US and Them: Why Emotions is Not Unique to Humans

Rachel Baker

Writer’s comment: Ever since I was a little girl, I have wanted to be a veterinarian. I began working in veterinary hospitals about six years ago and have come to realize the importance of human-animal emotional bonds. Most pet owners have little doubt that their animals experience emotions. However, among behaviorists and brain researchers, the topic is controversial. I chose to research the subject because I believe veterinarians should understand both sides of the debate. While researching the topic, I received insightful information from behaviorist Dr. Gabrielle Nevitt and veterinarian Dr. Barry Love. Because Dr. Nevitt and Dr. Love work closely with animals, they were able to provide examples of animal emotion that eventually led me to my thesis. Now, more than ever, I believe animals experience emotion.
—Rachel Baker

Instructor’s comment: Rachel Baker’s piece, written for my English 101 class, displays the intelligence and dexterity with which she approached her final research proposal. The final assignment is not an easy one. I ask students to do primary and secondary research in an area that arouses their interest and to write a proposal argument that integrates the logical and rhetorical strategies we have been working on all quarter. I request that they make explicit their evaluation of this research in a clear and balanced way and that they think judiciously of all possible counterclaims that their numerous arguments might invite from their audience. Their proposals—be they grant proposals, business proposals, or proposals that feature new scientific, philosophic, or cultural theories—must reflect original research or thought. For this essay, Rachel argues that despite the methodological problems of assessing the subjective states of creatures who can’t talk, the preponderance of evidence shows that emotion is not unique to humans. Rachel writes with the conviction, clarity, and ease of a writer who knows the needs of both a specific and general audience. Not for a moment does she lose her reader’s interest.
—Raquel Scherr, English Department

About two years ago, an even-tempered corgi mix named Titania arrived at our veterinary hospital to board for a few days. However, unexpected events in her owner’s life turned a few days into a few weeks, and then a few months. As time went by, Titania became noticeably thinner, quieter, and more irritable. She stopped wagging her tail and refused food and treats. No amount of attention seemed to lift her spirits, and she began to snap at the hospital employees whose hands she had once licked. Titania was no longer the friendly animal we had all known before.
         Most people would recognize Titania’s behavior as depression. We can empathize with her; many of us know what it feels like to be left behind. Loneliness is arguably one of the worst emotions we experience—and Titania couldn’t even understand why her owner had abandoned her. It is easy to assume the dog was depressed, since she certainly looked that way. We might also say she was frustrated, sad, bored, or even angry. Many behaviorists would argue that these assumptions are anthropomorphic, but recent evidence suggests that emotions are a major factor in animal behavior.

What is Emotion?
         According to Sherwood, emotion includes both feelings and the behaviors those feelings elicit (132). For example, depression includes moods of sadness and loneliness, which cause physical manifestations such as lethargy and, in humans, tears. By this definition, there can be little argument against animals having feelings. After all, if feelings are the direct cause of behavior, then how could behaviors exist without them? Tidy as it seems, this may be faulty reasoning. A behaviorist might argue that animals simply react to a stimulus without feelings coming into play at all. They rightly demand more concrete proof of animal emotion.
         Most researchers agree that animals experience the more primal emotions, such as fear and aggression. These emotions, after all, are responses to a threat and can save an animal’s life. But what about the more abstract emotions, such as love, hate, or jealousy? Many behaviorists ignore or discount the existence of abstract emotion in animals, writing off emotional interpretations of behavior as anthropomorphic (Milani 221). But the majority of pet owners believe just the opposite, and can provide what they see as undeniable evidence of their pets’ emotions (Milani 225-26).

Why the Controversy?
         Pet owners are notorious for ascribing human emotions to their animals. Fido wags his tail, so he must be happy. Fluffy purposely urinates on the new Persian rug, so she must be mad. However, according to many behaviorists, an animal’s actions do not necessarily imply emotion (Milani 221). An animal’s behavior usually has a logical purpose—most often, self-preservation. Most researchers do not link survival instincts to emotional feelings; in fact, they say much of how the brain responds to stimuli takes place unconsciously, leaving little time for feelings to get involved (LeDoux 156). In the human world, however, emotion governs much of how we live our daily lives. Sometimes these feelings seem counterproductive; our first response to an event is often emotional rather than intellectual, leading to strange behavior. For example, I am terrified of spiders. Simply the thought of a spider disturbs me, and when I actually see one—big or small—I cause quite a spectacle. More than once I have leapt away from a tiny spider only to stub my toe or bump my head in the process. This fear seems irrational because it appears to have no logical purpose, and sometimes even leads to injury. A behaviorist might argue that because emotions like this can interfere with normal survival behavior, an animal’s response to a stimulus cannot involve emotion. What we perceive as an animal’s emotion may in fact be an anthropomorphic interpretation of a completely natural, non-emotional behavior (Milani 221). For instance, according to Milani, a dog’s wagging tail has a variety of functions. While it can signal playtime, a waving tail can also be a greeting to strangers, or simply a result of breeding (227-28). Hounds, for example, are bred to wag their long tails high in the air so a hunter can follow them in tall grass. This behavior may not be emotional, but rather a result of instinct or genetics.
         Simply because a behavior has an obvious function, however, does not mean it does not involve emotion. Why then are scientists often so quick to discount the notion that animals have feelings? One reason may be the lack of legitimate evidence. An animal’s brain might show the same activity as a human brain in response to an “emotional” stimulus, but this does not mean the animal experiences the same feelings we do. There is a certain amount of subjectivity associated with all emotions, human or animal, making emotion difficult to measure (Griffin 6).

The Physiology and Purpose of Emotion
         Although many studies have shed light on the neurological mechanisms of emotion, no one is sure how much of the brain is involved in the process (LeDoux 156-57). Many researchers believe the limbic system governs emotion, yet no one can quite agree on exactly which parts of the brain comprise it (LeDoux 158). Most neurologists agree that the limbic system includes structures in the forebrain surrounding the brainstem (Sherwood 132), but recent research suggests parts of the midbrain and neocortex may also be involved (LeDoux 157). Figure 1 provides a diagram of structures commonly thought to be involved in the limbic system.

Figure 1: Structures involved in the limbic system. The limbic system is poorly understood and may actually comprise more than just the pictured areas. Note the amygdala, a structure important in fear responses. (Sherwood 133)

         Researchers often test human emotion with “emotional tasks,” in which they observe a subject’s brain activity while he or she views images designed to elicit an emotional response. This procedure often activates areas of the limbic system, supporting the view that the forebrain determines emotion (LeDoux 159). It is possible that the limbic system’s activity and the sensation of emotion are simply coincidental, but Sherwood cites more convincing evidence for the limbic system’s function. During brain surgery on humans, stimulating various limbic structures elicits emotions such as joy, anger, and fear (133). Comparative reasoning suggests that the limbic system causes these feelings in animals as well, since the anatomy involved is present in most mammals (LeDoux 157). Further comparative studies demonstrate that emotion testing elicits the same neural patterns in non-human primates as occur during emotion in humans (Parr and Hopkins 363).
         Gabrielle Nevitt, an animal behaviorist, believes emotion is like a “volume control” for behavior. She suggests it “works as an edifier to encode memory,” and argues that organisms could not develop without it. “Chemical stimuli that come with trauma can change neural pathways,” she says, “and to suggest that animals don’t have that is to argue that they have a totally different [neural] physiology.” Donald Griffin also suggests there is no reason to assume animals are fundamentally different from humans with regard to this cognitive processing. As far as researchers know, neural processes work basically the same way among all animals with a central nervous system. According to Griffin, we should not even rule out conscious thought in animals: It is best to keep an open mind about the possibility of consciousness in all animals that exhibit versatile behavior or communicate in ways that suggest they may be expressing thoughts or feelings. We are consciously aware of only a small fraction of what goes on in our brains, and there is no reason to suppose that this fraction will prove to be larger in other species. (4) If we cannot disprove that animals experience conscious thought, then how can we argue against their sense of emotion? If the neurological pathways and chemicals that influence feelings in humans are also present in mammals, “it would be harder to argue why animals wouldn’t have emotion,” says Dr. Nevitt.
         In addition to physiological evidence, there is also evolutionary evidence to support animal emotion. LeDoux (160) has shown through classical conditioning (eliciting a behavior with a stimulus normally not associated with that behavior [Nevitt, lecture 2001]) that the amygdala is involved in the fear response of animals ranging from rodents to humans. There is little doubt that animals experience some form of fear, since fear is really a self-preservation response to danger. Even a behaviorist who argues that “irrational” fears are counterproductive must admit that the fear makes sense from a Darwinian point of view. For instance, to a dog who flees the vacuum cleaner, the tool is not a harmless appliance but rather a large, aggressive predator. My fear of spiders is also a self-preservation reaction: since I cannot tell the difference between benign and venomous species, avoiding all spiders could save my life (even though it causes occasional bumps on the head). But more abstract emotions, such as love and jealousy, present a different problem. People often consider these emotions truly irrational, since we cannot always understand their purpose. However, from an evolutionary point of view, emotions arose to aid in species survival (McNaughton 603).
         In a recent interview, Barry Love, D.V.M., discussed some of the ways in which these “higher” emotions may promote self-preservation. According to Dr. Love, most pets experience the full range of feelings, from jealousy to love to grief. He gave an example of a dog displaying apparently jealous behavior toward a new baby: “The dog misbehaves by chewing only the new baby’s toys and clothes. Is he just trying to get ahead in the ‘pack,’ or is he resentful of all the attention now given to the baby?” Perhaps it is both. People usually define jealousy as the fear of losing someone’s affection to someone or something else. Although this response may seem illogical to humans because it implies that a person has a limited amount of love to give, it makes sense from an evolutionary perspective. In the wild, male mammals often guard females against other males to ensure their own reproductive success (Goodenough, McGuire, and Wallace 251-52). If other males have reproductive access to the females, the first male’s ability to contribute to the gene pool will suffer. Without sufficient motivation to protect his females, the male’s genetic line will disappear. Jealousy, at best an annoying feeling, could provide just that motivation. Similarly, wild pack dogs must often fight to protect their place in the hierarchy. Newcomers present a problem to other pack members, since the more dominant dogs have first access to food and other resources (Mech 73, 77). The dog who jealously guards his place in the pack is more likely to survive.
         Milani believes that in order to experience jealousy, one must first experience love (242-43). From an evolutional perspective, the ability to love is also an advantage. Dr. Love proposes that love exists between birds, many species of which are monogamous. Monogamy is another evolutionary adaptation that ensures an individual will pass on his genes to the next generation. Although males with only one mate are less prolific than those who impregnate many females, monogamy has several advantages. Individuals without the means to protect large groups of females can still reproduce, and monogamous species do not have to expend energy fighting other males (Goodenough, McGuire, and Wallace 351-53). Love may therefore have evolved to motivate monogamous species to pair up and reproduce. Similarly, love between a parent and child could be an adaptation to ensure offspring survival. A parent closely bonded with its young is more likely to provide proper care, thereby ensuring its offspring will survive to reproduce.
         In addition to jealousy and love, pet owners and veterinarians recognize grief in animals. “When someone owns two dogs, [and] one passes away… the other acts depressed,” says Dr. Love; “the [surviving dog] searches for the other dog for days after. I hear that a lot from owners.” I have witnessed this phenomenon firsthand with my own dog. My family had two basset hounds, one of whom we recently lost to cancer. For weeks afterward, our other dog hardly slept at night, refused food, and solicited our attention much more frequently than normal. Grief might appear to be a rather undesirable emotion from an evolutionary perspective, since it causes decreased food intake and inhibits other activities necessary for survival. However, according to Dr. Nevitt, the behaviors associated with grief are adaptive. “If the survivor shuts down, it won’t respond to whatever killed the other [animal],” she says. “If it was poisoned, [the survivor] doesn’t eat [the toxic food]. If a predator killed it, calming down makes it easier [for the survivor] to hide.” Grief could also be involved in operant conditioning, the use of reward and punishment to reinforce or inhibit a behavior (Goodenough, McGuire, and Wallace 21-22). The emotion may have evolved in this way to help animals preserve their lineage. For example, if a dam experiences grief at an offspring’s death, the emotion could serve as a sort of “punishment,” and she will be more likely to take better care of future offspring to avoid experiencing the emotion again. Dr. Love’s example also fits this scenario. Since a pack’s survival depends on its individuals, one member’s death may cause the other members to grieve. This “punishment” might cause the dogs to pay closer attention to other group members in the future, thereby preserving the pack as a whole.
         Physiological and adaptive evidence provide convincing support for animal emotion. Emotions are grounded in neural processes, and although we do not fully understand how they work, we know they are not supernatural or metaphysical. All organisms with a central nervous system have basically the same neural physiology, so it should not be so difficult to accept that they also experience the same feelings.

Us and Them: Permanent Barriers
         Based on brain activity and Darwinian theory, we can argue for the existence of emotion in animals. However, neurological research and comparative reasoning can only get us so far. In truth, we can never completely understand what emotion is like for another living creature. Even among people, feelings are subjective. We cannot truly know what other people feel, because we cannot get inside their heads. The only way we know of other people’s emotion is through communication, either verbal or postural. Many people believe their pets’ body language indicates emotion; people recognize similar behavior in themselves and connect the posture with a particular feeling (see Figure 2).

Figure 2: The Animal Welfare Institute (21) describes the wolf in the picture above as showing “a doglike expression of pleasure.” Is this an accurate interpretation of emotion or a case of anthropomorphism?

         Body language can be unreliable, however, since even in humans it is easy to misread. Just like some people, certain animals might appear angry or depressed when they feel no such thing. Persian cats, for example, have a naturally sour expression even when they sleep. It is easy to fall victim to anthropomorphism if we simply use body language to read animals’ feelings. Because of this, scientists are often quick to dismiss body language as proof of animal emotion.
         When body language fails, people have the luxury of using verbal language to communicate feelings to one another. Since animals generally don’t, we often consider the language barrier a major obstacle to our understanding of animals’ feelings. However, there have been cases of animals who undeniably communicated emotions. Koko the gorilla learned hundreds of words in American Sign Language and was able to carry on conversations with her keepers. According to Peterson and Linden, Koko could clearly indicate feelings such as sadness and jealousy to her keepers through sign language. Koko’s linguistic abilities made it easier for people to believe the gorilla experienced emotions. Unfortunately, this proof does not exist with most other animals.
         That said, is it really fair to require verbal confirmation as proof of another creature’s feelings? Even with people, it takes a certain amount of faith to believe that others feel what they say they feel; humans are good at deceiving one another. Since language is unreliable even between two people, we should not consider the lack of it such a hindrance in studies of animal emotion. Perhaps instead of absolutely trusting or discounting body language, we should simply take it with a grain of salt. Animal body language does not always mirror that of people. For instance, squinted eyes are a sign of hostility in humans, but signal appeasement to cats (Nevitt, lecture 2001). If we learn how to read an animal’s body language correctly, anthropomorphism will become less of a problem. Though not foolproof, posture can be a useful tool in reading emotion, and when properly understood, may be evidence of an animal’s feelings.

Implications
         If animals do experience “human” emotions, the implications affect every way in which we interact with animals—laboratory testing, livestock production, entertainment, even the way we keep pets. Animals are a huge part of our existence; they provide food, clothes, medicine, and amusement, but we rarely consider their emotions. We base much of our moral code on how our actions affect other people emotionally, but we do not usually show animals the same consideration. However, if research ever provides undeniable proof that animals also experience emotion, it will revolutionize the way humans conventionally think of animals.
         Dr. Nevitt believes culture and tradition are a major reason for our obstinacy in separating humans from beasts. She suggests that anthropocentrism is so ingrained in our psyches, so much a part of our culture, that we don’t even question it anymore. But the discovery of animal emotion would force us to look at animals in a different light, and reconsider traditional views of “us” and “them.” Our relationships with all of the creatures in our lives would change in ways we cannot anticipate. Perhaps we are afraid to believe humans and animals are not so different, because we are simply not ready for the consequences.

References

Animal Welfare Institute. Animal Expressions. Washington: Animal Welfare Institute. 1967.

Goodenough, J., McGuire, B., Wallace, R.A. Perspectives on Animal Behavior. 2nd ed. New York: John Wiley and Sons, 2001.

Donald R. Griffin. Animal Minds. Chicago: U of Chicago P, 1994.

The Holy Bible, King James Version. New York: Meridian, 1974.

LeDoux, J.E. “Emotion Circuits in the Brain.” Annual Review of Neuroscience 23 (2000) 155-184.

Love, Barry. Personal Interview. 25 May 2001.

McNaughton, N. Cognitive Dysfunction Resulting from Hippocampal Hyperactivity—A Possible Cause of Anxiety Disorder? Pharmacology Biochemistry and Behavior 56 (1997): 603-11.

David L. Mech. The Wolf: The Ecology and Behavior of an Endangered Species. Garden City: Natural History Press. 1970.

Myrna M. Milani. The Body Language and Emotion of Dogs. New York: William Morrow, 1986.

Nevitt, Gabrielle. Neurobiology, Physiology and Behavior 102 Lecture. University of California, Davis. Spring, 2001.

---. Personal interview. 30 May 2001.

Parr, L.A., and Hopkins, W.D. “Brain Temperature Asymmetries and Emotional Perception in Chimpanzees.” Pan troglodytes. Physiology and Behavior 71 (2000): 363-71.

Patterson, Francine, and Eugene Linden. The Education of Koko. New York: Holt, Rinehart, and Winston. 1981.

Sherwood, L. Human Physiology: From Cells to Systems. 3rd ed. Belmont: Wadsworth. 1997.