Scientists are finding that empathy is not just for humans. It plays a key biological role in other animals too, and in a paper published last December in Science, University of Chicago neuroscientists Peggy Mason, Inbal Ben-Ami Bartal, and Jean Decety showed that even rats display such pro-social behavior.
After placing pairs of rats in pens for two weeks, the researchers trapped one of the pair in a plastic restraining tube, while the other rat was free. Once they figured out how to free their rodent compatriots, 23 of 30 rats chose to liberate their peers. (In the control, instead of a trapped rat, the cage had either nothing or a toy.) In another experiment, the researchers set up one cage with a rat and another with a pile of chocolate chips. Most of the free rats opened both cages and shared the treats rather than keeping all the chocolate to themselves.
Some are calling this research evidence of altruism in rats, but senior co-author and CNS member Jean Decety is careful to distinguish this clearly empathetic behavior from truly selfless altruism, which has yet to be determined.
“Empathy,” Decety says, “is the spark of human concern for others.” It can shed light of everything from anti-social behavior to bullying in children, making it critical to understanding the underlying neural mechanisms. We caught up with Decety to learn more about this work on empathy and animals, and how it fits into the cognitive neuroscience picture.
CNS: Why study empathy?
Decety: Empathy, the natural ability to share and understand the emotional states of others, plays crucial roles in much of human social interaction. Empathy motivates caregiving and prosocial behaviors, and importantly it provides the affective base for moral development. Empathy is such a necessary component of healthy co-existence that its absence leads to serious social-emotional dysfunctions, including psychopathologies. Thus a better knowledge of the neural circuits and neurohormonal mechanisms underlying empathy not only advances our understanding of interpersonal sensitivity in general, but also sheds light on emotion processing, their relation with cognition and motivation, individual differences in personality traits, and mental health.
CNS: Can you give us an example of the evolutionary importance of empathy?
Decety: Mammalian reproductive fitness and survival depend crucially on the ability of members of the same species to communicate with each other, sharing information about their emotions and intentions and appropriately responding to their offspring or relatives needs. This is why one likely source of empathetic responses in mammals comes from the ancient practice of caring for ones offspring. It is thus no surprise that parental care is among the most highly motivated social behavior. For instance, maternal rats will cross electrical grids to retrieve pups. Postpartum female rats prefer a cage associated with pups to a cage associated with cocaine!
CNS: How does empathy in non-primate animals relate to empathy in humans?
Decety: While it is unlikely that non-human animals are aware of their feelings and emotions, most of the neural mechanisms that underlie empathy and caring are present (brainstem, hypothalamus, and amygdala) in mammals, and like in humans, are affected by various interpersonal and social factors. If we seek to understand how biological systems implement social behavior in general and empathy in particular, we need to understand how the molecular and cellular mechanisms underpinning social interaction have evolved across species.
Besides, animal models are critical because we can perform interventions which cannot be done with humans for obvious ethical reasons. We can manipulate the physical and social environment, examine genetic polymorphisms, make surgical lesions, and perform pharmacological interventions.
CNS: In your experiment published in Science, why study rats?
Decety: Rodents are mammals, very social, and parental care is clearly expressed. We have all what we need to develop an animal model of empathy and prosocial behavior.
CNS: You make a distinction between empathy and altruism. Can you explain that distinction and why it is important?
Empathy is the ability to understand and share the affective states of another member of the same species. Altruism refers to pro-social behaviors that benefit the recipient at a cost of resources to the donor. Empathy does not automatically lead to altruism, even in humans.
CNS: Would not the rats sharing their chocolate be considered a form of altruism?
Decety: I am not convinced this is what we have demonstrated so far. Altruism intrinsically requires a cost for the donor. Rats indeed shared the chocolate chips, which is really nice and can be considered as a prosocial behavior, but they had their cut. Would a starving rat share the chocolate chips? What about a human person? I am not so sure!
CNS: Since the Science study, what have you been working on?
Decety: This collaboration with my colleagues Peggy Mason and Inbal Ben-Ami Bartal is ongoing with several parallel lines of research, including looking at the cost of prosocial behavior, identifying neural circuits that are necessary for empathy and prosocial behavior, and investigating the role of neuro-hormones and impact of stress. All the work is once again with rats!
CNS: How does your work on empathy fit into the larger field of cognitive neuroscience?
Decety: Understanding empathy and caregiving, how they evolved, how they interact, how hormones modulate their expressions, how they develops in children, what relationship they have with morality, why and how empathy breaks down in a number of neurodevelopmental disorders such as psychopathy – all are important questions that we study in my laboratory.
CNS: What is the significance of your work for the average person?
Decety: Empathy is the glue that makes much of social life possible. Empathy is not unique to humans. It stems from evolutionarily ancient subcortical mechanisms associated with affective sensitivity, attachment and parental care of young. A scientific understanding of empathy is beneficial in the exploration of psychiatric conditions of abnormal emotional processing such as psychopathy, antisocial personality disorder, and bullying in children.
Media contact: Lisa M.P. Munoz, CNS Public Information Officer,