animals & emotions


What are emotions?

How can emotions be measured?

Are emotions contagious?

What can be deduced from knowledge about emotions?

About the deeper meaning of emotions


What are emotions?

While the words emotions and feelings occupy our daily speech as a matter of course, we are often not very familiar with their use. Scientists feel the same way. In the fledgling field of emotion and feelings research, there is not even agreement on what exactly emotions are! It is assumed that emotions are bioregulatory reactions, i.e. a response or reaction to a stimulus. Bioregulatory here means that the reaction serves to restore a balance. Put simply, emotions are what follows as a movement to an incoming stimulus perceived by the senses, for example. The word emotion also contains the word "E" for energy and the English word "motion". Thus, emotions could be described as energy in motion.


Scientists claim that these regulatory reactions prepare the organism for adaptive (adjusting) behavior. When a stimulus hits the body, the emotion prepares the organism to respond.  


Most contemporary researchers do not deny the existence of emotion in animals. Disagreements mostly concern feelings. Feelings are said to be the mental representations of the physiological changes that occur during an emotion. By this is meant that feelings are the outwardly visible interpretation of the stimulus response. Depending on how the stimulus was evaluated by thoughts, the emotion is now transformed as a subjective feeling and carried to the outside.


Scientists debate about the appropriate definitions regarding the words emotions and feelings. They do not even agree on which level the reactions happen consciously or unconsciously. However, it is assumed that for a feeling to arise, a mental evaluation process must take place. So only if a stimulus and the reaction perceived with it in the body receives an evaluation by thinking, a feeling can develop. Feelings are therefore always subjectively colored and very individual. While emotions are comparable within species with the same senses and brains, this would not be the case with feelings, since situations or stimuli are evaluated individually. By assuming that feelings require an evaluative thought process (conscious or unconscious), scientists argue about the existence of feelings in animals. But as we will see, one has to be careful with such claims!


There is disagreement about whether a strict distinction can be made between emotions and feelings, since the two concepts are closely intertwined. Some scientists postulate that animals have feelings, but because of the unique features of the human brain, other species would lack equal consciousness as well as the same linguistic distinctions that humans have. Thus, they say, it is questionable whether they can have feelings equal to ours. They are not saying that animals do not have feelings, just not in the same way that humans feel them. However, it is assumed that feelings between related species are similar. Each species has evolved under specific environmental selection pressures and has a body with brain, neurons and sensory cells that are unique in form. However, some species, such as chimpanzees and humans, are relatively similar because they share a long evolutionary history. Here, it is assumed that feelings are sensed similarly.


As for feelings, we know introspectively that we experience them ourselves. However, this is the only direct evidence we have. Feelings are not visible externally, which is why they are often denied in nonverbal organisms. However, there was a time when people believed the same thing about the feelings of human newborns. Today, most people would agree that this was a false belief even though the body and brain of an infant are very different from those of adults, sometimes even more so than in closely related but different species.


Feelings are most likely similar when evolutionary pathways overlap. Similar to the unique evolutionary pathways of different species, individuals within a species all have their own developmental pathways that shape the body and the and brain in form and performance. Thus, intraspecific differences in how feelings manifest are expected.


Scientists postulate that we would not know what it is like to be a bat until we are a bat. Similarly, however, we would not know what it is like to be our neighbor. Feelings are difficult to detect in other species because they cannot verbally communicate their internal states. But this also applies to humans. For they too would often not know what they are feeling. Many people would see a therapist to find out.


How can emotions be measured?

Scientists use behavioral or physiological characteristics. Many different methods are used. In animals, they use thermography, measure the temperature of different parts of the skin, interpret facial expressions, body postures or movements, measure heart rate or cortisol levels in blood and saliva, and much more. Through this, they draw conclusions about emotional stirrings in the individual. Feelings, on the other hand, especially in animals, are difficult to impossible to access by these measurement methods, assuming that they depend on individual interpretations of thought.


Are emotions contagious?

Several scientists nowadays agree that emotions can be transmitted within social species. Emotions are contagious! They spread easily in a social group and are involved in the process of empathy, empathizing with another living being. Emotional contagion is the emotional response triggered by the perception of another individual's emotional state, especially among members of the social group or family with whom they have a strong social relationship or bond.


Several studies showed basic forms of empathy in social species, from rodents to primates. It involves mimicking expressions of emotion, adapting to another's emotional state, and responding to the distress of others with reassuring behavior or helping actions. Some animals, such as ravens, not only match the emotions of their conspecifics at the behavioral level, but also match their judgment, interpreted as an emotional state, after observing a conspecific respond with obvious frustration to a negative manipulation.


Emotional contagion is described as a match of emotional state between subjects, and is thought to facilitate communication and coordination in complex social groups. Empirical studies have focused on measuring behavioral contagion in general, on the one hand, and emotional arousal, on the other. Emotional contagion occurs not only in mammals but also in birds. In particular, emotional contagion, which refers to the matching of emotional state between individuals, is a powerful mechanism for information sharing and, as a consequence, increased defense against predation and facilitation of group living. It is important to keep in mind that imitation of a particular behavior does not necessarily imply the contagion of a corresponding emotion. Behavioral and physiological measures do form meaningful indicators of an animal's emotional state and thus of potential contagion, but these components primarily assess emotional arousal. However, an emotion is defined by both its arousal level and its positive or negative valence. Thus, unlike the measurement of arousal, the quantification of emotional valence often remains unexplored. For this reason, changes in arousal, such as fluctuations in heart rate, are not necessarily accompanied by consistent changes in valence and thus may not be fully informative of specific quality. Changes in emotional states correlate with changes in behavioral, physiological, and cognitive components. Feelings include the additional subjective "feeling" component, which is often difficult to measure directly, as described earlier. In animal research, therefore, scientists often focus on objectively measurable components to determine the presence and nature of an emotional state. 

Studies report that emotional contagion exists not only between the same species, such as human to human, but also between different animal species. In particular, scientists are focusing on the interaction between humans and dogs. The dog is the oldest domesticated species. Dogs have coexisted with humans for more than 30,000 years and are woven into their society as bonding partners. Dogs have acquired human-like communication skills and, likely as a result of the domestication process, the ability to read human emotions; therefore, scientists hypothesize that there is emotional contagion between humans and dogs.


One study evaluated the emotional responses of dogs and humans using heart rate variability, which reflects emotions, under a psychological stress condition in owners. The correlation coefficients of heart rate intervals between dogs and owners were positively correlated with the duration of dog ownership. The sex of the dogs influenced this as well. Female animals showed stronger values. These results suggest that emotional contagion from owner to dog may occur primarily in female dogs and that the time they share the same environment is the key factor in the effectiveness of emotional contagion.


What can be derived from the knowledge of emotions?

Emotions are embedded in a complex network of brain structures that includes both cortical and subcortical areas that are activated in close interaction with the body. Depending on the situation, different brain regions are given special importance. In the case of threat, "old" brain structures are predominantly emphasized. Other studies have shown a close connection between the brain and the rest of the body. Accordingly, emotions are embedded in a complex interplay of brain regions and body in both humans and animals and do not take place in isolation in the individual, but are dependent on various influences and also on other interaction partners.


The spinal cord is also rapidly activated in response to emotional stimuli. Lesion of the spinal cord are associated with the influence of feelings in human patients, he said. The involvement of such structures, which are conserved in all vertebrates, casts doubt on the emphasis on consciousness, language, cultural construction, and the uniqueness of humans. Even the evolutionarily "younger" neural architecture of humans is largely shared with mammals and birds. The human brain is hardly categorically different from other brains. Yet scientists who emphasize this do not deny that the human brain has features that other species lack. These unique structures could potentially alter emotional experiences. At the same time, this is true for other species as well since all species have unique brains!


Furthermore, scientists wonder how related two species have to be in order to feel similar emotions. Apart from that, they see it as highly unreasonable to exclude feelings in all animals, especially those that are closely related to us and have similar bodies and brains. Scientists also warn other scientists not to doubt the existence of feelings in animals! Because people would have different feelings of duty towards living beings with or without feelings. Therefore the question of the sentience of animals is a central ethical point! This means that extreme care should be taken in this area so as not to give fodder to those who consider animals morally unworthy. Scientists have the obligation to state clearly what is a mere conjecture and what is a fact when it comes to the feelings of animals!

Scientists try to understand behavior and assign meaning to what is seen, often hypothesizing from physiology, neuroscience, and/or evolutionary theory. It is not always a matter of whether the postulated variables are known or not. Astronomers are not asked to represent gravity, which is invisible, to explain planetary motions, he said. Science is full of postulated intervening variables to make sense of observed phenomena. The invisibility of animal feelings is not a good argument against them!


Moreover, scientists emphasize that we should try to take more of the animal perspective when we ask questions and design studies. If we take a typically human phenomenon and ask whether it also occurs in chimpanzees, for example, it is more likely that this behavior will characterize us better than it does them. The literature on animal behavior is full of examples where we have misjudged animals based on human testing biases. These biases often dictate the search for human-like characteristics in animals, especially those that are closely related to us. In doing so, they overlook the uniqueness of other species! We have difficulty seeing a chimpanzee as a conspecific does. Instead of focusing on human-like emotions, we should consider the species-specific emotions of other animals as they have evolved in accordance with the specific needs of each species. The diversity of species that can be studied, with their unique brains and bodies, could provide new insights into emotions and feelings.


About the deeper meaning of emotions

Emotions remain a mystery to most of us. Nevertheless, we recognize their central importance for the reaction to external stimuli. Without emotions there is no life! And then there is another fascinating aspect: Emotions provide the prerequisite for reciprocal relationships with other emotional beings! Only by the existence of emotions this is made possible! Emotions can thereby not only cause responses to a stimulus, they can also, if they are transmitted, cause emotions in other living beings. This mutual engagement - sometimes referred to as moments of encounter or meeting with other souls - can be transformative. This kind of encounter or relationship allows us to be "seen," to be "known" by others, and in achieving this, emotions allow us to be persons. This plays a particular role in child development, where key phenomena of emotional encounters are central to development. However, if emotions now also transfer between different species that either feel similarly or feel differently due to differences in sensory perception, this raises fascinating questions. Through contact with other individuals who perceive the world similarly, yet differently, we can resonate and be "recognized" and "seen" in the same way, but presumably somewhat differently than when a human enters into a relationship with us. The encounter with animals thus takes on a whole new meaning for us humans!



·     Adriaense et al. (2019) Negative emotional contagion and cognitive bias in common ravens ( Corvus corax), Proc Natl Acad Sci U S A 116(23):11547-11552


·         Katayama et. al. (2019) Emotional Contagion From Humans to Dogs Is Facilitated by Duration of Ownership, Front Psychol 10:1678.


·         Kret et al. (2022) My Fear Is Not, and Never Will Be, Your Fear: On Emotions and Feelings in Animals, Affect Sci 3(1):182-189.


·         Reddy, V. (2019). Meeting infant affect. Developmental Psychology, 55(9), 2020–2024.