How many times have you seen someone receive a painful blow and doubled over yourself? People seem to have the ability to feel a kind of phantom pain when we see others getting hurt. What's the neurology behind sympathy pain?
A Tale of Two Primates
At the University of Parma, in Italy, Giacomo Rizzolatti was overseeing a project that involved wiring up monkey brains for science. Scientists studied a monkey's brain activity as it went through its regular activities. One of those activities was picking up peanuts. Whenever the monkey bent down and picked up a peanut, the scientists got a little ping from the monitoring machines, letting them know a certain neuron in its brain went off. Naturally this was a neuron that helped the monkey move. It was the "I pick up the peanut" neuron.
Then a scientist in the lab picked up a peanut in front of the monkey, and the machines went ping. The monkey was neither picking up the peanut, nor attempting to. It was just looking at a fellow primate, and recognizing that that primate was doing something it itself had done. The neuron wasn't "I pick up the peanut" neuron it was simply the "picking up the peanut" neuron. There are other neurons that engaged when the monkey saw humans acting in ways it recognized - most notably, an "enjoying the food" neuron that was simulated by the sight of seeing a lab assistant eat ice cream. These neurons did not distinguish between activities that the monkey engaged in and activities it saw others engage in. And these neurons are not limited to monkeys. Everyone has a section of their brain that goes ping when they see actions they recognize, whether those actions happen to them or to others.
The original nickname for the type of neurons that do this was "monkey see monkey do" neurons, but the title was shortened to "mirror" neurons. They're, of course, linked with empathy, as they literally give us the ability to understand what other people are feeling and feel something of the kind ourselves. Scientists are researching the idea that people with autism might be unable to share other people's perceptions of the world because they aren't able to engage their mirror neurons.
These mirror neurons may not be limited to emotions. They may physically sculpt the world around us. They're responsible for "the chameleon effect," the urge for people to imitate the expressions of others. When you see a person yawn, and feel the urge to yawn yourself, you're consciously aware of the chameleon effect. You may also be aware of it when a baby imitates your body language or facial expression. Long-term, scientists think that mirror neurons, and our urge to succumb to them, might be responsible for the facial similarity in long married couples. Imitate someone's expression and laugh for twenty years and you will literally carve the same lines into your face, and build up the same muscles.
Sympathy Pain and Empathy Pain
And then there's the flip side of empathy. Earlier this week a post about a couple of inquisitive scientists prompted many male commenters to discuss the sympathy pain they feel when they see someone getting kicked in the crotch. This is often referred to as sympathy pain, but it's better expressed as empathy pain. When people see others in pain, their mirror neurons kick in.
The somatosensory cortex is the part of the brain which deals with direct stimulation from the sensory neurons. Heat, pressure, and force, are all perceived here. This part of the brain can't be touched by a mirror response. However, the cingulate cortex and the insular cortex both light up when we observe people undergoing pain and trauma. The cingulate cortex deals with learning and memory. The insular cortex is all about self-awareness and emotion. Between the two of them, they force a person to experience all the unpleasant parts of pain - without the pain itself. You are wired to learn from other people's pain, because you have a share in it.
You are also wired to experience other people's exhilaration and triumph. Although everyone who has ever felt testicle pain experiences a male baseball player's agony when he gets a baseball to the crotch, everyone also experiences his joy when he wins, and his exhilaration as he plays. When we watch someone, a part of us literally shares their experiences. So go watch happy people this weekend.
Monkey Image: Bernal Saborio
[Via The Chameleon Effect, Mirror Neurons, I Feel Your Pain, Sharing Other People's Pain, Imitation, Mirror Neurons, and Autism.]