Daniel MillsUniversity of Lincoln · School of Life Sciences
Daniel Mills
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Introduction
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Publications
Publications (346)
Detection dogs are required to search for and alert to specific odours of interest, such as drugs, cadavers, disease markers and explosives. However, the odour released from different samples of the same target substance will vary for a number of reasons, including the production method, evaporation, degradation, or by being mixed with extraneous o...
Domestic cats use visual cues to communicate with conspecifics and humans. This includes the position and movement of the tail. The tail up signal (i.e. tail held vertically with the tip curled) has been identified as a friendly greeting signal between cats and from cats to humans. We present here a report of two cats unable to display the classic...
Fear and frustration are two emotions thought to frequently contribute to problem behaviour, often leading to relinquishment. Inferring these emotions is challenging as they may present with some similar general signs, but they potentially require different treatment approaches to efficiently address the behaviour of concern. Although behavioural a...
Animal affective computing is an emerging new field, which has so far mainly focused on pain, while other emotional states remain uncharted territories, especially in horses. This study is the first to develop AI models to automatically recognize horse emotional states from facial expressions using data collected in a controlled experiment. We expl...
This leaflet is intended to help all types of landlords and their agents get the most out of deciding to make their property pet friendly. Based on extensive information and our new research, it explains the benefits, the practicalities, the potential pitfalls (and how to avoid them) and how you can make it work for everyone.
Dog behavioural problems are one of the main reasons for dog relinquishment. Studies on how dog behavioural problems affect owner well-being are limited. We review the literature concerning the link between dog behavioural problems and owner well-being. We propose practical solutions to minimize the negative impacts of behavioural problems on human...
Sudden changes in sound and light (e.g., sirens and flashing police beacons) are a common component of working dogs’ on-duty environment. Yet, how such stimuli impact dogs’ ability to perform physical and cognitive tasks has not been explored. To address this shortcoming, we compared the accuracy and time taken for twelve dogs to complete a complex...
Facial landmarks, widely studied in human affective computing, are beginning to gain interest in the animal domain. Specifically, landmark-based geometric morphometric methods have been used to objectively assess facial expressions in cats, focusing on pain recognition and the impact of breed-specific morphology on facial signaling. These methods e...
Affective states are reflected in the facial expressions of all mammals. Facial behaviors linked to pain have attracted most of the attention so far in non-human animals, leading to the development of numerous instruments for evaluating pain through facial expressions for various animal species. Nevertheless, manual facial expression analysis is su...
Citizen science, which involves engaging the general public in research tasks, is increasingly used in animal behaviour studies. In this review we conducted a SWOT analysis (Strengths, Weaknesses, Opportunities, Threats) to evaluate two methodologies of data collection using citizen science in order to study cat-cat interactions: online survey resp...
Animal affective computing is an emerging new field, which has so far mainly focused on pain, while other emotional states remain uncharted territories, especially in horses. This study is the first to develop AI models to automatically recognize horse emotional states from facial expressions using data collected in a controlled experiment. We expl...
Manual tools for pain assessment from facial expressions have been suggested and validated for several animal species. However, facial expression analysis performed by humans is prone to subjectivity and bias, and in many cases also requires special expertise and training. This has led to an increasing body of work on automated pain recognition, wh...
Domestic cats are increasingly popular as companion animals, but behavioural problems are often reported, especially in multicat households. Social tension is a common stressor, so understanding intercat interactions and their dynamics is crucial. Nevertheless, direct research in the home setting is rare. As caregivers witness their cats’ behaviour...
Background:
Connections between the effects of pet ownership and exercise on mental health have previously been demonstrated in different populations. However, little is known about the potential effects of pet ownership and exercise on the mental health of veterinary professionals. Since these individuals have a high prevalence of poor mental hea...
There is a set of hypotheses commonly used in the literature to explain how pets affect human well-being (e.g., pets as social catalysts). Many studies are reported as giving results consistent with one or more of these, but they may not appear to be sufficient to explain the impacts of several pet-related activities on owner well-being. Confirmati...
Simple Summary
Understanding how dogs behave in different situations is an important question in the dog–human relationship. In fact, it is not yet fully understood how their behaviours might be linked to their emotional state, which generates obstacles to communication between species. The aim of this study was to investigate how different emotion...
Comparative studies of human–dog cognition have grown exponentially since the 2000’s, but the focus on how dogs look at us (as well as other dogs) as social partners is a more recent phenomenon despite its importance to human–dog interactions. Here, we briefly summarise the current state of research in visual perception of emotion cues in dogs and...
The concept of psychological resilience is well-explored in the human literature and is often described as the ability to ‘bounce back’ following adversity. However, it remains a neglected research area in dogs despite observations that like humans, dogs vary in their ability to cope with stress. This study aimed to develop the first canine ‘resili...
The correct interpretation of an animal’s emotional state is crucial for successful human–animal interaction. When studying dog and cat emotional expressions, a key source of information is the pet owner, given the extensive interactions they have had with their pets. In this online survey we asked 438 owners whether their dogs and/or cats could ex...
Pain associated with chronic health conditions in non-human animals is an important animal welfare issue. To identify animals in pain and develop an understanding of the mechanisms by which pain affects behaviour, it is therefore important to establish the direct behavioural effects of painful health conditions. We reanalyse data from a cross-secti...
Manual tools for pain assessment from facial expressions have been suggested and validated for several animal species. However, facial expression analysis performed by humans is prone to subjectivity and bias, and in many cases also requires special expertise and training. This has led to an increasing body of work on automated pain recognition, wh...
In animal research, automation of affective states recognition has so far mainly addressed pain in a few species. Emotional states remain uncharted territories, especially in dogs, due to the complexity of their facial morphology and expressions. This study contributes to fill this gap in two aspects. First, it is the first to address dog emotional...
Changes in facial expression provide cues for assessing emotional states in mammals and may provide non-verbal signals of pain. This study uses geometric morphometrics (GMM) to explore the facial shape variation in female Japanese macaques who underwent experimental laparotomy. Face image samples were collected from video footage of fourteen macaqu...
Both the public and clinicians are interested in the application of scientific knowledge concerning problem animal behaviour and its treatment. However, in order to do this effectively it is essential that individuals have not only scientific literacy but also an appreciation of philosophical concepts underpinning a particular approach and their pr...
SIMON, T., K. Guo, E. Frasnelli, A. Wilkinson and D.S. Mills. Testing of behavioural asymmetries as markers for brain lateralization of emotional states in pet dogs: a critical review. NEUROSCI BIOBEHAV REV XX(X) XXX-XXX, XXXX.
Domestic dogs (Canis familiaris) hold a unique position in human society, particularly in their role as social companions;...
Aggressive behaviour by dogs is a considerable social problem, but the ability to predict which individuals may have increased aggressive tendencies is very limited, restricting the development of efficient preventive measures. There is a common perception that certain breeds are more likely to exhibit aggressive behaviour, which has contributed to...
Children are often surrounded by other humans and companion animals (e.g., dogs, cats); and understanding facial expressions in all these social partners may be critical to successful social interactions. In an eye‐tracking study, we examined how children (4–10 years old) view and label facial expressions in adult humans and dogs. We found that chi...
Internal affective states are closely linked to facial expressions in both human and many non-human animals. For some animal species, objective tools for facial expression analysis such as AnimalFACS are available and are only just beginning to be increasingly used. However, their use requires special expertise, training, and certification, while t...
Similarly to humans, facial expressions in animals are closely linked with emotional states. However, in contrast to the human domain, automated recognition of emotional states from facial expressions in animals is underexplored, mainly due to difficulties in data collection and establishment of ground truth concerning emotional states of non-verba...
Facial expressions in non-human animals are closely linked to their internal affective states, with the majority of empirical work focusing on facial shape changes associated with pain. However, existing tools for facial expression analysis are prone to human subjectivity and bias, and in many cases also require special expertise and training. This...
Research with humans and other animals has suggested that preferential limb use is linked to emotionality. A better understanding of this still under-explored area has the potential to establish limb preference as a marker of emotional vulnerability and risk for affective disorders. This study explored the potential relationship between paw prefere...
The ability to infer emotional states and their wider consequences requires the establishment of relationships between the emotional display and subsequent actions. These abilities, together with the use of emotional information from others in social decision making, are cognitively demanding and require inferential skills that extend beyond the im...
Facial expressions in non-human animals are closely linked to their internal affective states , with the majority of empirical work focusing on facial shape changes associated with pain. However, existing tools for facial expression analysis are prone to human subjectivity and bias, and in many cases also require special expertise and training. Thi...
Arousal and distress are often important factors in problematic behaviours, and endogenous corticosteroids are important mediators in the associated stress responses. Exogenous corticosteroid treatments have been reported to change behaviour in human patients and laboratory animals, with similar changes also noted in pet dogs. These behaviours not...
Behavioural reactions towards a dead conspecific have been observed rarely in wild canids and there is no documented scientific evidence of grief in pet dogs. A quantitative analysis of grief-related responses in both dogs and owners was conducted, using the validated online Mourning Dog Questionnaire. The survey was completed by 426 Italian adults...
Rehoming organisations often undertake some type of behaviour evaluation to determine dogs' suitability for rehoming and/or the type of suitable home. Assessments can carry considerable weight in determining dogs' fates. Although evaluation of the validity and reliability of any test is important, a more fundamental consideration is if the nature o...
Mental health problems and suicide are more frequent in autistic adults than general population. Dog ownership can improve human well-being. This study aimed to generate a framework of well-being outcomes for dog-related activities in autistic adults and compare it to the framework generated for a general adult population. Thirty-six autistic dog o...
Besides inconsistent evidence relating to the mental health benefits of pet ownership, there is a specific lack of data in relation to cat ownership. Research in this field frequently fails to consider the effect of specific cat-human relationships or activities that might impact owner well-being. This study aimed to identify and address this gap b...
Despite the abundance of studies investigating the benefits of having a dog, the specific aspects of dog ownership that impacts human well-being are not well understood. This study used a qualitative approach to create a framework of the main dog-related activities perceived by Brazilian owners to impact their well-being and compared the findings w...
Cross-sectional comparisons of well-being between dog owners and non-owners commonly generate inconsistent results. Focusing on the uniqueness of the relationship might help address this issue and provide a stronger foundation for dog-related psychotherapeutic interventions. This study aims to evaluate the impact of dog-related activities (e.g., ex...
Frustration is a negative emotional state implicated in a range of canine behaviour problems. The Canine Frustration Questionnaire (CFQ) is the first psychometric tool developed to assess frustration tendencies in dogs based on owner report. However, to date, no published studies have assessed behavioural and physiological correlates of this trait....
Leash pulling is a concern for dog owners and can be detrimental to the health and welfare of dogs. Neck-collars and back-connection harnesses are popular restraint types. Harnesses have been proposed as a better and more considerate option for canine health and welfare. Anecdotally, dogs pull more when wearing a back-connection harness; however, t...
Background
Assessment of pain in macaques is challenging. The aims of this study were (1) to investigate current knowledge and attitudes of primate veterinarians concerning acute pain in macaques; (2) to synthesise current knowledge and opinion to facilitate pain assessment. A primary question of interest was whether more confident individuals diff...
Play in domestic cats has been largely studied using a contextual approach, i.e., with a focus on what the cat is playing with, such as an object, itself or another cat. Such classification may be superficially attractive scientifically but it limits the ability to investigate function. We propose consideration of a psychobiological approach, which...
Background:
Companion animals may be a positive presence for their owners during the COVID-19 pandemic. However, the welfare of a companion animal is strongly influenced by the behaviour of their owners, as well as their physical and social environment. We aimed to investigate the reported changes in companion animal welfare and behaviour and to e...
Cats form close emotional relationships with humans, yet little is known about this. This study characterized different types of relationship that cats might establish with their owners. Data were analyzed from 3994 responses to a questionnaire developed using expressions of social support and attachment in relation to everyday cat–owner interactio...
Animal-assisted therapy (AAT) is highly heterogeneous at many levels, for example with regards to the setting itself, recipients of the intervention, species involved as therapy animals and their therapeutic potential. Dogs are the most commonly involved species in this work, and there may be good reasons for this beyond their availability. Some sp...
In their commentary, Sargisson and McLean (2021) object to our conclusion that the use of e-collars are unnecessary in dog training (China et al 2020). Their criticisms make 4 broad claims: firstly that the training approaches were not the most effective means of training with e-collars; secondly that the paper focussed on measures of efficacy and...
Social buffering occurs when the presence of one animal attenuates another’s stress response during a stressful event and/or helps the subject to recover more quickly after a stressful event. Inconsistent previous results might reflect previously unrecognised contextual influences, such as the nature of the stimulus presented or social factors. We...
Domestication has greatly changed the social and reproductive behavior of dogs relative to that of wild members of the genus Canis, which typically exhibit social monogamy and extended parental care. Unlike a typical gray wolf pack that consists of a single breeding pair and their offspring from multiple seasons, a group of free-ranging dogs (FRDs)...
Dogs have remarkable abilities to synergise their behaviour with that of people, but how dogs read facial and bodily emotional cues in comparison to humans remains unclear. Both species share the same ecological niche, are highly social and expressive, making them an ideal comparative model for intra- and inter-species emotion perception. We compar...
Social buffering occurs when the presence of one animal attenuates another’s stress response during a stressful event and/or helps the subject to recover more quickly after a stressful event. Inconsistent previous results might reflect previously unrecognised contextual influences, such as the nature of the stimulus presented or social factors. We...
The inner brow raiser is a muscle movement that increases the size of the orbital cavity, leading to the appearance of so-called 'puppy dog eyes'. In domestic dogs, this expression was suggested to be enhanced by artificial selection and to play an important role in the dog-human relationship. Production of the inner brow raiser has been shown to b...
The coronavirus disease 2019 (COVID-19) pandemic presents an opportunity to explore
the role of animals as sources of emotional and physical support during a period when most of the population is experiencing social and environmental challenges. We investigated how companion animal owners perceived the influence of human–animal interaction on their...
There is much debate over the pros and cons of allowing cats to roam freely as opposed to keeping them confined indoors. We surveyed owners who implemented a commercial physical containment system to the outdoors to evaluate their characteristics and the apparent impact of this system on cat welfare and owner perceptions. As part of the latter aim,...
This book contains 16 chapters that discuss mental and emotional health in the veterinary practice, ruling out physical disorders leading to behavioural changes, addressing pain in veterinary psychiatry, normal behaviour, raising mentally and emotionally healthy pets, diagnosis, learning principles and behaviour modification, psychopharmacology, pr...
This book contains 16 chapters that discuss mental and emotional health in the veterinary practice, ruling out physical disorders leading to behavioural changes, addressing pain in veterinary psychiatry, normal behaviour, raising mentally and emotionally healthy pets, diagnosis, learning principles and behaviour modification, psychopharmacology, pr...
Using a popular method of behaviour evaluation which rates the intensity of behaviour in different contexts, we demonstrate how pooling item scores relating to a given construct can reveal different potential risk factors for the dependent variable depending on how the total score is constructed. We highlight how similar simple total scores can be...