intermediate-fit patients. Methods: In this phase II multicenter HOVON-143 study, IMWG Frailty index based intermediate-fit patients, were treated with 9 induction cycles of Ixa-Dara-dex, followed by maintenance with ID for a maximum of 2 years. The primary endpoint was overall response rate on induction treatment. Patients were included from October 2017 until May 2019. Trial Registration Number: NTR6297. Findings: Sixty-five patients were included. Induction therapy resulted in an overall response rate of 71%. Early mortality was 1.5%. At a median follow-up of 41.0 months, median progression-free survival (PFS) was 18.2 months and 3-year overall survival 83%. Discontinuation of therapy occurred in 77% of patients, 49% due to progression, 9% due to toxicity, 8% due to incompliance, 3% due to sudden death and 8% due to other reasons. Dose modifications of ixazomib were required frequently (37% and 53% of patients during induction and maintenance, respectively), mainly due to, often low grade, polyneuropathy. During maintenance 23% of patients received daratumumab alone. Global quality of life (QoL) improved significantly and was clinically relevant, which persisted during maintenance treatment. Interpretation: Ixazomib-Daratumumab-low-dose dexamethasone as first line treatment in intermediate-fit NDMM patients is safe and improves global QoL. However, efficacy was limited, partly explained by ixazomib-induced toxicity, hampering long term tolerability of this 3-drug regimen. This highlights the need for more efficacious and tolerable regimens improving the outcome in vulnerable intermediate-fit patients. Funding: Janssen Pharmaceuticals, Takeda Pharmaceutical Company Limited.</p

Gender and age differences in the recurrence of sickness absence due to common mental disorders: a longitudinal study

Background: Common mental disorders (CMDs) are an important cause of sickness absence and long-term work disability. Although CMDs are known to have high recurrence rates, little is known about the recurrence of sickness absence due to CMDs. The aim of this study was to investigate the recurrence of sickness absence due to CMDs, including distress, adjustment disorders, depressive disorders and anxiety disorders, according to age, in male and female employees in the Netherlands. Methods: Data on sickness absence episodes due to CMDs were obtained for 137,172 employees working in the Dutch Post and Telecommunication companies between 2001 and 2007. The incidence density (ID) and recurrence density (RD) of sickness absence due to CMDs was calculated per 1000 person-years in men and women in the age-groups of < 35 years, 35-44 years, 45-54 years, and >= 55 years. Results: The ID of one episode of CMDs sickness absence was 25.0 per 1000 person-years, and the RD was 76.7 per 1000 person-years. Sickness absence due to psychiatric disorders (anxiety and depression) does not have a higher recurrence density of sickness absence due to any CMDs as compared to stress-related disorders (distress and adjustment disorders): 81.6 versus 76.0 per 1000 person-years. The ID of sickness absence due to CMDs was higher in women than in men, but the RD was similar. Recurrences were more frequent in women < 35 years and in women between 35 and 44 years of age. We observed no differences between age groups in men. Recurrences among employees with recurrent episodes occurred within 3 years in 90% of cases and the median time-to-onset of recurrence was 11 (10-13) months in men and 10 (9-12) months in women. Conclusions: Employees who have been absent from work due to CMDs are at increased risk of recurrent sickness absence due to CMDs and should be monitored after they return to work. The RD was similar in men and in women. In women < 45 years the RD was higher than in women >= 45 years. In men no age differences were observed