Investigation into Animal Emotions

Abstract

The study of emotions is a common debate on the fundamental issues on how to define emotion, which isn’t particularly common within non-human emotional literature. Thus, it is continually investigated to address the issue, particularly in conditions that relate to animal emotion. There is continuous disagreement over the exact structure of emotions, and the overall nature of consciousness, which allows for a consistent variation within each researcher’s term of emotions. As various people believe that animals express emotions and encourage more investigation on animal emotion. Multiple measurements that can be used to investigate animal emotions, which provide the necessary information to distinguish various states to encourage further field research in the more difficult species, such as marine mammals. This research provides a baseline for new researchers to adopt a more positive insight, to acquire a more accurate set of results, by distinguishing the differences between trait and state of emotions and the use of rating methods. Emotions can be characterized as a conscious mental reaction which is a strong sense that’s directed towards a specific object which links physiological and behavioural alterations within the body. Emotions have been studied in the past and has been categorised into three groups; physiological (body response), behavioural (what one shows to others) and psychological responses (one feels). Reactions can be mixed up for sensations, which are only physical outcomes such as heat. 

Introduction

Emotions in animals were first examined by Charles Darwin in 1872. Darwin portrayed that emotions were a stereotyped facial and physical expression. Darwin then further examined the expression of emotion. In animals, which observed a similarity between humans and non-human expressions. The emotion was then further analysed in 1963, by Tinbergen, who then constructed “four questions of ethology” (Tinbergen, 1963), who deliberated the use of emotional perspective in animals. Animal emotions have been a focus of research through the years but still provides difficulty to apply the definition.  In these cases, notions of the internal, or conscious states are basically isolated. Nevertheless, the past decade or so there has been a dramatic upsurge in interest, particularly within the neurosciences, but also in ethology, in the topic of emotion and how it can be studied translationally in both humans and animals (Anderson and Adolphs, 2014; de Waal, 2011;Lang, 2010; LeDoux, 2012;Rolls, 2014).

The concept of emotion can differ from sensations in a physical sign such as heat or from reactions. This allows for interpretation in internal states with no reference to external reactions. Darwin, for example, explored further into the concept of emotions, such as the difference and similarities within both human and non-human, such as dogs, cats and numerous other animals. Darwin’s observation was evident there was a resemblance between both human and non-human animal expressions, in line with his theory between species.

Through acknowledging the circumstances of humans expressing themselves through ‘emotions’ which is theoretically tailored to our specific species/culture, which has then been imprinted on animals, that they also have emotions or an emotion like capacity, based upon the humans neural systems in response or anticipating a reward or punishment that will determine a specific species reaction.

However, it can also be argued that the overall capacity of various animal emotions according to their distinct prescriptive.  Through investigating further into the likelihood of animal emotions and breaking it down into categories, which will enhance the structure, and nature of animal emotions processes. This will also help distinguish animals emotional, physiological, neural behaviour and welfare.

An example of this would be to take a Primate who is able to experience empathy. As Primates have a complex social system, this allows the younger apes, and their mothers to have a strong bond. Thus, when I young ape or other family members within the group dies, the family members are known to grieve around the body for several days. This behaviour was observed by Jane Goodall who labelled it mournful behaviour. This behaviour was a witness within a captive gorilla called Koko who was trained to use sign language. Koko displayed is mournful behaviour after the passing of her pet cat, All Ball. Previous, studies have examined this emotional process within great apes, the majority within the chimpanzee’s species. The chimpanzees have displayed a video of emotional triggered scenes, such as a veterinary procedure or of their favourite food and were then required to match those scenes with one out of two types of facial expressions, one displaying happiness (play face) or sadness (baring teeth). In this experiment the chimpanzees correctly matched the video with the required facial expression that explained their “emotional” expression of the situation, providing adequate information that the chimpanzees understand emotional signals that pass the facial area. This emotional signal can also be read through measuring body temperature which further strengthened the thought of their emotional state towards the task presented.

Forms of Animal Emotions

The emotional states within numerous animals can be easily observed, through their facial expressions, such as their eyes, or posture position which can provide a strong indicator on how they are feeling; Changes in their muscle tone, posture, gait, facial expression, eye size and gaze, vocalisation and pheromones.

The primary expression of emotion is wired into the biological evolutionary limbic system (the amygdala), which acts as the emotional part of the brain (MacLean., 1952; Panksepp., 1998). Due to the formation of the limbic system, it accepts the connection of similar emotional pathways that allow animals to share amongst the different species, by providing a neural substrate within primary emotions. The secondary emotions are those that are experienced or felt, assessed and reflected on, this involves the use of a higher brain function within the cerebral cortex. Majority of emotional responses are generated subconsciously, whereas emotional response that is consciously within an individual, implies the connection between feelings and action of flight or fight.

Cognitive bias approaches to measure emotion

Cognitive emotion can be defined as a theoretical framework that derives the research in cognitive psychology. This can be investigated in various numbers of animals. In particular, this approach will rely on studying the elementary evaluation standards that can be identified within humans, in this case, sadness, angry, happiness etc, which can be perceived in animals and if they do express emotions that can be recognised by behavioural and physiological changes (Desire et al., 2002).

An example of cognitive bias behaviour was commonly observed within rats. In 2004 Harding studied the rat cognitive behaviour. This was done by training the rats to press a lever when they heard a certain sound which would either indicate a positive reward whereas when they hear the negative tone, they refrained from pressing the lever to avoid a negative event. These rats have also trained in two separate groups; either predictable or unpredictable housing over a period of nine days. From this research, it was concluded that rats that were housed in the unpredictable situation produced a slower response and tended to display few responses to ambiguous tones close to the positive tone, and to the tone itself.

Affective states approach to measure emotion

Emotions can be considered as an adaptive mechanism which allows for the enhancement chances of survival and successful reproductive. Affective states are made up of two components 1) acquiring valuable resources/ rewards and 2) avoiding harm/ punishment. Affective states also known as the emotional state it involves the influence on how humans recognize and respond to numerous stimuli and situations; For example, if an animal is in a state of fear, there is a higher chance that they will respond to their new situation regarding increased heart, facial expressions/positioning and an increased tendency to flee or hide. Fear itself can change the whole situation. This, in turn, can influence how stimuli are recognized.

The affective state of animal understandings is an important factor when implicated with animal welfare, as negative states can be used to indicate poor welfare, whereas positive states can improve animal welfare. By using Darwin’s proposal in 1872, this provided a baseline for further studies on animal emotion. Darwin portrayed that emotions are adaptive, communicative and motivational functions, Darwin stated that these 3 principles provide an understanding of emotional expression; the first principle is serviceable habits which will then be passed onto the offspring. The second principle involves contrast which is an expression of opposed expressions that help provide useful data. The final principle is the direct action of working within the nervous system within the body which will provide data on an emotional expression which is linked to the relationship of nervous energy which bypasses the threshold and required releases. These three principals were then considered as a type of communication of an inner state, which portrayed that could often be carried beyond its original adaptive use. In this case, it allowed for Darwin to claim that humans frequently present their canine’s when in a rage, which also suggested that this facial display meant that human ancestors probably displayed their canines in an act of aggression.

Whereas, a domesticated dog will wag his/her tail which has been interpreted as a subtle way to convey happiness and various others. This was illustrated in Darwin’s journal on “The Expression of the Emotions in Man and Animals”, published in 1872.

Behavioural approaches to measuring emotion

Behavioural emotion was suggested by Darwin, which illustrate that emotions perform a role in communication and has thus been indicated as the prime behaviour that is displayed as one emotional state that can be observed by others. There are various other theories that link emotional states to action temperaments, such as flight in a situation of fear (Frijda., 1986). Corresponding to the various theories on behavioural emotion, it provided essential information on emotional states from vocalisation, facial display and body language behaviour. First by breaking up the three main factors of behavioural emotion;

Vocal characteristics

Vocal characteristics can be broken down by using acoustic waveforms. By using this process, it allows for the determination of acoustic properties. The common measures that are focused on to measure are the amplitude (the volume) and pitch, which is known as a fundamental frequency. The observed higher frequencies were noticed during arousal and vocal pitch that has been linked to having a relationship. For example; Scherer et al (1991) investigated the acoustic features of emotional behaviour within humans. When people depicted a high-arousal emotion e.g. fear, joy or anger, the pitch was higher than when they depicted at a lower-arousal e.g. sadness. This is a difficult process as determining the vocal characteristics that have a sensitive response to valence (denoting electrons involved in or available for chemical bond formation). E.g. Anger and joy have a similar response in emotional arousal but differ in valence, even though both emotions are linked to similar vocal pitch and vocal amplitude (Johnstone & Scherer., 2000).

Facial behaviour

Contrast facial behaviour appears to be particularly sensitive to the valence of emotional state. However, it is necessary to consider gender, expressiveness and vocal. However, facial behaviour cannot be associated with the absence of emotion and vice versa.

Body Language

Research on this behavioural trait is relatively thin, the research that has been carried out on body language has determined that certain emotional states may have distinct body postures. For example; pride and embarrassment are linked to the expansive and minuscule body postures, correspondingly. It was discovered that members displayed greater pride with a display of higher stance. Whereas, embarrassment displayed a lower stance regarding spatial presence. This provided a clear determination of dominance or submissive posture.

These emotions should then be systematically associated with behaviours that will display a clear signal to larger groups/ individuals of the emotional state.

Neural approaches to measure emotion

A neural approach to measuring emotion can be demonstrated through the influence of emotion on cognition can be neutrally reflected within a section of the brain, including the prefrontal cortex, amygdala and the insular cortex. Thus, the activations that occur within the required part of the brain which displays an increased trend in cognitive pressures. Therefore, the neural activation in the that occurs in the left inferior frontal junctions/precentral gyrus which acts as an indicator of cognitive control due to the neutral prime trials compared to trials that implicate negative prime. The functions of the prefrontal brain include amygdala and insula which provide the indication of relevant emotion – cognition interactions or emotional conflict resolution. However, certain parts of the brain become active due to certain actions being carried which require cognitive reappraisal (an emotional regulation strategy which provides a stimulus that reinterpreted the downregulated emotional valence). Thus, investigated by Ochsner et al in 2002 they obtained information on animal emotion that displayed the same activities within the correct section of the brain that would active during emotional cognitive reappraisal in humans.

Physiological approaches to measuring emotion

In the absence of a direct measure within an animal understanding, thus physiological measures can be used as it’s an indirect measure. The theory behind physiological measures is that the animal’s sensory input which is a genetic process that helps with them adapt to their environment. If the animal hears, smells or feels something their brain processes the new information which will then create a negative emotion, such as anxiety, or a positive emotion, such as pleasure. However, if the sensory input is neutral then no emotion will be seen. The behavioural and physiological responses like to the body response which can either determine the presence of emotions. This allows animals to adapt to their environment and increases their survival chances.

Discussion

Through identifying the brain states underlying the basic form of anthropomorphism,  it is still necessary to carry out more research by using sophisticated methods, such as ANS which takes into account the combinations of variables or using an fMRI which examines the activity of the brains pathways/circuits rather than the region in the brain, this will allow for more support to separate emotions perspectives on the present findings. 

It has scientifically been found that indicates the importance of emotions in the role of rational decision-making, perception, learning and a variety of other cognitive emotions. Even though Darwin’s original work on animal emotions was criticised for roughly 100 years, until relatively recently when scientists thought it was impossible to methodically study animal emotion, and anyone who did so was thought to be wrongly assigning human thoughts and feelings onto animals (anthropomorphism). Through using anthropomorphism to explain animals’ emotions/feelings (Allen and Bekoff., 1997). However, by referring to the acontextual function of sending and receiving neurons or the response of different muscles in the absence of behavioural information or context. Using anthropomorphism language does not have to affect the animal’s point of view. Anthropomorphism allows various animal behaviour and emotions to be observed.  

It has been investigated that animals have emotional responses, such as an increased heart rate or release of hormones in the blood (Physiological) and responses such as attempts to escape a situation (behavioural). However, more research is still needed to provide accurate results that prove animals have feelings just like humans. As it is a complex mechanism which is impossible due to being able to understand what is going on inside an animal’s mind. Animal emotion within a social play is a perfect example of emotional behaviour in which various animals partake, a one that seems to provide an enjoyed emotional observation. Individuals become immersed in the activity and provide no goal to part take in anything else but play. As pointed out by Groos in 1898 who discovered that animals that appear to play with one another are less stressed.

Conclusion

There is still a large disagreement about animal emotions. There are numerous questions that can be asked to adapt the information on animal expression; 1) Our moods affect us, so why not animals? 2) Emotions allow humans to adapt to specific circumstances, so why can’t animals? 3) Emotions are an integral part of the human functions, so why can’t animals have the same function? Through measuring the emotional response can be structured along dimensions e.g. arousal rather than separate emotional states e.g. sadness, fear or anger. Therefore, different measures of emotion appear sensitive to valence. Thus, stating that there is no clear definition of emotions. We suggest that measures of emotional responding appear to be structured along dimensions (valence, arousal) rather than discrete emotional states (sadness, fear, anger). Additionally, different measures of emotion appear sensitive to different dimensional aspects of the state (facial EMG is sensitive to valence, whereas skin conductance is sensitive to arousal) and are not strongly related to one another. Practically speaking, then, there is no ‘‘gold standard’’ measure of emotional responding.

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