I was barely six months into my masters in neuroscience when our neuropsychology professor introduced us to “mirror neurons.” These distinct brain cells were supposedly the key for our empathy, social interaction, and perception of motor-action. I couldn’t believe how such a group of neurons have that big of an impact in our life. Our professor threw on some videos of people getting hurt and falling in love. He explained that mirror neurons were recreating all these scenes in our brain and that’s why we had reactions like flinching or smiling to the love scene. In theory, these neurons, deep in Broca’s area, fire when performing a motor action or when seeing someone else performing the action. Mirror neurons became a common finding in the neuroscience literature that I read. Everybody had something positive to say about these distinct neurons and how they could shape our future.
In theory, what many propose is the following: let say you fall, and I observe the action, my brain creates an image (mirror neurons) of me falling as you did. This, in simple terms, makes me emphatic to your pain, because I could visualize myself how it felt. Another example: let say I see a tennis match; my mirror neurons will make me visualize myself recreating that action. That’s how it was explained to me on my neuroscience course and how popular articles depict the function of mirror neurons.
The Rise and Fall of Mirror Neurons
A Reality Check for the Mystical Cells
But science evolves, and booming scientific literature that peaked in 2014 suddenly stopped. Its biggest proponents, like the great neurologist V.S. Ramachandran, were no longer slamming the drums of the future of mirror neurons, and books like Gregory Hickok’s The Myth of Mirror Neurons dealt a reality check to a promising field in neuroscience. Now, a systematic review pinned mirror neurons into a corner. As psychologist and author Christian Jarrett exclaimed on social media:
Seven years ago a science writer with attitude dubbed mirror neurons "the most hyped concept in neuroscience" – a new meta-analysis & review backs this up with over 2 decades of research providing only weak evidence that the cells underlie human empathy: https://t.co/xl6A4I65gD
— Christian Jarrett (@Psych_Writer) March 26, 2019
A systematic review done at the University of Deakin by Soukayna Bekkali and five other colleagues broke down the myth that mirror neurons were “the seat for human empathy.” Here’s Jarrett reporting the conclusions of the paper:
“Regarding motor empathy, the accumulated evidence pointed to no association with mirror neuron activity. Regarding emotional empathy, there was no evidence for a link with mirror neuron activity in one key brain region where these cells are thought to reside (the inferior parietal lobule; IPL) and only weak evidence for an association with postulated mirror neuron activity in another key brain area, the inferior frontal gyrus (IFG). ‘It remains unclear how the mirror neuron system relates to the experience of emotional empathy,’ the researchers said.
In terms of cognitive empathy, there was no evidence for a mirror neuron link in the IPL and weak evidence of a link with activity in the IFG. ‘The current results suggest mirror neuron activity may play a role in cognitive empathy,’ the researchers said, adding that ‘the mirror neuron system may potentially be one neurophysiological mechanism subserving cognitive empathy.'”
The mirror neuron research, as with research regarding the effectiveness of mindfulness, showed the lack of rigorous studies, and the overwhelm of publications of studies showing positive results on the mechanism of mirror neurons elevated its mystical powers.
The History of Mirror Neurons
To find out why this is a big deal and why mirror neurons were so big, we must go back to the late twentieth century. Mirror neurons were first discovered and described by a research group in Italy that included Giacomo Rizzolatti and Vittorio Gallese at the University of Parma. They studied the firing of neurons in the premotor cortex when a monkey was doing a motor action. Then, after recording the neural response (like a code for that specific neural firing), they observed that the same class of neurons that fired when the monkey reached and grasped for food were activated when the monkey saw the action. This paper, which first was rejected from the famous journal Nature, was the beginning of research on one of the most popular neural cells in neuroscience.
The Parma group kept doing studies and mirror neurons’ popularity kept growing; a simulator in the mind that could explain our theory of mind (thinking about the thought of others), empathy and even mimicry. The most thrown quote on this pandemonium was that of Ramachandran, the famous neurologist, psychologist, and as Richard Dawkins describes, “the Sherlock Holmes of neuroscience.” Rama wrote the following on Mirror Neurons in an essay for Edge.org:
“The discovery of mirror neurons in the frontal lobes of monkeys, and their potential relevance to human brain evolution — which I speculate on in this essay — is the single most important ‘unreported’ (or at least, unpublicized) story of the decade. I predict that mirror neurons will do for psychology what DNA did for biology: they will provide a unifying framework and help explain a host of mental abilities that have hitherto remained mysterious and inaccessible to experiments.”
Later in 2004, in his book, A Brief Tour of Human Consciousness*, Ramachandran explained the role of mirror neurons in human evolution:
“I believe that these neurons may have played an important role in human evolution. One of the hallmarks of our species is what we call culture. Culture depends crucially on imitation of parents and teachers, and the imitation of complex skills may require the participation of mirror neurons. I think that, somewhere around 50,000 years ago, maybe the mirror neurons system became sufficiently sophisticated that there was an explosive evolution of this ability of mime complex actions, in turn leading to cultural transmission of information, which is what characterizes us humans.”
As we can, see Ramachandran had set very high stakes for the future of mirror neurons and their function. Heralded as neurons that create a virtual simulator in our brain, the media became also static on these neurons. One New York Times article’s title read, “Cells That Read Minds”. Even I was in love we the idea that these neurons were responsible for our inferring on other minds and actions, as an article early in this magazine last year shows. Suddenly, there was therapy based on these neurons, business training on how to use these neurons to sell, and articles on how mirror neurons could explain sex, music, and other things. In fact, there was a theory known as the “Broken Mirrors Theory,” which argued that because of the lack of these neurons in autistic kids, it explained their problems in socializing and inferring in other’s thoughts and emotions.
Skepticism on Mirror Neurons
The only man battling hard for the demystification of these neurons was Gregory Hickok. The professor of the University of California Irvine started to teach about these neurons and started to find a lot of inconsistency on them. He concluded in an infamous article in MIT press back in 2009 with the following:
“Mirror neurons are a fascinating class of cells that deserve to be thoroughly investigated in the monkey, and explored systematically for possible homologues in humans. The early hypothesis that these cells underlie action understanding is likewise an interesting and prima facie reasonable idea. However, despite its widespread acceptance, the proposal has never been adequately tested in monkeys, and in humans there is strong empirical evidence, in the form of physiological and neuropsychological (double) dissociations, against the claim.”
Hickok who does believe in the existence of such neurons, found some contradicting facts that detached the mystical veil off these cells. For example, he argued that action understanding doesn’t need the involvement of mirror neurons. As he explains, “Cells in portions of the macaque STS [Superior Temporal Sulcus] respond to a wide range of actions in a manner that appears more sophisticated than that found in mirror neurons.” He also added scepticism on how monkey vs. Human mirror neurons manifested themselves:
“The assumption made by these authors is that in the evolution of this system, old properties of mirror neurons are fully conserved. But what if the mirror system evolved in humans such that it now supports imitation but no longer supports action understanding? Perhaps humans evolved a more sophisticated semantic system, distinct from the motor system, that freed the mirror system to support imitation. Possibilities such as this are not considered in mainstream mirror neuron theorizing. Instead, monkey data and theories are typically imported to human work without empirical validation of the assumptions.”
Indeed, Hickok and Christian Jarrett were waving a red flag on how important mirror neurons might not be. As Hickok told in a presentation on the myth of mirror neurons for the Skeptic Society, even pigeons had been found with these set of neurons, which would not make them holy unique for a primate. Also, other studies are quick to assign mirror neurons on actions when the Broca’s area is activated, as Hickok say, that’s not always the case.
Last Word on Mirror Neurons’ Importance
Now, mirror neuron research is in trouble and will surely put a skeptical cloud, like in mindfulness, in its future research. That’s not to say that they aren’t useful. Mirror neurons could play a bigger picture in the sensorimotor system in the brain. Moreover, more in-depth details must be tackled. For example, does the mirror neuron really make us imagine ourselves having the same experience, or is it because of mental association (that we have previously experienced such action, so we know how it feels). Also, since different types of mirror neurons have been found, will these distinctions and further discoveries be highlighted in finding their true potential role? These and more other questions should be answered in the following years by researchers.
*V.S. Ramachandran’s book A Brief Tour of Human Consciousness (The Emerging Mind originally in Britain) can be found at this link completely free. The book was originally part of The Reith Lecture on BBC.