From a dad hugging his daughter who lost a sports game to a husband trying to alleviate his wife’s distress by listening to her, humans have the capacity to adopt others’ points of view and relate to others’ emotions. This ability to share and understand what others might be feeling is known as empathy, and it has a crucial role in how we interact with one another. At first glance, it might seem that empathy is a human trait; however, several studies in the neuroscience and primatology fields have shown that other mammals may feel empathy as well.
“For de Waals, the empathic response is composed of several layers, which build on top of each other and remain functionally integrated.”
Scientists have attributed different meanings to the term ‘empathy’ throughout the years. When the term empathy was coined, in the early 1900s, it was not primarily related to feeling another person’s emotions. Instead, it was about projecting our imagined feelings and movements into objects. By the 1950s, as scientists began to investigate social relations, empathy’s definition shifted from an imaginative projection to the connection between people. It was only in the last few decades that the interest in empathy spread beyond psychology to other scientific fields such as neuroscience and primatology (Lanzoni, 2015). From this moment on, broader definitions of empathy began to pop up, and more scientists began to recognize empathy in other animals, especially non-human mammals.
Among these scientists is the primatologist Frans de Waal who studies primate social behavior. He understands empathy as an ‘umbrella’ term for all the processes that begin when an animal understands another’s emotional state. Thus, an animal empathizes with another when it is affected by and shares the other’s emotional state and also when it assesses the reasons for it and adopts the other’s point of view. For de Waals, the empathic response is composed of several layers, which build on top of each other and remain functionally integrated (De Waal and Preston, 2017). He calls this a Russian-Doll model of the empathic response, named for a stacking-doll set in which a small doll is placed inside a bigger one.
“There is evidence showing that fear, as well as pain, can be socially transferred.”
The different layers of the Russian-Doll model
At the core of the empathic response, we have motor mimicry and emotional contagion. Motor mimicry is when an animal copies another animal’s bodily and facial expression. When a baby blinks in response to an adult’s blinking, he or she is mimicking. In a similar way, when a dog yawns in response to another’s dog yawning, it is also mimicking. Besides dogs, the behavior of mirroring another’s facial and/or body expression has also been described in other non-human primates such as chimpanzees and macaques.
Emotional contagion, as the name suggests, occurs when an emotion is passed to another animal. There is evidence showing that fear, as well as pain, can be socially transferred. For example, in the phenomenon of fear contagion, the sight, sound, or smell of a scared mouse may trigger or increase fear responses such as freezing in another mouse (Debiec and Olsson, 2017). Pain can also be transferred from one animal to another. Witnessing another mouse in pain increases the pain response of the observer mouse (Smith et al., 2016). In addition to fear and pain, mice can also pass along pain relief. In a study published in early 2021, researchers injected two mice with a pain-inducing solution, but one also got a soothing dose of morphine, a medication used to relieve pain. After mice had spent an hour in the same cage, their pain sensitivity was measured. Mice in pain that socially interact with morphine-treated animals behaved as though they also got the drug, indicating that the relief of pain, known as analgesia, is also socially transferred (Smith et al., 2021).
“Rats can also offer help to alleviate another rat’s distress. “
In the mid-layer of the empathic response, we find empathic concern. An animal shows empathic concern when it worries about the emotional state of another animal and tries to alleviate that state. Animals concerned with others often express consolation behavior, defined as a reassuring behavior by a bystander towards a distressed fellow (De Waal, 2011). In 2010, a study compiling data from more than 3,000 observations of chimpanzee fights showed that chimpanzees often offer consolation to a fellow chimpanzee that lost a fight. This behavior was shown to be more frequent in socially close individuals and was more typical of females (Romero et al., 2010). Rats can also offer help to alleviate another rat’s distress. In a study published in 2011, rat cagemates were placed daily in an arena, with one animal trapped in a plastic tube and the other free to roam around. Within a few days, the free rats learned to open the door that kept their cagemate trapped. This door-opening behavior was less common when the tubes contained a toy rat or were empty, and it also happened even when rats were given the choice between freeing a cagemate and eating chocolate chips – a food that rodents enjoy eating (Bartal et al., 2011).
In the outer layer of the empathic response, we find perspective-taking and targeted helping. Perspective-taking allows an animal to understand another’s situation and needs, while targeted helping, which is considered a clear example of perspective-taking, is a behavior shown by an animal that understands other animal’s situations and acts accordingly to this evaluation. A younger ape bringing fruits from a tree to older apes that can no longer climb or a mother ape that helps her whimpering youngster to move from one tree to another are examples of targeted helping (De Waal, 2008; De Waal and Preston, 2017).
“[…] if humans and animals share levels of the empathic response, the basic neural mechanisms underlying these behaviors might be shared too.”
From emotional contagion to perspective-taking, all processes discussed above tell us that empathy may be an ability shared among several mammalian species. And, even though some species might not have the full empathic response that we see in humans, it does not necessarily mean that they do not share or relate to one another’s emotions. As discussed here, social mammals such as apes and rats are affected by the distress of a familiar fellow and act on their behalf, showing that they might simply relate to others in a different way. Additionally, if humans and animals share levels of the empathic response, the basic neural mechanisms underlying these behaviors might be shared too. Thus, studying these animals might aid scientists to understand better human disorders in which social abilities are affected.
Written by Mariella Careaga. Illustrated by Sumana Shrestha.
Edited by Elizabeth Burnette and Zoe Guttman.
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Bartal, I. B. A., Decety, J., & Mason, P. (2011). Empathy and pro-social behavior in rats. Science, 334(6061), 1427-1430.
Debiec, J., & Olsson, A. (2017). Social fear learning: from animal models to human function. Trends in cognitive sciences, 21(7), 546-555.
De Waal, F. B. (2008). Putting the altruism back into altruism: the evolution of empathy. Annu. Rev. Psychol., 59, 279-300.
De Waal, F. B. (2011). What is an animal emotion?. Annals of the New York Academy of Sciences, 1224(1), 191-206.
De Waal, F. B., & Preston, S. D. (2017). Mammalian empathy: behavioural manifestations and neural basis. Nature Reviews Neuroscience, 18(8), 498.
Grenier, F., & Lüthi, A. (2010). Mouse brains wired for empathy? Nature neuroscience, 13(4), 406-408.
Lanzoni, S. (2015). A Short History of Empathy. The Atlantic.
Romero, T., Castellanos, M. A. and De Waal, F. B. (2010). Consolation as possible expression of sympathetic concern among chimpanzees. Proceedings of the National Academy of Sciences, 107(27), 12110-12115.
Smith, M. L., Hostetler, C. M., Heinricher, M. M., & Ryabinin, A. E. (2016). Social transfer of pain in mice. Science advances, 2(10), e1600855.
Smith, M. L., Asada, N., & Malenka, R. C. (2021). Anterior cingulate inputs to nucleus accumbens control the social transfer of pain and analgesia. Science, 371(6525), 153-159.