‘Goats that stare at men’: dwarf goats alter their behaviour in response to human head orientation, but do not spontaneously use head direction as a cue in a food-related context

Exploring horses' (Equus caballus) gaze and asymmetric ear position in relation to human attentional cues

Studies have shown that horses are sensitive to human attentional cues. Also, there is some evidence that they might be able to infer the knowledge state of a human and communicate intentionally with us. However, this ability is not fully characterized and certain behaviors, like gaze, asymmetric ears position or vocalizations, which could work as attention-getting behaviors, have been scarcely studied in this context. The aim of the present study was to assess whether horses' gaze toward a person, asymmetric ears position and vocalizations are subject to audience effects and adjust to human attentional cues, which would suggest a communicative function. For this purpose, we adapted a protocol used with domestic dogs [Kaminski et al. 2017] and observed horses' spontaneous behavior (gaze, asymmetric ears position and vocalizations) in the presence of a human holding and not holding food in an attentive position (facing the horse with open eyes) and in a non-attentive position (with her back turned towards the horse). We found significant evidence of horses being sensitive to human attentional cues (reflected in the horses' gaze duration and asymmetric position of the ears), but not of intentional communication towards humans.

Domestication and breeding objective did not shape the interpretation of physical and social cues in goats (Capra hircus)

Artificial selection by humans, either through domestication or subsequent selection for specific breeding objectives, drives changes in animal cognition and behaviour. However, most previous cognitive research comparing domestic and wild animals has focused on companion animals such as canids, limiting any general claims about the effects of artificial selection by humans. Using a cognitive test battery, we investigated the ability of wild goats (non-domestic, seven subjects), dwarf goats (domestic, not selected for milk production, 15 subjects) and dairy goats (domestic, selected for high milk yield, 18 subjects) to utilise physical and social cues in an object choice task. To increase the heterogeneity of our test samples, data for domestic goats were collected by two experimenters at two research stations (Agroscope; Research Institute for Farm Animal Biology). We did not find performance differences between the three groups in the cognitive test battery for either physical or social cues. This indicates that for a domestic non-companion animal species, domestication and selection for certain breeding objectives did not measurably shape the physical and cognitive skills of goats.

Following the human point: Research with nonhuman animals since Povinelli, Nelson, and Boysen (1990)

For this special issue in honor of Dr. Sarah (Sally) Boysen's career, we review studies on point following in nonhuman animals. Of the 126 papers that we documented on this topic published since the publication of Povinelli, Nelson, and Boysen (1990, Journal of Comparative Psychology, 104, 203-210), 94 (75%) were published in the past 15 years, including 22 in the past 5 years, indicating that this topic is still an active area of interest in the field of animal behavior and cognition. We present results of a survey of publication trends, discussing the species tested and the sample sizes, and we note methodological considerations and current multilaboratory approaches. We then categorize and synthesize the research questions addressed in these studies, which have been at both the ultimate level (e.g., questions related to evolutionary adaptiveness and phylogenetic differences) and proximate level (e.g., questions related to experiential and temperamental processes). Throughout, we consider future directions for this area of research.

Gaze following: A socio-cognitive skill rooted in deep time

Social gaze has received much attention in social cognition research in both human and non-human animals. Gaze following appears to be a central skill for acquiring social information, such as the location of food and predators, but can also draw attention to important social interactions, which in turn promotes the evolution of more complex socio-cognitive processes such as theory of mind and social learning. In the past decades, a large number of studies has been conducted in this field introducing differing methodologies. Thereby, various factors influencing the results of gaze following experiments have been identified. This review provides an overview of the advances in the study of gaze following, but also highlights some limitations within the research area. The majority of gaze following studies on animals have focused on primates and canids, which limits evolutionary interpretations to only a few and closely related evolutionary lineages. This review incorporates new insights gained from previously understudied taxa, such as fishes, reptiles, and birds, but it will also provide a brief outline of mammal studies. We propose that the foundations of gaze following emerged early in evolutionary history. Basic, reflexive co-orienting responses might have already evolved in fishes, which would explain the ubiquity of gaze following seen in the amniotes. More complex skills, such as geometrical gaze following and the ability to form social predictions based on gaze, seem to have evolved separately at least two times and appear to be correlated with growing complexity in brain anatomy such as increased numbers of brain neurons. However, more studies on different taxa in key phylogenetic positions are needed to better understand the evolutionary history of this fundamental socio-cognitive skill.

Humans and Goats: Improving Knowledge for a Better Relationship

Simple Summary

A good relationship between humans (e.g., farmers, owners) and farm animals is vital for the well-being of both parties: on the one hand, people are satisfied with their work, which becomes less stressful and more profitable, and may receive social benefits in terms of education or animal-assisted therapy; on the other hand, animals are rewarded by the presence of humans and are not afraid of them. Goats have high cognitive and communicative abilities towards humans: recognising these abilities helps humans to work properly on the quality of this relationship that is built from the first hours of the goat kids’ life, thanks to frequent and positive contacts (e.g., stroking, talking in a calm voice). Improving the quality of this relationship is an investment in the future of livestock farming and meets public demands for ethical and sustainable production. This review outlines the characteristics and predisposing factors for the establishment of a good human–goat relationship and for its evaluation.

Abstract

There is consensus that the quality of the human–animal relationship (HAR) is relevant to guarantee appropriate levels of animal welfare. Given the impact that HAR may have on both goats and human beings, the aim of the present review is to elucidate: (1) how humans and goats communicate; (2) which are the factors affecting human–goat interactions; (3) how we can measure the quality of this relationship. The systematic review led to the selection of 58 relevant articles. Effective human–goat communication takes place by means of visual, tactile and auditory stimuli and, to a less extent, via olfactory and gustative stimuli. Goats have well-developed socio-cognitive abilities and rely on humans to get relevant information. A deep knowledge of goats’ communication means and socio-cognitive abilities may greatly help improving the human–goat relationship. Management practices (e.g., rearing methods, amount and quality of interactions), as well as genetic selection for suitable individual traits, may contribute to improving HAR. Several measures to assess the quality of HAR have been validated, including avoidance in the pen and at the feeding rack and latency to first contact. Finally, farmers’ attitudes and empathy with goats, as well as their motivation to work with animals, should be improved through appropriate training.

Comparative cognition in three understudied ungulate species: European bison, forest buffalos and giraffes

Background

Comparative cognition has historically focused on a few taxa such as primates, birds or rodents. However, a broader perspective is essential to understand how different selective pressures affect cognition in different taxa, as more recently shown in several studies. Here we present the same battery of cognitive tasks to two understudied ungulate species with different socio-ecological characteristics, European bison (Bison bonasus) and forest buffalos (Syncerus caffer nanus), and we compare their performance to previous findings in giraffes (Giraffa camelopardalis). We presented subjects with an Object permanence task, Memory tasks with 30 and 60 s delays, two inference tasks based on acoustic cues (i.e. Acoustic inference tasks) and a control task to check for the use of olfactory cues (i.e. Olfactory task).

Results

Overall, giraffes outperformed bison and buffalos, and bison outperformed buffalos (that performed at chance level). All species performed better in the Object permanence task than in the Memory tasks and one of the Acoustic inference tasks (which they likely solved by relying on stimulus enhancement). Giraffes performed better than buffalos in the Shake full Acoustic inference task, but worse than bison and buffalos in the Shake empty Acoustic inference task.

Conclusions

In sum, our results are in line with the hypothesis that specific socio-ecological characteristics played a crucial role in the evolution of cognition, and that higher fission-fusion levels and larger dietary breadth are linked to higher cognitive skills. This study shows that ungulates may be an excellent model to test evolutionary hypotheses on the emergence of cognition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12983-021-00417-w.

The Role of Animal Cognition in Human-Wildlife Interactions

Humans have a profound effect on the planet's ecosystems, and unprecedented rates of human population growth and urbanization have brought wild animals into increasing contact with people. For many species, appropriate responses toward humans are likely to be critical to survival and reproductive success. Although numerous studies have investigated the impacts of human activity on biodiversity and species distributions, relatively few have examined the effects of humans on the behavioral responses of animals during human-wildlife encounters, and the cognitive processes underpinning those responses. Furthermore, while humans often present a significant threat to animals, the presence or behavior of people may be also associated with benefits, such as food rewards. In scenarios where humans vary in their behavior, wild animals would be expected to benefit from the ability to discriminate between dangerous, neutral and rewarding people. Additionally, individual differences in cognitive and behavioral phenotypes and past experiences with humans may affect animals' ability to exploit human-dominated environments and respond appropriately to human cues. In this review, we examine the cues that wild animals use to modulate their behavioral responses toward humans, such as human facial features and gaze direction. We discuss when wild animals are expected to attend to certain cues, how information is used, and the cognitive mechanisms involved. We consider how the cognitive abilities of wild animals are likely to be under selection by humans and therefore influence population and community composition. We conclude by highlighting the need for long-term studies on free-living, wild animals to fully understand the causes and ecological consequences of variation in responses to human cues. The effects of humans on wildlife behavior are likely to be substantial, and a detailed understanding of these effects is key to implementing effective conservation strategies and managing human-wildlife conflict.

Giraffes go for more: a quantity discrimination study in giraffes (Giraffa camelopardalis)

Many species, including humans, rely on an ability to differentiate between quantities to make decisions about social relationships, territories, and food. This study is the first to investigate whether giraffes (Giraffa camelopardalis) are able to select the larger of two sets of quantities in different conditions, and how size and density affect these decisions. In Task 1, we presented five captive giraffes with two sets containing a different quantity of identical foods items. In Tasks 2 and 3, we also modified the size and density of the food reward distribution. The results showed that giraffes (i) can successfully make quantity judgments following Weber's law, (ii) can reliably rely on size to maximize their food income, and (iii) are more successful when comparing sparser than denser distributions. More studies on different taxa are needed to understand whether specific selective pressures have favored the evolution of these skills in certain taxa.

Goats Follow Human Pointing Gestures in an Object Choice Task

Dogs (Canis lupus familiaris) are extremely adept in interpreting human-given cues, such as the pointing gesture. However, the underlying mechanisms on how domestic non-companion species use these cues are not well understood. We investigated the use of human-given pointing gestures by goats (Capra hircus) in an object choice task, where an experimenter surreptitiously hid food in one of two buckets. Subjects first had to pass a pre-test where the experimenter indicated the location of the food to the subject by a proximal pointing gesture. Subjects that succeeded in the use of this gesture were transferred to the actual test. In these subsequent test trials, the experimenter indicated the location of the food to the subject by using three different pointing gestures: proximal pointing from a middle position (distance between target and index finger: 30 cm), crossed pointing from the middle position (distance between target and index finger: 40 cm), asymmetric pointing from the position of the non-baited bucket (distance between target and index finger: 90 cm). Goats succeeded in the pointing gestures that presented an element of proximity (proximal and crossed) compared to when the experimenter was further away from the rewarded location (asymmetric). This indicates that goats can generalize their use of the human pointing gesture but might rely on stimulus/local enhancement rather than referential information. In addition, goats did not improve their responses over time, indicating that no learning took place. The results provide a greater understanding of human–animal interactions and social-cognitive abilities of farm animals, which allows for the provision of enhanced management practices and welfare conditions.

Long-Term Socialization with Humans Affects Human-Directed Behavior in Goats

Throughout their evolutionary history, humans have tried to domesticate a variety of wild terrestrial mammals, resulting in a limited number that has been successfully domesticated. Among these domesticated species, domestic goats (Capra aegagrus hircus) are a useful model species to study the effects of ontogenesis on the socio-cognitive abilities of domestic non-companion animals in their interactions with humans. To this end, the behavioral responses of two groups of goats with a different background of human socialization (high and low socialization) were compared in the impossible task test, an experimental paradigm aimed to study socio-cognitive skills and the tendency to interact with humans. Our results show that, when the task became impossible to solve, goats with a higher level of socialization interacted with the experimenter for a greater amount of time than subjects in the low socialization group, whereas the latter group exhibited increased door directed behavior. Overall, highly socialized goats made more social contact with humans compared to the other group in the impossible task paradigm.

Urban herring gulls use human behavioural cues to locate food

While many animals are negatively affected by urbanization, some species appear to thrive in urban environments. Herring gulls (Larus argentatus) are commonly found in urban areas and often scavenge food discarded by humans. Despite increasing interactions between humans and gulls, little is known about the cognitive underpinnings of urban gull behaviour and to what extent they use human behavioural cues when making foraging decisions. We investigated whether gulls are more attracted to anthropogenic items when they have been handled by a human. We first presented free-living gulls with two identical food objects, one of which was handled, and found that gulls preferentially pecked at the handled food object. We then tested whether gulls' attraction to human-handled objects generalizes to non-food items by presenting a new sample of gulls with two non-food objects, where, again, only one was handled. While similar numbers of gulls approached food and non-food objects in both experiments, they did not peck at handled non-food objects above chance levels. These results suggest that urban gulls generally show low levels of neophobia, but that they use human handling as a cue specifically in the context of food. These behaviours may contribute to gulls' successful exploitation of urban environments.

Farm Animal Cognition-Linking Behavior, Welfare and Ethics

Farm animal welfare is a major concern for society and food production. To more accurately evaluate animal farming in general and to avoid exposing farm animals to poor welfare situations, it is necessary to understand not only their behavioral but also their cognitive needs and capacities. Thus, general knowledge of how farm animals perceive and interact with their environment is of major importance for a range of stakeholders, from citizens to politicians to cognitive ethologists to philosophers. This review aims to outline the current state of farm animal cognition research and focuses on ungulate livestock species, such as cattle, horses, pigs and small ruminants, and reflects upon a defined set of cognitive capacities (physical cognition: categorization, numerical ability, object permanence, reasoning, tool use; social cognition: individual discrimination and recognition, communication with humans, social learning, attribution of attention, prosociality, fairness). We identify a lack of information on certain aspects of physico-cognitive capacities in most farm animal species, such as numerosity discrimination and object permanence. This leads to further questions on how livestock comprehend their physical environment and understand causal relationships. Increasing our knowledge in this area will facilitate efforts to adjust husbandry systems and enrichment items to meet the needs and preferences of farm animals. Research in the socio-cognitive domain indicates that ungulate livestock possess sophisticated mental capacities, such as the discrimination between, and recognition of, conspecifics as well as human handlers using multiple modalities. Livestock also react to very subtle behavioral cues of conspecifics and humans. These socio-cognitive capacities can impact human-animal interactions during management practices and introduce ethical considerations on how to treat livestock in general. We emphasize the importance of gaining a better understanding of how livestock species interact with their physical and social environments, as this information can improve housing and management conditions and can be used to evaluate the use and treatment of animals during production.

Understanding natural behavior to improve dairy goat (Capra hircus) management systems

Public interest is stimulating farming industries to improve animal welfare in production systems. Indoor housing of ruminants has received scrutiny because of perceived intensiveness and lack of naturalness. Animal welfare has traditionally focused on health benefits (e.g., bedding management and reducing disease) and reducing negative experiences (e.g., painful husbandry practices). Recent attention to animals having "a life worth living" extends expectations to provide increased care and opportunities for positive experiences and natural behaviors. Although not all natural behaviors necessarily contribute to improved welfare, we present evidence for why many are important, and for how they can be promoted in commercial systems. Worldwide, commercial dairy goats (Capra hircus) are frequently housed in large open barns with space to move and soft bedding for lying; however, this is not sufficient to promote the range of natural behaviors of goats, which in turn suggests that commercial housing could be improved. The basis for this thinking is from the range of behaviors expressed by the Capra genus. Collectively, these species have evolved cognitive and behavioral strategies to cope with harsh and changing environments, as well as variable and limited vegetation. The rocky and often steep terrain that goats inhabit allows for predator avoidance and access to shelter, so it is not surprising that domesticated goats also seek out elevation and hiding spaces; indeed, their hoof structure is designed for the movement and grip in such rugged environments. The browsing techniques and flexibility in diet selection of wild, feral and extensively managed goats, appears to be equally important to housed goats, highlighting the need for more complexity in how and what goats are fed. Goats naturally live in small, dynamic groups, governed by complex social structures in which horns play a strong role. Commercial housing systems should consider the benefits of more natural-sized social groups and revisit the rationale behind horn removal. We suggest that cognitive stimulation is a potential welfare improvement for goats in commercial settings. Goat cognitive abilities, which enabled success in complex and variable social and physical environments, are unchallenged in uniform environments, potentially leading to negative affective states. We make suggestions for housing improvements that could be readily adopted into current systems without compromising production efficiency.

Motor self-regulation in goats (Capra aegagrus hircus) in a detour-reaching task

Motor self-regulation is the ability to inhibit a prepotent response to a salient cue in favour of a more appropriate response. Motor self-regulation is an important component of the processes that interact to generate effective inhibitory control of behaviour, and is theorized to be a prerequisite of complex cognitive abilities in humans and other animals. In a large comparative study using the cylinder task, motor self-regulation was studied in 36 different species, mostly birds and primates. To broaden the range of species to comprehensively evaluate this phenomenon, motor self-regulation was studied in the domestic goat, which is a social ungulate species and moderate food specialist. Using the cylinder task, goats were first trained to perform a detour-reaching response to retrieve a reward from an opaque cylinder. Subsequently, an otherwise identical transparent cylinder was substituted for the opaque cylinder over 10 test trials. The goats' ability to resist approaching the visible reward directly by touching the cylinder and to retain the trained detour-reaching response was measured. The results indicated that goats showed motor self-regulation at a level comparable to or better than that of many of the bird and mammal species tested to date. However, the individual reaction patterns revealed large intra- and inter-individual variability regarding motor self-regulation. An improvement across trials was observed only in latency to make contact with the reward; no improvement in the proportion of accurate trials was observed. A short, distinct pointing gesture by the experimenter during baiting did not have any impact on the side of the cylinder to which the goats detoured. In half of goats, individual side biases were observed when detouring to the side of the cylinder, but there was no bias at the population level for either the left or right side. The results underline the need for a detailed examination of individual performance and additional measures to achieve a complete understanding of animal performance in motor self-regulation tasks.

Goats display audience-dependent human-directed gazing behaviour in a problem-solving task

Domestication is an important factor driving changes in animal cognition and behaviour. In particular, the capacity of dogs to communicate in a referential and intentional way with humans is considered a key outcome of how domestication as a companion animal shaped the canid brain. However, the lack of comparison with other domestic animals makes general conclusions about how domestication has affected these important cognitive features difficult. We investigated human-directed behaviour in an 'unsolvable problem' task in a domestic, but non-companion species: goats. During the test, goats experienced a forward-facing or an away-facing person. They gazed towards the forward-facing person earlier and for longer and showed more gaze alternations and a lower latency until the first gaze alternation when the person was forward-facing. Our results provide strong evidence for audience-dependent human-directed visual orienting behaviour in a species that was domesticated primarily for production, and show similarities with the referential and intentional communicative behaviour exhibited by domestic companion animals such as dogs and horses. This indicates that domestication has a much broader impact on heterospecific communication than previously believed.

Cognitive test batteries in animal cognition research: evaluating the past, present and future of comparative psychometrics

For the past two decades, behavioural ecologists have documented consistent individual differences in behavioural traits within species and found evidence for animal "personality". It is only relatively recently, however, that increasing numbers of researchers have begun to investigate individual differences in cognitive ability within species. It has been suggested that cognitive test batteries may provide an ideal tool for this growing research endeavour. In fact, cognitive test batteries have now been used to examine the causes, consequences and underlying structure of cognitive performance within and between many species. In this review, we document the existing attempts to develop cognitive test batteries for non-human animals and review the claims that these studies have made in terms of the structure and evolution of cognition. We argue that our current test battery methods could be improved on multiple fronts, from the design of tasks, to the domains targeted and the species tested. Refining and optimising test battery design will provide many benefits. In future, we envisage that well-designed cognitive test batteries may provide answers to a range of exciting questions, including giving us greater insight into the evolution and structure of cognition.

Human head orientation and eye visibility as indicators of attention for goats (Capra hircus)

Animals domesticated for working closely with humans (e.g. dogs) have been shown to be remarkable in adjusting their behaviour to human attentional stance. However, there is little evidence for this form of information perception in species domesticated for production rather than companionship. We tested domestic ungulates (goats) for their ability to differentiate attentional states of humans. In the first experiment, we investigated the effect of body and head orientation of one human experimenter on approach behaviour by goats. Test subjects (N = 24) significantly changed their behaviour when the experimenter turned its back to the subjects, but did not take into account head orientation alone. In the second experiment, goats (N = 24) could choose to approach one of two experimenters, while only one was paying attention to them. Goats preferred to approach humans that oriented their body and head towards the subject, whereas head orientation alone had no effect on choice behaviour. In the third experiment, goats (N = 32) were transferred to a separate test arena and were rewarded for approaching two experimenters providing a food reward during training trials. In subsequent probe test trials, goats had to choose between the two experimenters differing in their attentional states. Like in Experiments 1 and 2, goats did not show a preference for the attentive person when the inattentive person turned her head away from the subject. In this last experiment, goats preferred to approach the attentive person compared to a person who closed their eyes or covered the whole face with a blind. However, goats showed no preference when one person covered only the eyes. Our results show that animals bred for production rather than companionship show differences in their approach and choice behaviour depending on human attentive state. However, our results contrast with previous findings regarding the use of the head orientation to attribute attention and show the importance of cross-validating results.

Comment on "Ducklings imprint on the relational concept of 'same or different'"

Martinho and Kacelnik (Reports, 15 July 2016, p. 286) reported that newly hatched ducklings imprinted on relational concepts. We argue that reanalyzing the data at the individual level shows that this conclusion cannot be applied for all sets of stimuli presented and that the ability to grasp relational concepts is limited to the stimulus category that is most beneficial for survival.

'Goats that stare at men'--revisited: do dwarf goats alter their behaviour in response to eye visibility and head direction of a human?

Being able to recognise when one is being observed by someone else is thought to be adaptive during cooperative or competitive events. In particular for prey species, this ability should be of use in the context of predation. A previous study reported that goats (Capra aegagrus hircus) alter their behaviour according to the body and head orientation of a human experimenter. During a food anticipation task, an experimenter remained in a particular posture for 30 s before delivering a reward, and the goats' active anticipation and standing alert behaviour were analysed. To further evaluate the specific mechanisms at work, we here present two additional test conditions. In particular, we investigated the effects of the eye visibility and head orientation of a human experimenter on the behaviour of the goats (N = 7). We found that the level of the subjects' active anticipatory behaviour was highest in the conditions where the experimenter was directing his head and body towards the goat ('Control' and 'Eyes closed' conditions), but the anticipatory behaviour was significantly decreased when the body ('Head only') or the head and body of the experimenter were directed away from the subject ('Back' condition). For standing alert, we found no significant differences between the three conditions in which the experimenter was directing his head towards the subject ('Control', 'Eyes closed' and 'Head only'). This lack of differences in the expression of standing alert suggests that goats evaluate the direction of a human's head as an important cue in their anticipatory behaviour. However, goats did not respond to the visibility of the experimenter's eyes alone.

A mobile, high-throughput semi-automated system for testing cognition in large non-primate animal models of Huntington disease

BACKGROUND

For reasons of cost and ethical concerns, models of neurodegenerative disorders such as Huntington disease (HD) are currently being developed in farm animals, as an alternative to non-human primates. Developing reliable methods of testing cognitive function is essential to determining the usefulness of such models. Nevertheless, cognitive testing of farm animal species presents a unique set of challenges. The primary aims of this study were to develop and validate a mobile operant system suitable for high throughput cognitive testing of sheep.

NEW METHOD

We designed a semi-automated testing system with the capability of presenting stimuli (visual, auditory) and reward at six spatial locations. Fourteen normal sheep were used to validate the system using a two-choice visual discrimination task. Four stages of training devised to acclimatise animals to the system are also presented.

RESULTS

All sheep progressed rapidly through the training stages, over eight sessions. All sheep learned the 2CVDT and performed at least one reversal stage. The mean number of trials the sheep took to reach criterion in the first acquisition learning was 13.9±1.5 and for the reversal learning was 19.1±1.8.

COMPARISON WITH EXISTING METHOD(S)

This is the first mobile semi-automated operant system developed for testing cognitive function in sheep.

CONCLUSIONS

We have designed and validated an automated operant behavioural testing system suitable for high throughput cognitive testing in sheep and other medium-sized quadrupeds, such as pigs and dogs. Sheep performance in the two-choice visual discrimination task was very similar to that reported for non-human primates and strongly supports the use of farm animals as pre-clinical models for the study of neurodegenerative diseases.