Jorg J M Massen

Utrecht University | UU · Institute of Environmental Biology

Prosocial behaviour (i.e. benefitting others without receiving a direct gain) has long been perceived as an evolutionary puzzle but is nevertheless relatively common among non‐human animals. Prosocial food provisioning has recently been documented in several large‐brained bird species, such as corvids and parrots. Yet, to date, little is known abou...

A growing number of studies have investigated the evolutionary drivers of external eye appearance in primates, but conclusive evidence is lacking. The literature has distinguished between two types of functions. Communicative functions, such as announcing a tame temperament via conjunctival depigmentation, and photo-regulatory functions towards the...

Cooperation is widespread and arguably a pivotal evolutionary force in maintaining animal societies. Yet, proximately, what underlying motivators drive individuals to cooperate remains relatively unclear. Since ′free-riders′ can exploit the benefits by cheating, selecting the right partner is paramount. Such decision rules need not be based on comp...

Animals regularly experience stressful situations, ranging from predation to social stress, yet successfully deal with them on most occasions. This adaptive mechanism, coping, reduces the adverse effects of stressors through behavioural and physiological efforts, failing to which may result in reduced fitness. However, considerable variation in cop...

The structure and functioning of the brain are lateralized-the right hemisphere processes unexpected stimuli and controls spontaneous behavior, while the left deals with familiar stimuli and routine responses. Hemispheric dominance, the predisposition of an individual using one hemisphere over the other, may lead to behavioral differences; particul...

External eye appearance in diverse avian taxa has been proposed to be driven by social and ecological functions in different studies. Recent research using quantitative measurements and phylogenetically informed analyses in primates suggest that instead photoprotective functions are important drivers of external eye appearance. Using similar method...

Prosociality is the intent to improve others’ well-being. Existing hypotheses postulate that enhanced social tolerance and inter-individual dependence may facilitate prosocial preferences, which may favor the evolution of altruism. While most studies are restricted to ‘‘tolerant’’ (cooperatively breeding and self domesticated) species, despotic soc...

The structure and functioning of the brain are lateralized – the right hemisphere processes unexpected stimuli and controls spontaneous behavior, while the left deals with familiar stimuli and routine responses. Hemispheric dominance, the predisposition of an individual using one hemisphere over the other, may lead to behavioral differences; partic...

The self-initiated split of a social group, known as fission, is a challenge faced by many group-living animals. The study of group fission and the social restructuring process in real time provides insights into the mechanism of this biologically important process. Previous studies on fission in Japanese macaques (Macaca fuscata) assigned individu...

You may have wondered whether birds that are performing seemingly useless aerial acrobatics may in fact be enjoying themselves. Since birds cannot report (verbally) on their emotions, assigning such emotions has been notoriously difficult. Recently though, researchers started to adopt a componential view on emotions, which contains behavioural, psy...

Mirror self-recognition (MSR) assessed by the Mark Test has been the staple test for the study of animal self-awareness. When tested in this paradigm, corvid species return discrepant results, with only the Eurasian magpies and the Indian house crow successfully passing the test so far, whereas multiple other corvid species fail. The lack of replic...

Humans possess remarkable prosocial tendencies beyond the confinement of kinship, which may be instrumental in promoting cooperative interactions and sociality at large. Yet, prosociality is an evolutionary conundrum as it does not provide immediate benefits to the actor. The ‘domestication’ and ‘cooperative-breeding’ hypotheses postulated that enh...

Time-activity budget, i.e., how a population or an individual divides their day into various behaviours and activities, is an important ecological aspect. Existing research primarily focused on group-level time-activity budgets, while individual variations have only been reported recently. However, little is known about how consistent inter-individ...

The overt and reflexive matching of behaviors among conspecifics has been observed in a growing number of social vertebrates, including avian species. In general, behavioral contagion—such as the spread of yawning—may serve important functions in group synchronization and vigilance behavior. Here, we performed an exploratory study to investigate ya...

Consistent inter-individual variation in cognition has been increasingly explored in recent years in terms of its patterns, causes and consequences. One of its possible causes are consistent inter- individual differences in behaviour, also referred to as animal personalities, which are shaped by both the physical and the social environment. The lat...

Dear Editor, In a recent paper in Sleep and Breathing entitled “Yawning and airway physiology: a scoping review and novel hypothesis”, Doelman and Rijken [1] propose a novel hypothesis for the main function of yawning based on the physics involved in this stereotypical behaviour. In particular, they suggest that, by repositioning the muscles aroun...

Do nonhuman animals (henceforth, animals) have emotions, and if so, are these similar to ours? This opinion piece aims to add to the recent debate about this question and provides a critical re-evaluation of what can be concluded about animal and human emotions. Emotions, and their cognitive interpretation, i.e., feelings, serve important survival...

Dominance hierarchies typically emerge in systems where group members regularly encounter and compete for resources. In birds, the ‘open’ and dynamic structure of foraging groups may prevent the emergence of structured hierarchies, although this assumption have hardly been tested. We report on agonistic data for ravens Corvus corax , collected over...

Considerable variation exists in the contagiousness of yawning, and numerous studies have been conducted to investigate the proximate mechanisms involved in this response. Yet, findings within the psychological literature are mixed, with many studies conducted on relatively small and homogeneous samples. Here, we aimed to replicate and extend upon...

Behavioral responses to novelty, including fear and subsequent avoidance of novel stimuli, i.e., neophobia, determine how animals interact with their environment. Neophobia aids in navigating risk and impacts on adaptability and survival. There is variation within and between individuals and species; however, lack of large-scale, comparative studie...

Oxytocin is involved in a broad array of social behaviours. While saliva has been used regularly to investigate the role of oxytocin in social behaviour of mammal species, so far, to our knowledge, no-one has tried to measure its homolog, mesotocin, in birds' saliva. Therefore, in this study we measured salivary mesotocin in common ravens (Corvus c...

Behavioural responses to novelty, including fear and subsequent avoidance of novel stimuli, behaviours referred to as neophobia, determine how animals interact with their environment. Neophobia aids in navigating risk and impacts on adaptability and survival. There is variation within and between individuals and species, however, lack of large-scal...

Flexible targeted helping is considered an advanced form of prosocial behavior in hominoids, as it requires the actor to assess different situations that a conspecific may be in, and to subsequently flexibly satisfy different needs of that partner depending on the nature of those situations. So far, apart from humans such behaviour has only been ex...

Multiple studies have shown that women’s likelihood of receiving research funding is lower than that of their male colleagues. Thus far, all research on this gender gap in academia has focused on post-PhD academics, making it difficult to discern whether the female disadvantages in number of publications, previous grants, maternity leave, and h-ind...

To study the evolution of humans’ cooperative nature, researchers have recently sought comparisons with other species. Studies investigating corvids, for example, showed that carrion crows and azure-winged magpies delivered food to group members when tested in naturalistic or simple experimental paradigms. Here, we investigated whether we could rep...

Cooperation occurs amongst individuals embedded in a social environment. Conse‐ quently, cooperative interactions involve a variety of persistent social influences such as the dynam‐ ics of partner choice and reward division. To test for the effects of such dynamics, we conducted cooperation experiments in a captive population of Japanese macaques...

Recent studies indicate that yawning evolved as a brain cooling mechanism. Given that larger brains have greater thermolytic needs and brain temperature is determined in part by heat production from neuronal activity, it was hypothesized that animals with larger brains and more neurons would yawn longer to produce comparable cooling effects. To tes...

Prosocial motivation has been suggested to facilitate the initiation and maintenance of cooperative interactions , as well as the evolution of social systems reliant on helping behaviour and social coordination. Previous comparative research on the link between prosociality and cooperation has been limited, however, by the absence of directly compa...

Personality in animals has been extensively researched in recent decades. Temporal consistency of behaviors is almost always part of the personality definition and is usually explored in several different testing sessions or observation periods. However, it is still unclear whether the obtained personality constructs are stable across several years...

Supplemental Electronic Material

Yawning is highly contagious, yet both its proximate mechanism(s) and its ultimate causation remain poorly understood. Scholars have suggested a link between contagious yawning (CY) and sociality due to its appearance in mostly social species. Nevertheless, as findings are inconsistent, CY’s function and evolution remains heavily debated. One way t...

The investigation of prosocial behavior is of particular interest from an evolutionary perspective. Comparisons of prosociality across non-human animal species have, however, so far largely focused on primates, and their interpretation is hampered by the diversity of paradigms and procedures used. Here, we present the first systematic comparison of...

Abstract Helping others is a key feature of human behavior. However, recent studies render this feature not uniquely human, and describe discoveries of prosocial behavior in non-human primates, other social mammals, and most recently in some bird species. Nevertheless, the cognitive underpinnings of this prosociality; i.e., whether animals take oth...

Many animal species cooperate with conspecifics in various social contexts. While ultimate causes of cooperation are being studied extensively, its proximate causes, particularly endocrine mechanisms, have received comparatively little attention. Here, we present a study investigating the link between the hormone cortisol, cooperation and social bo...

Over the last decade, comparative work on animal cooperative problem solving has gained considerable momentum. Specifically, several primates, social carnivores, elephants, and some parrots and corvids have now been shown to master the cooperative ‘loose-string’ paradigm in which two individuals must simultaneously pull a string to obtain rewards....

Numerous birds and mammals use vocal signals to advertise feeding opportunities but often such signals vary with individual and contextual factors. Non-breeding ravens call at food that is difficult to access, resulting in the attraction of nearby conspecifics. Although callers may benefit from group formation in various ways, we recently found sub...

A central premise of the science of comparative affect is that we can best learn about the causes and consequences of affect by comparing affective phenomena across a variety of species, including humans. We take as a given that affect is widely shared across animals, but a key challenge is to accurately represent each species' affective experience...

Allogrooming in primates serves not only a hygienic function, but also plays a crucial role in maintaining strong affiliative bonds between group members, which in turn, underpin the emergence of cooperative behavior. In contrast, although allopreening occurs in many avian species, we know little about its social functions. Our study addresses this...

Previous research shows that yawning enhances intracranial circulation and regulates brain temperature. Consistent with these functional outcomes, yawn duration correlates positively with interspecies variation in brain weight across mammals, with robust relationshipsdocumented at both the taxonomic rank of class and the more restricted scale of fa...

Mirror reflections can elicit various behavioral responses ranging from social behavior, which suggests that an animal treats its own reflection as a conspecific, to mirror-guided self-directed behaviors, which appears to be an indication for mirror self-recognition (MSR). MSR is scarcely spread in the animal kingdom. Until recently, only great ape...

One hallmark in the evolution of cooperation is the ability to evaluate one's own payoff for a task against that of another person. To trace its evolutionary history, there has recently been a surge in comparative studies across different species. In non‐human animals, evidence of inequity aversion has so far been identified in several primate spec...

Yawning is a basic mechanism, ubiquitous among vertebrate species. Although its function remains a hotly debated topic, it has been suggested that yawning serves as a cooling function for the brain. In line with that hypothesis, previous studies on mammals found a positive correlation of interspecific variation in mean yawn duration and the brain w...

In the last decades, the assumption that complex social life is cognitively challenging, and thus can drive mental evolution, has received much support from empirical studies in nonhuman primates. While extending the scope to other mammals and birds, different views have been adopted on what constitutes social complexity and which specific cognitiv...

1.Behavioural syndromes refer to correlated suites of behavioural traits exhibiting consistent among‐individual variation, i.e. personality. Factor analysis (FA) is currently the dominant method for modelling behavioural syndromes in humans and animals. Although FA is useful for inferring the latent causes underlying trait correlations, it does not...

Prosocial behaviour (i.e., voluntary behaviour intended to benefit another) seems to be fully developed in children by the age of 6 years. However, questions about which factors modify prosocial behaviour at that age remain understudied. Here we used a resource allocation paradigm to test prosocial behaviour in 6–9-year-old school children. They co...

Humans are considered to be highly prosocial, especially in comparison to other species. However, most tests of prosociality are conducted in highly artificial settings among anonymous participants. To gain a better understanding of how human hyper-cooperation may have evolved, we tested humans’ willingness to share in one of the most competitive f...

Various studies and researchers have proposed a link between contagious yawning and empathy, yet the conceptual basis for the proposed connection is not clear and deserves critical evaluation. Therefore, we systematically examined the available empirical evidence addressing this association; i.e., a critical review of studies on inter-individual di...

Keywords: animal memory common ravens cooperation exchange paradigm indirect reciprocity reciprocity To explain reciprocity, direct or indirect, several proximate mechanisms have been proposed, yet little attention has been given to the specific underlying cognitive mechanisms. Regardless of what proximate rules underlie reciprocity, some kind of m...

The cognitive abilities of birds are remarkable: hummingbirds integrate spatial and temporal information about food sources, day-old chicks have a sense of numbers, parrots can make and use tools, and ravens have sophisticated insights in social relationships. This volume describes the full range of avian cognitive abilities, the mechanisms behind...

Table S1. Behavioural parameters. Table S2. Best fitting model on PC1. Table S3. Best fitting model on PC2. Table S4. Best fitting model on PC3. Table S5. Best fitting model (=null model) on PC1 on the first day of separation. Table S6. Best fitting model on PC2 on the first day of separation. Table S7. Best fitting model on PC3 on the first...

Keywords: altruism avian cognition corvid Corvus corax prosociality raven In recent years, there has been considerable research effort to determine whether other species exhibit prosocial motivations parallel to those of humans; however, these studies have focused primarily on primates, and with mixed results. We presented captive ravens with a mod...

Social life is profitable, but it facilitates conflicts over resources and creates interdependence between individuals. Separating highly social animals triggers intense reactions aimed at re-establishing lost connections. Less is known, however, about behavioural and physiological responses to sepa- ration in socially facultative species, where in...

Controlled studies that focus on intraspecific cooperation tasks have revealed striking similarities, but also differences, in abilities across taxa as diverse as primates, fish, and birds. Such comparisons may provide insight into the specific socio-ecological selection pressures that led to the evolution of cooperation. Unfortunately, however, co...

One of the contemporary hypotheses concerning the evolution of human altru-ism is the cooperative breeding hypothesis (CBH) which has recently been tested in non-human primates. Using a similar paradigm, we investigated pro-sociality in a cooperatively breeding corvid, the azure-winged magpie. We found that the magpies delivered food to their group...

Behavioral contagion is suggested to promote group coordination that may facilitate activity transitions, increased vigilance, and state matching. Apart from contagious yawning, however, very little attention has been given to this phenomenon, and studies on contagious yawning in primates have so far only focused on Old World monkeys and apes. Here...

Norscia et al. [1] recently reported the first evidence for a sex bias in contagious yawning among humans. Based on previous research showing an indirect connection between contagious yawning and empathy (e.g. [2–4], but see [5,6]) and that levels of empathy appear to be higher in women compared with men (e.g. [7–9]), the authors investigated wheth...

Supporting Information.

Although social animals frequently make decisions about when or with whom to cooperate, little is known about the underlying mechanisms of partner choice. Most previous studies compared different dyads' performances, though did not allow an actual choice among partners. We tested eleven ravens, Corvus corax, in triads, giving them first the choice...

The study of animal personality, defined as consistent inter-individual differences in correlated behavioral traits stable throughout time and/or contexts, has recently become one of the fastest growing areas in animal biology, with study species ranging from insects to non-human primates. The latter have, however, only occasionally been tested wit...

Showing a trial from experiment 2 in which the focal bird (Laggie) first chooses to cooperate with its friend; i.e., the bird on its right side (Adele), and then also cooperates with the other bird (Louise) which waited and did not yet pull. The left and right part of the video, show exactly the same trial, but shot from two different angles. (MP4)

Corrigendum

The long-term effects of early adverse experiences on later psychosocial functioning are well described in humans, but sparsely documented for chimpanzees. In our earlier studies, we investigated the effects of maternal and social deprivation on three groups of ex-laboratory chimpanzees who experienced either an early or later onset of long-term de...