Scientific Papers on Animal Sentience

The concept of ‘sentience’ includes emotional capacity and the ability to experience pain and pleasure. Sentient animals are ones which have the biological capacity for such characteristics, and which engage in behaviour suggestive of such awareness and emotion. Many scientific articles have demonstrated widespread anatomical, neurochemical, and physiological capabilities among animals. This current article reveals a tendency of bonobos, which are primates closely related to chimpanzees, that is strong behavioural evidence of sentience.
It turns out that bonobos voluntarily share their food with others of their species, as the title of the article suggests. When scientists gave the animals the choice of either monopolizing food, or actively sharing it, “bonobos preferred to release a recipient from an adjacent room and feed together instead of eating the food all alone.” (R230) This did not depend on kinship or on harassment. In other words, the two bonobos did not need to be related to engage in this behaviour, and the sharing was not a result of aggression.
The sharing was costly in an evolutionary sense, as the scientists pointed out, because only a small amount of food was available – an amount that one bonobo could easily finish by himself. The sharing pattern was also striking because bonobos, like other animals, are averse to food loss and usually act in ways that will lead to conservation of edible items.
So humans are not alone in preferring to eat in company. The research suggests that bonobos, and presumably other species, are not purely competitive, and sometimes choose to act in ways that transcend individual and kin survival.

Sentience is the only yardstick we should use for including species in the moral community, according to Gary Francione. A lawyer and philosopher who has written widely on animal issues, Professor Francione argues in this essay that animals should be treated morally simply because they are sentient, i.e. capable of experiencing pain and suffering. Whether nonhuman animals have cognitive capacities like humans – or do not – is not relevant, he suggests. In this, Prof. Francione takes a strong position in the ongoing debate over what factors are important for determining how humans should treat animals. Some scientists promote what this author calls the ‘similar-minds theory’ that many species should be accorded moral rights because they possess human-like cognitive. Studies have demonstrated that species from primates to crows to sheep have remarkable memories, can engage in abstract thought, and are sophisticated makers and users of tools. But Prof. Francione cautions that this approach still allows us to exclude many species from the ‘moral community,’ and argues that any species that can suffer, should not do so at human hands.

Keywords: Avoidance; crustacean; hermit crab; memory; nociception; Pagurus bernhardus; pain

Keywords: NHPI; habitat preference; learning; Drosophila; genotype; natal disperser

This paper investigates the experience of emotion in sheep, using a recognised cognitive system originally applied to human studies. They describe human emotions as “the result of how an individual evaluates a triggering situation”. The stages involved in the evaluation are: relevance; implications; coping potential and normative significance. The sheeps’ potential to experience these stages was tested in various ways, centred around scenarios involving a highly palatable food. Sheep were found to meet every requirement in the framework for experiencing emotion, and this has important implications for farming systems that they are exposed to. The authors suggest that increasing the degree of control that animals have over their environment is important, as is providing a balance between predictability and unpredictability in their daily routine.
Keywords: Animal welfare; appraisal theories; ear postures; emotion; heart rate; sheep

Keywords: Rooks; cognition; support; expectancy violation

Keywords: Population; culture; primates; tools; problem solving

Keywords: Animacy; audiovisual speech; avatar; face processing; human robot interaction

Keywords: Vocal learning; radio telemetry; song learning; Melospiza melodia; eavesdropping; song sparrow

Keywords: Stegodyphus tentoriicola; subsocial spider; competition; feeding behaviour; family

Social learning, a feature of humans and other complex and long-lived animals, has also recently been observed in a range of species that may traditionally be considered less complex. Defined as the acquisition and use of new information from other individuals, social learning has now been demonstrated in many animals, ranging from octopi to honeybees. This current study asked whether fruitflies, the ubiquitous Drosphila melanogaster of research laboratories, can learn by observing other fruitflies, and demonstrated that indeed they can. The study was based on the need of female fruitflies to choose substrates on which to lay eggs. One set of female fruitflies acted as models and laid eggs on a particular novel food, while another set of female fruitflies watched the proceedings. Subsequently, the observer fruitflies preferentially chose to lay their eggs on that same novel food rather than elsewhere. Control conditions provided strong evidence that the fruitflies had learned by watching. According to the authors, the observer flies “biased their food preference only after observing models who had decided that a given food was suitable for egg laying.” It is interesting that this paper discusses insect decision-making, a concept which might have been considered unscientific years ago.

This article introduces a volume of the Journal of Social Issues devoted to human-animal relations, exploring attitudes toward animals and the implications of our interactions with non-human species. Noting the human dilemma in which people are fond of animals yet benefit from their use and sometimes abuse, the article calls human-animal questions “morally significant” and increasingly “a serious topic for scientific study.”

Many scientists who support using animals in research nevertheless agree that a wide range of species possess sentience, the capacity for pain and suffering. That was one of the findings of this study, which explored various groups’ attitudes toward animals and their uses by humans. Based on a questionnaire to 372 animal welfarists, scientists and laypersons, the study showed that scientists believe numerous species to have at least a moderate capacity for sentience. Scientists as a group also tended not to support the use of animals for dissection, personal decoration, or entertainment. “Hence, the negative image of the science community that is often portrayed was not supported by our data.” However, many of the scientists supported using animals in medical research, possibly suggesting lack of confidence in effective alternatives. All groups’ attitudes toward animal cognition and sentience reflected the traditional phylogenetic scale.

Discussions of animal welfare often rest on evidence for animals’ awareness and consciousness, especially of ill treatment. This article suggests a different focus. Noting the difficulty of agreeing on, and measuring, awareness and consciousness, Dr. Burghardt suggests that these might be “overvalued as markers on the ethical ruler.” As well, the author asserts that animals with higher levels of consciousness may not automatically be treated more kindly, noting that “Children get passes that adults do not.” The author suggests a more holistic vision focussed on enriching animal lives rather than measuring how much they might suffer. This will require more attention to healthy societies and ecosystems for both animals and humans.

Human beings exhibit “extraordinary inconsistencies” in their attitudes and behaviours toward animals, notes this article; wearing leather but refusing to eat veal, opposing animal experiments but using shampoos tested on four-legged creatures. The truth is that “we want to have our dogs (and cats) and eat them too.” Yet each society has taboos concerning animals. Noting the growing trend in South Korea for dogs as companion pets, the author suggests it will be interesting to see whether eating dog meat becomes less popular there, or whether Koreans will be able to compartmentalize that custom. Such compartmentalization is one common strategy for humans who believe animals are sentient and cognitively sophisticated, yet who wish to harvest their benefits with clear consciences. This is among the techniques that people have used throughout history to justify the abuse of other humans, notes the author, which is another reason that the animal-human relationship is compelling scientifically and socially.

This article points out the increasing interest among philosophers in the topic of animal studies. It reviews and discusses three recently-published books in philosophy, all of which explore animals’ perceptions and the differences but also commonalities between human and non-human animals. The three books are, Zoographies: The question of the animal, by M. Calarco, Animal Subjects: An ethics reader in a posthuman world, edited by J. Castricano, and Philosophy and Animal Life, edited by C. Diamond et al.

This academic article analyzed popular news media to gain a systematic overview of how journalists refer to farm animals. After examining more than 100 print and broadcast news items in the United States between 2000 and 2003, the research demonstrated that journalists tend to refer to farm animals dispassionately as commodities lacking in emotion or inherent value as beings. It showed that the majority discuss farm animals using language that supports “the speciesist status quo.” Whether writing about livestock production or more specialized issues such as genetic modification, journalists usually focus on human health, consumer safety, and other human-centred concerns, but rarely on farm animal welfare. The article pointed out that popular news media plays a large role in shaping attitudes in society.

Just as humans exhibit characteristic physiological reactions to undesirable or stressful situations, so do sheep. In this study, 19 ewes were conditioned to expect a particular quality of feed. Then, hooked up to equipment measuring heart rate, respiration rate, and other variables, the sheep were administered feed that was better than, worse than, or the same as what they had learned to expect. When the sheep received inferior feed in the form of unpalatable wooden pellets, their heart and respiration rates increased, whilst procurement of standard or enriched feed did not elicit the same response. These results lead the scientists to conclude that “presumed negative and positive emotional states in sheep differ in their physiological reactions.” Such human-like reactions have also been demonstrated in other species.

Animal suffering and welfare were the unifying topics this month of the May 2009 issue of Applied Animal Behaviour Science.
It is interesting to note that the titles of several of the articles contain phrases such as: “suffering in diseased pigs,” and “emotional valence in sheep” and “cognitive bias as an indicator of animal emotion.” One article asks: “Does environmental enrichment affect the behaviour of fish commonly used in laboratory work?” These reflect a growing scientific acceptance of animal sentience and emotion.
Summaries by Compassion in World Farming of two of the papers follow below.

This article presents arguments and evidence for the important role of pleasure in the lives of non-human animals. Noting that the discourse on animal sentience focuses almost entirely on negative experience of pain, stress, distress, and suffering, the author argues for the importance of positive aspects of sentience such as pleasure and reward. He draws on evolutionary and other evidence to demonstrate that animals are motivated to seek reward and positive feeling, not simply to avoid pain. The central aspect of pleasure and reward in the lives of animals, he says, “amplifies the moral burden of depriving animals the opportunity to lead fulfilling, enjoyable lives.”

This article gives scientific credence and support to naturalistic and observational work on animals. The article notes that most scientific study of animal behaviour and affect has tended to focus on discrete characteristics in numerous animals in controlled experimental conditions, then describe the resulting data quantitatively. However, an alternative methodology has examined “the unique features of individual animals” through complex behaviours rather than select and discrete ones and has amassed qualitative and narrative, as well as quantitative, data. Exemplified by the work of Jane Goodall, Barbara Smuts and others, such research is useful for our understanding of animal affect and animal welfare.

Keywords: Environmental enrichment; behavioural style; spatial learning; exploration; social reinstatement.

Keywords: Attachment; primate; parental care; early experience.

Keywords: Anti-predator vigilance; group size; gulls; Larus sp.; sleep; visual monitoring

Keywords: Sheep; behaviour; physiology; stress; welfare; mulesing.

Keywords: Animal models; animal welfare; ethics; laboratory animals; pain; three rs.

Keywords: Animal welfare; cognition; farm animals; learning; motivation; reward.

Keywords: Rhesus monkeys (Macaca mulatta); language; numerosity; evolution.

Keywords: Fish; nociception; pain; acetic acid test.

Keywords: Fish; nociception; pain; stress-induced analgesia.

Keywords: Bees; animal consciousness; awareness.

Keywords: Enrichment review; behaviour; health; welfare; performance; meat quality; pigs.

Keywords: Horses; social relationships; interventions; mares; geldings; play; allogrooming; social network.