Abstract Conflicts are a perennial issue for gregarious animals and the stability of their groups. Reconciliation can mitigate the damage caused by conflicts. Chimpanzees provide an ideal model animal for understanding conflicts and their resolutions, due to both their high aggressiveness and large fission-fusion communities, which regularly split into smaller groups of different compositions. Different mechanisms have been proposed to explain their reconciliation behaviour, with the valuable relationship hypothesis receiving frequent empirical support – namely, chimpanzees with stronger social bonds are more likely to reconcile after a conflict. Despite its success, it is nonetheless insufficient to explain the large variability which is often observed in conciliatory tendencies. The benign intent hypothesis predicts that non-contact affiliative behaviours function to facilitate reconciliation and together with relationship value, these signals may help explain variation in conciliatory tendencies. Hence, this matched-control study investigated both hypotheses in a group of captive chimpanzees. While sex affected conciliatory tendencies, particularly valuable male–male relationships were not observed to reconcile more often than male–male dyads. By contrast, former combatants with a higher association index, a more detailed measure of relationship quality, were more likely to reconcile than those with a lower index. Signals of benign intent, although rarely displayed, were consistent with facilitating reconciliation. Namely, hold-out-hand was observed only after conflicts and before reconciliation. Importantly, these signals were displayed between individuals of different association scores, suggesting that both hypotheses have explanatory power and may interact. Rather than being explained by a single hypothesis, chimpanzee conciliatory tendencies likely result from the interaction of complementary mechanisms.
Abstract This article examines the legacy of Frans de Waal (1948–2024) in relation to child and family studies (Dutch: pedagogiek). De Waal’s prediction that evolutionary approaches would become the dominant explanatory framework within psychology has been partially fulfilled: evolutionary developmental psychology and related frameworks such as the evolved developmental niche have grown into active research traditions since the early 2000s. Yet this literature has been slow to reach applied child and family studies — parenting support, child welfare and youth care — a field concerned with one of the most defining behaviours of our species, the raising of offspring. Building on de Waal’s critique of the behavioural sciences, Tinbergen’s four levels of explanation and Hrdy’s work on cooperative breeding and alloparenting, the article argues that child and family studies would benefit from an evolutionary pedagogy that bridges this gap between developmental-evolutionary theory and applied practice. Such an approach situates child-rearing and development within the evolutionary history of the human species without neglecting social and cultural dimensions. The article further argues that this persistent gap between theory and practice leaves the field of child and family studies vulnerable to recurring overestimations of the malleability of children and the influence of upbringing and to advice that overlooks the flexible, cooperative nature of human caregiving.
Abstract Understanding how social insects regulate collective foraging is central to behavioural ecology, yet empirical quantification of termite trail dynamics under natural conditions remains limited. Here, we investigated the temporal dynamics of open-air foraging trails in the arboreal termite Constrictotermes cyphergaster using a standardised and low-cost video approach. Field observations were conducted in a semiarid Caatinga ecosystem, where nocturnal foraging trails were monitored throughout the entire foraging event. By applying a spatial reference frame to smartphone video recordings, we quantified termite abundance and velocity over time. Termite abundance declined as foraging progressed, revealing a gradual reduction in termite recruitment throughout the observation period. Likewise, termite velocity decreased over time, whereas variation in termite velocity was not explained by the number of individuals present on the trail. These findings demonstrate that collective foraging behaviour in C. cyphergaster changes dynamically throughout the foraging event and suggest that temporal factors contribute to shaping termite movement patterns. Additionally, our standardised protocol provides a simple and replicable approach for quantifying termite foraging behaviour under field conditions and may facilitate future studies of open-air foraging dynamics in termites and other insects.
Abstract As synthetic materials have rapidly accumulated in the environment over the past decades, birds have increasingly incorporated them into their nests. However, it is not clear whether such materials affect the nest’s insulative properties, a builder’s behaviour and/or the hatching success of its clutch. Here, we used laboratory-bred zebra finches Taeniopygia guttata to test whether the use of synthetic fibres (acrylic yarn) as nesting material: (i) changes nest building and incubation behaviours and/or (ii), alters the insulation properties of a nest and whether any of these ultimately (iii) influence the hatching success of the builder’s eggs. We saw no impact of acrylic yarn on any of these variables relative to nests built with non-synthetic wool fibres. The main driver of hatching success was, instead, the degree to which parents managed to keep their clutch warm by attending their nest during incubation. Our results demonstrate that nests entirely built with either synthetically-produced or naturally-derived fibres do not necessarily differ in their insulation properties. It is therefore possible that the inclusion of some types of synthetic material into a nest is not always detrimental to the builder or their offspring.
Abstract Frans de Waal transformed the study of animal cognition by showing that many capacities once regarded as uniquely human have deep evolutionary roots shared with other animals. Yet the success of this continuity perspective raises what this article calls the De Waal paradox: if human and nonhuman capacities largely differ in degree and organisation, how can we account for the extraordinary historical trajectory of humans? This article argues that part of the answer may lie in recursive organisation: processes in which outputs become inputs for further applications of the same type of operation. Comparative evidence suggests that recursive capacities occur across nonhuman species, whereas the strongest evidence for open-ended recursion concerns human symbolic and cumulative cultural systems. In particular, human cultural products can become externally stabilised and productively reused across individuals, generations and domains. Technologies become means for producing further technologies, symbolic products enable further symbolic operations and accumulated knowledge becomes a resource for generating new knowledge. Such recursion can amplify relatively modest cognitive differences by transforming not only what is accumulated but also the means of producing what comes next. The framework complements established accounts of cumulative culture, cooperation, teaching and niche construction while generating distinct empirical predictions.
