Source: R. Douglas Fields
Empathy is the remarkable ability to perceive the thoughts, intentions, and emotions of other individuals. In human relations, empathy binds us together in interpersonal and social relations. It organizes our social behaviors, is the foundation of our commitment to justice, sparks selfless acts of altruism and heroism, and can be lifesaving by alerting us to danger when witnessing fear in others.
Impaired empathy, on the other hand, corrupts civilized behavior and can result in psychopathology, violent crime, and war. The horrific succession of mass murders of innocent people in the United States is unimaginable for anyone with a normal sense of empathy. Indeed, of all human attributes, empathy is widely considered one of the noblest, and is often seen as a defining characteristic of human beings. But how unique is our species in our ability to feel the pain, fear, and intentions of others?
Can Animals Experience Empathy?
Just as empathy is vital for human relations, so too could empathy be critical for other social animals, and there is a compelling body of behavioral research to support this. (This may be obvious to owners of “man’s best friend” and other devoted pets.) In recent years, neuroscientists have begun to identify the neural circuits of empathy in experiments on animals—for example, by using brain imaging to trace brain circuits that are activated in rodents and monkeys while behaving in situations that demonstrate the ability to respond empathetically to another animal’s emotions. The same neural circuits that are activated in a “victim” exhibiting a behavioral response to a threat are activated in the brain of the witness. At a neural circuit level, it is as though the observer was having the same experience, including feeling pain.
These circuits span from the prefrontal cortex to the amygdala and beyond, and the same neural networks are activated in human beings during empathetic experiences. But this is only an observation, or a correlation, not proof that these neural networks shared by animals and people are what produce empathy. The vital test of that question would be to manipulate this circuitry in experimental animals to see if empathetic behavioral responses are changed.
New Neuroscientific Evidence of Animal Empathy
As summarized in a new paper by researchers at the Netherlands Institute for Neuroscience in Amsterdam, new methods of driving and squelching neural activity in these brain circuits that are associated with empathy in experimental animals do indeed alter empathetic responses that are shared across species.
If a mouse observes another mouse receiving a foot shock it will tend to freeze. This is considered a model of empathetic emotional “contagion” wherein an individual witnessing pain or fear in another animal will behave in a similar manner. We wince reflexively when we see another person trip and skin their knees, and it is our prefrontal cortex that unleashes that shared experience.
One region of the prefrontal cortex responds actively in an observer mouse in experiments on emotional contagion—notably, the left anterior cingulate cortical (ACC) region. Intriguingly, this region is also where emotional “mirror neurons” are located. These neurons fire in both the behaving individual and the observer (human or animal) that either performs or witnesses the action—including painful reactions of another individual.
When a variety of precision methods are used to inhibit or stimulate the firing of neurons in this brain region, the freezing behavior of the witness mouse is inhibited or stimulated respectively. That is, stimulating the ACC in these experiments produces fear and freezing in the witness, and dampening neuronal firing in this brain circuit suppresses the empathetic response.
Damage to this and other circuits that underlie empathetic behavior renders human patients unable to experience the emotions of others. In sum, there is now a compelling body of neuroscience data showing that the same brain circuits responsible for empathy in humans are shared with animals from mice to monkeys (and probably more).
How Oxytocin Affects the Empathic Response
One of the interesting results of this area of research is the discovery that the hormone and neurotransmitter oxytocin, popularly dubbed the “love hormone,” drives empathy and attachment. The production of oxytocin is involved in reproduction, birth, parental bonding with offspring, and a broad range of powerful social bonding behaviors.
When your dog gazes lovingly into your eyes, oxytocin levels are boosted in both your pet and in your brain, according to Japanese researchers publishing their findings in a 2015 article in the journal Science. In studies on monkeys, infusion of oxytocin into the amygdala boosts empathetic behavior. Although the actions of oxytocin and normal and abnormal behavior are more complicated in humans, these animal studies open the possibility of using oxytocin drugs therapeutically for treating antisocial behavior.
Kindness and brutality hinge on the extremely complicated neural mechanisms that enable one individual to feel the same feelings they witness in someone else. Without empathy, there would be no humanity—but we share the same capabilities, and the same neural circuitry, with other social animals.