Imagine you’re watching a film about Holocaust and you find yourself feeling very anxious and sad even to the point that tears start running down your face. Or for those of you that identify as more manly, I bet you found yourself cheering vigorously for your favorite team and felt extreme happiness when they won or disappointment and anger when the opposing team scored that last minute goal. Those are common situations so we don’t think much of them, however from a scientific point of view they are quite a puzzle.

Similarly scientists and psychologists wondered why, for example, does one person observing disgust on the face of another who just had a sip of spoiled milk also feels disgust in his stomach as if he himself tasted the foul milk? So much so that some of those people even vomit themselves.

Those and similar observations urged scientists to find answers and some think they found it in the way our brain functions, specifically in mirror neurons. Mirror neurons are a type of brain cell that respond equally when we perform an action and when we witness someone else perform the same action.

Mirror neurons were first discovered at the end of the 20th century by a team of neuroscientists observing brain activities of macaque monkeys. The monkeys watched their peers perform simple actions of grabbing an object. What the scientists knew from the previous studies of the brain activity is that when monkeys would grab an object a certain set of neurons called ordinary motor command neurons would “fire”. However when they observed what is happening in the brain of monkeys that only watched other monkeys grab an object astonished them: the brain activity was the same as if they were grabbing the object themselves!

Mirror neurons

Neuroscientist Giacomo Rizzolatti, who with his colleagues at the University of Parma first identified mirror neurons, claims that the neurons could help explain how and why we can understand the minds of others and feel empathy for them. If watching an action and performing that action can activate the same parts of the brain in monkeys, down to a single neuron, then it makes sense that watching an action and performing an action could also elicit the same feelings in people.

In the decades that followed many studies have been performed that explored the mirror neuron activity in humans. That proved a bit tricky because the scientists couldn’t do the experiments on humans the same way they did on monkeys. On the poor monkeys they attached electrodes directly to the brain and on humans they had to do it indirectly via neuroimaging in the fMRI machine that records brain activity.

Mirror neurons

Christian Keysers, a neuroscientist from the University of Groningen in the Netherlands explains: “When we record signals from neurons in monkeys, we can really know that a single neuron is involved in both doing the task and seeing someone else do the task,” he says. “With imaging, you know that within a little box about three millimeters by three millimeters by three millimeters, you have activation from both doing and seeing. But this little box contains millions of neurons, so you cannot know for sure that they are the same neurons–perhaps they’re just neighbors.”

But some of the most interesting questions that mirror neurons raise can’t be answered by the motor neurons alone–researchers want to understand how we perceive other people’s emotions and sensations, not only their actions.

As VS Ramachandran, a psychologist from UC San Diego explains: “Mirror neurons must be involved in things like imitation and emulation. Because to imitate a complex act requires my brain to adopt the other person’s point of view. So, this is important for imitation and emulation. If take a look at human culture and you go back in time about 75,000 to 100,000 years ago, let’s look at human evolution, it turns out that something very important happened around 75,000 years ago. And that is, there is a sudden emergence and rapid spread of a number of skills that are unique to human beings like tool use, the use of fire, the use of shelters, and, of course, language, and the ability to read somebody else’s mind and interpret that person’s behavior. All of that happened relatively quickly… And I claim that what happened was the sudden emergence of a sophisticated mirror neuron system, which allowed you to emulate and imitate other people’s actions.”

In other words mirror mechanism plays a fundamental role in action understanding. By ‘action understanding’ philosophers, psychologists and cognitive neuroscientists often indicate concepts that are widely different one from another. They range from goal ascription (that is, the process of identifying the goal to which an action is directed) to belief and desire attribution, and even to complex forms of practical reasoning concerning on one’s own or others’ actions and thoughts.

What Ramachandran and other researchers “stumbled upon” is the basis of culture and civilization. By using their mirror neurons a child or a member of a group can learn from others and use that knowledge to his benefit. That’s why humans don’t have to learn things over and over again, the knowledge is passed horizontally, across members of a group and vertically, through generations.

Mirror neurons

As Ramachandran puts it: “This made evolution suddenly Lamarckian, instead of Darwinian. Darwinian evolution is slow; it takes hundreds of thousands of years. A polar bear, to evolve a coat, will take thousands of generations, maybe 100,000 years. A human being, a child, can just watch its parent kill another polar bear, and skin it and put the skin on its body, fur on the body, and learn it in one step. What the polar bear took 100,000 years to learn, it can learn in five minutes, maybe 10 minutes. And then once it’s learned this it spreads in geometric proportion across a population.”

This post, intended to spark your interest, is unfortunately just a mere scratch on the surface of a huge body of research about neuroscience in general and mirror neurons in particular. The deeper one digs the more complex things turn out to be. None the less, I don’t mean to discourage you, bold explorer! Only by boldly marching forward into the unknown we can deepen our understanding of the world and ourselves!