Читать книгу The Behavior of Animals - Группа авторов - Страница 85

I have defined emotion as the subjective aspect (feeling) of strongly activated behavior systems. Since we have no access to the subjective experience of any animal (except ourselves), any discussion of nonhuman emotion must rely on investigation of the expression of such strongly activated behavior systems. One of the first systematic studies of the expression of the emotions in man and (other) animals was that of Darwin (1872). Darwin was primarily interested in similarities between animal expression of presumed emotional states such as anger, terror, and joy and human expression of these and other emotions. Darwin assumed that animals such as dogs, cats, horses, and monkeys had such emotional states and tried to show that the expression of these emotions in humans could be traced to their expression in various animals as support for his theory of evolution. Since we know that the nervous systems of all animals have similar components, it should be possible to infer the emotional state of an animal from observations of its behavior. We would be inferring the state of activation of an animal’s various behavior systems, irrespective of whatever subjective experience the animal might be having. In effect, we would be performing a motivation analysis (p. 62). We have already seen examples of this with respect to the upright posture of the herring gull, the zig-zag dance of the stickleback, and waltzing in junglefowl. A similar example is Lorenz’s (1966) analysis of the facial expressions of fear and aggression in dogs (Figure 3.8). In this figure, increasing aggression goes from left to right and increasing fear goes from top to bottom. In (a) the dog is calm and unemotional; in (b) and (c) it is becoming more afraid; in (d) and (g) it is becoming more aggressive. The other figures depict ambivalent expressions. It can be seen that as fear is increasing, the ears and the corners of the mouth are drawn backward and downward; as aggression is increasing, the upper lip is raised and the mouth opened. These examples show that it is possible to ascertain which behavior systems in an animal are activated. But how strongly does the system have to be activated in order to be considered an emotion? And how do we measure strength?

Figure 3.8 Facial expressions of fear and aggression in dogs. Explanation in text. (From Lorenz 1966).

Strength has been measured both behaviorally and physiologically, and recently, “cognitively” as well. An early investigator of “emotionality” in animals (the rat in this case) was Hall (1934). He showed that defecation and urination in a standard situation were valid measures of individual differences in emotionality. Hall considered emotionality a trait, characteristic of an individual. He felt that attempts to differentiate specific emotions were extremely speculative, a view still held by many investigators of human emotion, as we have seen above. Hall, as also most prior and subsequent investigators of animal emotion, was really interested in using animal studies as a model for understanding human emotion. And soon thereafter, many other measures of bodily changes in animals, both behavioral and physiological, began to be used in investigations of various aspects of emotion. Paul et al. (2005) review the various approaches to measuring emotional processes in animals, past and present, including new non-linguistic cognitive measures.

Most studies of animal emotion are directed to understanding human emotion, but the rise of interest in animal welfare has led many investigators to study animal emotion per se. In the context of welfare, it is crucial to discover what makes an animal ‘feel good’ (or, at least, not suffer). However, feelings are subjective and we can never know what an animal feels (see Panksepp 2010 and Dawkins 2015 for recent discussions of animal consciousness). M. Dawkins (2008) suggests that a scientific study of animal suffering and welfare can be based on answers to two questions: Will the situation improve animal health? And, will it give animals something they want? The answer to the second question can be determined by discovering what the animal finds positively and negatively reinforcing (what they want and do not want) in a learning situation. Even here, however, a difference between “wanting” and “liking” (Berridge 2004) makes interpretation of the results not straightforward (an animal may like something, but not want it at this moment). Nonetheless, Dawkins’ approach seems the most reasonable proposal to date. Theoretically, Mendl et al. (2010) have proposed a framework that integrates the discrete emotion approach (i.e., the basic emotion approach above) with the dimensional approach (i.e., the psychological construction approach above) for the study of animal emotion and mood. The cognitive aspects of the dimensional approach allow one to experimentally dissociate “liking” something from currently “wanting” it, which solves some problems. In all cases, however, the feelings of the animal remain a conjecture. The topic of animal welfare is considered again in Chapter 10.