Elizabeth S. Paul

Measuring emotional processes in animals: the utility of a cognitive approach.

Contemporary researchers regard emotional states as multifaceted, comprising physiological, behavioural, cognitive and subjective components. Subjective, conscious experience of emotion can be inferred from linguistic report in humans, but is inaccessible to direct measurement in non-human animals. However, measurement of other components of emotion is possible, and a variety of methods exist for monitoring emotional processes in animals by measuring behavioural and physiological changes. These are important tools, but they have limitations including difficulties of interpretation and the likelihood that many may be sensitive indicators of emotional arousal but not valence-pleasantness/unpleasantness. Cognitive components of emotion are a largely unexplored source of information about animal emotions, despite the fact that cognition-emotion links have been extensively researched in human cognitive science indicating that cognitive processes-appraisals of stimuli, events and situations-play an important role in the generation of emotional states, and that emotional states influence cognitive functioning by inducing attentional, memory and judgement biases. Building on this research, it is possible to design non-linguistic cognitive measures of animal emotion that may be especially informative in offering new methods for assessing emotional valence (positive as well as negative), discriminating same-valenced emotion of different types, identifying phenotypes with a cognitive predisposition to develop affective disorders, and perhaps shedding light on the issue of conscious emotional experiences in animals.

An integrative and functional framework for the study of animal emotion and mood

A better understanding of animal emotion is an important goal in disciplines ranging from neuroscience to animal welfare science. The conscious experience of emotion cannot be assessed directly, but neural, behavioural and physiological indicators of emotion can be measured. Researchers have used these measures to characterize how animals respond to situations assumed to induce discrete emotional states (e.g. fear). While advancing our understanding of specific emotions, this discrete emotion approach lacks an overarching framework that can incorporate and integrate the wide range of possible emotional states. Dimensional approaches that conceptualize emotions in terms of universal core affective characteristics (e.g. valence (positivity versus negativity) and arousal) can provide such a framework. Here, we bring together discrete and dimensional approaches to: (i) offer a structure for integrating different discrete emotions that provides a functional perspective on the adaptive value of emotional states, (ii) suggest how long-term mood states arise from short-term discrete emotions, how they also influence these discrete emotions through a bi-directional relationship and how they may function to guide decision-making, and (iii) generate novel hypothesis-driven measures of animal emotion and mood.

Mammalian choices: combining fast-but-inaccurate and slow-but-accurate decision-making systems

Empirical findings suggest that the mammalian brain has two decision-making systems that act at different speeds. We represent the faster system using standard signal detection theory. We represent the slower (but more accurate) cortical system as the integration of sensory evidence over time until a certain level of confidence is reached. We then consider how two such systems should be combined optimally for a range of information linkage mechanisms. We conclude with some performance predictions that will hold if our representation is realistic.

Decision-making under uncertainty: biases and Bayesians

Animals (including humans) often face circumstances in which the best choice of action is not certain. Environmental cues may be ambiguous, and choices may be risky. This paper reviews the theoretical side of decision-making under uncertainty, particularly with regard to unknown risk (ambiguity). We use simple models to show that, irrespective of pay-offs, whether it is optimal to bias probability estimates depends upon how those estimates have been generated. In particular, if estimates have been calculated in a Bayesian framework with a sensible prior, it is best to use unbiased estimates. We review the extent of evidence for and against viewing animals (including humans) as Bayesian decision-makers. We pay particular attention to the Ellsberg Paradox, a classic result from experimental economics, in which human subjects appear to deviate from optimal decision-making by demonstrating an apparent aversion to ambiguity in a choice between two options with equal expected rewards. The paradox initially seems to be an example where decision-making estimates are biased relative to the Bayesian optimum. We discuss the extent to which the Bayesian paradigm might be applied to the evolution of decision-makers and how the Ellsberg Paradox may, with a deeper understanding, be resolved.

Sensitivity to reward loss as an indicator of animal emotion and welfare

The scientific study of animal emotion is an important emerging discipline in subjects ranging from neuroscience to animal welfare research. In the absence of direct measures of conscious emotion, indirect behavioural and physiological measures are used. However, these may have significant limitations (e.g. indicating emotional arousal but not valence (positivity versus negativity)). A new approach, taking its impetus from human studies, proposes that biases in information processing, and underlying mechanisms relating to the evaluation of reward gains and losses, may reliably reflect emotional valence in animals. In general, people are more sensitive to reward losses than gains, but people in a negative affective state (e.g. depression) are particularly sensitive to losses. This may underlie broader findings such as an enhanced attention to, and memory of, negative events in depressed individuals. Here we show that rats in unenriched housing, who typically exhibit indicators of poorer welfare and a more negative affective state than those in enriched housing, display a prolonged response to a decrease in anticipated food reward, indicating enhanced sensitivity to reward loss. Sensitivity to reward reduction may thus be a valuable new indicator of animal emotion and welfare.

Pet ownership is associated with increased risk of non-atopic asthma and reduced risk of atopy in childhood: findings from a UK birth cohort.

Studies have shown an inverse association of pet ownership with allergy but inconclusive findings for asthma.

Housing conditions affect rat responses to two types of ambiguity in a reward–reward discrimination cognitive bias task

Highlights • We investigated how an unpredictable housing treatment (UHT) influenced measures of rat affect.• Control rats showed more anxiety-like behaviour in open-field and elevated plus maze tests than UHT rats.• Controls also made more ‘pessimistic’ decisions in an automated cognitive bias task.• Our go/go reward–reward task was learnt faster than previous automated go/go tasks.• We developed a new ambiguity test that may probe biases in attentional processes.

The Representation of Animals on Children'S Television

The representation of animals on British childrens television was investigated by means of content analysis of 364 weekday programs, collected over a two-year period. Animals are a major subject a...

On the Evolution and Optimality of Mood States

Moods can be regarded as fluctuating dispositions to make positive and negative evaluations. Developing an evolutionary approach to mood as an adaptive process, we consider the structure and function of such states in guiding behavioural decisions regarding the acquisition of resources and the avoidance of harm in different circumstances. We use a drift diffusion model of decision making to consider the information required by individuals to optimise decisions between two alternatives, such as whether to approach or withdraw from a stimulus that may be life enhancing or life threatening. We show that two dimensions of variation (expectation and preparedness) are sufficient for such optimal decisions to be made. These two dispositional dimensions enable individuals to maximize the overall benefits of behavioural decisions by modulating both the choice made (e.g., approach/withdraw) and decision speed. Such a structure is compatible with circumplex models of subjectively experienced mood and core affect, and provides testable hypotheses concerning the relationships that occur between valence and arousal components of mood in differing ecological niches. The paper is therefore a useful step toward being able to predict moods (and the effect of moods) using an optimality approach.

Farmers' attitudes to methods for controlling tail biting in pigs

OUTBREAKS of tail biting on pig farms can have serious welfare (van Putten 1969, Penny and Hill 1974, SchroderPetersen and Simonsen 2001) and economic (Penny and Hill 1974) consequences. Many farmers dock the tails of newborn piglets in an attempt to prevent tail biting. However, recent slaughterhouse surveys (Hunter and others 1999, 2001) and epidemiological studies (Chambers and others 1995, Moinard and others 2003) have suggested that while farmers with a tail-biting problem in their pigs may be more likely to dock their pigs’ tails, docking may not actually be successful in preventing tail biting. There is therefore a need for alternative methods for preventing tail biting, particularly in view of the likely pain caused by tail docking and associated formation of neuroma (Simonsen and others 1991), and the fact that the routine docking of piglets’ tails is illegal in the UK (Anon 1994) unless approved by a veterinary surgeon. Tail biting has multifactorial causes (Schroder-Petersen and Simonsen 2001). Epidemiological studies can identify which causes have the greatest influence under commercial farm conditions, and hence suggest novel strategies that may help to minimise the problem. To maximise the likelihood of these approaches being successful, however, it is important that farmers are willing to implement them. This short communication describes a study to investigate farmers’ opinions about the causes of tail biting and possible methods of prevention, including methods suggested by an epidemiological study that indicated that the provision of straw, both preand postweaning, and low stocking densities were important preventive factors (Moinard and others 2003). Confidential questionnaires were distributed, via the Royal Society for the Prevention of Cruelty to Animals (RSPCA), to 429 members of the Freedom Foods Assurance Scheme on February 22, 2001, and reminders were sent on March 14; 157 (36·6 per cent) questionnaires were completed and returned. Not all the questionnaires gave complete answers to all the questions, so the sample size varied according to the subset of data being analysed. Most of the respondents ran finisher units (69·1 per cent); breeder-finisher (11·2 per cent), nursery (6·6 per cent), breeder-grower (5·2 per cent), weaner-finisher (4·6 per cent), grower (2·6 per cent) and breeder (0·7 per cent) units were also represented (sample size of 152). The first part of the questionnaire contained background questions about the farm, its current tail docking practices, and recent occurrences of tail biting. The answers to this section allowed the classification of 101 (66·9 per cent) ‘case’ farms (on which tail biting was reported as having occurred last week, last month, or six months ago) and 50 (33·1 per cent) ‘control’ farms (on which tail biting was reported as having occurred one year or longer ago, or never, or the farmer answered ‘don’t know’). Of 141 farmers, 59 farmers (42 per cent) reported that none of their pigs had docked tails, 41 (29 per cent) said all the pigs were docked, and the remaining 41 (29 per cent) reported that some of the pigs were docked. The second part of the questionnaire consisted of structured questions concerning the respondents’ beliefs about the possible causes and methods of prevention of tail biting, and the costs (both financial and time) of implementing prevention measures. Each of these questions listed a series of possible answers (for example, listed suggestions of causes of tail biting included ‘boredom’, ‘high stocking density’ and ‘lack of straw’), based on the answers given by farmers to open-ended questions in a previous study by Moinard and others (2003). Farmers were asked to use a five-point scale for each suggested answer (for example, ranging from 1 Very important to 5 Not important at all). Not all the questions were responded to in their entirety, so the sample size varied according to the subset of data being analysed. Mann-Whitney U tests were conducted using SPSS software. Table 1 shows how the farmers rated the relative importance of the suggested causes of tail biting listed in the questionnaire. Their responses were in agreement with findings from research indicating that a lack of a foraging substrate and high stocking densities are key risk factors, but also that tail biting may often have multifactorial, more sporadic, causes (Schroder-Petersen and Simonsen 2001, Moinard and others 2003). Farmers of ‘case’ farms were more likely to regard variable tail length within a group as an important cause of tail biting (U=1485·5, P<0·05), while ‘control’ farmers were more likely to view high levels of ammonia and high stocking densities as important causes of tail biting (U=1603·0, P<0·05; U=1936·0, P<0·05, respectively). Farmers with docked pigs were more likely to believe that ventilation problems were an important cause of tail biting (U=823·5, P<0·05), and that tail biting occurred more in the spring and autumn (U=797·5, P<0·05). Veterinary Record (2007) 160, 803-805