Human empathy depends on the ability to share the emotions of others--to “feel” what other people feel.
It is regarded by many people as the foundation of moral behavior.
But to some, the concept seems rather airy-fairy. What does it mean to say “I feel your pain”? Isn’t that just a fanciful flight of the imagination?
For one thing, it turns out nonhuman animals--even rodents--show evidence of empathy.
For another, empathy has a neurological basis.
The same brain regions that process our first-hand experiences of pain are also activated when we observe other people in pain.
Moreover, when we observe the emotional signals of others, we recruit brain regions associated with theory of mind, the mechanism that permits us to take the perspective of another person (Schulte-Rüther et al 2007).
This theory of mind mechanism, along with the ability to keep our own emotional reactions under control, may be of crucial importance for showing empathic concern, or sympathy. If I don't consider your perspective and control my impulses, I might react to your pain as if it's primarily an irritant or assault on me.
So empathy and empathic concern aren't just ideas. They are rooted in concrete, measurable, physical phenomena, and are part of our nature. That doesn't mean we aren't heavily influenced by ideas, but it suggests that humans don't depend on entirely on cultural training to develop a sense of empathy.
Here’s a quick guide to the biology of empathy, including information about the development of empathy in children.
Empathy among nonhuman animals
In one experiment, 15 rhesus monkeys were trained to get food by pulling chains. Monkeys quickly learned that one chain delivered twice as much food than the other. But then the rules changed. If a monkey pulled the chain associated with the bigger reward, another “bystander” monkey received an electric shock.
After seeing their conspecific get a shock, 10 of the monkeys switched their preferences to the chain associated with the lesser food reward. Two other monkeys stopped pulling either chain—preferring to starve rather than see another monkey in pain (Masserman et al 1964).
Mice, too, respond to the display of pain by their companions. Researchers at McGill University put pairs of mice together and injected one or both of them with a substance that induces mild stomach ache.
Mice reacted to the pain by wriggling and stretching their legs. But the intensity of the reaction depended on social cues. Mice wriggled and stretched more when their companions were also in pain (Langford 2006).
Moreover, mice exposed to the sight of a suffering cage mate were quicker to back away from an unpleasant heat source—suggesting that witnessing their companion’s discomfort made mice more sensitive to their own pain.
So there is nothing particularly human about finding the painful experiences of others unpleasant.
But why is “second-hand” pain unpleasant or upsetting?
Empathy in children
New research by neuroscientist Jean Decety suggests a fascinating neurological link between our own, first-hand experience of pain and our perception of pain in other people.
When typically developing kids (aged 7 to 12 years) were presented with images of people getting hurt, the kids experienced more activity in the same neural circuits that process first-hand experiences of pain (Decety et al 2008).
This automatic response--termed “mirroring”--has been documented in a number of other studies, including studies of adults (Lamm et al 2011; Jackson et al 2006). The phenomenon may reflect the activation of mirror neurons, nerve cells that fire both when a person performs an action and he sees that action being performed by others.
To date, researchers have identified specific neurons involved in the mirroring of hand movements in monkeys (Rizzolatti and Craighero 2004), and an exciting new experiment has pinpointed specific regions of the premotor cortex (PMC) that permit humans to understand and imitate such movements:
When researchers selectively (and temporarily) knocked out one part of the PMC, people had more difficulty recognizing pantomimed hand actions but not lip movements. Knocking out another, nearby region yielded the opposite effect (Michael et al 2014).
No one yet has isolated specific mirror neurons for pain or emotion, but evidence in favor of their existence is accumulating (Corradini and Antonietti 2013).
More than mirrors
Mirror neurons may explain how we can experience “second-hand” pain or emotion.
But to respond with empathic concern, we need other information, too.
We need to understand the perspectives of other people.
We also need to overcome our own negative reactions to the display of another person’s pain or distress.
Brain-imaging research seems to confirm this link between theory of mind and empathy. For instance, when people have been asked to evaluate the emotional facial expressions of others, they showed activation in the brain regions associated with theory of mind tasks (Schulte-Rüther et al 2007).
And theory of mind is probably important in other ways. For instance, Jean Decety and his colleagues have investigated how the brain distinguishes between the victims of accidents and victims of aggression.
The neural basis of morality?
To better understand how theory of mind contributes to the perception of “second hand” pain, Decety’s team showed kids two sets of images. One set depicted people experiencing painful accidents. The other set showed people who were being victimized by aggressors (Decety et al 2008).
In both scenarios, functional magnetic resonance imaging (fMRI) revealed that merely looking at images activated brain regions associated with the first-hand experience of pain.
But when kids watched images of one person deliberately inflicting pain on another person, additional brain regions (in the orbital medial frontal cortex and the paracingulate cortex) were activated.
Brain imaging research and studies of brain-damaged patients suggest that these regions are associated with social interaction, emotional self-control, and moral reasoning (Blair 2007; Sturm et al 2006).
Were the additional brain regions activated because the kids were engaged in social and moral thinking? It seems very plausible.
The activation wasn’t caused by the mere presence of multiple people in the images, because researchers controlled for that.
And, when kids were debriefed at the end of the experiment, most of them commented on the unfairness with which the victims had been treated.
Empathy and the brain: When kids are cruel
The study mentioned above measured the responses of normally-developing kids. What about kids who show a cruel streak?
Decety’s group (2009) conducted a similar fMRI study on teenage boys with conduct disorder, or CD.
This disorder is a serious psychiatric condition linked with behaviors like physical aggression, manipulative lying, sexual assault, cruelty to animals, vandalism, and bullying. It’s also a precursor to antisocial personality disorder in adulthood (Lahey et al 2005).
Researchers screened boys (aged 16-18) for CD, and showed them the same types of images of accidents and assaults mentioned above.
The results were very interesting.
I feel your pain…and it makes me lash out
In some respects, the boys with CD responded like boys in the control group.
In particular, the mirror neuron system for pain was activated in both groups.
But there were dramatic differences.
First, the boys with conduct disorder experienced less activation in brain regions associated with self-regulation, theory of mind, and moral reasoning.
Second, the boys with CD actually exhibited a stronger “mirror” response to accidentally-caused pain.
And, unlike controls, the boys with conduct disorder experienced strong, bilateral activation in the amygdala and striatum.
What does this mean? It’s not clear. The amygdala processes emotion. And the striatum is activated by strong stimuli—both pleasurable and aversive.
So there are at least two possibilities.
The aggressive boys might have gotten a pleasurable “kick” out of viewing the pain of others.
But given that their own pain centers were strongly activated, it’s also possible that observing second-hand pain triggered negative emotions—emotions that make the boys behave more aggressively.
As Decety and his colleagues point out, negative emotions—particularly in people with poor emotional control—can cause agitation and outbursts of aggression (Berkowitz 2003). This effect may be magnified in kids who have trouble distinguishing their own first-hand pain from the pain of others.
Decety and colleagues speculate that boys with conduct disorder may experience high levels of agitation or distress when they experience second-hand pain. When this distress is combined with poor self-regulation of emotion, they lash out.
But whether second-hand pain makes aggressive kids feel good or irritable, one thing seems pretty certain:
The brains of boys with conduct disorder responded more intensely to images of other people experiencing pain.
And this intensity was linked with the boys’ aggressive tendencies. The more strongly a boy’s brain responded to second-hand pain, the more highly he scored on measures of daring and sadism.
Can empathy be taught?
Animal studies and brain scan research might make us wonder if feeling empathy is a purely automatic process.
But, as noted above, empathy is really a package of abilities, and there is overwhelming evidence that empathy and empathic concern can be shaped by experience and culture.
On the negative side, experiments suggest that exposure to media violence can desensitize us, blunting the brain's response to second-hand pain (Guo et al 2013). It's also pretty clear that people downgrade the pain they perceive in victims when those victims are
That might sound bleak, but this same research suggests ways that we might enhance empathy. For instance, it seems likely that we can increase empathy for members of outgroups by reflecting on the similarities between us.
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