QUICK FACTS
Created Jan 0001
Status Verified Sarcastic
Type Existential Dread
Keywords
emotion, charles darwin, cognitive bias, learned helplessness, jaak panksepp, valence, comparative psychology, ethology, behaviourism

Emotion In Animals

“Itā€™s a curious thing, this obsession with the inner lives of creatures incapable of articulating it. Humans, with their endless capacity for self-deception and...”

Contents
  • 1. Overview
  • 2. Etymology
  • 3. Cultural Impact

Itā€™s a curious thing, this obsession with the inner lives of creatures incapable of articulating it. Humans, with their endless capacity for self-deception and projection, seem intent on mapping their own messy emotional landscapes onto anything with a heartbeat. And why not? Itā€™s far easier than confronting the void within themselves.

Emotion in the Animal Kingdom: A Comprehensive Examination

The very notion of emotion is typically defined by a rather intense, subjectively felt experience, often tinged with a distinct flavor of pleasure or displeasure. The question of whether this same internal landscape exists in non-human animals is, to put it mildly, a persistent thorn in the side of scientific inquiry. However, the prevailing sentimentā€”or perhaps, the most convenient oneā€”is that these feelings, whatever their exact nature, likely share a common evolutionary root with our own. After all, Charles Darwin , a man who certainly observed more than most, dedicated significant effort to documenting the outward manifestations of what he believed to be inner states in both humans and animals. His initial, rather observational approach has since blossomed into a more rigorous, hypothesis-driven scientific endeavor.

Modern investigative techniques, such as cognitive bias tests and models of learned helplessness , have revealed a surprising range of emotional expression in species as diverse as rats, dogs, cats, rhesus macaques, sheep, chicks, starlings, pigs, and even honeybees. These studies suggest that creatures we often dismiss as simple automatons are, in fact, capable of experiencing states akin to optimism and pessimism. Then thereā€™s Jaak Panksepp , a figure whose work on the neurological underpinnings of animal emotion is, frankly, difficult to ignore. He posited the existence of seven core emotional systems in mammals: seeking, fear, rage, lust, care, panic, and play. His research, often involving direct brain stimulation and pharmacological challenges, provides a tangible, albeit complex, view of these internal states.

The study of animal emotion is approached from a multitude of angles. There’s the behavioral lens, the comparative perspective, the anecdotal accounts that fuel much of our popular understanding, and Darwin’s foundational work. But the gold standard, the one that attempts to untangle the messy wires of biology and experience, is the rigorous scientific approach, which itself branches into functional, mechanistic, cognitive bias testing, self-medication studies, investigations into spindle neurons, vocalizations, and sheer neurology.

Despite the growing body of evidence, the very idea of animal emotion remains a contentious subject. Yet, research has been conducted across an astonishing array of species, from the grandest primates and elephants to the smallest honeybees and even crayfish. The effort to understand their internal worlds continues, driven by a curiosity that borders on obsession.

Etymology, Definitions, and Differentiation

The word “emotion” itself is a relatively recent import, appearing around 1579, borrowed from the French “Ć©mouvoir,” meaning “to stir up.” One can only speculate about the linguistic roots that predated this, but itā€™s safe to assume the concept of being “stirred” by something is as old as language itself.

At its core, an emotion is often described as a distinct, consistent response to an event, internal or external, that holds some form of significance for the organism. These responses are typically fleeting, a symphony of coordinated reactions that can manifest physiologically, behaviorally, and neurologically. Itā€™s also argued that emotions are the elegant, evolved solutions to the persistent challenges our ancestors faced, a testament to the adaptive power of feeling.

Laterality

A fascinating hypothesis, known as the “laterality-valence hypothesis,” suggests a division of labor in the brain. It posits that negative emotions, those that prompt withdrawal, are primarily processed by the right hemisphere, while positive, approach-oriented emotions find their home in the left. Whether this holds true across the animal kingdom is another complex question, but it offers a compelling framework for understanding emotional processing.

Basic and Complex Human Emotions

Within the human experience, there’s a common distinction drawn between “basic” and “complex” emotions. The former typically includes anger, disgust, fear, happiness, sadness, and surpriseā€”the foundational palette of our feelings. Complex emotions, on the other hand, are seen as more nuanced, encompassing states like contempt, jealousy, and sympathy. However, this neat categorization is perpetually being challenged, especially when considering the possibility that animals might express even these more intricate emotional states.

Background
Behaviourist Approach

Before the advent of more sophisticated fields like comparative psychology and ethology , the interpretation of animal behavior often fell under the umbrella of behaviourism . This school of thought advocated for the simplest possible explanation for any given behavior, resisting the temptation to attribute more complex mental processes than absolutely necessary. The core argument was pragmatic: if a behavior can be explained by a straightforward stimulus-response mechanism, why complicate matters by inferring consciousness or higher cognitive functions?

Some prominent behaviourists, such as John B. Watson , maintained that stimulusā€“response models were entirely sufficient to explain even those behaviors that appeared emotional. For Watson, the goal of psychology was predictive: “to predict, given the stimulus, what reaction will take place; or given the reaction, state what the situation or stimulus is that has caused the reaction.” This perspective, while offering a certain elegant simplicity, tends to strip away the subjective experience, reducing complex inner states to mere predictable outputs.

The cautious wording of Dixon exemplifies this viewpoint:

Recent work in the area of ethics and animals suggests that it is philosophically legitimate to ascribe emotions to animals. Furthermore, it is sometimes argued that emotionality is a morally relevant psychological state shared by humans and non-humans. What is missing from the philosophical literature that makes reference to emotions in animals is an attempt to clarify and defend some particular account of the nature of emotion, and the role that emotions play in a characterization of human nature. I argue in this paper that some analyses of emotion are more credible than others. Because this is so, the thesis that humans and nonhumans share emotions may well be a more difficult case to make than has been recognized thus far.

Moussaieff Masson and McCarthy, while disagreeing with this strict behaviorist stance, articulate a similar sentiment:

While the study of emotion is a respectable field, those who work in it are usually academic psychologists who confine their studies to human emotions. The standard reference work, The Oxford Companion to Animal Behaviour , advises animal behaviourists that “One is well advised to study the behaviour, rather than attempting to get at any underlying emotion. There is considerable uncertainty and difficulty related to the interpretation and ambiguity of emotion: an animal may make certain movements and sounds, and show certain brain and chemical signals when its body is damaged in a particular way. But does this mean an animal feelsā€”is aware ofā€”pain as we are, or does it merely mean it is programmed to act a certain way with certain stimuli? Similar questions can be asked of any activity an animal (including a human) might undertake, in principle. Many scientists regard all emotion and cognition (in humans and animals) as having a purely mechanistic basis.

The inherent philosophical quandaries surrounding consciousness and the mind have led many scientists to steer clear of the emotional realm altogether, opting instead for the more tangible, measurable landscape of neuroscience .

Comparative Approach

In 1903, C. Lloyd Morgan introduced Morgan’s Canon , a principle akin to Occam’s razor specifically for ethology. It advises that:

In no case is an animal activity to be interpreted in terms of higher psychological processes, if it can be fairly interpreted in terms of processes which stand lower in the scale of psychological evolution and development.

This principle, while promoting parsimony, can also be a convenient excuse to avoid delving into potentially more complex explanations.

Darwin’s Approach

Charles Darwin , in his seminal work, The Expression of the Emotions in Man and Animals , proposed that emotions are not mere epiphenomena but rather adaptive mechanisms serving crucial communicative and motivational functions. He articulated three principles to guide our understanding of emotional expression:

  1. The Principle of Serviceable Habits: This principle, with its Lamarckian undertones, suggests that emotional expressions that prove beneficial to an organism are passed down to its offspring.
  2. The Principle of Antithesis: This principle posits that some expressions exist simply because they are the direct opposite of expressions that are demonstrably useful. The evolutionary advantage here is less clear, but it suggests a binary opposition in certain expressive behaviors.
  3. The Principle of the Direct Action of the Excited Nervous System on the Body: This principle states that emotional expressions are a byproduct of nervous energy reaching a threshold and requiring release. Itā€™s the physiological overflow of intense internal states.

Darwin viewed emotional expression as an external broadcast of an internal condition. He observed, for instance, that humans often bare their canine teeth when sneering in rage, suggesting that this gesture might have originated from a more literal, tooth-baring aggressive action in our ancestors. He even noted the subtle nuances in a dog’s tail wag, illustrating in his book how this simple movement could convey a spectrum of meanings, from aggression to affection.

  • Examples of tail position indicating different emotions in dogs:
    • “Small dog watching a cat on a table”
    • “Dog approaching another dog with hostile intentions”
    • “Dog in a humble and affectionate frame of mind”
    • “Half-bred shepherd dog”
    • “Dog caressing his master”
Anecdotal Approach

Much of the evidence for animal emotions has historically been anecdotal, stemming from the observations of individuals who spend extensive time with animals, particularly pets. However, critics are quick to point out the potential for anthropomorphism ā€”attributing human qualities to non-human beingsā€”as a driving force behind these interpretations. The debate is further complicated by the inherent difficulty in defining emotions and the cognitive prerequisites believed necessary for animals to experience them in a manner comparable to humans. This difficulty is compounded by the challenges in empirically testing for emotions in animals, given that our understanding of human emotion is largely derived from our capacity for verbal communication.

Scientific Approach

In recent times, the scientific community has shown a growing acceptance of the idea that animals do indeed experience emotions. Research has illuminated striking similarities in the physiological changes that occur in both humans and animals when subjected to emotional stimuli.

A significant part of the support for animal emotion stems from the idea that feeling emotions does not necessarily require complex cognitive processes. Instead, emotions could be primarily driven by the need to act in an adaptive manner, as Darwin himself suggested. Contemporary research has introduced innovative experimental designs and data collection methods. Professor Marian Dawkins proposed that emotions could be studied from both a functional and a mechanistic perspective, suggesting that a combination of both approaches would yield the most substantial insights.

  • Functional: This approach focuses on understanding the roles emotions play in humans and then investigating similar roles in animals. Oatley and Jenkins described a three-stage framework: (i) appraisal, where an event is evaluated as relevant to a goal, leading to a positive emotion if the goal is advanced and negative if impeded; (ii) action readiness, where the emotion prioritizes certain actions; and (iii) physiological changes, facial expression, and behavioral action. However, this framework is broad enough to potentially encompass the entire animal kingdom, and even some plants, raising questions about its specificity.

  • Mechanistic: This approach delves into the underlying mechanisms that drive emotions, seeking parallels in animals. Paul, Harding, and Mendl, for instance, acknowledge the challenges of studying emotion in non-verbal animals but propose that focusing on similar mechanisms observed in humans can offer valuable insights. They suggest that variations in cognitive biases according to emotional state in humans could serve as a starting point for examining animal emotion. By inducing specific emotions in trained animals through controlled stimuli, researchers might be able to identify the basic emotions they experience.

Cognitive Bias Test

A cognitive bias is essentially a systematic deviation in judgment, leading to illogical inferences about situations and other beings. Itā€™s about how individuals construct their “subjective social reality” based on their perceptions. The classic illustration is the question, “Is the glass half empty or half full? ”, which serves as an indicator of optimism or pessimism.

To test this in animals, a common method involves training them to associate a specific stimulus (e.g., a particular tone) with a positive outcome (e.g., desirable food) and another stimulus with a negative outcome (e.g., less appealing food). Then, an intermediate stimulus is presented, and the animal’s choiceā€”whether to pursue the positive or negative outcomeā€”reveals its prevailing mood or emotional state. This can be influenced by factors like the animal’s living conditions. For example, rats exposed to enjoyable interactions like handling or tickling demonstrated more optimistic responses to intermediate stimuli than those who weren’t. This research has been credited with establishing a link between positive affective states and decision-making under uncertainty in animal models.

Cognitive biases have been observed in a wide array of species, including rats, dogs, rhesus macaques, sheep, chicks, starlings, and honeybees.

Self-Medication with Psychoactive Drugs

The human capacity to suffer from emotional and mood disorders like depression and anxiety is well-documented, leading to the development of psychoactive drugs, such as anxiolytics . The irony, or perhaps the logical consistency, lies in the fact that many of these drugs are developed and tested on laboratory animals. If these drugs are effective in treating human emotions, it raises the question of whether the animals on which they are tested are also experiencing similar emotional states.

Standard laboratory cages, often lacking enrichment, can prevent animals from engaging in natural, motivated behaviors, sometimes leading to abnormal behaviors indicative of emotional distress. Studies have explored whether enriching these environments can influence the consumption of drugs like Midazolam , an anxiolytic used in humans. Mice housed in enriched cages drank less of the anxiolytic solution compared to those in standard or unpredictable cages, suggesting that the latter experienced higher levels of anxiety.

Spindle Neurons

Spindle neurons , a specialized type of nerve cell, are found in specific regions of the human brain associated with emotional regulation, empathy, and social cognition. Intriguingly, these neurons are also present in the brains of various cetaceans, including humpback whales, fin whales, killer whales, sperm whales, bottlenose dolphins, Risso’s dolphins, and beluga whales, as well as in elephants.

Whales possess a significantly higher number of spindle neurons than humans, and these neurons are maintained for a longer duration. While their precise function in whale brains remains elusive, researchers theorize they act as high-speed conduits for information processing, enabling rapid responses to emotional cues during complex social interactions. However, itā€™s crucial to avoid simply projecting human emotional experiences onto these animals; further research is necessary to ascertain the nature of their feelings.

Vocalizations

While animals lack the ability to verbally articulate their feelings, their vocalizations can offer valuable clues about their affective states. Darwin himself noted the laugh-like vocalizations of chimpanzees, which he saw as symbolic self-reports of their emotional experiences.

Research on rats has identified 50-kHz ultrasonic vocalizations (USVs) that are believed to reflect a positive affective state, akin to primitive joy or “laughter” in animals. These calls are elicited by rewarding stimuli like tickling , brain stimulation, certain drugs, mating, play, and even aggression, and are suppressed by aversive stimuli. Tickling by humans, notably, elicits the highest rate of these calls.

In domestic cats, purring is often associated with positive valence, occurring during mother-kitten interactions, contact with familiar individuals, or tactile stimulation. It’s generally considered an indicator of “pleasure.” Similarly, low-pitched bleating in sheep has been linked to positive situations, such as when females approach receptive males or when mothers interact with their lambs.

Neurological Approach

Neuroscientific studies focusing on the instinctual, emotional action tendencies in animals, coupled with observed neurochemical and electrical changes in their brains, are considered the most effective way to monitor primary emotional and affective states. By extrapolating from animal research, scientists can develop hypotheses about the neural infrastructure relevant to human emotions. This cross-species approach, sometimes termed “psycho-neuro-ethological triangulation,” allows for deeper experimentation. Studying animals that exhibit clear indicators of emotional states helps decode the underlying neural systems regulating these expressions, which in turn informs our understanding of human affect. For instance, observing changes in playfulness or separation distress in animals can lead to predictions about corresponding changes in feelings of joy or sadness in humans, building a robust neural hypothesis that supports the emotional continuity across species.

Criticism

The assertion that animals experience emotions is not universally accepted. Critics often cite a lack of high-quality evidence and the pervasive influence of anthropomorphism in interpreting animal behavior. Those who deny animals the capacity for emotion frequently point to inconsistencies in studies that support the existence of animal emotions. Without the benefit of linguistic communication, the interpretation of animal emotions relies heavily on behavioral observation and experimental extrapolation from human subjects, a process fraught with potential for misinterpretation.

While the existence of basic emotions like fear in animals is rarely disputed, there’s a concern that anthropomorphism can lead humans to attribute more complex emotions than are actually present. An experiment involving dog owners and treats illustrated this: dogs’ behavior was not correlated with whether they had eaten the treat, but owners were more likely to perceive guilt when the dog hadn’t eaten it, especially if the owner had scolded them. The researchers highlighted that misattributing complex emotions risks unfair treatment of animals.

Some argue that emotions are not universal, even among humans, and therefore, a phylogenetic link between human and non-human emotions cannot be assumed. From this perspective, observed similarities might merely reflect mechanistic features that promote adaptivity, lacking the complexity of human emotional constructs. The development of more complex emotions might, therefore, be tied to social living.

Darwin, through his extensive surveys, concluded that humans share universal emotive expressions and suggested that animals likely share these to some degree. Social constructionists , however, reject the universality of emotions, while others adopt an intermediate stance, positing that basic emotional expressions are universal but their intricacies are culturally shaped. Studies have indeed shown that individuals within a culture are better at recognizing the emotions of others from the same culture.

Examples

Primates

Primates , particularly great apes, are frequently considered candidates for experiencing empathy and possessing a theory of mind . Their complex social structures and strong mother-infant bonds are evident. Accounts from figures like Jane Goodall describe chimpanzees exhibiting behaviors suggestive of grief, such as mothers carrying deceased infants for extended periods. Koko, the gorilla trained in sign language, was reported to have expressed sadness following the death of her pet cat.

Experimental studies have provided further support. In one study, rhesus macaques refused to pull a chain for food if it meant delivering an electric shock to a companion, a behavior more pronounced between familiar individuals, mirroring human empathy . Research into consolation behavior in chimpanzees, where third parties attempt to comfort individuals who have experienced aggression, also suggests a sophisticated understanding of others’ emotional states. Similar observations have not been consistently replicated in monkeys, hinting at potential differences in empathy levels.

Chimpanzees have also demonstrated an understanding of emotional facial expressions. When shown video clips of emotionally charged scenes, they correctly matched them to species-specific facial expressions (“happy” or “sad”), indicating they grasp the emotional significance of these displays.

Rodents

Jaak Panksepp proposed that all mammalian brains are equipped to generate emotional experiences, and subsequent research on rodents has provided foundational support for this idea. Studies have shown that rats will actively work to alleviate the distress of conspecifics, suggesting a form of empathy. For instance, rats that had witnessed another rat in distress responded more readily to lower a distressed companion than those without such experience.

Neuroscientific investigations into rodent empathy have revealed that mice experiencing pain together exhibit heightened pain-related behaviors. Furthermore, the pain sensitivity of a mouse observing a conspecific in pain is comparable to that of the mouse directly experiencing the pain, a phenomenon linked to emotional contagion , which has also been observed in pigs. Freezing behavior in rats, a response associated with fear, is also influenced by observing another rat being shocked, creating an “empathy loop.”

Rodents have also demonstrated the ability to respond to conditioned stimuli associated with a conspecific’s distress as if they were experiencing the distress themselves, suggesting a capacity for shared affect .

Horses

While direct evidence is elusive, studies indicate that domestic horses react differently to photographs of human facial expressions. They exhibit more stress-related behaviors and increased heart rates when viewing angry faces, looking with their left eye, which is associated with processing negative stimuli. Experienced riders often report an ability to discern subtle moods in horses through nuanced physical cues, suggesting a rich internal emotional life.

Birds

Marc Bekoff , in his book The Emotional Lives of Animals, recounts observations of magpies exhibiting what appears to be mourning behavior around a deceased companion. This includes gently pecking at the body and bringing grass to lay by the corpse, followed by a vigil.

Bystander affiliation, a form of empathy where individuals attempt to console distressed others, has been observed in ravens. They engage in behaviors like contact sitting and preening with distressed individuals, suggesting sensitivity to each other’s emotional states, though relationship dynamics play a role.

Domestic hens have shown the capacity for empathy towards their distressed chicks, a key attribute of this emotion. However, evidence for empathy between adult hens is less clear.

Dogs

Research suggests that domestic dogs may experience negative emotions akin to human psychological conditions, such as learned helplessness , a phenomenon studied by Martin Seligman in relation to depression. Dogs conditioned to associate a warning signal with inescapable shocks later failed to escape when the warning was given, even when escape was simple. This perceived helplessness led to chronic symptoms resembling clinical depression in some cases.

Interestingly, a subset of dogs under similar stress conditions did not develop learned helplessness, exhibiting resilience akin to humans with an optimistic explanatory style . Symptoms analogous to clinical depression and neurosis are now recognized within the scope of canine emotion.

Dogs also exhibit a unique instinct: when meeting humans, they instinctively gaze to the right side of the face, mirroring a human behavior used to gather emotional information. This is the only non-primate species known to share this trait.

Studies have identified stable personality traits in dogs, including playfulness, curiosity/fearlessness, chase-proneness, sociability, and aggressiveness. Furthermore, dogs have demonstrated an ability to recognize human and dog emotions by looking at faces and listening to vocalizations, a capacity previously thought to be exclusive to humans. However, the interpretation of a dog’s tail wag requires caution, as it can signify not only happiness but also fear, insecurity, dominance challenges, or a warning of potential aggression. Researchers are now employing magnetic resonance imaging to further investigate the emotional lives of dogs.

Elephants

Elephants are renowned for their empathy and remarkable memory. Observations show they exhibit concern for distressed or deceased members of their species, showing particular interest in dead bodies. While some interpret this behavior as anthropomorphic, it suggests a deep social and emotional connection.

Elephants have also been proposed to pass mirror self-recognition tests , a capacity linked to empathy. However, the methodology of some of these studies has been questioned, and earlier attempts failed, making this claim contentious.

Elephants also communicate emotions through vocalizations, specifically “rumbles,” which can indicate negative emotions or heightened emotional intensity during social interactions or agitation.

Cats

Domestic cats have been observed to manipulate their owners through vocalizations that can resemble human infant cries, sometimes incorporating a purr to make the sound more insistent. Individual cats learn these vocalizations through trial-and-error, reinforcing those that elicit a positive response.

Growling in cats can signal annoyance or fear. When displeased, a cat’s tail movements become more vigorous. Hissing, a vocalization associated with aggression, is often accompanied by postural displays intended to intimidate. Kittens as young as two to three weeks can hiss when handled.

Honeybees

Even honeybees exhibit behaviors suggestive of emotional states. Studies have shown that honeybees subjected to stressful events, like vigorous shaking simulating a predatory attack, become more “pessimistic.” They are more likely to withhold responses to stimuli that previously predicted a reward, mirroring anxious or fearful behavior. Researchers argue that this pessimistic bias in honeybees challenges the notion that such cognitive states are exclusive to vertebrates.

Crayfish

Remarkably, even crustaceans display behaviors analogous to anxiety. Studies on freshwater crayfish have shown that individuals subjected to electric shocks exhibit enhanced fearfulness, preferring dark shelters over lit areas. These shocked crayfish also showed elevated serotonin levels and stress responses. Importantly, the administration of a benzodiazepine anxiolytic, commonly used in humans, reduced these anxiety-like behaviors. This suggests that stress-induced avoidance in crayfish shares striking homologies with vertebrate anxiety. Further research indicated a quantitative relationship between the intensity of stress and the degree of anxiety-like behavior, another common feature of anxiety in vertebrates.

See Also