Abstract Behavioural contagion occurs when the behaviour of one individual elicits the same behaviour in another individual observing the event, and it is considered one of the fundamental mechanisms promoting group coordination and cohesion in social species, including humans. Empirical research on behavioural contagion has focused primarily on yawning and has shown evidence of it in several animal species. Here, we studied behavioural contagion in 2 groups of captive wolves (N = 20) and 3 groups of captive dog-admixed wolves (N = 13). We conducted behavioural observations of naturally occurring yawning events and monitored the yawning behaviour of the other group members in the two minutes following each event. Our results showed that, in both admixed and non-admixed wolves, individuals who had the opportunity to observe the initial yawn were significantly more likely to yawn within the subsequent two minutes than those who had not observed the event. Crucially, this effect was stronger in non-admixed than in admixed wolves. Furthermore, individuals that were more socially integrated were more likely to elicit behavioural contagion in both admixed and non-admixed wolves. In contrast, neither individual rank nor dyadic relationship quality between the yawner and the observer mediated the probability of contagion. By revealing variation in behavioural contagion patterns between admixed and non-admixed wolves, this study provides insights into how introgressive hybridization with domestic species may influence mechanisms underlying social coordination and pack cohesion in wolves.
Behavioural innovations can be crucial for animals to adjust to changing environments and to exploit novel resources. While ecological and evolutionary implications of innovativeness have been investigated intensely, the proximate mechanisms underlying this behaviour are less well understood. Intrinsic individual differences arising from differences in competitive abilities have been hypothesised to drive differences in innovation propensity (bad-competitor hypothesis). We here investigated the relationship between early-life competition among siblings as well as effects of several physiological and personality traits on innovation propensity in young wild cavies (Cavia aperea). Our study aimed to test whether competitive situations in early life, such as being a small sibling or being born in larger litters, enhanced innovation propensity. Furthermore, we tested if intrinsic physiological or behavioural characteristics differed between solvers and non-solvers. We found that neither size rank nor litter size influenced innovation propensity in young cavies at independence. Likewise, physiological traits such as cortisol level, heart rate, and resting metabolic rate did not differ systematically between solvers and non-solvers, although heart rate and resting metabolic rate were repeatable. However, individuals that interacted more with novel objects and innovation tasks were more likely to solve them. Our results suggest that innovation propensity is not shaped by early-life competition or physiological differences but may rather develop consistent individual differences later in life, potentially by competition for mating opportunities. Behavioural innovation, often measured by problem solving tests, often helps animals to cope with environmental change and adjust to novel environments. How and when individual differences in innovative propensities arise and are shaped during development remains currently unknown. Poor competitive abilities are generally suggested to drive enhanced innovation propensity. Here, we tested if sibling competition during early life or physiological and behavioural differences drive innovativeness in the wild cavy (Cavia aperea). Innovation propensity was not shaped by early-life competition or physiological traits. Individuals interacting more with novel objects and innovation tasks were more likely to innovate. Our study contributes to a more comprehensive understanding of the role of behavioural and physiological traits of animals for the propensity to innovate.
Abstract Experiences of social isolation alter the developing social behavior of animals. Association preference is an important behavioral tendency for amphibian larvae (tadpoles) that exhibit social aggregation as a means of predator avoidance. For tadpoles that exhibit social aggregation, the learning period during exposure to conspecifics could be crucial. This study investigated how water quality and social experience influence association preferences to unfamiliar conspecifics in Bufo formosus (Eastern-Japanese common toad) tadpoles. Using a 2 × 2 factorial design, subject tadpoles were reared either in tap or pond water and under group or solitary conditions. Binary-choice tests were then conducted to examine whether the tadpoles preferred siblings, non-siblings, or neither (neutral zone). No significant kin-biased association was detected in any treatment. However, social experience significantly affected the proportion of time spent in neutral zone. Solitary-raised tadpoles spent the most time in the neutral zone, whereas group-raised tadpoles spent more time on the effective-stimulus sides irrespective of water quality. It suggests that social isolation in early developmental stage reduces responsiveness to conspecifics. These findings indicate that social aggregation in B. formosus is shaped by social experience rather than kinship and aquatic environment.
Anthropogenic noise pollution is a major global stressor that affects vertebrate physiology and behaviour. However, at present, little is known about the impacts of anthropogenic noise on cognition. To evaluate the effects of noise on fish cognition, we utilized an associative learning protocol. We trained adult zebra danios (Danio rerio) to associate a red card located in one arm of a maze with the presence of conspecifics, usually a positive reward for these social fish. Immediately afterwards we exposed the zebrafish to either no noise (control) or one of four noise treatments (white noise, at high or medium intensity crossed with either a regular or irregular pattern) then tested their learning in the absence of noise. Furthermore, to understand the possible molecular mechanism underlying any neuro-behavioural effects, we also quantified the changes in gamma-aminobutyric acid (GABA) level in zebrafish brain. Our results showed that control fish learned the location of the social reward as evident by their attraction to the correct maze arm. Noise exposure impaired cognition as evident by the lowered time these fish spent in the target arm of the maze compared to control fish. Noise intensity did not appear to influence maze performance, but the irregular pattern of noise resulted in poorer performance in the maze. Most interestingly, fish in the irregular noise treatments showed significant avoidance of the target arm compared to random chance. Our results suggest that zebrafish were unable to learn the association of the red arm with the presence of conspecifics in the presence of noise, or alternatively that they did learn but the presence of conspecifics was devalued as a reward. This study highlights that anthropogenic noise can have far reaching and paradoxical ecological consequences.
Gambling disorder is characterized by a maladaptive behavioral pattern that persists despite significant negative consequences. Neuropsychological paradigms such as the Iowa Gambling Task (IGT) and its adaptation to animal models, have provided critical insights into the mechanisms underlying this type of decision-making. In the present report, we introduce an adaptation of the IGT for pigeons, to determine whether the pigeons’ suboptimality that has been found in other choice tasks extends to this paradigm, a result that would point toward a generalized suboptimal-choice profile in this species. The IGT’s results were compared to those obtained with rats and with human participants, observing that pigeons exhibit a predominantly optimal pattern, with inter-individual variability consistent with other species. These results validate the implementation of the IGT for pigeons as a robust model. Finally, based on the analysis of individual-performance differences in the IGT, we suggest future research directions for understanding them, and propose the use of the present findings as a baseline to explore the relationship between maladaptive behavior and key variables involved in gambling-like behavior in pigeons and in other species.
Play invitation signals mark interactions as non-threatening and playful, serving as a key mechanism for coordinating social play among great apes. Within the framework of gestural origins theories, particularly the contrast between genetic codification and ontogenetic ritualization, this systematic review—conducted following PRISMA guidelines—examined empirical evidence on play invitation signals in Pan troglodytes, Pan paniscus, Gorilla gorilla, Pongo pygmaeus, and Pongo abelii. Studies were included if they provided developmental categorization or detailed age information and an ethogram explicitly describing play invitations. A total of 29 studies met these criteria. Results revealed marked ontogenetic variation across species, with play invitation signals peaking during infancy and juvenility, declining in subadults, and showing a secondary rise among adult females. These findings highlight the importance of developmental trajectories for understanding cognitive and communicative flexibility in great apes. They suggest that the structure of interspecific variation in play invitation repertoires does not align consistently with phylogenetic relationships, supporting a model in which socio-developmental factors play a substantial role in shaping ludic communicative displays.
Underwater anthropogenic noise is a pervasive environmental stressor, yet its impact on the ontogeny of cognitive processes and behavioural coping styles in fish remains poorly understood. This study investigates how chronic exposure to boat noise during early development affects the behavioural phenotype and associative learning in juvenile cichlids (Maylandia zebra). Using a split-brood design to control for genetic variation, siblings were reared under either control (lab-silent) or intermittent boat noise conditions for 12 weeks. Subjects were subsequently tested to assess boldness, anxiety-like responses, social aggression, and aversive learning performance. Results revealed that chronic noise exposure induced a complex shift in coping behaviours: noise-reared juveniles exhibited faster engagement with novel objects (indicating increased risk-taking) but simultaneously displayed heightened anxiety-like responses in light/dark preference tests, compared to the silent-reared control group. Noise-reared fish also showed impaired performance on a colour discrimination learning task conducted under silent conditions. These findings demonstrate that the cognitive deficit was not a result of acute attentional distraction, but rather a persistent consequence of developmental stress. Conversely, social aggression was unaffected by rearing history and decreased only during acute noise playback. These findings suggest that early-life acoustic stress reshapes the behavioural phenotype towards a high-anxiety, reactive state and imposes lasting costs on cognitive integrity, potentially compromising fitness in noise-polluted ecosystems.
Judgement bias tasks assess the ways in which affective states influence information processing. The Active Choice task, a subtype of judgement bias task, allows researchers to distinguish between low motivation and negative mood, making it more powerful than other paradigms. However, Active Choice tasks have never been successfully applied in a population of zoo-housed primates, nor in any population of great apes. We aimed to investigate affect-derived judgement biases in zoo-housed bonobos using a novel Active Choice paradigm. Fourteen bonobos were trained on a visual discrimination Active Choice judgement bias task, with seven animals passing criteria. Outcomes of the task were compared to four quantitative affective indicators as well as one holistic qualitative welfare indicator. A sixth variable, group size, was included in the models due to the unique fission-fusion husbandry style used at the zoo. We found that animals made more pessimistic choices as the number of test sessions they completed increased. Furthermore, animals made more pessimistic choices on days when they spent more time performing abnormal behaviors. Conversely, animals made more optimistic choices on days when they spent more time playing and on days when their social group was larger. Our results, therefore, suggest that task responses were related to changes in affective states. Moreover, Active Choice judgement bias tasks could be useful for exploring both theoretical and applied questions about mood in bonobos.
Crossmodal correspondences, spontaneous links between sensory modalities, are well documented in humans and other animals. The Bouba–Kiki effect, where sharp sounds typically map onto angular shapes and soft sounds onto rounded ones, possibly constitute a peculiar case of such correspondences, as it was documented in preverbal infants and non-human species. Here we test whether a spontaneous association between “Bouba” and “Kiki” sounds, and round and spiky shapes respectively, also appears in a reptile, the Testudo marginata. In a free-exploration task, 10 tortoises were exposed to repeated “Bouba” or “Kiki” sounds while presented with a round and a spiky 3D object. Strikingly, tortoises showed a reversed mapping compared to humans and birds: they spent longer exploring the round object during “Kiki” playbacks and the spiky object during “Bouba”. This unexpected inversion raises key questions about the origins of crossmodal cognition. We argue that the reversed pattern may reflect the interaction between an underlying sound-shape correspondence and the structure of the free-exploration task. Under this interpretation, auditory stimuli may generate expectations regarding visual shapes, whereas exploratory behaviour may promote investigation of unexpected sound-shape combinations. Alternatively, tortoises may rely on fundamentally different principles of perceptual organisation, revealing that crossmodal associations are not universally aligned across species.
Past studies show that dogs react to human fear odour with avoidant but individually variable behaviours, yet it remains unclear whether this response is an effect of domestication or an ancient trait. We tested similarly raised, human-socialized dogs and wolves, comparing their reactions to human fear versus neutral odours. Using a within-subject design, animals were asked to choose between two targets: either both containing neutral human samples (Control condition) or one neutral and one fear sample (Experimental condition). While neither showed a preference for the fear or neutral smell, both dogs and wolves spent less time near the targets, looked more at the handler, and refused a choice less frequently in the Experimental condition, when the fear scent was present, compared to the Control (when it was absent). Additionally, dogs, but not wolves, were more likely to end the session prematurely in the Experimental condition compared to the Control. Finally, neither species showed greater individual variability in one condition compared to the other. These findings indicate that, like dogs, wolves alter their behaviour in response to human fear odour if they have the same life experience, suggesting a sensitivity that may precede domestication.
Social learning is essential to the development of culture in humans, non-human primates, and other cultural species. Transmission biases (social learning strategies), the cognitive processes that guide conscious and subconscious decisions about when and from whom to learn, are a key branch of social learning. Primatological research has primarily explored single biases in isolation, such as chimpanzee bias toward adopting behavior demonstrated by higher-ranking individuals. However, few studies have considered how simultaneous strategies interact when subjects are given a conflicting choice involving two potentially adaptive biases. This study used a token-reward task with 35 sanctuary-housed chimpanzees at Ngamba Island Sanctuary in Uganda to determine whether chimpanzees more frequently adopt behaviors from high- or low-ranking female demonstrators when those behaviors differ in payoff, providing either a preferred pineapple piece (high-payoff) or a less favored carrot piece (low-payoff). Individuals in Group 1 observed a low-ranking demonstrator collecting the high-payoff reward (pineapple) and a high-ranking demonstrator collecting the low-payoff reward (carrot). Chimpanzees in Group 1 did not adopt one behavior significantly more frequently than the other. In Group 2, the demonstrator roles were reversed, and the frequency of high-payoff selection was higher. This suggests that high-payoff behaviors are more likely to propagate when presented by higher-ranking demonstrators. Additionally, adoption of high-payoff behaviors may be constrained by the presence of alternative, lower-payoff behaviors demonstrated by socially preferred individuals. In turn, this may contribute to explanations of why chimpanzee culture is relatively simple compared to that of humans.
The executive functions are a suite of cognitive-control processes that enable goal-directed behaviour. Executive functioning is vital in allowing animals to adapt their behaviour to changing environmental conditions, which is a key determinant of the success of individuals, populations, and species under anthropogenic change. Despite this, very little is known about the mechanisms that underpin executive functioning in animals and how it manifests in behaviour. Moreover, whether and how executive functioning is impacted by environmentally realistic levels of chemical pollution is completely unknown, despite neuroactive pollutants, such as pharmaceuticals, having become widespread in ecosystems around the globe. We employed the Free Movement Pattern Y-maze to investigate how executive functioning manifests in decision-making and behaviour in a wild population of guppies (Poecilia reticulata), and whether this was disrupted by exposure to two environmentally realistic concentrations (9 ng/L or 309 ng/L) of the neuroactive pharmaceutical pollutant amitriptyline. We found that two of the three domains of executive function-working memory and cognitive flexibility-actively regulated cognition to inform behaviour during maze exploration. However, the role of executive functioning in directing navigation behaviour was not affected by exposure to amitriptyline. Given that neuroactive pharmaceuticals are increasingly detected in waterways, and executive functioning is critical for behaviours that dictate fitness, it is crucial that we better understand whether and how these contaminants affect executive functioning, and what implications this may have for wildlife living in human-impacted ecosystems.
Self-control, the ability to resist an immediate reward for a more beneficial delayed outcome, is an adaptive skill underlying decision-making. While widely studied in non-human primates and birds, its evolution remains debated. Factors such as brain size, metabolic rate, longevity, social complexity, or foraging ecology may shape self-control across species. To investigate further the link between these factors and self-control, we compared two domesticated ungulates, sheep (Ovis aries, n = 7) and goats (Capra hircus, n = 7), in a delay of gratification task. These species mostly differ on their level of social cohesion and foraging ecology but share a relatively similar evolutionary and domestication history. In our study, sheep waited for 54.3 ± 15.1 s while goats waited for 62.9 ± 13.8 s (group level mean ± SD). Some individuals from both species delayed gratification for up to 80 s. The moderate higher success rate of goats may relate to their feeding ecology as dispersed foragers or to their social flexibility compared to sheep. The two species adapted their decision according to different parameters, such as the duration of the upcoming delay or the relative values of the rewards and engaged in distraction behaviours to increase their success rate in waiting, indicating that they share common cognitive strategies. These findings suggest that factors such as social complexity or foraging ecology may shape self-control in these domesticated species.
Athletes practice, artists craft, and academics read; often for no nominal outcome. According to the overjustification hypothesis, these intrinsically motivated behaviors can be reduced if followed by a reinforcer. Those listed above are uniquely human behaviors, but there are little data evaluating this effect in other animals. Two experiments evaluated the overjustification effect in rats. In Experiment 1, rats lever pressed for no reinforcer (initial baseline), followed by a manipulation period where lever presses resulted in an expected or unexpected reinforcer (food), or no reinforcer, and lastly, rats again lever pressed for no reinforcer (final baseline period). Increased lever pressing was observed initially for groups that received a reinforcer, but it quickly returned to baseline and no evidence for the overjustification effect was found. In Experiment 2, sensory effects of lever pressing were added to increase the rate of behavior. The baseline rate of lever pressing increased for all groups, and lever pressing after unexpected reinforcement occurred at a higher rate than after expected reinforcement, but this group did not differ from the group with no reinforcement. These findings underscore the challenge of predicting overjustification effects and point to additional factors that may be critical for identifying intrinsically motivated behavior in human and non-human animals.
Animals living in human-dominated environments often face constrains on expression of natural behavioural repertoire and compromised welfare. Domestic dogs (Canis lupus familiaris) housed in shelters provide a valuable model for examining both welfare outcomes and methodological approaches to behavioural assessment in an artificial, and human organised, setting. Here we evaluate behavioural sampling methods within an ecologically valid experimental framework. Specifically, we compared continuous recording (CR) and instantaneous sampling (IS; 15s, 30s, and 6s intervals) following enrichment manipulation, reflecting a real-world research context for behavioural data collection. From a methodological perspective, results showed that IS systematically underestimated behavioural expression compared to CR, with increasing underestimation from IS-15 to IS-60. Regarding enrichment, using CR as the most reliable approach, we investigated the short-term behavioural effects of social interaction with conspecifics and food-based olfactory stimulation. We found that, while overall behavioural repertoires did not differ markedly between enrichment conditions, inactive lying increased following social interaction compared to olfactory enrichment. Stress-related behaviours were rare, indicating that neither enrichment type was aversive and that both social and olfactory enrichment can be safely implemented in shelters. Our findings highlight the importance of aligning sampling methods with specific research aims and behavioural outcomes and inform the implementation of different enrichment programs in shelter dogs. This integrated approach aligns with the principle of reduction by maximising information from a single dataset, allowing methodological and experimental conclusions under realistic conditions.
In recent years, avian cognition has become a subject of intensive research. Most studies have, nevertheless, only focused on a few bird taxa known for their high cognitive capacities and comparative studies of other species are scarce. Testing problem-solving abilities of birds can give us an insight into how they can adapt to changing environments through innovation. Lever-pulling is a well-known paradigm to investigate problem-solving in various species, and analysing subjects’ behaviour leading to solving the task could give us important insights into the cognitive mechanisms and motor propensities potentially affecting success. Although blue tits (Cyanistes caeruleus) and great tits (Parus major) are known for successful performance during various cognitive tasks, other small passerine species inhabiting similar environments remain understudied. In contrast to great tits and blue tits, coal tits (Periparus ater) and nuthatches (Sitta europaea) are food-storing species, thus interspecific comparisons could reveal whether different foraging strategies are linked to problem-solving performance. We tested wild-caught blue and great tit adults and hand-reared juveniles of all four species in a food-motivated lever-pulling task. Results indicate species-specific differences among juveniles, with coal tits and nuthatches demonstrating greater success. Birds from both age categories performed similarly, but juveniles were faster to solve the task than adults. Success was positively influenced by individual traits such as persistence, accuracy and motivation from prior experience, but not by the initial latency to approach the apparatus. Our results reveal how both foraging strategy and individual traits could be related to innovative problem-solving in small passerines.
Abstract Understanding whether non-human animals interpret human pointing as cooperative communication remains a central question in comparative cognition. Pointing is a foundational aspect of human communication, yet success in traditional object-choice tasks could theoretically reflect conditioned responses rather than comprehension of communicative intent. Recent work therefore focuses on testing flexible, spontaneous use of gestures in novel contexts. Here, we examined whether bottlenose dolphins ( Tursiops truncatus ) could interpret a human point to solve a new problem in a modified “do-as-I-do” task: selecting which of two conspecific models to imitate. Subjects ( n = 3) were already proficient in imitating a single model. In this version, they observed two models simultaneously performing different behaviors while the trainer gave the signal to imitate and pointed to one model. To succeed, dolphins had to interpret the point as indicating which model to imitate. All dolphins performed significantly above chance, both in overall imitation accuracy (chance = 1/11) and when analysis was limited to trials in which they imitated one of the two models (chance = ½). Performance did not improve across trials, indicating spontaneous rather than learned interpretation. These findings demonstrate that non-language-trained dolphins can flexibly apply the meaning of a familiar gesture in a novel context, responding to the same gesture with different behaviors by spontaneously interpreting the meaning of the gesture within the new game. This interpretation suggests an understanding of pointing as cooperative communication rather than a simple discriminative cue, paralleling results in dogs and raising the possibility that dolphins’ abilities evolved through self-domestication and/or conspecific distal referencing systems such as echolocation.
The last few decades have indubitably advanced comparative research with non-human participants, often thanks to the implementation of digital interfaces. Nonetheless, the top-down application of anthropocentric designs - fitting animals to human-centered technology and scenarios - has gained almost unquestionable acceptance. This approach presents potential limitations regarding data quality and its impact on participants, caregivers, and researchers alike. We critically assess this situation, proposing the adoption of a bottom-up biocentric approach in which computer systems and test paradigms center around the animals’ behavior and cognition rather than vice versa. We combine this proposal with insights from iterative design to create biocentric computer apparatuses. By embracing a biocentric perspective, researchers can align study designs with animals’ natural tendencies rather than adapting the animals to fit methodologies and computer systems initially designed for humans. This approach recognizes ecological and cognitive factors unique to each species, prompting researchers to question whether current paradigms effectively capture the cognitive phenomena they intend to measure. As comparative research advances, incorporating more flexible, biocentric methodologies could yield more scientifically robust and ethically sound findings. While digital technologies remain a cornerstone of animal cognition research, we advocate for innovation beyond training animals towards human-centric paradigms. This shift invites a more nuanced and respectful understanding of animal cognition, aligning research objectives with the genuine interests and welfare of non-human participants.
Dogs (Canis familiaris) are an increasingly popular model in comparative cognition research. Traditional research paradigms often rely on heavy experimenter involvement, which can introduce biases and inconsistencies. Touchscreen-based automated systems offer a solution by enhancing standardization, reducing experimenter effects, and improving data quality, and have been widely adopted for research with diverse species. However, their adoption in dog research has remained underexplored. This systematic review quantified dog behaviour and cognition literature in relation to touchscreen-based methodologies and evaluated existing touchscreen-based approaches. Our search confirmed that while the field of dog cognition continues to grow, touchscreen-based studies are exceptionally rare, with only fourteen such publications identified for the entire indexed record. We explored the potential reasons for this limited adoption by categorizing them into three main barriers: technical, such as the need for interdisciplinary skills; practical, including high costs and lengthy training requirements and Umwelt, relating to the dogs’ species-specific constraints. Finally, we propose strategies to overcome these obstacles, including the use of open-source solutions, establishing multi-lab collaborations, and designing interfaces better aligned with dogs’ Umwelt. We conclude that despite being underutilized, touchscreen-based methods hold significant promise for advancing canine research. By addressing current challenges through collaborative, open, and dog-centred practices, the field can integrate touchscreen-based methods more widely, enhance reproducibility, accelerate discovery, and obtain objective indicators of dogs’ behavioural and cognitive capabilities.
