What Are Mirror Neurons? A Simple Overview of Mirror Neurons.
Mirror neurons are neurons that “fire” when observing an action and when performing an action, this allows for learning through imitation (“mirroring”).
It is thought that mirror neurons aid in empathy, as it seems emotions can be mirrored, learned from, and experienced indirectly with the assistance of mirror neurons (for instance by mirroring facial expressions related with emotional states to better understand another’s emotions). It also seems that mirror neurons have predictive powers being able to distinguish intention, and to use memories of past experiences, to decide what behaviors and which individuals are worthy of imitation. There is a lot of interesting facts about these unique nervous system cells, but the neuroscience is still fuzzy on the details.
So far mirror neurons have been proven to exist in monkeys (see study below), but proving the existence of mirror neurons in humans is still a point of contention, as humans are harder to study due to ethics. Despite mirror neurons being discovered in the 1990’s, we have a long way to go before we fully understand their functionality.
Below we will discuss how mirror neurons relate to empathy, imitation, and autism, and how they might play an important role in evolution. We will also try to separate the facts from myths in terms of “the mirror neuron hype”. Mirror neurons are real science, but their nature lends itself to pseudoscience and metaphysical musings, and thus some clarification is needed.
TIP: Wrapping your head around mirror neurons can be a little tricky without someone to observer (puns intended). I suggest watching the videos to supplement the content on this page.
TIP: When you observe and imitate someone you can be thought of as mirroring them. Mirror neurons fire in response to this observation-imitation combination. “Firing” is just neuroscience slang for “learning”. This is why they are called mirror neurons. Mirror neurons are uniquely interesting because, unlike all our other neurons, they respond to indirect experience (observing) and direct experience (imitating), rather than just direct experience or just observation.
TIP: Neurons were responding to the sound or sight of some actions, but only to the execution of actions, are not mirror neurons. (Motor command neurons are not the same as mirror neurons). Mirror neurons initiate activity both when an individual does something and when they see someone doing it.
How Do Neurons Work?
To understand why mirror neurons are important you have to know how neurons work. Neurons are, in simple terms, where we store sensory data (all information from our environment gleaned by the senses). Different neurons in the brain respond to different sensory data types. When a neuron responds it is called “firing”.
When multiple neurons “fire” at the same time, synaptic connections are made between neurons, and sensory memories are created. This is all called, in common language, learning and memory.
This can all be summed up by saying, “neurons that fire together, wire together“, and, “neurons that fire apart, wire apart“.
Mirror neurons fire when observing an action and when performing an action, and seem to primarily fire when an action (or actor) is providing useful information (for instance if a parent picks up and drinks out of a cup, instead of a stranger picking up a cup to put it away).
The most interesting type of imitation-based learning they seem to be connected to is the indirect learning of emotional states (AKA empathizing).
TIP: Just like other neurons, mirror neurons are part of our nervous system. Neurons help us sense the world around us, and learn from it. Just like our optical nerves and interconnected neurons help us understand the world by processing light-based information, mirror neurons are thought to help us understand the world by mimicking and observing others. Just like our brain filters out the optical data we don’t need (like our noses), mirror neurons seem to be able to discern between useful actions and actors, and less useful ones (likely by referring to memories of past experiences).
Why Are Mirror Neurons Important?
In the past it was thought that we used logic to interpret, predict, and empathize with other people’s actions, using our intelligence to figure out what the action meant. Mirror neurons show us that understanding others may be an empathetic process rather than an intellectual one, allowing us to understand feeling and intention through imitation, rather than just through analysis. This could explain a lot about the way culture evolves and why we seem to be “hardwired to be social“.
New therapies for helping stroke victims regain lost movement.
How Do Mirror Neurons Work With Empathy?
Mirror Neurons are thought to be aid in mirroring emotions, allowing us to understand how other people feel by observing and mimicking their emotional states (we can mimic their body language, tone, facial expressions, and potentially even the emotion itself). Thus, mirror neurons could be a key to understanding empathy. This leads some to muse that this could have played a major role in evolution and society forming.
With mirror neurons, a person doesn’t need to know what it is like to lose a child, they can see the sadness the mother feels, they can enact their emotions like they are their own, and they can empathically understand the pain of loss this way. They can learn through mirroring emotional states and related behavior of that emotional state by using mirror neurons.
How Do Mirror Neurons Work With Intention and Prediction?
One of the keys to mirror neurons is that they seem to respond to intention and to have predictive power. If a person picks up a cup to drink some water, they are more likely to fire than if the cup is picked up to be put away.
A Radical Theory of Autism. How the mirror neuron connects to autism. Mirror neurons might be deficient in people with autism. Drugs like ecstasy that enhance empathy could perhaps be used to treat this deficiency.
Where are Mirror Neurons in the Brain?
Mirror neurons are a small circuit of cells in the premotor cortex and inferior parietal cortex that activate both when an action is performed and when an action is observed. They might be found elsewhere in the brain, but that has not yet been proven
A neonatal (newborn) macaque is imitating facial expressions (source). Some think mirror neurons may be linked to empathy and imitation, as they can fire in response to seeing and imitating facial expressions (and thus potentially aid in understanding another’s emotions).
How Do Mirror Neurons Relate to Empathy and Imitation?
We don’t fully understand empathy, or mirror neurons, or how imitation plays a role in the process, but it is possible that mirror neurons help explain some of our sense of empathy. The neuroscience behind mirror neurons is in its infancy, so even though some scientists think that the mirror neuron is a key to understanding empathy, it will be a long time before we know for sure.
As “social creatures” it is useful to understand subtle social cues (especially for monkeys who can’t communicate in spoken language).
The implication that we can learn through mirroring means monkey one may be able to learn how to crack a nut from monkey two, or that monkey one may understand the sadness monkey two feels when the other monkey doesn’t have any nuts to eat and can share one.
Being “hardwired for empathy” and learning through imitation are concepts that have many implications. You can read more about Mirror Neurons and Empathy here. The video below, while a little romantic, does an excellent job of summing up why mirror neurons are important and what their role could be in the evolution of society.
Are Mirror Neurons the Only Neuron that Relates to Empathy and Imitation?
It is tempting to think of the mirror neuron as the empathy neuron or the imitation neuron, but it seems clear that there is more to empathy than just the mirror neuron, and we know there is more to “observational learning” than mirror neurons. Still, what we know about the functionality of mirror neurons can help us to understand better how empathy, imitation, and other such traits affect social dynamics and learning.
Below we look at facts and myths about mirror neurons to take a closer look at the science behind the mirror neuron.
TIP: A basic rule of neurons is “neurons that fire together wire together”. Our neural networks are continually being shaped by sensory information and thoughts that stimulate our neurons.
Does Science Prove That Mirror Neurons Exist?
We have a very limited number of studies on mirror neurons in humans and do not know exactly how they work, but evidence of their existence in monkeys goes back to the 90’s.
Mirror neurons were first detected in the 1990’s by Giacomo Rizzolatti and his colleagues in the midst of an experiment involving monitoring the frontal lobe of monkeys using intracellular electrodes. The anecdotes describe a researcher eating either a sandwich or a peanut, and noticing that a test monkey’s electrodes showed the same brain cells were firing when watching the action of eating as would fire if that individual were eating. Further research indicated more responses to picking up a cup to drink than picking it up while clearing the table.  Simple facial expressions such as those indicating joy, anger, or disgust also appear to activate mirror neurons.
To see Dr. Rizzolatti talk about Mirror neurons: from monkey to human, please see:
Finding mirror neurons in monkeys has led some researchers to hope that the test data from monkeys can be applied to humans. Some also believe that emotions are communicated and learned using the mirror neuron system. This idea is controversial.
It is a fascinating idea that mirror neurons allow us to learn emotions by observing them. One of the most outspoken believers in the power of mirror neurons is Vilayanur Ramachandran.
You can see his TED Talk, The neurons that shaped civilization, below:
Why Don’t We Know More About Mirror Neurons in Humans?
The methods used to collect direct evidence in monkeys are different from those used with people and that has led to many debates about the validity of data. Intracranial electrodes are too invasive to be used with human subjects, except in some instances involving brain surgery, where they are a medical necessity. Brain imaging of various sorts is used for human studies. The disagreements in this branch of neuroscience center around the validity and interpretation of the data.
One of the pioneers in motor neuron research, Marco Iacoboni, maintains that the mirror neuron system is basic, and recognizes only simple actions and intentions. Iacoboni argues that identifying a purpose behind an action is a far more sophisticated skill than recognizing that an action is intentional. He cautions that you cannot extrapolate lower-level neural activity to complex behavior.
We know that intentional action has a neural trigger from other neurological experiments. You can see an interesting talk by Greg Gage on that subject here: Greg Gage – How to control someone else’s arm with your brain. We also know that monkeys have mirror neurons that respond at a very basic level to simple actions and emotional displays. The neurons first seemed to respond to a visual stimulant (watching an action), but now appear triggered as part of the brain’s effort to predict sensory input. Some interpreted early research as a link between autism and a dysfunctional mirror neuron system. This idea was debated hotly and has largely been discredited.
In an analysis of 25 primary sources for mirror neuron research, James Kilner and Roger Lemon recognize that there is reliable evidence that mirror neurons exist throughout monkey’s brains rather than in the small area initially found. They acknowledge that mirror neurons probably exist in humans, but caution that understanding the function and significance of these cells in people has just begun. 
This is opinion, but perhaps the reason mirror neuron findings are so contested is the implications of proving their existence. To show we have mirror neurons exist is to show another link between humans and monkeys, and to show that we are naturally social and empathetic creatures. Can you think of an ideology that doesn’t want to say “we are all one people, who should work together, and have evolved from monkeys”? Only science can show us the truth, and the way science works is we have to wait for studies to jump to conclusions. Don’t get confused by the junk science and metaphysics, there is real science behind mirror neurons, and there are more discoveries to be made.
Mirror neurons are very likely linked to things like empathy in humans, but the exact science isn’t here yet. Like other exciting neuroscience, we have to remember not to cross the line into junk science and metaphysics. Reality is no more magical than it already is.
Author: Linda deSolla Price
Linda deSolla Price is the daughter of Derek de Solla Price, a physicist, historian, and Yale professor who was the first to formally study the History of Science. She holds...