Sensitivity to reward change: a novel cognitive approach to understanding and measuring affective state in animals

动物可能或可能没有感受的问题不仅是对动物福利评估的基础，也是公众对圈养动物如何对待的关注。随着用于农业、研究和作为宠物饲养的动物数量不断增加，例如，仅在英国，每年就有超过7亿只鸡被饲养和杀死用于肉类生产，许多动物物种都有忍受痛苦的能力，这一信念促使我们渴望改善这些动物的住房条件和饲养程序。然而，由于这些体验是私有的，因此无法直接访问。相反，福利科学家使用被认为能反映动物情绪状态的间接方法。这些指标通常是行为（如接近食物）或生理（如心率变化）。然而，尽管这些措施有好处，它们也有严重的局限性。例如，动物在面对可怕的事物（如捕食者）时心率会加快，但在经历愉悦的事物（如食物）时心率也会加快，因此对这一测量的可靠解释就变得不可能了。因此，迫切需要研究开发测量动物情感和情绪的新方法，以便对动物福利进行更准确和有针对性的评估。以这种方式支持和推进动物福利科学的研究将对由大量个体组成的圈养动物种群产生重大影响。例如，据估计，英国有1000万只狗（2006年）。因此，这项拟议研究计划的目的是开发一种全新的方法来理解和测量动物的情绪和情绪，这将大大推进我们对动物福利的评估，这种方法是基于奖励评估。我们对得到的奖励的感觉不仅取决于它的绝对值，还取决于它与预期值的比较。所以，虽然你通常会很高兴得到加薪，但如果你期望得到晋升，你会失望的。这种对期望和实际收获之间的对比的敏感性，在许多动物物种中都很普遍，被认为有助于个体做出适当的决定。最近有研究首次证明，个体当前的情绪会影响其对奖励变化的敏感性，那些情绪积极的动物会更快地从意外的奖励损失中恢复过来。因此，这提供了一个令人兴奋的机会，将对奖励变化的敏感性作为一种衡量动物情感和情绪的新方法。最初的研究表明，对奖励变化的敏感性是一种快速、有效和非侵入性的测量动物情绪的方法。但是，需要对这种办法进行更详细的研究，以便确定其潜力的全部程度。在这个项目中，我们将研究家养狗的情绪和情绪，包括拥有（宠物）的狗和那些住在救援中心的狗。与实验室动物和农场动物相比，对狗的情绪、情绪和相关行为的研究，因为它们与人类有着密切的关系和环境，可以揭示认知（例如决策）和情感之间相互作用的有价值的见解，这不仅适用于狗和其他动物物种，也适用于人类自身。虽然这项研究的结果显然会对狗的福利评估产生直接影响，从而改善救援中心和重新安置狗的方法，但它将产生更广泛的影响，提供可应用于圈养动物物种的技术。

The question as to what feelings animals might or might not experience underlies not just the assessment of animal welfare, but public concern for how captive animals are treated. As the number of animals used in agriculture, research and kept as pets continues to increase, for example over 700million chickens are farmed and killed annually in the UK for meat production alone, the belief that many animal species have the capacity to suffer drives our desire to improve the housing conditions and husbandry procedures of those animals. Yet, because such experiences are private, they cannot be accessed directly. Instead, welfare scientists use indirect measures thought to reflect animals' emotional states. These indicators are often behavioural (e.g. approaching food) or physiological (e.g. a change in heart rate). However, despite the benefits of these measures, they have critical limitations. For example, an animal's heart rate will increase in the presence of something fearful (e.g. a predator), but will also increase during the experience of something pleasurable (e.g. food), such that reliable interpretation of this measure becomes impossible. For this reason, research into developing new approaches to measuring animal emotion and mood is urgently required to allow a more accurate and targeted assessment of animal welfare. Research that underpins and advances in animal welfare science in this way will have a major impact on a captive animal population that consists of large numbers of individuals. For example, there are an estimated 10 million owned dogs in the UK (2006).The aim of this proposed research programme is therefore to develop a completely new approach to understanding and measuring emotions and moods in animals that will significantly advance our assessment of animal welfare, and this approach is based on reward evaluation.How we feel about a reward that we have been given depends not just upon its absolute value, but its value compared to what was expected. So, although you might normally be happy to receive a pay rise, you will be disappointed if you were expecting to be offered a promotion as well. This sensitivity to the contrast between what you expected and what you actually received is common to many animal species and is thought to help individuals to make appropriate decisions. It has recently been demonstrated for the first time that the mood an individual is currently experiencing can influence its sensitivity to a change in reward, with those animals in a positive mood recovering sooner from an unexpected loss of reward. This therefore provides an exciting opportunity to use sensitivity to reward change as a novel measure of animal emotion and mood. Initial research indicates that sensitivity to reward change is a quick, effective and non-invasive way of measuring moods in animals. However, this approach needs to be studied in more detail in order to determine the full extent of its potential.In this project we will be studying emotions and moods in domestic dogs, both owned (pet) dogs and those housed at rescue centres. In contrast to laboratory and farm animals, the study of emotions, moods and associated behaviour in dogs, because they share a close relationship and environment with people, can reveal valuable insights into the interaction between cognition (e.g. decision-making) and emotion that applies not just to dogs and other animal species, but also to humans themselves. Whilst the outcomes of the study will clearly have a direct impact upon the welfare assessment of dogs, resulting in ways to improve the welfare of dogs housed in rescue centres and rehoming success, it will have a far wider impact, delivering techniques that can be applied across captive animal species.