Before we determine whether cats and dogs can feel jealousy, we should first have a clear understanding of what jealousy is. There is no standard definition of jealousy, but psychological research suggests that any definition should be based on three key aspects of the concept: standard examples, typical characteristics, and explanations. The typical traits of jealousy include the person experiencing jealousy, the loved one who triggers it, and the rival who is the object of jealousy. For example, Othello felt jealousy because he believed his wife Desdemona was having an affair with the soldier Cassio.Jealousy is different from envy. Envy involves only two parties, whereas jealousy requires a third-party rival who threatens the existing relationship. Emotions commonly associated with jealousy include fear of loss, a sense of relational threat, sadness, anger, anxiety, and insecurity. Attributing these emotions to jealousy helps explain why people experience such feelings and why they may react with withdrawal, aggression, or even actions like murder.The first, and weakest, piece of evidence for cats and dogs feeling jealousy is that many pet owners believe their animals experience it. One study found that 81% of dog owners and 66% of cat owners reported that their pets seem to get jealous. If we assume that pets can feel jealousy, this would explain the owners’ observations. Another hypothesis is that pet owners, who are deeply attached to their animals, may be exaggerating the psychological complexity of their pets. For example, 74% of people report that their dogs sometimes seem guilty. However, careful experiments show that behaviors that appear to express guilt (such as a dog pressing its paw to its head) are better explained as submissive behavior driven by fear of punishment. Regardless of whether a dog has actually done something wrong, the behavior remains the same. Many pet owners with religious beliefs also think their dogs and cats have souls, but there is no evidence to support this claim.
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Dog Behavior is Similar to That of Toddlers Under Two
A 2014 study provided stronger evidence supporting the idea that dogs can feel jealousy. The researchers adapted an existing experimental design originally used to identify a form of non-verbal jealousy in six-month-old infants. When a mother focused on another baby, the infant’s negative response was more intense than when the mother focused on a book. Similarly, when dogs saw their owners interacting with a lifelike fake dog, they displayed more aggressive behaviors such as growling, biting, and seeking attention more frequently, interrupting the interaction. In contrast, if the owner focused on a Halloween lantern or a book, the dog did not exhibit increased aggression or seek attention more often. Skeptics might argue that these dogs were simply reacting to a strange object, but the dogs in the experiment did not appear to realize the dog was fake—they even sniffed its rear end. However, the dogs’ behavior could also be due to reasons other than jealousy, such as the desire to establish dominance over the new dog or dislike for the fake dog challenging their territory.In 2018, Hungarian animal behaviorist Judith Abell and colleagues modified the experiment to reduce other possible explanations. The rival dog was a real dog, not a fake one, which eliminated the hypothesis that the aggression was due to the novelty of a foreign object. To prevent territorial behavior, the experiment was conducted in an unfamiliar location, not the dogs’ home. The study also compared dogs’ behavior with familiar and unfamiliar rival dogs to eliminate factors related to dominance. The experimenters concluded that the behaviors previously labeled as “jealousy” in dogs were similar to those of toddlers under two. However, the researchers stopped short of definitively concluding that dogs feel jealousy. They took a more cautious approach, stating that dogs were exhibiting behaviors consistent with jealousy.
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The Amygdala Activation Does Not Confirm Jealousy
Recently, researchers have trained dogs to remain still inside a functional MRI scanner, which can identify the active regions of the brain during task performance. In 2018, psychologist Peter Cook and colleagues at New College of Florida conducted a study involving brain imaging to investigate whether dogs feel jealousy. They had dogs watch their caregivers give food rewards to a fake dog and scanned their brains, predicting that the amygdala, a region of the brain associated with emotions, would be more activated in dogs when their owners rewarded the fake dog than when food was simply placed in a bucket. The results confirmed this prediction. They also found that dogs with more aggressive tendencies showed higher amygdala activation than those with less aggressive temperaments.However, this experiment does not prove that the dogs felt jealousy toward the fake dog, as other emotions such as anger, frustration, hostility, or unfairness might explain their reactions. The activation of the amygdala does not guarantee that the emotion is jealousy, as the amygdala is also involved in other emotions such as anxiety, fear, and even positive feelings. Nevertheless, this experiment points to a potential neural mechanism that could explain how dogs might experience jealousy. When a dog sees its owner rewarding another dog, the dog’s brain reacts in a way that could trigger aggressive behaviors, such as growling or biting. While this evidence supports the idea that dogs exhibit jealous behaviors, the question of whether dogs truly feel jealousy remains complex and intertwined with cognitive issues and the challenge of understanding animal consciousness.
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The Idea That Pets Can Feel Jealousy Can’t Be Dismissed by Cognitive Issues
A similar line of reasoning can be used to argue that pets have the conscious experience of jealousy, not just the behaviors associated with it. When humans recognize their own consciousness, the explanation is coherent because we all have a range of conscious experiences, including pain, emotions, thoughts, and self-awareness. Despite the objections from behaviorists and other skeptics, there is no better explanation for your experiences and actions than the fact that you are consciously aware. Believing that other creatures also possess consciousness carries risks, since we cannot experience their inner lives. However, the similarity in behavior and measurable brain processes between humans and animals makes the idea that “other animals also have consciousness” highly plausible. This analogy is not simply an unsubstantiated argument. Instead, it serves as one component of the broader conclusion that “other animals also have consciousness,” which best explains their actions.When trying to prove that babies have consciousness, the analogy weakens, but we know that their brains share a remarkably similar emotional structure and function with adult humans. We have similar understanding about other mammals, such as cats and dogs, which also have brain regions like the amygdala and cortex, which are involved in emotions in humans, though humans have a larger prefrontal cortex. While there may be reasonable doubts about whether cats, dogs, or babies truly possess consciousness, the evidence strongly suggests that they do. Therefore, the conclusion that “pets can feel jealousy” cannot be dismissed by concerns over cognitive complexity or consciousness.The studies mentioned here only address whether dogs experience jealousy, and do not examine whether cats do as well. Dogs are larger than cats and have roughly twice the number of brain neurons. However, the brain structures of cats are similar to those of dogs and other mammals, so from a structural perspective, we should not assume that cats and dogs have any emotional differences. On the other hand, dogs have developed an emotional bond with humans over approximately 20,000 years of evolution, gaining cognitive and emotional abilities that cats have not. Dogs are generally more attached to their owners than cats are, which might make them more prone to jealousy.
Additionally, for both dogs and cats, there may be differences in attachment levels and aggression across different breeds, and both of these factors are linked to jealousy. These breed-specific differences, coupled with the fact that there are currently no behavioral or neural studies supporting the claim that cats experience jealousy, suggest that we should be more cautious when identifying jealousy in cats compared to how we identify jealousy in dogs.
