The Neurons that bind us together
Mirror Neurons and their role in shared learning, empathy & consciousness
Let’s start with a thought experiment…
When you see someone reaching out to grab a glass of water, you know what’s going to follow, right? Have you ever wondered how does that happen?
Before you jump to the conclusion that this is a silly question since the simple explanation is that the brain has seen the action too many times to not remember it, think again. When was the last time you remembered something as quickly as understanding the intention of the person picking up a glass of water. Rarely right? And that’s because recalling information from the memory centre in the brain is simply not fast enough to help us make sense of the world moment to moment
So if it’s not memory, then what could be it? One theory is that once our visual system is able to describe the action “visually” there is a mechanism to put things together. An alternate hypothesis is that the act of action identification is not one of logical inference. Instead it involves activating a part of the motor system (the same system that activates when we perform that action) of our brain as if their action becomes a part of our action
This part of the motor system, that activates when we perform an action as well as when someone else performs an action, is called “Mirror Neuron”. Now in this article, I am not going into the inner workings of Mirror Neurons. Instead the focus shall more on understanding the evolution of human mind and nature through the lens of this neurological phenomena
Readers interested in deep-diving into this topic should read the seminar work on Mirror neurons done by Giacomo Rizzolatti & team in 1996
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Why mirror neurons are needed in the first place?
At its core, Mirror Neurons simply translate sensory information (e.g. seeing a hand move towards a glass of water) into complex motor pattern (e.g. the action of holding an object and drinking from it).
That’s because the visual system is well equipped to understand spatial information i.e.understanding what’s happening in the present. It is not equipped to understand temporal information i.e. what follows next or what can happen. Generalisations of this type can only be done by the motor system
At first, it may sound bizarre that in order to recognize an action getting performed in front of us, we need activate the motor system. But upon introspection we will understand that a mere visual perception, without involvement of the motor system would only provide a description of the visible aspects of the movements. It would not give, however, information on the intrinsic components of the observed action, on what it means to do the action, and on the links between the observed action and other actions related to it. This can be achieved only if the observed action is mapped onto the motor system of the observer. Thus, the activation of the mirror circuit is essential to provide the observer with a real experiential comprehension of the observed action.
Source: scholarpedia.org/article/Mirror_neurons
From recognising actions to understanding intentions
So we have established that action recognition requires activation of certain neurons called as Mirror Neurons. But a complete grasp of the setting in front of us requires us to understand not just the action (what & how, e.g. grabbing a glass of water) but also the context behind the action (why, e.g. to drink or to water a plant)
So do mirror neurons play a role in developing this holistic understanding. A decade after the discovery of mirror neurons, Marco Iacoboni and his team (while included Giacomo Rizzolatti) were able to conduct FMRI experiments to confirm this hypothesis.
They examined 23 participants watching videos of a hand picking up a teacup. In some videos, the teacup was table with a neatly arranged pot of tea and a plate of cookies. In some others, the table on which the teacup was placed was messy and scattered with crumbs. In a third set of videos the cup was alone, removed from any context. It was found that mirror neurons reacted more intensely to the action of picking up a teacup in the tea-party context than to the contextless scene.
Readers who want to know more about this experiment should go through this paper titled Grasping the intention of others with one’s mirror neuron system, published by Marco Iacoboni & team in 2005
From understanding intentions to language evolution
It’s widely believed that the vocal language in its present shape and form did not fall out of the sky one fine morning. That it evolved from a very rudimentary gestural communication system that was already in place and provided a scaffolding for the emergence of vocal language?
This raises two questions
How did this primitive gestural system get established in the first place?
How did it evolve into the complex speech structure of today?
While mirror neurons doesn’t help us tackle the first question, it does provide a sound explanation to the first question i.e. how what is valid for the sender of a message became valid also for the receiver.
And the explanation is that just as mirror neurons help us understand & imitate actions of others, it may also have helped us understand—and possibly mime—the lip and tongue movements of others which, in turn, could provide the opportunity for language to evolve. (This is why, when you stick your tongue out at a newborn baby it will reciprocate!) Once the ability to read someone's intentions and the ability to mime their vocalisations were in place—it would have set in motion the evolution of language.
Readers interested understanding this hypothesis better can go through this short note on Mirror Neurons & Imitation Learning by Professor V.S. Ramachandran
From learning to developing a shared sense of empathy
Most of the original research work on mirror neurons was restricted around the motor cortex. And it gave a good understanding of how homo-sapiens evolved together as a culture, understanding each other through a common set of day to day actions & habits
However this shared sense of understanding is incomplete without the ability to perceive emotions and sensations. So then the question that arose was—When we see someone in pain and genuinely empathise with them, or when we see a gesture of affection and feel like reciprocating it… is it because of mirror neurons?
Recent evidence supports this hypothesis. In a fMRI experiment conducted in 2003, one set of participants were exposed to disgusting odorants and, another set were exposed to short movie clips showing individuals displaying a facial expression of disgust. It was found that both the exposure to the odorant as well as seeing others getting exposed to the odorant activated the same part of the brain
And finally, a potential key for understanding what connects us all
We had started with a thought experiment. It’s only fitting that we end with one.
Think about what have have understood so far. At some point in the timeline of evolution, we started developing an ability to comprehend and understand the physical world around us. It’s quite likely that this was much before the homo sapiens came into existence.
This then evolved into the ability to understand & comprehend the world from the point of view of those around us, not through logical inference but instead through a mechanism that puts us in their shoes as if their actions & their emotions are a part of our actions & emotions
At this point, one may be tempted to ask this question—If our motor system makes us feel the pain of others as if we are actually feeling that pain, why do we not actually feel that pain? A simple explanation to that is that there’s also a sensory input from the skin that combines with the motor input that tells you to feel the pain but not as if you are actually feeling the pain.
Now if your next question is ‘what if i remove the skin?’… You see that’s where things get exciting. There’s a medical condition called Phantom Limb where a patients with amputated limbs still feel all the itching, discomfort etc that they would have felt as if there was a limb. This syndrome occurs in about 90% of amputees while in two-thirds of those it manifests as an insatiable itch in the missing limb, many feel extreme discomfort or even chronic pain.
While in most cases, pain-killers and surgical treatment have no effect, it has been found that simply seeing someone massage their arm relives the patients of their pain. In the absence of the sensory input from the skin, the patients literally feel that act of massaging in their motor cortex. In other words the barrier between the ‘observer’ and the ‘observed’ is no more there and whatever the ‘observed’ does or experiences can be experienced in the mind of the ‘observer’ as well.
Interesting, isn’t it?