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An integrative and functional framework for the study of animal emotion and mood
... Consequently, in order to assess well-being, it is also necessary to be able to assess emotions. To date, there is no single definition of emotion [1][2][3], however, in 2010 Mendl and his colleagues proposed a two-dimensional definition [4]. This approach defines an emotion in terms of its valence (positive or negative) and its arousal (low or high). ...
... In Equids, studies have shown that positive anticipation contexts induce an overall increase in locomotor activity [11,37], a decrease in maintenance behaviour [11], and an increase in exploratory behaviour [27]. These behaviours, as well as avoidance and attraction behaviours, provide information about the valence of a stimulus or situation [4,38]. Finally, the analysis of facial movements can be employed as a promising indicator for characterising facial expressions linked to emotional states. ...
... First, we aimed to validate our two experimental procedures by demonstrating that they indeed induce contrasting emotional valences. To achieve this, we utilised established behavioural and physiological indicators, namely approach latency, heart rate and cortisol variation [2,4,38,54]. We hypothesized that horses would show lower cortisol variation in the positive condition (going to pasture) compared to the negative condition (social isolation) and would take less time to approach the pasture than to enter the social isolation box, reflecting attraction versus avoidance. ...
The welfare of an animal is closely linked to their emotional experiences, making it essential to identify reliable indicators of these emotions. This study aimed to identify behaviours and facial movements in horses experiencing contrasting emotional valence, triggered by the anticipation of a positive condition (going to pasture) or a negative condition (going alone to a novel environment). Twenty horses were daily trained to wait in a starting box before being exposed to these two conditions. After one week of positive training or negative training, we analysed horses’ behaviours, cortisol variations, and facial movements while they waited in their starting box. First, we confirmed that the two conditions induced contrasting emotional valence, as evidenced by the shorter time taken to approach in the positive condition compared to the negative, and by the higher maximal heart rate and cortisol variation in the negative condition. Then using the Equine Facial Action Coding System (EquiFACS) and network analysis (NetFACS) we revealed distinct behaviours and facial expression profiles. In positive anticipation, the horses exhibited a greater range of behaviours, including shaking their heads from side to side, stepping back, sniffing, and pawing at the ground. Additionally, two distinct facial expression profiles were identified as specific to positive and negative anticipation. In positive anticipation, the horses displayed a higher neck, accompanied by a greater frequency of half-blinks and mouth movements. Conversely, in negative anticipation, the horses exhibited a medium neck, with ears backward accompanied by more flattened ears and expressed more nostril movements. The findings highlight the importance of these indicators in characterising horses’ emotions and emphasise their significance for assessing equine welfare.
... Paul et al. (2020), p. 750), for instance, argue that emotions are "state[s] characterized by loosely coordinated changes in the following five components: (i) feeling---changes in subjective experience, (ii) cognition--changes in attentional, perceptual, and inferential processes (appraisals), (iii) action--changes in the predisposition for or execution of specific responses, (iv) expression--changes in facial, vocal, postural appearance, and (v) physiology--changes in physiological and neural activity." While there are disagreements about the roles of each component, this view has paved the way for much recent research on animal emotions (e. g., Paul et al., 2005;Mendl et al., 2010;Anderson and Adolphs, 2014;De Vere and Kuczaj, 2016;Adolphs, 2017;Crump et al., 2020;Kremer et al., 2020;a.m.o.). ...
... To achieve this, the subjective component is assumed to be brought about by two bipolar-independent neurophysiological systems. One system is related to "valence"-the hedonic quality of the state, ranging from negative to positive-and the other to "arousal"-the degree of somatic activation, ranging from low to high (Russell, 1979;Barrett et al., 2017;Mendl et al., 2010). In this view, called the "Circumplex Model", "Happy" and "Calm" would arise from the same two neurophysiological systems but differ in their degree of arousal (Fig. 1). ...
... In this view, called the "Circumplex Model", "Happy" and "Calm" would arise from the same two neurophysiological systems but differ in their degree of arousal (Fig. 1). The quadrants of the resulting bi-dimensional space are then operationalized using behavioral, somatic, or cognitive changes, such as approach (or "reward acquisition") and avoidance (Mendl et al., 2010). ...
This paper introduces a mechanistic framework for understanding animal emotions, which is designed for biologists studying animal behavior and welfare. Researchers often examine emotions—short-term valenced experiences—through behavioral, somatic, and cognitive indicators. However, proposed indicators are often ambivalent (emerge in contexts with opposing emotional valence) or undetermined (arise in both affective and non-affective processes). To ground hypothesis formulation regarding animal emotions on a better foundation, the paper advocates for building on what we know regarding the mechanisms of human emotions—the behavioral rules that transform sensory input into motor output during emotional episodes. In particular, it integrates key assumptions from three dominant psychological theories of emotion—innate, appraisal, and network theories—into a single framework and argues that this can serve as a common ground to transfer insights from human to animal emotion research. Additionally, the paper tackles the question of how emotions relate to closely linked processes such as decision-making, distinguishing between parallel architecture models—where emotions and decision-making processes interact but remain distinct—and unified models—where affective states are conceived as integral to goal-oriented processes. Finally, we discuss how our mechanistic proposal can help us address four key questions in animal emotion research: Do animals experience emotions? If so, which animals experience emotions? Which emotions do they experience? And how do these emotions compare to human emotions? The paper concludes by emphasizing the need for further empirical research on the mechanisms of animal emotions and their distinction from other processes.
... In the study of human emotions, dimensional theories (Russell 1980;Watson et al. 1999;Posner et al. 2005) have gained considerable influence and provide a conceptual framework that is extendable to the study of animals as they rely on few empirically measurable dimensions (Mendl et al. 2010;Anderson and Adolphs 2014). One of the most widely used dimensional theories is the circumplex model that is based on two bipolar dimensions thought to represent two independent neurophysiological systems: arousal (active/ activated-inactive/ inactivated) and valence (positive/ pleasure-negative/displeasure) (Russell 1980;Posner et al. 2005). ...
... A great advantage of the circumplex model is that the degree of arousal and valence cannot only be obtained by oral report but also by objective physiological and behavioural measurements. This allows to extend the circumplex model to non-human animals where subjective report is absent but behaviour and physiology can still be measured (Mendl et al. 2010). Based on the conclusion that WAFO can be used as a proxy for valence, we asked whether TOWA can be used as a proxy for arousal, and hence whether the observed OFT behaviour in the fly can be plotted in a circumplex-like manner. ...
... fold change of -WAFO with respect to the prestimulus condition), and TOWA as a proxy of relative arousal (i.e. fold change of TOWA with respect to the prestimulus condition) in analogy to the circumplex model (Fig. 6), most conditions and treatments lead to a location in the upper left Q4 quadrant that in humans is associated with conditions like "fearful", "stressed" or "nervous", or the lower right Q2 quadrant that in humans is typically associated with states like "relaxed", "calm" or "contented" (Russell 1980;Posner et al. 2005;Mendl et al. 2010). Few conditions and treatments led to a location in the Q1-Q3 axis. ...
Emotions, defined as transient states preparing organisms for adaptive responses, are thought to be based on evolutionarily conserved building blocks (“emotion primitives”) that are present across mammalian and other vertebrate species. Whether and to which extent these building blocks are found in insects is largely undefined. In this study, we employ the open field test in fruit flies and focus on wall-following and total walking activity as behavioural indicators of emotion-like states.
Wildtype and transgenic flies were subjected to various conditions, including social isolation, starvation, and exposure to anxiolytic substances prior to behavioural testing in the open field test. The results indicate that wall-following and total walking activity are modulated by these conditions, with generally increased wall-following observed under aversive stimuli and decreased values under positive conditions. Notably, the behaviour was consistent across different times of the day and independent of circadian rhythms. Genetic manipulation of neuromodulatory systems, such as serotonin, dopamine, and neuropeptide F, supports the role of these pathways in modulating emotion-like states in the fruit fly. Activation of reward-related neurons decreased wall-following, while inhibition increased it, aligning with known effects in mammalian models. Additionally, pharmacological treatments with ethanol and diazepam produced predictable changes in wall-following and total walking activity, reinforcing the validity of the open field test as a measure of emotion-like states in the fly.
The findings suggest that Drosophila exhibits core emotion-like states, with wall-following and total walking activity serving as reliable indicators of emotional valence and arousal. Our results promote the use of Drosophila as a powerful genetic model to dissect the neuronal and neurochemical substrates of emotion primitives, shedding light on the evolution of basic emotional processing mechanisms.
... Interest in the study of animal emotions increased exponentially around 30 years ago, propelled by the needs of the pharmaceutical industry (e.g., treatment of human disorders), comparative neuroscience (e.g., development of animal models of human neurological disorders) and animal welfare (Fraser, 2009;Panksepp, 2011). Nowadays, several frameworks allow studying animal emotions (e.g., Désiré et al., 2002;Mendl et al., 2010), encompassing the four components of emotions accessible in these species, along with their indicators and the tools to measure them: neural (e.g., brain activity), peripheral physiological (e.g., heart rate, stress hormones), cognitive (e.g., cognitive bias), and behavioural (e.g., body postures, facial and vocal expressions) indicators (Kremer et al., 2020). This focus on four components excludes the generally accepted fifth component of emotion accessible in humans, that is, the subjective, conscious component (Sander, 2013). ...
... The frameworks developed for studying animal emotions have been adapted from human psychology to animals: appraisal theories (Ellsworth & Scherer, 2003) suggest that discrete or modal emotions, arise as a function of specific features of the situation and how the animal appraises them (Désiré et al., 2002). By contrast, the two-dimensional framework (Russell, 1980) suggests that emotions can be mapped according to their arousal (bodily excitation) and valence (positive vs. negative), which can be assessed based on the pleasant (rewarding/attractive) or unpleasant (punishing/repulsive) nature of the situation triggering the emotion (Mendl et al., 2010). ...
... The more general term of 'affective states' encompasses short and longer-term states (e.g., 'moods') that are valenced. Emotions and moods play an important role for animal survival: emotions guide responses to stimuli, while moods inform about expectations in the environment (Mendl et al., 2010). By contrast, motivation states reflect the likelihood of performing a given behaviour, or the force that drives this behaviour ('drives' or 'wants';Dawkins, 2008). ...
Humans and other animals communicate a large quantity of information vocally through nonverbal means. Here, we review the domains of animal vocalizations, human nonverbal vocal communication and computer-mediated communication (CMC), under the common thread of emotion, which, we suggest, connects them as a dimension of all these types of communication. After reviewing the use of emotions across domains, we focus on two concepts that have often been opposed to emotion in the animal versus human communication literature: control and meaning. Non-human vocal communication is commonly described as emotional, preventing either control or meaning; in contrast, the emotional dimension of human nonverbal signals does not prevent them from being perceived as both intentionally produced and meaningful. Amongst others, we disagree with this position, highlighting here that emotions should be integrated across species and modalities such as the written modality. We conclude by delineating ways in which each of these domains can meaningfully influence each other, and debates in their respective fields, and more generally the debate on the evolution of communication.
... care, and play systems 10 and therefore unlikely to be performed by animals in negative affect 1,2,11,12 . Some of these are included in behavioural measures of the AWIN project 13 which developed a welfare assessment protocol for horses which included: social interaction; stereotypy performance (or absence of); fear (or absence of); humananimal relationships assessed via avoidance distance, voluntary animal approach and forced human approach tests; and qualitative behaviour assessment (QBA). ...
... Variable 'RR mean' showed a greater distribution during and after wither scratching compared with the other three induction stimuli. 2 following evaluation of measurement variable relationships. Dimension 1 is proposed as the arousal dimension and dimension 2 as the valence dimension. ...
There is increasing focus on how to induce and measure positive affective states in animals and the development of social license to operate has brought this to the forefront within equestrianism. This study aimed to utilise a range of methods to induce and measure positive affect in horses in real-world settings. Twenty healthy horses were scored for personality, exposed to four induction methods (wither scratching, high value food provision, positive reinforcement training and the addition of an affiliative conspecific), and data collected on their behaviour (QBA and ethograms) and physiology (heart and respiratory rate, heart rate variability, eye and ear thermography and salivary cortisol). Analyses identified potentially sensitive and specific behavioural (ear and eye position, QBA items, frustration items) and physiological (RR mean, HF power, LF power, LF/HF ratio, mean HR, RMSSD and pNN50) measures of affective state across the four quadrants of core affect. Individual difference effects were found, and personality traits such as unfriendly, nervous and unresponsive were associated with differing responses to induction stimuli indicating that all four induction stimuli are potentially useful for inducing positive affect depending on their salience to the individual. Research measuring and inducing positive affect in animals rarely considers personality, but this study underscores its importance. The dimensional approach taken allowed for assessment of the broad arousal and valence components of affect without ascribing measures to discrete emotions. Accurate, real-world measures of affect could benefit 116 million equines globally, and exploring ways to promote positive affect in horses can significantly enhance their welfare.
... Animal personality, involving consistent behavioral patterns, interacts with cognitive processes and varies between proactive and reactive types (Sih and Del, 2012;Dall et al., 2004). Mood affects cognitive performance, with (Mendl et al., 2010;Nettle and Bateson, 2012;Moors et al., 2013). Motivation, influenced by rewards and prior experiences, is essential for task completion (W atanabe et al., 2001). ...
... The gut microbiome influences cognitive function through bidirectional communication with the brain (Mayer, 2011;Galland, 2014). Environmental factors, such as housing conditions, enrichment and stress, also affect cognitive processes and welfare (Mendl, 2010;Newberry, 1995;Manteuffel et al., 2009). ...
The cognitive abilities of farm animals, particularly dairy cattle, play a crucial role in their adaptation to and interaction with their surroundings, influencing their performance, welfare and the safety of handlers. Despite the growing recognition of the importance of cognitive capabilities in animal welfare assessment, there remains a limited understanding of the cognitive repertoire of farm animals. Animals can acquire, process, store and act upon information from their environment through a variety of cognitive processes, including perception, learning, memory and decision-making. In order to address the behavioural and cognitive needs of farm animals and eventually improve their welfare and performance, housing systems and management techniques must be tailored with an understanding of these cognitive mechanisms. The practice of removing calves from their mothers immediately after birth, although aimed at disease control and ease of management, raises concerns regarding calf welfare and cognitive development due to social isolation. By providing cognitive enrichment opportunities, such as social interaction and environmental stimulation, animals can develop coping mechanisms for stressful events and enhance their ability to adapt to environmental changes. Moreover, the interconnection between cognition and welfare is complex, with cognitive processes influencing and being influenced by welfare conditions. This bidirectional relationship underscores the importance of considering cognitive functioning in welfare assessment and management practices. It highlights the need for further research to advance our knowledge of farm animal cognition and its implications for welfare and performance.
... For example, in response to an emotional state, certain muscles contract while others are inhibited, resulting in changes in the acoustic properties of the caller's vocalization [20,21]. Emotional state is commonly characterized by its arousal (from low to high) and valence (positive, neutral or negative) [22]. Arousal refers to the intensity of the emotion, ranging from low levels, such as calmness or boredom, to high levels, like excitement or anxiety. ...
... While arousal captures how energized or subdued an emotion feels, valence indicates whether the emotional experience is pleasant or unpleasant. Together, these two dimensions form a comprehensive framework for analysing emotions, allowing us to categorize feelings on a broad spectrum [22]. ...
Nonlinear phenomena (NLP) are widely observed in mammal vocalizations. One prominent, albeit rarely empirically tested, theory suggests that NLP serve to communicate individual emotional states. Here, we test this ‘emotional hypothesis’ by assessing NLP production in the vocalizations of chimpanzees and bonobos across various social contexts. These two species are relevant to test this hypothesis since bonobos are more socially opportunistic than chimpanzees. We found that both species produced, albeit at different frequencies, the same five distinct NLP types. Contextual valence influenced NLP production in both species with negative valence being associated with more frequent NLP production than positive and neutral valence. In contrast, using aggression severity and caller role as proxies for arousal, we found that in bonobos, but not in chimpanzees, vocalizations uttered during contact aggression or from victims and females contained more NLP. In contrast, the type of NLP produced was neither influenced by valence nor arousal in either species. Our study supports the emotional hypothesis regarding the occurrence of NLP production in mammals, particularly in opportunistics such as bonobos. This reinforces the hypothesis of an adaptative role of NLP in animal communication and prompts further investigations into their communicative functions.
This article is part of the theme issue ‘Nonlinear phenomena in vertebrate vocalizations: mechanisms and communicative functions’.
... AB tasks were first developed to assess emotion in humans and have revealed that the allocation of attention to emotional stimuli changes with affective state (Bar-Haim et al., 2007;MacLeod et al., 1986). Here, affective state is defined as an animal's mood or emotional state and can encompass high and low arousal (intensity) and positive and negative valance (Mendl et al., 2010). Affective state is considered to be a key component of welfare (Mendl et al., 2010;Monk et al., 2023). ...
... Here, affective state is defined as an animal's mood or emotional state and can encompass high and low arousal (intensity) and positive and negative valance (Mendl et al., 2010). Affective state is considered to be a key component of welfare (Mendl et al., 2010;Monk et al., 2023). AB has since been adapted as a noninvasive method of determining affective state for welfare assessment in a range of animal species (review Crump et al., 2018). ...
A welfare assessment tool in development must satisfy several criteria before it is considered ready for general use. Some tools that meet many of these criteria have been criticized for their negative effect on welfare. We conducted a preliminary assessment of the impact of attention bias (AB) trials using threat-neutral conspecific face pairs followed by presumed neutral-positive filler stimuli on the behavior of 21 rhesus macaques(Macaca mulatta; 15 female). Behavioral observations were conducted following AB trials and repeated two weeks later when no AB trials had occurred (no trial: NT). The association between observation period and behavior was assessed using linear mixed-effects models in R. Trials did not impact any observed behavior except for fear, which was displayed by five monkeys over six trials (four NT). For this sample, there was a significant reduction in fear behavior following AB trials. We, therefore, found no evidence suggesting that AB trials negatively affect behaviour. AB protocols may be suitable for continued development for primate welfare assessment and we encourage researchers to include assessing test impact on welfare in their AB protocols.
... These findings point to the possibility that people's perception of dog emotions may be influenced by more than just the behavior of the dog itself. Mendl et al. (2010) proposed mitigating anthropomorphic tendencies in animal emotion perception research by refraining from asking individuals to rate an animal's emotions based on the six basic human emotions and instead having them rate the animal's affect. Affect describes a general feeling or mood (Russell, 2003) which can be analyzed in a two-dimensional space ( Figure 1). ...
... Sample emotional words are placed to indicate what each quadrant represents (e.g., medium arousal and high valence indicate a sense of happiness for humans). Modified fromMendl et al. (2010). ...
... This state varies according to the perception of the animal towards the situation (Morm ede et al., 2018). Emotional state is characterized by the positive or negative emotional valence experienced by the animal (Fraser, 2008;Mendl et al., 2010), and results from the accumulation of positive (pleasant) or negative (unpleasant) emotions. The primary function of emotions is hypothesized to be to guide an animal's decision making to enhance its survival (Mendl et al., 2009;Rolls, 2000Rolls, , 2005. ...
... Thus, an animal living in a poor environment that does not meet its needs will repeatedly feel negative emotions, creating a negative emotional state. Emotions come with behavioural and cognitive changes that provide valuable insights into the emotional state (Mendl et al., 2010). For example, approach and avoidance could be useful indicators to determine the emotional valence associated with a specific situation . ...
... A positive balance between positive and negative affective states is necessary to demonstrate that a horse can be argued to be truly in a state of good welfare. To describe affective states in animals, a two-dimensional framework has been suggested [29]. This approach characterizes animals' affective state based on two key dimensions: valence (such as positive or negative, pleasant or unpleasant) and arousal/intensity level (such as contentment versus excitement). ...
... The inclusion of similar behavioural observations in both studies underscores the importance of evaluating equine responses during EAS sessions to ensure not only the welfare of the horse but also the effectiveness of the service. In the present study, behaviours were carefully selected to represent the horse's subjective emotional experiences [87], characterized by both valence (e.g., positive or negative, pleasant or unpleasant) and arousal/intensity level (e.g., contentment versus excitement) [29,88]. While some behaviours arguably indicate a positive or negative valence (ears forward and ears flattened, respectively), others can only be understood when considered alongside a combination of different behaviours. ...
Equine-Assisted Services (EAS) offer significant benefits for individuals with intellectual and/or physical disabilities. However, ensuring the welfare of the horses involved remains a key ethical concern. The objective of this study was to assess the affective states of horses involved in EAS while also establishing behavioural thresholds for indicators of positive or negative affective states. A total of 98 horses were observed over a two-month period, accumulating data about horse behaviour and session characteristics from 830 EAS sessions. Horses participating in coaching programs averaged four sessions in two months; those involved in therapeutic riding averaged 31 sessions. Equine behaviour and field experts defined behavioural thresholds to assess welfare standards. Negative state behaviours were predominantly aligned within excellent or neutral thresholds, while positive state behaviours were observed from unacceptable to excellent. Principal Component Analysis (PCA) of the gathered behavioural data identified six affective states in coaching sessions and four in therapeutic riding, explaining 63% and 73% of the total variation, respectively. Among these states, “comfortable” was the most frequently observed. Multiple linear regression showed several significant variables, highlighting the importance of health, suitable horse selection, and proper management in promoting positive affective states in EAS.
... Further, a recent dog owner survey reported that~82% of respondents utilized at least one aversive dog training technique, which was associated with the presence of behavioural problems [19], as has been reported elsewhere [20]. While it is unclear whether aversive techniques are used in response to the development of a problem or are a direct cause of a problem (or both), there are significant welfare consequences to dogs of such techniques [21][22][23][24][25][26][27][28]. ...
... However, it is also likely that by reducing the development or severity of problematic behaviours, there will be an indirect welfare benefit, in that it may reduce the use of aversives towards dogs [65]. Aversive training is generally associated with behavioural problems and reductions in welfare in the dog-specific literature (e.g., see [22] for a review in dogs), and the negatively valenced emotional states resulting from punishments are well defined in general animal welfare theory [25][26][27]. Further, recent estimates of the incidence of utilizing at least one form of aversive technique is still very high at~82% [19]. Unfortunately, we do not have data on training approaches used by participants in the current study (other than knowing the Zigzag app promotes welfare-friendly approaches). ...
Behavioural problems in dogs are a major welfare concern for both dogs and owners, which can lead to relinquishment or euthanasia. As such, it is important to find ways to minimize the risk of development or severity of problematic behaviour. Such interventions should ideally occur early in the dog’s development and need to be widely and easily accessible. One way to implement such interventions, given modern smart phone use, is via an educational application (app). Here, we conducted a cross-sectional observational study where we sought to estimate associations between use of the Zigzag dog-training app (Zigzag Pet Care Services Ltd.) and the development and severity of problematic behaviours. We focused on a subset of the survey population (n = 367) who did no training at all (n = 194) or only used the app (did not attend formal classes or in person training; n = 173). Proportional odds ordinal logistic regression models were used to estimate odds ratios and 95% confidence intervals for a range of behaviours as a function of percentage completion of the first four chapters of the app while controlling for age, sex, health, and where the puppy was from. While sample sizes were relatively small and confidence intervals wide, 19 out of 21 odds ratio point estimates were in favour of severity being lower with increasing Zigzag app completion (the remaining 2 were marginally above 1). There was no good evidence that Zigzag increased the severity of any behaviours. On the contrary, there was reasonable evidence against the null hypothesis of no association in favour of Zigzag reducing the severity of familiar aggression, house soiling, chewing, barking, escaping, and noise fear. While causal effects cannot be claimed, overall, the reported associations are favourable and suggest that further study is warranted.
... Emotions, defined as short term affective responses to eliciting stimuli, influence how animals, across taxa, process and respond to the world around them (Mendl et al., 2011;Mendl et al., 2010). Emotions can be described across two dimensions of valence (positive or negative) and arousal (bodily activation; high or low) (Mendl et al., 2010;Russell, 1980). ...
... Emotions, defined as short term affective responses to eliciting stimuli, influence how animals, across taxa, process and respond to the world around them (Mendl et al., 2011;Mendl et al., 2010). Emotions can be described across two dimensions of valence (positive or negative) and arousal (bodily activation; high or low) (Mendl et al., 2010;Russell, 1980). Emotional states can influence observable responses, such as behaviour or vocal production (Briefer, 2020;Briefer, 2012). ...
... Acoustic signals have also been used to assess the affective states of wild animals [16][17][18], both in captivity [19] as well as in a natural wild environment [20,21]. This is possible because when emitting a call an animal uses specific organs such as the larynx, syrinx and vocal fold [16,22], which carry physiological [23], emotional [24,25], and individual information [26,27]. ...
Acoustic monitoring is emerging as a key tool in wildlife conservation, especially for species in inaccessible habitats like the rock cavy (Kerodon rupestris), an endangered species native to Brazil’s threatened Caatinga biome. Emotional stress from threatening situations affects breathing, heart rate, and vocal muscle tension, altering vocal acoustic parameters. This allows researchers to gauge the animal’s environmental perception through its vocalizations. We aimed to evaluate emotional disturbance indicators in free-range rock cavies’ vocalizations to suggest an acoustic index during threats. We compared calls from rock cavies in two areas with similar habitats but that differ in terms of anthropic impacts. Area 1 (A1) is near urban areas and disturbed by livestock and dogs, and Area 2 (A2) is farther from urban areas and free from human disturbance. Data on calls and behaviors were collected ad libitum in both areas. The alarm whistle call, making up 73.5% of total calls, was most common. Across 108 observation hours per area, 392 alarm whistle calls were recorded, with more calls in A1 than A2 (223 vs. 169; Chi-square = 29.44, DF = 1, P < 0.001). This resulted in a 32% higher hourly call rate in A1 (2.6 calls/h vs. 1.6 calls/h). Both male and female cavies in A1 had higher high-frequency (F1, 388 = 7.80, P = 0.005) and peak-frequency calls (F1, 388 = 21.32, P < 0.001). Given the similar landscape and resource availability in both areas, the differences in call emission rate and parameters are likely linked to emotional responses to human disturbances in A1. Thus, alarm whistle calls at an hourly rate of 2.6 calls/h or higher, with high-frequency and peak-frequency at or above 7222 Hz and 2603 Hz, can indicate anthropogenic disturbance in the Caatinga biome, aiding remote monitoring efforts.
... As a result, the dynamic metric may behave randomly and contain misleading values. To mitigate that, we introduced masking padding around the missing landmarks by computing the number of consecutive frames where the model's confidence is below a certain threshold (the value of 0.6 was chosen empirically) and masking a sequence of frames of length equal to 1 4 of this number (minimum of 1 frame) before and after the missing landmarks. By this, ...
This study develops a novel automated method for measuring continuous dynamics of dog facial behavior based on video-based tracking of 46 facial landmarks grounded in the Dog Facial Action Coding System. This method is applied for comparing the facial behavior of () brachycephalic (Boston Terrier) and () normocephalic (Jack Russel Terrier) dogs in four different contexts, eliciting various inner states: positive (play and called by name) and negative (separation and stranger). Having objectively quantified facial dynamics in brachycephalic and normocephalic dogs, we have found that brachycephalic dogs exhibited consistently lower facial dynamics across all four tested contexts and facial regions (eyes, mouth, and ears) compared to normocephalic dogs. They further demonstrated relatively higher dynamics in positive play and negative stranger conditions than in the other two conditions. In contrast, normocephalic dogs showed elevated dynamics exclusively in the positive play condition, with significantly reduced dynamics in the negative stranger condition. These findings highlight distinct patterns of facial expressivity between the two morphological groups, suggesting decreased facial expression in brachycephalic dogs and demonstrating our method’s value in providing novel insights into canine communication.
... Nostril dilator (AD38) is a facial movement associated with deep breathing and sniffing, where the nostril diameter can vary depending on the animal's physiological and psychological state [65]. Nostril dilator was observed in alert postures where the cardiorespiratory system is activated to prepare for potential flight [66], and it is detected in stressful situations [17]. Mares exhibited a higher frequency of this expression when exposed to new age music, concurrently with an increased frequency of ear rotator (EAD104). ...
This study aimed to evaluate the effect of auditory stimuli on mares and geldings during social isolation and movement restriction, and their ability to promote the reduction of stress responses. The research was conducted with eight Pantaneiro horses, divided into Experiment I (4 mares) and Experiment II (4 geldings), both experiments were executed equally using a 4x4 Latin square design with experimental (classical, country and new age) and control (no music) treatments. Physiological parameters (heart rate, heart rate variability, respiratory rate, ocular temperature by infrared thermography, and surface temperature by infrared thermometer) and facial expressions (eye closure (AU143), blink (AU145), half blink (AU47), inner brow raiser (AU101), eye white increase (AD1), tongue show (AD19), nostril dilator (AD38), chewing (AD81), ears forward (EAD101), and ear rotator (EAD104)) were assessed throughout the 24 minutes that the animals remained in the restraining stock. In Experiment I, there was a reduction (p < 0.05) in heart rate during classical and country treatments and an increase (p < 0.05) in auricular and body temperatures during the classical treatment. Additionally, the frequencies of expressions of nostril dilator (AD38), ear rotator (EAD104), and half blink (AU47) were lower (p < 0.05). In Experiment II, there was an increase (p < 0.05) in ocular temperature during the country and control treatments, and a higher frequency (p < 0.05) of ears forward (EAD101) during the country treatment. Exposure to Beethoven’s 9th Symphony (classical genre) and Hank Williams Jr.’s “Ramblin’ In My Shoes” (country genre) reduced stress in mares. Geldings showed less pronounced responses to music genres, indicating a possible preference for Janet Marlow’s “Horsing Around” (new age genre). Music can be used as auditory enrichment for horses in the specific context of this study.
... The maximum rein tension applied during EXP necessary to induce the horse to step back altered the sympathetic-vagal balance heightening arousal: the higher the tension, the lower the MEAN RR ( Figure 3b). Moreover, we found an effect of the type of headstall and maximum rein tension on the levels of MEAN RR (Figure 3c): at the same levels of the maximum rein tension, the horses equipped with halter experienced an even higher negative affective state (Mendl et al., 2010;Baragli et al., 2015;McLan and Christensen, 2017). The results coming from the different models applied to the B-EXP-R phases and the maximum rein tension are only apparently in contrast. ...
Studies on stress and emotions are fundamental to assessing welfare in wild and domestic animals. In this study, we experimentally investigated how different levels of rein tension affect autonomic nervous system activation and heart rate variability (HRV) in horses. We hypothesized that increased rein tension, through a learning process, would elevate sympathetic nervous system activity and HRV, and that adult horses would be less affected by stimulus administration (EXP) than young horses due to their experience. The magnitude of rein tension significantly altered the sympatho-vagal balance in horses. Both the type of equipment (bit versus halter) and the age of the horses influenced their responses. HRV frequency domain analysis showed a significant shift in sympatho-vagal balance during EXP, with values returning to baseline during the recovery period (R) (p<0.001). Notably, during EXP, the observed increase in LF power alongside a decrease in HF power suggests a shift toward sympathetic dominance and a reduction in vagal modulation. Interestingly, the maximum rein tension did not affect the parameters used to measure these activities, suggesting the tension levels were within an acceptable range for the horses. The balance between sympathetic and parasympathetic activities improved in R with the low-frequency/high-frequency power ratio decreasing by 49.4% from EXP to the baseline condition (B) and by 37.5% from B to R, indicating stress release and increased vagal activity (p=0.002). During EXP, we recorded an elevated heart rate, indicating heightened arousal, particularly in young horses (p=0.005) and when using a bridle with a bit (p=0.024). Our findings suggest that rein tension can induce mild stress, potentially enhancing the learning process. A better understanding of these effects could improve training practices for equids welfare.
... The high proportion of WTS calves exhibiting a positive emotional state and high excitability may have been triggered by the receipt of a reward (e.g., tactile stimulation) or a motivational state [49,50], characterized by signals indicating that the body is returning to equilibrium [49]. Alternatively, these responses could be attributed to a "searching state", an emotion linked to the activation of one of the brain's basic emotional circuits, present from the first day of life and critical for survival [51]. ...
This study aimed to evaluate the effects of tactile stimulation on calf welfare. A total of 54 Nellore calves were assessed, with 28 of them receiving tactile stimulation (WTS) for ~60 s and 26 serving as a control. Five body movements and seven facial expressions were scored. Heart rates (HRs) were recorded in three situations: when the calves were placed in lateral recumbency (HR1), during identification procedures (HR2), and after completion of identification procedures (HR3). The differences between HR3 and HR1, as well as HR3 and HR2 were calculated. Initial and weaning weights were recorded, and ADG and weaning weights adjusted to 240 days were determined. Tactile stimulation significantly influenced “head movements”, “third eyelid” exposure, “eye-opening”, and “strained nostrils”. Except for “strained nostrils”, WTS calves exhibited higher scores in these behavioral categories. Treatment also influenced the difference between HR3 and HR2 (p < 0.05) and showed a trend for HR3 and the difference between HR3 and HR1 (p < 0.06). A qualitative behavior assessment (QBA) was applied using facial expressions. Two main principal components were identified, PC1 explaining 63.01% of the data variance and reflecting the calves’ emotionality, and PC2 explaining 19.88% and reflecting excitability. Most WTS calves displayed positive emotional states and high excitability, whereas most NTS calves exhibited the opposite. Treatment did not significantly impact PC1 and PC2 indexes and long-term performance indicators (p > 0.05). We conclude that tactile stimulation of newborn Nellore calves during their initial handling has the potential to enhance their short-term welfare, but only to a limited extent.
... This is particularly true for studies of the lateral and basal nuclei of the amygdala (LA/B), a crucial brain region for integrating sensory, salience and valence (aversive and rewarding) information [11][12][13][14][15][16][17][18][19][20][21] to produce behavioral repertoires representing defensive and appetitive forms of emotional learning and memory [22][23][24][25][26] . Prominent theories suggest that emotions can be defined in a 2-dimensional framework superimposed along salience and valence axes [27][28][29] . While LA/B neurons encode these features, whether there are identified cell types that serve unique aversive, rewarding or salience functions is unclear. ...
Neurons communicate information across circuits and the function of cells in these circuits is determined by both the afferent inputs they receive and the efferent outputs they send to other brain regions 1,2 . To study the activity and function of specific neuronal populations, transneuronal anterograde ³ and retrograde 4–6 viral approaches have been employed to define neural circuit elements by inputs or outputs, respectively. However, what is missing is a way to study the function of neurons based on both their inputs and outputs. Applying a combination of multiple recombinases and transneuronal anterograde/retrograde viruses, we developed a technique called input-output P rojection-based IN tersectional C ircuit-tagging E nabled by R ecombinases (PINCER) to target specific neuronal cell types and investigate functional input-output organization in neural circuits. We show the logic and application of this technique with in vivo calcium imaging and optogenetic approaches to reveal the distinct functions and neural dynamics of connectivity defined neuronal populations in the amygdala for emotional processing. Specifically, PINCER allowed the parsing of valence and salience functions of the amygdala to reveal an input-output cell type selectively mediating aversive memory formation. This technique allows neuroscientists to identify novel subclasses of cells based on their combinatorial input-output anatomical connectivity, providing a tool for fine dissection of the functional properties of neural circuits.
... Unlike previously employed physiological and behavioural measurements, CJB tests allow the objective assessment of both negative and positive affect 15,17 . Additionally, CJB distinguishes between emotion and arousal, whereas physiological measures such as corticosterone levels may not; for example, distinguishing between arousal from excitement or arousal from fear 18,19 . A landmark test in the CJB field was developed for rodents by Harding et al., in which rats were trained to press a lever to receive reward when one tone was played, withhold response to avoid white noise when a different tone was played, and were subsequently assessed on their response rate to ambiguous, untrained tones 20 . ...
Cognitive judgement bias (CJB) refers to the interpretation of ambiguous stimuli in a negative (pessimistic) or positive (optimistic) way. Negative CJB is observed in depression and anxiety, conditions that burden affected individuals and their caregivers. Pre-clinical animal research is key to understanding CJB and developing therapies for affective and anxiety disorders, so a translationally relevant CJB test would be a useful addition to the existing pre-clinical rodent touchscreen test battery. Here, a CJB task in mouse touchscreen operant chambers was adapted and validated using pharmacological agents, bupropion and tetrabenazine, known to induce positive and negative CJB, respectively. Further, negative shifts in CJB were observed following an injection procedure (handling and intraperitoneal injection with a saline solution), demonstrating the sensitivity of the task. Interestingly, whereas social isolation has been linked to changes in affective state in humans, 8 weeks of single-housing in mice did not alter CJB but did induce anxiety-like behaviour in an open field. Collectively, these results present a validated task to assess CJB in mice, which will facilitate future explorations into the underlying neurobiology and potential treatment of affective and anxiety disorders.
... Alternatively, despite hair cortisol generally being used as a measure of chronically impaired welfare (Heimbürge et al., 2019), concerns exist regarding its validity (Linstädt et al., 2024). Specifically, in the sense that cortisol levels can reflect overall arousal, but cannot assess valence (Mendl et al., 2010;Iyasere et al., 2022). In line with this, positive reinforcement training (which was used during the training process in the current study) has been associated with increased anticipatory behavior (Heinsius et al., 2024), behavioral changes (Meagher et al., 2020), and heart rate (Hagen and Broom, 2004) in cattle. ...
... JBTs have been used as a marker of affective state in studies of dogs experiencing situations likely to generate negative states, finding, for example, that separation-related behaviour is associated with a 'pessimistic' judgement bias [10,11], as is training using aversive methods [12]. There is also evidence that, in dogs with separation-related behaviours, pharmacological treatment can reverse 'pessimistic' decision-making under ambiguity [13], and that more 'optimistic' decisions are observed in dogs administered oxytocin, which is thought to induce a relatively positive state [14], and after an olfactory enrichment programme [15,16]. ...
Medical detection dogs search for diseases from remote samples (biodetection) and assist patients with chronic conditions (medical alert assistance). There is scarce information on how dogs’ decision-making tendencies relate to task performance. This study explored the relationships between medical detection dog demographics, responses in a behavioural test battery, ‘optimistic’ or ‘pessimistic’ decisions in a judgement bias task, and their performance in detection tasks. A sample of 58 trainee and trained medical detection dogs were studied in a Go/NoGo spatial judgement bias test. For trainee dogs (n = 39), training outcome (pass/fail) and trainer ratings of behavioural traits; yielding a composite score of ability in detection tasks, were used as markers of task performance. For trained biodetection dogs (n = 27), scent sensitivity and specificity scores derived during training and testing trials were used. Older dogs (p < 0.001), those showing higher ‘Confidence’ (p = 0.009), ‘Food orientation’ (p = 0.014) and ‘Playfulness’ (p = 0.005) in the test battery, and those who made more ‘optimistic’ decisions in the judgement bias task (p = 0.002), had higher detection task ability scores. For trained dogs, latency to approach ambiguous stimuli was positively correlated with scent specificity levels (n = 25, p = 0.021), suggesting that more ‘pessimistic’ dogs tended to be more specific. Our findings suggest relationships between behaviour in judgement bias tests and other learning and discrimination tasks, which may reflect underlying individual or personality differences in affective and/or cognitive processes that influence dogs’ style of searching and performance ability in medical detection tasks. Future research is needed to explore these associations further and investigate the value of judgement bias tasks in predicting later search performance in medical and other types of search dogs.
... Vocal signals play an essential role in alerting conspecifics and promoting survival [1,2] by effectively conveying warnings, especially in environments where visibility is limited. One common strategy to intensify exogenous sensory perception and ensure powerful reactions in the listener is screaming. ...
The propensity to communicate extreme emotional states and arousal through salient, non-referential vocalizations is ubiquitous among mammals and beyond. Screams, whether intended to warn conspecifics or deter aggressors, require a rapid increase of air influx through vocal folds to induce nonlinear distortions of the signal. These distortions contain salient, temporally patterned acoustic features in a restricted range of the audible spectrum. These features may have a biological significance, triggering fast behavioural responses in the receivers. We present converging neurophysiological and behavioural evidence from humans and animals supporting that the properties emerging from nonlinear vocal phenomena are ideally adapted to induce efficient sensory, emotional and behavioural responses. We argue that these fast temporal—rough—modulations are unlikely to be an epiphenomenon of vocal production but rather the result of selective evolutionary pressure on vocal warning signals to promote efficient communication. In this view, rough features may have been selected and conserved as an acoustic trait to recruit ancestral sensory salience pathways and elicit optimal reactions in the receiver. By exploring the impact of rough vocalizations at the receiver’s end, we review the perceptual, behavioural and neural factors that may have shaped these signals to evolve as powerful communication tools.
This article is part of the theme issue ‘Nonlinear phenomena in vertebrate vocalizations: mechanisms and communicative functions’.
... Affective signaling and communication between conspecifics contribute to inclusive fitness by facilitating coordination and cohesion, increasing defense against predators, and bonding individuals to one another within a social group. It is a widespread phenomenon in a great many species (Mendl et al., 2010). Discriminating and communicating emotions to conspecifics (at least the main dimensions of valence and intensity) allows the facilitation and the regulation of social interactions. ...
The Cambridge Handbook of Moral Psychology is an essential guide to the study of moral cognition and behavior. Originating as a philosophical exploration of values and virtues, moral psychology has evolved into a robust empirical science intersecting psychology, philosophy, anthropology, sociology, and neuroscience. Contributors to this interdisciplinary handbook explore a diverse set of topics, including moral judgment and decision making, altruism and empathy, and blame and punishment. Tailored for graduate students and researchers across psychology, philosophy, anthropology, neuroscience, political science, and economics, it offers a comprehensive survey of the latest research in moral psychology, illuminating both foundational concepts and cutting-edge developments.
... Indeed, her observation that (at least many) animals experience the world with affective valence is a mainstream belief within the realm of animal welfare science. The premise here is to defer focus on particular, discrete emotions in favor of characterizing the core affect of a sensation by charting it along the axes of valence and arousal [25]. So, rather than say that an animal is joyful, one might say that it demonstrates an affect with positive valence and high arousal. ...
The prospect of shared decision-making with animals is an elusive one. Its elusiveness comes largely from how difficult it is to assess the linguistic abilities of animals, whether that be their ability to ‘speak’ or their ability to maintain propositional values. In this paper, I suggest a path to shared decision-making with animals that attempts to avoid these deadlocks by using resources from biosemiotics and Umwelt theory. I begin with an examination of the general structure of decision-making, demonstrating its future-orientation, comparison of imagined futures, and assessment of what things matter to participants in decision-making. Animals’ capability of having things matter to them, due to their residence in Umwelten, offers a means to shared decision-making with animals via a process I call ‘imaginative adjuncting.’
... Secondly, for ease of processing, many studies simplify the continuous emotion model into a classification problem by dividing emotions into four quadrants based on the positive or negative values of valence and arousal [4]. While this simplification reduces operational complexity, it overlooks the multidimensionality of musical emotions and blurs fine-grained emotional distinctions [5,6]. Furthermore, since the continuous model is not specifically designed for music emotions, datasets partitioned based on it often exhibit imbalances, with certain quadrants containing significantly less data than others [7]. ...
This study introduces a large-scale, multilingual, and multi-label dataset for Music Emotion Recognition (MER), addressing key limitations in existing resources. Notably, it represents the largest MER dataset to date that incorporates Chinese, offering rich information such as lyrics and metadata. By leveraging user-generated playlist tags from music platforms, the dataset captures diverse emotional attributes using a probabilistic framework across 12 emotion categories, with both discrete and continuous representations. Extensive experiments with various baseline models validate the dataset’s effectiveness, particularly in recognizing complex emotional patterns. A detailed analysis further investigates the influence of annotator quantity and quality on data reliability, demonstrating that increasing annotator numbers and enhancing their expertise improve label consistency and mitigate noise. This dataset serves as a valuable resource for advancing MER research and supports practical applications, including music recommendation and emotion analysis.
... How animals perceive their world is a crucial and ethically relevant question because their perception of environmental stimuli can be either more or less positive or negative. Perception can depend on the valence of an individual's underlying mood, i.e., long-lasting affective state arising from the accumulation and integration of short-lasting emotions in response to specific stimuli [2,3]. Positive mood depends on internal physiological balance, a satisfaction of behavioural needs, an absence of negative emotions, and the presence of positive emotions [4]. ...
Animal-assisted interventions (AAIs) have become increasingly popular, with horses being one of the most commonly used species. While the effects of equine-assisted interventions (EAIs) have been widely studied in humans, research focusing on animals involved in such work is limited. Understanding how animals perceive their world is ethically important because their perception reflects the valence of their underlying mood. We investigated the cognitive judgement bias (pessimistic vs. optimistic) and perception of humans (negative vs. positive) in horses from three different facilities, divided into two groups: horses involved only in riding school lessons (RS, N = 14) and horses participating in both riding school and EAI lessons (EAI-RS, N = 16). We hypothesised that horses engaged in both types of work would be more negatively impacted than RS horses because the two activities may be demanding. No significant effects of work on pessimistic bias and negative perception of humans were found. However, a modulating effect was found in the interaction between work type and facility management. These findings highlight the impact of both the type of work and facility management on the cognition and underlying affective states of EAI-RS horses.
... These interventions and their specific hypothesis are detailed in Table 1. While the focus of the study was on the contextual intervention, emotional experiences are discussed around the arousal and valence model 37 . Valence, which indicates the level of pleasantness of the intervention, was not specifically measured in this experiment but it is generally considered negative for isolation (as horses prefer the company of conspecifics 38 ) and nociception 32 . ...
Facial expressions in prey animals such as equines can convey information regarding their internal state and are therefore often used as cues for welfare and pain evaluation. The state of pain is commonly compared to a neutral state with little consideration given to other experiences that could affect the animal, although this situation is rare outside of experimental contexts. To evaluate the effect of managerial contexts on facial expressions from a nociceptive input, conspecific isolation and sedation with known physiological effects were compared to compound states of nociception. Using an anatomically based facial action coding system and a short acting pain model, patterns of facial activity could discriminate between horses experiencing conspecific isolation, sedation, and a nociceptive stimulus separately. Nociception occurring together with conspecific isolation could not be discriminated from the conspecific isolation alone, and compound nociception and sedation could not be discriminated from control. While blinking frequency demonstrated potential to be a valuable marker when evaluating a nociceptive stimulus in sedated horses, careful consideration must be given to the biological interpretation of facial expressions during situations where managerial or drug effects may be present.
Supplementary Information
The online version contains supplementary material available at 10.1038/s41598-025-89329-x.
... The model in this study excelled in detecting "Happy" emotions, likely due to distinct visual cues such as playful postures and relaxed appearances, as reported in studies like those of Boneh-Shitrit et al. [6] and Bhave et al. [11], where clear positive expressions are easier to identify than subtle or overlapping emotions such as sadness or fear. The struggles with "Angry" and "Sad" classifications underscore the limitations of generic models in distinguishing subtle emotional markers, echoing the findings of Mendl et al. [20] on the importance of context and dimensional approaches in emotion analysis. ...
Animal emotion detection has emerged as a critical domain in understanding animal welfare and enhancing human–animal interactions. This study evaluates the performance of GPT-4, a generative AI model, in recognizing and classifying pet emotions from images, with a particular focus on dogs. The research was conducted in two phases: a general pet emotion classification across multiple species and a dog-specific classification. In Phase 1, GPT-4 achieved an overall accuracy of 50.2%, reflecting its baseline capability in handling diverse animal images. In Phase 2, accuracy significantly improved to 76.7% due to refined prompts and the use of a targeted dataset. Sentiment analysis of the model’s textual justifications revealed alignment with visual cues in correct predictions and highlighted challenges in ambiguous cases. These findings demonstrate the potential of generative AI in animal emotion detection and emphasize the importance of targeted datasets and advanced prompt engineering. This study contributes to bridging the gap between AI capabilities and practical applications in animal welfare and behavioral research.
... The defined area was the ear base of both sides, left and right. The emotions of animals are regarded to consist of two dimensions, i.e., valence (an emotion is positive or negative) and arousal (intensity of the emotion) [39][40][41]. Skin temperature can likely be used as an indicator of valence and arousal in both humans and animals [42][43][44]. When aroused by a stimulus, the activation of the sympathetic branch of the autonomic nervous system leads to peripheral blood vessels to constrict in order to direct blood and, thereby, energy and oxygen to the core of the body where it is needed [45,46]. ...
Using deep learning or artificial intelligence (AI) in research with animals is a new interdisciplinary area of research. In this study, we have explored the potential of thermal imaging and AI in pig research. Thermal cameras play a vital role in obtaining and collecting a large amount of data, and AI has the capabilities of processing and extracting valuable information from these data. The amount of data collected using thermal imaging is huge, and automation techniques are therefore crucial to find a meaningful interpretation of the changes in temperature. In this paper, we present a complete pipeline to extract temperature automatically from a selected Region of Interest (ROI). This system consists of three stages: the first one checks whether the ROI is completely visible to observe the thermal temperature, and then the second stage uses an encoder–decoder structure of a convolution neural network to segment the ROI, if the condition was met at stage one. In the last stage, the maximum temperature is extracted and saved in an external file. The segmentation model showed good performance, with a mean Pixel Class accuracy of 92.3%, and a mean Intersection over Union of 87.1%. The extracted temperature observed by the model entirely matched the manually observed temperature. The system showed reliable results to be used independently without human intervention to determine the temperature in the selected ROI in pigs.
... Nevertheless, interest in searching for and evaluating positive mental states, such as joy and relaxation, has been rising (e.g [1,4,[32][33][34][35][36]). Animals' mental states may be indicated by changes in behaviour, cognition and physiology [37]. For instance, optimistic cognitive judgement biases, hypothesized to reflect positive mental states [38], have been reported across taxa ranging from mammals to eusocial insects [39,40]. ...
The concept of animal welfare is evolving due to progress in our scientific understanding of animal biology and changing societal expectations. Animal welfare science has been primarily concerned with minimizing suffering, but there is growing interest in also promoting positive experiences, grouped under the term positive animal welfare (PAW). However, there are discrepancies in the use of the term PAW. An interdisciplinary group arrived at a consensus that ‘PAW can be defined as the animal flourishing through the experience of predominantly positive mental states and the development of competence and resilience. PAW goes beyond ensuring good physical health and the prevention and alleviation of suffering. It encompasses animals experiencing positive mental states resulting from rewarding experiences, including having choices and opportunities to actively pursue goals and achieve desired outcomes’. The definition also considers individual and species-specific differences. It provides a framework for researchers to investigate PAW and thereby generate innovative, informative and reproducible science. Studies of PAW can contribute to a richer picture of an animal’s life and may elucidate the biological foundations of happiness. The definition creates opportunities to inspire scientific progress in animal biology and to align animal care practices, legislation and markets with societal expectations.
... At a more applied level, the impact of the design of housing and equipment [18] and management practices [19] on behaviour has long been investigated to better meet the needs of animals and enhance their welfare. The more recent approach of including affective states as an essential part in the welfare status of the individual has given rise to the development of behavioural tests to better understand animal emotion [20][21][22]. Overall, the importance of behaviour and applied ethology to understand, assess, and improve animal welfare has increased over time and expanded to new disciplines of knowledge. This Special Issue is a collection of papers encompassing different species and targeting different aims in which behaviours are a key element in the assessment of or improvement in animal welfare, including both the avoidance of negative experiences and promotion of positive affective states. ...
The papers in this Special Issue, entitled “Editorial Board Members’ Collection Series: Behaviour, Applied Ethology and Welfare of Farmed Animals”, bring to the forefront empirical data and theoretical discussions that contribute to the discussion of contemporary issues, from environmental enrichment to improvements in animal welfare, the intensification of animal rearing systems, and innovations like virtual fencing and dietary adjustments to improve animal health and welfare in organic systems [...]
Successive negative contrast (SNC) is a decrease in response when animals unexpectedly face reward devaluation to levels below those of animals always receiving low-value rewards. SNC appears to be influenced by background affective states and has thus been proposed as a tool for assessing animal welfare. While reported in several mammal species, findings of SNC in dogs ( Canis lups familiaris ) have been inconsistent. This study aimed to investigate the suitability of SNC to assess affective states in dogs. For this purpose, it is important that the test can be consistently used across populations, and we therefore tested the reaction to reward devaluation in laboratory, shelter, and owned dogs (n = 12 per population). After assessing individual food preferences, reward devaluation tasks were performed where animals first solved a puzzle toy for high-value rewards (pre-shift), then for low-value rewards (post-shift), and again for high-value rewards (re-shift). Results showed that shelter dogs and three owned dogs removed fewer cones of the puzzle, ate fewer rewards, and took longer to complete the task (remove all cones) in the post-shift phase compared to pre- and re-shift phases. Conversely, no reduction in number of cones removed nor in number of rewards eaten was found for laboratory and the remaining nine owned dogs. The behaviour of the first group (response reduction following reward devaluation) is consistent with SNC, whereas the behaviour of the second (no change in behaviour after reward devaluation) is not. The inconsistency of SNC within and across dog populations raises questions regarding its suitability for evaluating dog welfare.
Veterinary behavioural medicine is undergoing a significant shift. Although psychopharmacology has become more accessible and frequently utilized, its application often remains reactive, inconsistent, and lacking the systematic approach required for complex behavioural cases [1]. The assumption that a diagnosis alone justifies medication must be questioned—particularly within a system that often encourages early prescribing yet seldom incorporates structured follow-up.
A more effective approach integrates a systems-thinking model for behavioural medication decisions, prioritizing three key elements: the dog’s neurobiology, caregiver involvement, and measurable behavioural indicators. Instead of rigid protocols, this model emphasizes adaptable decision-making principles. It advocates for shared responsibility between veterinarians and owners, precise timing in medication use, and strategic clarity—transforming medication from a temporary fix into a carefully aligned tool that works in harmony with the dog’s physiology.
This perspective challenges the current norms, urging a re-evaluation of when and how behavioural medication is prescribed. The goal is to ensure it genuinely supports lasting behavioural change rather than serving as an automatic or isolated intervention. By refining prescribing practices, veterinary professionals can better align medication with long-term behavioural outcomes.
Automated analysis of facial expressions is a vibrant field in human affective computing, while research in nonhuman animals is still in its early stages. Compared to labor-intensive manual coding, automation can provide a more reliable and objective alternative, eliminating subjectivity and bias. However, using automated approaches of facial analysis in nonhuman animals ''in the wild”, i.e. outside of controlled laboratory conditions, is a challenge given the nature of noisy datasets. Here we present the first study using a fully automated analysis of facial landmarks associated with different emotional states in a morphologically diverse sample of pet dogs. We applied a novel AI-pipeline to study fear expressions of dogs in their home environment, analysing owner-provided video recordings during a real-life firework situation on New Year’s Eve in comparison to a control evening without fireworks. Using a static geometric morphometrics-inspired analysis, the pipeline allows for quantifying dog facial expressions in an extremely noisy and diverse ''in the wild” dataset, encompassing various breeds, angles and environments. We used an automated facial landmark system of 46 dog facial landmarks based on the Dog Facial Action Coding System. Due to the great variety in morphology of the included dogs, landmarks denoting the ear pinnae were excluded. Nonetheless, landmarks relating to the base of the ears differentiated most strongly between the conditions, suggesting backwards-drawn ears as the best indicator of the firework condition, which is in agreement with manually coded data. Additionally, the firework condition was associated with more mouth-opening, possibly reflecting panting in a subset of dogs. We conclude that automated analysis of dog facial expressions, based on the previously validated landmark system, is feasible in a diverse sample of pet dogs, paving the way towards automated emotion detection.
This study develops a novel automated method for measuring continuous dynamics of dog facial behavior based on video-based tracking of 46 facial landmarks grounded in the Dog Facial Action Coding System. This method is applied for comparing the facial behavior of (n1=7) brachycephalic (Boston Terrier) and (n2=7) normocephalic (Jack Russel Terrier) dogs in four different contexts, eliciting various inner states: positive (play and called by name) and negative (separation and stranger). Having objectively quantified facial dynamics in brachycephalic and normocephalic dogs, we have found that brachycephalic dogs exhibited consistently lower facial dynamics across all four tested contexts and facial regions (eyes, mouth, and ears) compared to normocephalic dogs. They further demonstrated relatively higher dynamics in positive play and negative stranger conditions than in the other two conditions. In contrast, normocephalic dogs showed elevated dynamics exclusively in the positive play condition, with significantly reduced dynamics in the negative stranger condition. These findings highlight distinct patterns of facial expressivity between the two morphological groups, suggesting decreased facial expression in brachycephalic dogs and demonstrating our method's value in providing novel insights into canine communication.
An animal's behaviour and its state, including its health and affective state, are dynamic and tightly coupled, influencing each other over time. Although both are relevant to the animal's welfare, there has been limited research on their dynamics in welfare studies. Here we aim to: ( i ) review evidence for feedbacks between state and behaviour that could have beneficial or detrimental consequences for farm animal welfare; ( ii ) propose ways in which an understanding of such feedbacks could be used to enhance welfare; and ( iii ) provide practical guidance. We include as state variables any features that could influence the costs and benefits of an animal's behavioural actions, including individual characteristics and aspects of its social environment. We find evidence supporting positive state–behaviour feedback loops in various livestock species, suggesting that these loops could be common in farm settings and have significant welfare implications, such as leading to abnormal behaviours and persistent negative affective states. We suggest ( i ) estimating within‐individual feedback loops to extract individual characteristics for studying differences in welfare; ( ii ) identifying scenarios where change accelerated by positive feedbacks pushes an animal (or a group of animals) to a new state, also called tipping points; and ( iii ) generating positive feedback loops to elicit and maintain positive affective states. We end by encouraging use of dynamic models that integrate longitudinal data on animals' behaviour and state to enable exploration of their dynamics, and we provide a practical guide with annotated R code for support. Since the principles and ideas discussed here are relevant to any animals under human care, this approach could foster new perspectives for improving the welfare of all captive animals.
Recognition and interpretation of dogs’ emotional and motivational states from visual behavioural signs are important for public safety and dog welfare. This study used an online survey to explore the ability of members of the public (n = 4,133) to recognise the underlying emotional or motivational states of dogs in silent videos (n=30). Participants scored each video for nine pre-determined emotional and motivational states on a scale from 0 to 15 and rated the relative difficulty of scoring each video. Participants could also select “I am uncertain” for individual states which translated to missing values. Public scores were compared with those of eleven dog behaviour experts. The states “nervous/anxious”, “stressed”, “relaxed”, “comfortable”, “playful”, “interested/curious”, “excited”, and “frustrated” showed high inter-expert agreement and were used in further analysis. “Boredom” was removed due to low inter-expert agreement. Principal components and cluster analyses on both datasets were used to collapse categories into two dimensions, identify groupings and compare overall perception. Results indicate similarity in perception of underlying states between public and experts. Correlation between expert difficulty rating, and both inter-expert agreement and public accuracy, indicates that experts effectively assessed the relative difficulty of determining underlying state. Members of the public perceived playful, excited, and curious dogs as easier to interpret than anxious and stressed dogs; however, this was not reflected in how accurately they scored videos (i.e., how different a participant’s scores were from the expert scores) and instead was reflected by how likely a participant was to score a video in full, rather than selecting that they were “uncertain” in response to any of the listed states. Findings of this study inform human behaviour change interventions to improve public interpretation of dog emotional and motivational states.
Stalls (or crates) are still a common type of housing in the swine industry, despite public concern and regional legislation restricting their use. In this study, we examined the motivation of gilts to exit a stall. Sixteen stall-naïve gilts (Large White x Landrace) were locked for 60 min in a gestation crate that had been mounted with a novel apparatus allowing continuous monitoring (2 Hz measuring frequency) of the force applied to its back gate by the animal. Raw force measurements were low-pass filtered and discrete pushing events identified via local maxima. All gilts displayed some level of motivation to exit the crate, ranging from 41 to 173 in the number of pushing events, as well as exerting a maximum force applied from 124 to 645 N. A hierarchical cluster analysis applied to the median and interquartile range (IQR) of force generated during individual pushing events yielded two behavioural profiles. One group of eight animals was more active than the other. This group exhibited a greater number of pushes, recorded a higher maximum, median force and its IQR, as well as a shorter time interval between two pushes (all t-tests with a P < 0.05). While all these naïve animals worked to leave the stall, gilts displayed different motivation profiles in trying to exit the stall consistent with a reactive/proactive framework. Taken together these findings provide further evidence to support stall confinement as aversive to swine but highlight the complexities in understanding and improving pig welfare.
The welfare of an animal is closely linked to their emotional experiences, making it essential to identify reliable indicators of these emotions. This study aimed to identify behaviours and facial movements in horses experiencing contrasting emotional valence, triggered by the anticipation of a positive condition (going to pasture) or a negative condition (going alone to a novel environment). Twenty horses were daily trained to wait in a starting box before being exposed to these two conditions. After one week of positive training or negative training, we analysed horses' behaviours, cortisol variations, and facial movements while they waited in their starting box. First, we confirmed that the two conditions induced contrasting emotional valence, as evidenced by the shorter time taken to approach in the positive condition compared to the negative, and by the higher maximal heart rate and cortisol variation in the negative condition. Then using the Equine Facial Action Coding System (EquiFACS) and network analysis (NetFACS) we revealed distinct behaviours and facial expression profiles. In positive anticipation, the horses exhibited a greater range of behaviours, including shaking their heads from side to side, stepping back, sniffing, and pawing at the ground. Additionally, two distinct facial expression profiles were identified as specific to positive and negative anticipation. In positive anticipation, the horses displayed a higher neck, accompanied by a greater frequency of half-blinks and mouth movements. Conversely, in negative anticipation, the horses exhibited a medium neck, with ears backward accompanied by more flattened ears and expressed more nostril movements. The findings highlight the importance of these indicators in characterising horses' emotions and emphasize their significance for assessing equine welfare.
Improving the quality of life of captive animals is dependent on developing valid measures of how animals feel about their lives. It has recently been suggested that biases in information processing may offer a novel means of understanding animal emotions. Anxious and depressed people tend to interpret ambiguous information negatively. We explored the proposal that such cognitive biases also exist in non-human animals and could therefore be used as novel measures of animal welfare. We used a novel cognitive bias task based on a learnt taste aversion to determine whether birds deprived of environmental enrichment show biases in their classification of ambiguous signals. We hypothesised that starlings in enriched cages should be more likely to classify ambiguous signals as being associated with a positive outcome than starlings housed in standard, unenriched cages. Starlings were trained on a go/no-go procedure to discriminate between two visual stimuli (cardboard lids of white and dark grey) associated with outcomes of a different value (palatable and unpalatable mealworms hidden underneath). Individual birds' responses to unreinforced, intermediate stimuli (various shades of grey between white and dark grey) were subsequently examined while each bird was housed sequentially in both standard and enriched cages. The probability of a bird classifying an ambiguous pale grey lid as hiding a palatable mealworm was lower in standard cages than enriched cages, but this difference was found only in birds that received enriched cages first. Our results can be interpreted as showing a pessimistic bias in birds that have recently experienced a decline in environmental quality. These findings support the use of cognitive bias-based tasks as a novel, non-invasive technique for assessing welfare in non-human animals.
Discussions of the dimensional structure of affect usually are based on results of factor analyses. Disagreements focus largely on issues of measurement and measurement er - ror. I argue that the structure of affect is not discussed meaningfully without considering functional implications of affects. A functional analysis is outlined in which approach and incentive-related affects (both positive and negative) are managed by 1 self-regula - tory system, and avoidance and threat-related affects (positive and negative) are man - aged by another self-regulatory system. In both cases, positive and negative affects are posited to convey information about whether the behavior being engaged in is going well or poorly. This view argues for the existence of 2 bipolar affective dimensions, the properties of which are informed by an understanding of both behavior and feelings. Transient affective experience is marked by a hedonic quality—a valence, a sense of positivity or negativity. How is this hedonic quality properly conceptualized? Is there a single bipolar dimension, ranging from positive to negative? Are there two distinct dimensions, one ranging from zero valence to a strong positive valence, the other ranging from zero to a strong negative valence? Are there two distinct dimensions, both of them bipolar? A set of more basic questions lies behind the attempt to answer the ones just posed: How should researchers and theorists go about deciding what conceptualization is best? What criteria should be satisfied by a candidate model? The primary strategy over several decades has been to ex- amine the factor structure of diverse affective qualities. In this article, I argue that that strategy is insufficient in itself, and it may even be misleading in some respects.
Accurate assessment of animal emotion (affect) is an important goal in animal welfare science, and in areas such as neuroscience and psychopharmacology. Direct measures of conscious emotion are not available, so assessment of animal affect has relied on measures of the behavioural and physiological components of affective states. These are important indicators but have some limitations (e.g. measuring emotional arousal rather than valence (positivity vs negativity)). Human psychology research suggests that changes in cognitive function (information processing) can also be reliable indicators of emotional state (especially valence). For example, people in negative states attend to threats, retrieve negative memories, and make negative judgements about ambiguous stimuli more than happier people. Here we review a new research area investigating the possibility that such affect-induced ‘cognitive biases’ also occur in animals. We focus on a novel ‘judgement bias’ paradigm in which animals are trained that one cue predicts a positive event and another cue predicts a less positive/negative event, and are then presented with ambiguous (intermediate) cues. The hypothesis is that animals in a negative affective state will be more likely to respond to (‘judge’) these ambiguous cues as if they predict the negative event (a ‘pessimistic’ response), than animals in a more positive state. Recent studies of rats, dogs, rhesus monkeys, starlings and humans provide face-value support for this hypothesis. We discuss the strengths and weaknesses of the affect manipulation treatments used in these studies, and the possibility that treatment-induced changes in feeding motivation, general activity and learning are responsible for the effects observed, and we consider whether the type of bias observed and the precise design of the judgement bias task can provide information about different types of affective state. Judgement biases may result from the influence of affect on decision-making processes including attention to and perception of the ambiguous cue, evaluation of the value and probability (expected utility) of the outcomes of different responses, and action selection. Affect might also modulate general tendencies of loss, risk and ambiguity aversion, hence biasing decisions. We discuss these possibilities in relation to theory and findings from neurobiological and psychological studies of decision-making, in order to better understand the potential mechanisms underlying judgement biases. We conclude with some specific recommendations for study design and interpretation, and suggestions for future research in this area.
The present study presents a replication and methodological extension of MacLeod, Tata, Kentish, and Jacobsen (1997) with a nonclinical sample, using future-directed imagery to assess prospective cognitions. Results showed that only anxiety (but not depression) was related to enhanced imagery for future negative events. Both anxiety and depression showed significant zero-order correlations with reduced imagery for future positive events. However, when the overlap between anxiety and depression was controlled for, only depression (but not anxiety) showed a unique association with reduced imagery for positive events. Implications of these findings for cognitive models of anxiety and depression are discussed.
Investigated, in 2 experiments, whether judgments of happiness and satisfaction with one's life are influenced by mood at the time of judgment. In Exp I, moods were induced by asking 61 undergraduates for vivid descriptions of a recent happy or sad event in their lives. In Exp II, moods were induced by interviewing 84 participants on sunny or rainy days. In both experiments, Ss reported more happiness and satisfaction with their life as a whole when in a good mood than when in a bad mood. However, the negative impact of bad moods was eliminated when Ss were induced to attribute their present feelings to transient external sources irrelevant to the evaluation of their lives; but Ss who were in a good mood were not affected by misattribution manipulations. The data suggest that (a) people use their momentary affective states in making judgments of how happy and satisfied they are with their lives in general and (b) people in unpleasant affective states are more likely to search for and use information to explain their state than are people in pleasant affective states. (18 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The affect system has been shaped by the hammer and chisel of adaptation and natural selection such that form follows function. The characteristics of the system thus differ across the nervous system as a function of the unique constraints existent at each level. For instance, although physical limitations constrain behavioral expressions and incline behavioral predispositions toward a bipolar (good–bad, approach–withdraw) organization, these limiting conditions lose their power at the level of underlying mechanisms. According to the authors' model of evaluative space (J. T. Cacioppo & G. G. Berntson, 1994; J. T. Cacioppo, W. L. Gardner, & G. G. Berntson, 1997), the common metric governing approach–withdrawal is generally a single dimension at response stages that itself is the consequence of multiple operations, such as the activation function for positivity (appetition) and the activation function for negativity (aversion), at earlier affective processing stages. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
D. Watson and A. Tellegen (1985) proposed a "consensual" structure of affect based on J. A. Russell's (1980) circumplex. The authors' review of the literature indicates that this 2-factor model captures robust structural properties of self-rated mood. Nevertheless, the evidence also indicates that the circumplex does not fit the data closely and needs to be refined. Most notably, the model's dimensions are not entirely independent; moreover, with the exception of Pleasantness–Unpleasantness, they are not completely bipolar. More generally, the data suggest a model that falls somewhere between classic simple structure and a true circumplex. The authors then examine two of the dimensions imbedded in this structure, which they label
Negative Activation (NA) and
Positive Activation (PA). The authors argue that PA and NA represent the subjective components of broader biobehavioral systems of approach and withdrawal, respectively. The authors conclude by demonstrating how this framework helps to clarify various affect-related phenomena, including circadian rhythms, sleep, and the mood disorders. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Virtually all current theories of choice under risk or uncertainty are cognitive and consequentialist. They assume that people assess the desirability and likelihood of possible outcomes of choice alternatives and integrate this information through some type of expectation-based calculus to arrive at a decision. The authors propose an alternative theoretical perspective, the risk-as-feelings hypothesis, that highlights the role of affect experienced at the moment of decision making. Drawing on research from clinical, physiological, and other subfields of psychology, they show that emotional reactions to risky situations often diverge from cognitive assessments of those risks. When such divergence occurs, emotional reactions often drive behavior. The risk-as-feelings hypothesis is shown to explain a wide range of phenomena that have resisted interpretation in cognitive-consequentialist terms.
Many of the body's adaptive responses, such as pain, fever, and fear, are defenses that remain latent until they are aroused by cues that indicate the presence of a threat. Natural selection should shape regulation mechanisms that express defenses only in situations where their benefits exceed their costs, but defenses are often expressed in situations where they seem unnecessary, with much resulting useless suffering. An explanation emerges from a signal detection analysis of the costs and benefits that shaped defense regulation mechanisms. Quantitative modeling of optimal regulation for all-or-none defenses and for continuously variable defenses leads to several conclusions. First, an optimal system for regulating inexpensive all-or-none defenses against the uncertain presence of large threats will express many false alarms. Second, the optimum level of expression for graded defenses is not at the point where the costs of the defense and the danger are equal, but is instead where the marginal cost of additional defense exceeds the marginal benefit. Third, in the face of uncertainty and skewed payoff functions, the optimal response threshold may not be the point with the lowest cost. Finally, repeated exposures to certain kinds of danger may adaptively lower response thresholds, making systems vulnerable to runaway positive feedback. While we await quantitative data that can refine such models, a general theoretical perspective on the evolution of defense regulation can help to guide research and assist clinical decision making.
Affect is considered by most contemporary theories to be postcognitive,
that is, to occur only after considerable cognitive operations have
been accomplished. Yet a number of experimental results on preferences,
attitudes, impression formation, and decision making, as well as
some clinical phenomena, suggest that affective judgments may be
fairly independent of, and precede in time, the sorts of perceptual
and cognitive operations commonly assumed to be the basis of these
affective judgments. Affective reactions to stimuli are often the
very first reactions of the organism, and for lower organisms they
are the dominant reactions. Affective reactions can occur without
extensive perceptual and cognitive encoding, are made with greater
confidence than cognitive judgments, and can be made sooner. Experimental
evidence is presented demonstrating that reliable affective discriminations
(likedislike ratings) can be made in the total absence of recognition
memory (oldnew judgments). Various differences between judgments
based on affect and those based on perceptual and cognitive processes
are examined. It is concluded that affect and cognition are under
the control of separate and partially independent systems that can
influence each other in a variety of ways, and that both constitute
independent sources of effects in information processing. (139 ref)
(PsycINFO Database Record (c) 2009 APA, all rights reserved)
Negative cognitive bias-the tendency to interpret ambiguous situations pessimistically-is a central feature of stress-related disorders such as depression. The underlying neurobiology of this bias, however, remains unclear, not least because of a lack of translational tools. We established a new ambiguous-cue interpretation paradigm and, with respect to the etiology of depression, evaluated if environmental and genetic factors contribute to a negative bias. Rats were trained to press a lever to receive a food reward contingent to one tone and to press another lever in response to a different tone to avoid punishment by electric foot-shock. In the ambiguous-cue test, the lever-press responses to tones with frequencies intermediate to the trained tones were taken as indicators for the rats' expectation of a positive or negative event. A negative response bias because of decreased positive and increased negative responding was found in congenitally helpless rats, a genetic animal model of depression. Moreover, treatment with a combined noradrenergic-glucocorticoid challenge, mimicking stress-related changes in endogenous neuromodulation, biased rats away from positive responding. This response shift was accompanied by neuronal activation in dentate gyrus and amygdala. Thus, environmental and genetic risk factors for depression induce a response bias, which resembles the pessimistic bias of patients suffering from depression. The behavioral paradigm described constitutes a useful tool to study the neuronal basis of decision making under ambiguous conditions and may promote innovative pharmaco- and psychotherapy for depression.
Recently, there has been a convergence in lesion and neuroimaging data in the identification of circuits underlying positive and negative emotion in the human brain. Emphasis is placed on the prefrontal cortex (PFC) and the amygdala as two key components of this circuitry. Emotion guides action and organizes behavior towards salient goals. To accomplish this, it is essential that the organism have a means of representing affect in the absence of immediate elicitors. It is proposed that the PFC plays a crucial role in affective working memory. The ventromedial sector of the PFC is most directly involved in the representation of elementary positive and negative emotional states while the dorsolateral PFC may be involved in the representation of the goal states towards which these elementary positive and negative states are directed. The amygdala has been consistently identified as playing a crucial role in both the perception of emotional cues and the production of emotional responses, with some evidence suggesting that it is particularly involved with fear-related negative affect. Individual differences in amygdala activation are implicated in dispositional affective styles and increased reactivity to negative incentives. The ventral striatum, anterior cingulate and insular cortex also provide unique contributions to emotional processing.
The book links the analysis of the brain mechanisms of emotion and motivation to the wider context of what emotions are, what their functions are, how emotions evolved, and the larger issue of why emotional and motivational feelings and consciousness might arise in a system organized like the brain. The topics in motivation covered are hunger, thirst, sexual behaviour, brain-stimulation reward, and addiction. The book proposes a theory of what emotions are, and an evolutionary, Darwinian, theory of the adaptive value of emotion, and then describes the brain mechanisms of emotion. The book examines how cognitive states can influence emotions, and in turn, how emotions can influence cognitive states. The book also examines emotion and decision-making, with links to the burgeoning field of neuroeconomics. The book describes the brain mechanisms that underlie both emotion and motivation in a scientific form that can be used by both students and scientists in the fields of neuroscience, psychology, cognitive neuroscience, biology, physiology, psychiatry, and medicine.
Reinforcement Sensitivity Theory (RST) is composed of two main components: (a) a state description of neural systems and associated, relatively short-term, emotions and behaviours; and (b) a trait description of longer-term dispositions to such emotions and behaviours. McNaughton and Corr (chapter 2) outlined the state level of description; this chapter explores the trait level of description and takes a more general view of the problems posed by the revised Gray and McNaughton (2000) theory. ‘Top-down’ and ‘bottom-up’ approaches to personality The standard biological approach to personality adopts the well-established procedure from biology: first describe (taxonomy) and then explain (theorize about form of taxonomy; e.g., evolution). As noted by Gray (1972a, p. 372), ‘The study of personality is the attempt (a) to discover consistent patterns of individual differences and (b) to account for the form taken by these patterns.’ This ‘top-down’ approach has considerable merit and many empirical successes to its name. But it cannot be applied in a simple one-step fashion. Even within species and genera, taxonomy ((a) above) is not independent of causal theories ((b) above) – findings in molecular biology can alter taxonomy based on superficial description. With the study of personality it is a moot point whether the underlying variation in sensitivity of causal brain systems – which must control the psychological phenomena we classify under ‘personality’ – correspond in any obvious fashion to the manifest aspects of personality (i.e., factors, traits, facets, etc.).
Personality factors, as normally studied, are sources of variation that are stable over time and that derive from underlying properties of an individual more than current changes in their environment. They account for behavioural differences between individuals presented with identical environments that show consistent patterns within that individual across time. As such, an ultimate goal of personality research must be to identify the relatively static biological variables that determine the superficial factor structure evident in behaviour and other measures. This is not to deny the importance of the environment in controlling personality. But, to produce consistent long-term effects, environmental influences must be mediated by, and instantiated in, biological systems. Biology can also be viewed as more fundamental in that environmental events (such as an impact to the front of the head) have permanent effects on personality not in relation to the external parameters of the event (such as the force of impact) but rather in relation to the precise extent of change the event induces in the brain. Those interested in individual variation in the tendency to neurotic disorders have been particularly inclined to theorize in terms of either the real or the conceptual nervous system. Pavlov saw variation in the response of his dogs to both traumatic and everyday events as arising from the ‘Strength of the Nervous System’ – a purely theoretical construct, albeit with a consistent behavioural structure (Gray 1964, 1967).
The present study presents a replication and methodological extension of MacLeod, Tata, Kentish, and Jacobsen (1997) with a nonclinical sample, using future-directed imagery to assess prospective cognitions. Results showed that only anxiety (but not depression) was related to enhanced imagery for future negative events. Both anxiety and depression showed significant zero-order correlations with reduced imagery for future positive events. However, when the overlap between anxiety and depression was controlled for, only depression Gout not anxiety) showed a unique association with reduced imagery for positive events. Implications of these findings for cognitive models of anxiety and depression are discussed.
Some investigators have argued that emotions, especially animal emotions, are illusory concepts outside the realm of scientific inquiry. With advances in neurobiology and neuroscience, however, researchers are proving this position wrong while moving closer to understanding the biology and psychology of emotion. In Affective Neuroscience, Jaak Panksepp argues that emotional systems in humans, as well as other animals, are necessarily combinations of innate and learned tendencies; there are no routine and credible ways to really separate the influences of nature and nurture in the control of behavior. The book shows how to move toward a new understanding by taking a psychobiological approach to the subject, examining how the neurobiology and neurochemistry of the mammalian brain shape the psychological experience of emotion. It includes chapters on sleep and arousal, pleasure and pain systems, the sources of rage and anger, and the neural control of sexuality. The book will appeal to researchers and professors in the field of emotion.
Abundant neurobehavioral data, not discussed by Lisa Feldman Barrett (2006), support the existence of a variety of core emotional operating systems in ancient subneocortical regions of the brain (Panksepp, 1998a, 2005a). Such brain systems are the primary-process ancestral birthrights of all mammals. There may be as many genetically and neurochemically coded subcortical affect systems in emotionally rich medial regions of the brain as there are "natural" emotional action systems in the brain. When emotional primes are aroused directly, as with local electrical or chemical stimulation, the affective changes sustain conditioned place preferences and place aversions, which are the premier secondary-process indices of affective states in animals. Humans are not immune to such brain manipulations; they typically exhibit strong emotional feelings. Human emotion researchers should not ignore these systems and simply look at the complex and highly variable culturally molded manifestations of emotions in humans if they wish to determine what kinds of "natural" emotional processes exist within all mammalian brain. Basic emotion science has generated workable epistemological strategies for under-standing the primal sources of human emotional feelings by detailed study of emotional circuits in our fellow animals.
© 2007 Association for Psychological Science.
This paper takes a closer look at the subjectivity/objectivity relationship, as it plays a role in the science of animal welfare. It argues that subjective, experiential states in animals such as well-being and suffering are, contrary to what is often assumed, open to empirical observation and scientific assessment. The presumably purely private, inaccessible nature of such states is not an inherent property of these states, but derives from their misguided conception as ‘causal objects’ in mechanistic models of behaviour. This inevitably endows subjective experience with a ‘hidden’ status. However, subjective experience should be approached on its own conceptual grounds, i.e. as a perspective, in terms of ‘what-it-is-like-to-be’ a particular individual animal. Neither behaviour nor subjective experience then can be regarded as causal objects; they form an integrated, dynamic, expressive whole. The animal is perceived as an agent, whose perspective on a given situation is manifest in the way in which it interacts with and pays attention to that situation. In this framework, concepts of subjective experience such as enthusiasm, timidity, fear or contentedness, may be defined as categories of ‘attentional style’. Testing the scientific validity and reliability of such categories requires development of a qualitative methodology for the measurement of behaviour. Starting-points for such a method are put forward for discussion.
Individual differences in emotional reactivity or affective style can be decomposed into more elementary constituents. Several separable of affective style are identified such as the threshold for reactivity, peak amplitude of response, the rise time to peak and the recovery time. latter two characteristics constitute components of affective chronometry The circuitry that underlies two fundamental forms of motivation and and withdrawal-related processes-is described. Data on differences in functional activity in certain components of these are next reviewed, with an emphasis on the nomological network of surrounding individual differences in asymmetric prefrontal The relevance of such differences for understanding the nature affective dysfunction in affective disorders is then considered. The ends by considering what the prefrontal cortex “does” in certain of affective style and highlights some of the important questions for future research.
This article focuses on differences between anxiety and depression. The first study is concerned with the timing (past, present, future) of negative events associated with high levels of anxiety and depression in normal participants. Depression was associated more with past events than future events, whereas the opposite was the case with anxiety. These findings are consistent with those reported in several studies on clinical samples. In a second study, participants provided their emotional reactions to scenarios referring to negative events lying in the past or in the future with the future events being either uncertain or probable. Past events were associated with more depression and less anxiety than future events whether uncertain or probable. Probable future events were associated with more anxiety and depression than uncertain ones. Theoretical implications of these findings are discussed.
A study is reported that examined memory for past experiences and anticipation of future experiences within panic disorder patients (N = 17), depressed patients (N = 16), and controls (N = 17). Anticipation and recall of positive and negative experiences were examined by administering an adapted verbal fluency paradigm. Participants were asked to generate future and past, positive and negative experiences in response to various time-frame cues. Anxiety was associated with generating more negative experiences but not fewer positive experiences; depression was associated with generating fewer positive experiences but not more negative experiences. The patterns for recall of past experiences and anticipation of future experiences were very similar.
Positive feelings are considered within the framework of a general model of origins and functions of affect. This model treats affect as reflecting the error signal of a feedback loop managing rate of incentive-seeking (and threat-avoidant) behaviour. In this view, positive feelings represent a sign that things are going better than necessary and are presumed to induce coasting. A tendency to coast is seen as facilitating the shift of attention and effort to other behavioural domains, where they may be needed more or where unforeseen opportunities have arisen. Such a function for positive feelings would permit the person both to maintain satisfactory standing with regard to multiple goals and to take advantage of unforeseen opportunities, thus providing adaptive value. Comparisons are made to other recently developed ideas concerning the functions of positive feelings.
The study of judgement biases in animals has attracted interest as a way of potentially measuring emotional states by being able to detect pessimistic-like or optimistic-like evaluations of their environment. While judgement biases have been successfully identified in laboratory species, no such research has been reported in livestock species. Twenty ewes were trained to learn a spatial location task that required a go/no-go response according to the location of a bucket in a pen. One bucket location was associated with a feed reward, and the other associated with a negative reinforcer (no food and the presentation of a dog). Ten sheep were then subjected to a 6h restraint and isolation stress (RIS), for three consecutive days. Following RIS on each day, all sheep were tested for biases in judgement by measuring their response to three previously unseen bucket locations and the learnt locations. Serum cortisol, haematological parameters, and behaviour of the sheep in an open field test were also recorded. Restrained and isolated sheep were more likely to approach the ambiguous bucket locations compared to control sheep (P=0.008), suggesting RIS-treated animals had a more optimistic-like judgement bias. This was despite serum cortisol concentrations showing that sheep were highly stressed by the RIS treatment (P=0.019). This finding provides evidence that it is possible to measure judgement biases in a livestock species. When released from RIS the sheep may have had a more positive emotional state, or a lesser perception of risk, than that exhibited by control sheep.
A pessimistic view of the future is an important feature of depressive thinking, and appears to be influenced at least as strongly by reduced positive expectancies as it is by increased negative expectancies. The present study examined whether reduced positive future-thinking in depression could be accounted for by a reduced capacity to anticipate experiencing pleasure. Depressed and nondepressed participants were asked to generate positive future expectancies using a future-thinking task, and their capacity to anticipate experiencing pleasure in such events was also assessed. Depressed participants provided fewer anticipated positive experiences, a finding which was not accountable for by their reduced pleasure ratings. This reduced positive anticipation was related to levels of depression but not to levels of anxiety. The results are consistent with the view that the lack of anticipated positive experiences in depression arises from a difficulty in accessing mental representations of such experiences.
The study of optimal life histories involves the maximization of lifetime fitness but usually ignores the details of behavioral sequences. In contrast, the study of optimal behavioral sequences usually looks at the details of a sequence in isolation and not as part of the whole life history of the animal. The currency that is maximized is assumed to be related to lifetime fitness, but this relationship is rarely explored. In this paper we develop a common currency for behavioral decisions that is directly related to lifetime fitness. The common currency makes it possible to compare the benefits of qualitatively different behaviors. We show that many different costs can be used to explain a given behavioral sequence. Most of these costs have no biological interpretation. From these we single out a particular cost, the canonical cost, which measures the reduction in fitness that results from choosing a suboptimal action. Our general framework is illustrated by the example of a small bird in winter. We quantify the value of energy in terms of fitness and show how this value depends on energy reserves and time of day. As a result of this dependence, optimal foraging decisions depend on energy reserves and time of day, as does the optimal trade-off between foraging and looking around for predators.
Are nonhuman animals conscious? When do babies begin to feel pain? What function is served by consciousness? What evidence could resolve these issues?
These questions are tackled by exploring psychologists' findings on topics as diverse as animal cognition, unconscious learning and perception in humans, infantile amnesia, theory of mind in primates, and the nature of pleasure and pain. Experimental results are placed in theoretical context by tracing the development of concepts of consciousness in animals and humans (from Plato to Penrose). Two themes emerge: first, the capacity for language marks a fundamental difference between humans and nonhumans; second, there is neither proof that any non-human species is conscious, nor any convincing function to be found for consciousness. Finally, a sketch is offered of a novel functionalist theory according to which the developing capacity for language allows the creation by infants of a 'self,' which may be a precondition for consciousness. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Laypeople and scientists alike believe that they know anger, or sadness, or fear, when they see it. These emotions and a few others are presumed to have specific causal mechanisms in the brain and properties that are observable (on the face, in the voice, in the body, or in experience)-that is, they are assumed to be natural kinds. If a given emotion is a natural kind and can be identified objectively, then it is possible to make discoveries about that emotion. Indeed, the scientific study of emotion is founded on this assumption. In this article, I review the accumulating empirical evidence that is inconsistent with the view that there are kinds of emotion with boundaries that are carved in nature. I then consider what moving beyond a natural-kind view might mean for the scientific understanding of emotion.
© 2006 Association for Psychological Science.
In this review we attempt to link the efficiency by which animals behave (economy of animal behaviour) to a neuronal substrate and subjective states to arrive at a definition of animal welfare which broadens the scope of its study. Welfare is defined as the balance between positive (reward, satisfaction) and negative (stress) experiences or affective states. The state of this balance may range from positive (good welfare) to negative (poor welfare). These affective states are momentary or transient states which occur against the background of and are integrated with the state of this balancing system. As will be argued the efficiency in behaviour requires that, for instance, satisfaction is like a moving target: reward provides the necessary feedback to guide behaviour; it is a not steady-state which can be maintained for long. This balancing system is reflected in the brain by the concerted action of opioid and mesolimbic dopaminergic systems. The state of this system reflects the coping capacity of the animal and is determined by previous events. In other words, this integrative approach of behavioural biology and neurobiology aims at understanding how the coping capacity of animals may be affected and measured. We argue that this balancing system underlies the economy of behaviour. Furthermore we argue that among other techniques anticipation in Pavlovian conditioning is an easy and useful tool to assess the state of this balancing system: for estimating the state of an animal in terms of welfare we focus on the conditions when an animal is facing a challenge.
The assessment of emotional states in animals, particularly positive ones, remains a scientific challenge. We investigated differences in behavioural and physiological measures recorded in sheep, Ovis orientalis aries, during situations likely to coincide with negative, intermediate and positive emotional valence. Reactions of 15 sheep were observed during separation from group members (negative valence), standing in the feeding area (intermediate valence) and being voluntarily groomed by a familiar human (positive valence). Several ear postures, relative eye aperture, cardiorespiration and body surface humidity and temperature were recorded continuously for up to 4 min in each experimental situation. Data were analysed using linear mixed-effects models, and correlations were calculated between ethophysiological measurements. Groomed sheep showed few ear posture changes, low proportions of forward ear postures, low relative eye aperture and a low variance in body surface humidity. The values of most of these measures increased linearly towards standing in the feeding area and further towards separation from group members. Conversely, groomed sheep showed high proportions of axial ear postures, long mean interheartbeat intervals and high heart rate variability, with values declining linearly towards the negative situation. In addition, behavioural and cardiac measurements correlated moderately to strongly. In conclusion, emotional valence in sheep could be differentiated by both behavioural and physiological measures. Based on our data, it may be possible to replace some physiological measures with observations of ear postures. The findings provide valuable insights for assessing both negative and positive emotion in animals, which can help to promote positive experiences in captive housing conditions.
Humans experiencing different background emotional states display contrasting cognitive (e.g. judgement) biases when responding to ambiguous stimuli. We have proposed that such biases may be used as indicators of animal emotional state. Here, we used a spatial judgement task, in which animals were trained to expect food in one location and not another, to determine whether rats in relatively positive or negative emotional states respond differently to ambiguous stimuli of intermediate spatial location. We housed 24 rats with environmental enrichment for 7 weeks. We removed the enrichment from half the animals prior to the start of training to induce a relatively negative emotional state, whereas we left it in place for the remaining rats. After 6 training days, the rats successfully discriminated between the rewarded and the unrewarded locations in terms of an increased latency to arrive at the unrewarded location, with no housing treatment difference. The subjects then underwent 3 days of testing in which three ambiguous ‘probe’ locations, intermediate between the rewarded and the unrewarded locations, were introduced. There was no difference between the treatments in the rats' judgement of two of the three probe locations, the exception being when the ambiguous probe was positioned closest to the unrewarded location. This result suggests that rats housed without enrichment, and in an assumed relatively negative emotional state, respond differently to an ambiguous stimulus compared to rats housed with enrichment, providing evidence that cognitive biases may be used to assess animal emotional state in a spatial judgement task.
If fearfulness is stable, consistent and trait-like, then valid measures of fearfulness should be stable, consistent and independent of influences unrelated to fear. We assessed the validity of six fear measures using Japanese quail, Coturnix coturnix japonica, a common species in fear research. Measures were made during emergence, novel object, novel food and predator surprise tests. These were considered to have internal validity if they were stable over 18 days, when we controlled for nonexperimental variables including season of testing and cage location. We determined convergent and discriminant validity by factor analysis of fear measures plus measures of sociality, activity level and repetitive behaviour. Fear measures with good convergent validity showed agreement in their factor loadings. Those with good discriminant validity loaded on to different factors from nonfear measures. Most of the fear measures examined were moderately stable over time, but only half had good discriminant validity. Convergence was good among measures from the same test but poor across tests. Measures from each fear test loaded separately. Overall, flight distance and freezing duration in the predator surprise test and amount eaten in the novel food test showed the best internal, convergent and discriminant validity. When we considered only these three measures, convergence remained higher among measures from the same test than from different tests. Fearfulness thus appeared somewhat unstable over time and inconsistent across situations, which, if true across species, greatly limits the utility of fear tests.
Anxious and depressed humans typically view circumstances more pessimistically than non-depressed individuals. Here, we explore the proposal that such cognitive biases also exist in non-human animals, and could be used as novel measures of animal welfare. Specifically, we test the hypothesis that wild-caught captive European starlings (Sturnus vulgaris) are more optimistic in their interpretation of ambiguous stimuli when they are housed in cages designed to promote greater welfare compared with when they are housed in standard laboratory cages. Starlings were trained using a choice procedure to discriminate between two temporal stimuli (2s versus 10s duration light stimulus) associated with outcomes of a different value (instant or delayed food). Next, the birds’ responses to ambiguous, unreinforced stimuli of intermediate duration ranging from 2 to 10s were examined under two housing regimes designed to manipulate the birds’ welfare: big enriched cages versus standard cages (smaller and unenriched). The birds’ probability of classifying an intermediate stimulus as that associated with the instant food outcome was significantly higher in the enriched cage compared with the standard cage. Thus, the birds displayed greater optimism in the face of uncertainty under housing conditions in which other measures indicate better welfare. These findings support the use of cognitive bias-based tasks as a novel, non-invasive technique for assessing affective state in non-human animals.
Research on emotion flourishes in many disciplines and specialties, yet experts cannot agree on its definition. Theorists and researchers use the term emotion in ways that imply different processes and meanings. Debate continues about the nature of emotions, their functions, their relations to broad affective dimensions, the processes that activate them, and their role in our daily activities and pursuits. I will address these issues here, specifically in terms of basic emotions as natural kinds, the nature of emotion schemas, the development of emotion-cognition relations that lead to emotion schemas, and discrete emotions in relation to affective dimensions. Finally, I propose a new paradigm that assumes continual emotion as a factor in organizing consciousness and as an influence on mind and behavior. The evidence reviewed suggests that a theory that builds on concepts of both basic emotions and emotion schemas provides a viable research tool and is compatible with more holistic or dimensional approaches.
© 2007 Association for Psychological Science.
Although the cognitive model of depression has evolved appreciably since its first formulation over 40 years ago, the potential interaction of genetic, neurochemical, and cognitive factors has only recently been demonstrated. Combining findings from behavioral genetics and cognitive neuroscience with the accumulated research on the cognitive model opens new opportunities for integrated research. Drawing on advances in cognitive, personality, and social psychology as well as clinical observations, expansions of the original cognitive model have incorporated in successive stages automatic thoughts, cognitive distortions, dysfunctional beliefs, and information-processing biases. The developmental model identified early traumatic experiences and the formation of dysfunctional beliefs as predisposing events and congruent stressors in later life as precipitating factors. It is now possible to sketch out possible genetic and neurochemical pathways that interact with or are parallel to cognitive variables. A hypersensitive amygdala is associated with both a genetic polymorphism and a pattern of negative cognitive biases and dysfunctional beliefs, all of which constitute risk factors for depression. Further, the combination of a hyperactive amygdala and hypoactive prefrontal regions is associated with diminished cognitive appraisal and the occurrence of depression. Genetic polymorphisms also are involved in the overreaction to the stress and the hypercortisolemia in the development of depression--probably mediated by cognitive distortions. I suggest that comprehensive study of the psychological as well as biological correlates of depression can provide a new understanding of this debilitating disorder.
Green, Goldman, and Salovey (1993) challenged the view that "positive affect" and "negative affect" are largely uncorrelated dimensions. On the basis of factor analytic studies of happiness and sadness, and of positive and negative emotional activation (PA and NA), they claimed that a "largely bipolar structure of affect" (p. 1029) emerges when random and nonrandom error are taken into account. A reappraisal of their own findings and confirmatory analysis of additional data do not support this claim. Happiness and sadness form a largely unidimensional bipolar structure, but PA and NA are relatively independent. However, exploratory analyses yield a three-level hierarchy incorporating in one structure a general bipolar Happiness-Versus-Unhappiness dimension, the relatively independent PA and NA dimensions at the level below it, and discrete emotions at the base. We emphasize the heuristic value of a hierarchical perspective.
Recent scientific findings indicate that consciousness is a fundamental biological adaptation. The known brain correlates of consciousness appear to be phylogenetically ancient, going back at least to early mammals. In all mammals, alertness and sensory consciousness are required for the goal-directed behaviours that make species survival and reproduction possible. In all mammals, the anatomy, neurochemistry and electrical activity of the brain in alert states show striking similarities.
After more than seven decades of cumulative discoveries about waking and sensory consciousness, we have not yet found any fundamental differences between humans and other mammals. Species differences such as the size of neocortex seem to be irrelevant to the existence of alertness and sensory consciousness, though different mammals obviously specialize in different kinds of sensory, cognitive and motor abilities.
Sceptics sometimes claim that objective evidence for consciousness tells us little about subjective experience, such as the experience of conscious pain. Scientifically, however, plausible inferences are routinely based on reliable and consistent patterns of evidence. In other humans, we invariably infer subjective experiences from objective behavioural and brain evidence - if someone yells ‘Ouch!’ after striking a finger with a hammer, we infer that they feel pain. The brain and behavioural evidence for subjective consciousness is essentially identical in humans and other mammals. On the weight of the objective evidence, therefore, subjective experience would seem to be equally plausible in all species with human-like brains and behaviour. Either we deny this experience to other humans (which is rarely done) or, to be consistent, we must also attribute it to other species that meet the same objective standards. It seems that the burden of proof for the absence of subjectivity in mammals should be placed on the sceptics.
Although few studies dispute that there are gender differences in depression, the etiology is still unknown. In this review, we cover a number of proposed factors and the evidences for and against these factors that may account for gender differences in depression. These include the possible role of estrogens at puberty, differences in exposure to childhood trauma, differences in stress perception between men and women and the biological differences in stress response. None of these factors seem to explain gender differences in depression. Finally, we do know that when depressed, women show greater hypothalamic-pituitary-adrenal (HPA) axis activation than men and that menopause with loss of estrogens show the greatest HPA axis dysregulation. It may be the constantly changing steroid milieu that contributes to these phenomena and vulnerability to depression.