“A unifying neural hypothesis on how individuals understand the actions and emotions of others” was presented to the world in 2004 by neuroscientists Gallese, Keysers and Rizzolatti. Our understanding of other minds, they claimed, is facilitated by “mirror neurons,” so-called because they fire when an individual performs or observes an action, and when she experiences an emotion herself or observes that emotion in someone else. The authors described mirror neurons as a system that enables humans and other social primates to simulate each other’s behaviour and internal states, thereby enabling learning, communication, and prediction of others’ actions.
Humans are an exquisitely social species. Our survival and success depends crucially on our ability to thrive in complex social situations. One of the most striking features of our experience of others is its intuitive nature. This implicit grasp of what other people do or feel will be the focus of our review. We will posit that, in our brain, there are neural mechanisms (mirror mechanisms) that allow us to directly understand the meaning of the actions and emotions of others without any explicit reflective mediation. Conceptual reasoning is not necessary for this understanding. [Gallese et al, 2004, p 396]
The mirror neuron hypothesis sparked a storm of interest among scientists and philosophers concerned with the human mind. It sparked controversy too, with some researchers cautioning that the data vastly underdetermines the interpretation placed on it, and that animal studies have been extrapolated to conclusions about the human species. This caution is justified, but so is the excitement. The bare facts of what has been discovered so far are hard to reconcile with any hypothesis that could be considered boring, and the current pace of discovery suggests that we will soon know much more. If the Gallese/Keysers/Rizzolatti theory is even approximately right, neuroscience is giving birth to an intellectual revolution with the potential to profoundly change both scientific and common-sense understanding of how our minds work.
Mirror neuron theory is revolutionary in its claim that we have special ways of gaining knowledge of other people that do not apply to inanimate things. Experiencing people is not like experiencing cars, trees, or buildings. We simulate other people. Internalizing their actions and emotions makes us more effective in our social interactions. We model other people using the same neural ‘programs’ we use to model ourselves—a use of computational resources which I, as a longtime software designer, admire for its efficiency. The good engineering sense of this design lends intuitive appeal to the mirror neuron theory. Self-directed, high-functioning animals like humans must have an self-model to guide their own behaviour and allow them to successfully exploit their environment and avoid danger. To construct such an elaborate model of one human being, and not reuse it to model others, would be wasteful. The cost of generalizing is low, and the benefits huge, for any species that depends, as ours does, on social interaction.
Modeling other people the way we model ourselves opens the door to a low-level, direct, experiential way of understanding them, that does not depend on high-level cognitive abilities to formulate and test hypotheses. To appreciate this, think about the difference between finding out what is wrong with your computer and finding out what is wrong with your partner. When something doesn’t work on my computer, I am often led into a hypothesis/test cycle. When I recently added a new desktop computer to our home network, I decided to make it the printer server. After that, my wife could no longer print from her laptop, so I advised her to add a network printer. When she tried to do so, the dialog boxes did not let her to browse for the printer. Remembering that I hadn’t shared the printer on the network, I corrected that, but she still couldn’t ‘see’ it. After verifying that she was registered as a user of the desktop machine, with correctly-spelled username and the right password, I began to suspect the security configuration. Sure enough, a little digging revealed that the new desktop computer was “untrusted” by her security software on her laptop. When that was fixed, she could browse shared folders on the desktop machine and connect to the printer.
If we had to rely on the hypothesis/test cycle for all our social interactions, how dysfunctional we would be! Understanding the internal states of people around us is usually straightforward and effortless. Exceptions occur when they are concealing something, or when their condition is outside our own experience (a mental illness, or a drugged state, or the hubris that comes with having too much money). In such cases, we may need to use powers of deduction to gain even a sketchy understanding of how another person feels. But for most of us, most of the time, our experience of other people resembles Kathryn Schulz’s description:
An expression flickers across a stranger’s face and you have a very good chance of correctly deducing his feelings. You and a friend sit through a particularly ludicrous meeting together and carefully avoid catching each other’s eyes, because if you did, you would each know so much about what was going on in the other’s mind that you would both laugh out loud. [Schulz, 2010, p. 250]
According to the mirror neuron theory, we can do this because we run simulations of each other—models of other people which are similar to, and based on, the self-models through which we regulate our lives. If, at a cocktail party, I see you glance at a bowl of salted nuts, I understand that you want some. I know that because if I know that if glanced at the nuts that way, it would be because I wanted some. Without any conscious deliberation, I feel your urge, and pass you the bowl.
This internalization of others inspired VS Ramachandran to give mirror neurons the over-the-moon description of “Ghandi neurons” because they “dissolve the boundary between ourselves and others.” [Ramachandran, 2011, p. 124]
Evidence for Mirror Neurons
Rizzolatti and his colleagues at the University of Parma first observed mirror neurons in macaque monkeys. About 10% of the neurons in the premotor cortex that fired when the monkeys performed a specific goal-directed action, such as grasping a piece of food, also fired when they observed another monkey, or a person, doing the same thing. Further experiments prompted by this unexpected finding showed that the premotor response was not only triggered by seeing an action. A distinctive sound, such as the cracking of peanut shells, evoked the same response as the sight (with or without sound) of another monkey cracking peanuts. Even more impressively, the response to a grasping action did not depend on the monkey actually seeing the object grasped. In one study, a small block was shown to the monkey, then hidden by a screen that slid between the block and the monkey’s eyes. The monkey then was shown a human hand reaching behind the screen to the spot where it had last seen the block. The monkey’s premotor response to this screened action was almost identical to its response when the monkey saw the same action without the sliding screen. However, if the hand merely mimed a grasping action when no block was present, the premotor response was much weaker. The weak response to the mimed action occurred both when the screen was in place and when it was not. What’s striking is that the same visual input—a hand reaching behind a screen as though to grasp something—produced markedly different responses depending on whether or not the monkey had previously seen the target object in the screened-off space. It is difficult to avoid concluding that the distinctive neural response is correlated with the monkey’s belief that the experimenter was actually grasping an object, not empty air.
The scientists’ efforts to explain these results gave rise to the hypothesis that:
…observation of an action leads to the activation of the same parts of the same cortical neural network that is active during its execution. The observer understands the action because he knows its outcomes when he does it. [Gallese et al, 2004, p 396]
Thin wires were implanted in the monkeys’ brains to monitor responses of individual neurons. Such invasive technology is not used in research on human subjects. However, Rizzolatti and his colleagues were able to use fMRI scanning to show that when normal humans heard tell-tale sounds of specific actions (a pop can being opened and poured, a zipper being pulled), the same brain areas were activated as when they performed those actions, “albeit more weakly.” [Keysers, 2011, p 41] fMRI works by detecting increased blood flow to regions of the brain. Its resolution is limited to about 2.5 mm (0.1 in.) Since a cube of 2.5 mm on each side contains hundreds of millions of neurons, fMRI cannot monitor the activity of individual neurons, but can only give a statistical overview for each region.
Transcranial magnetic stimulation (TMS) uses a focused magnetic pulse to stimulate the brain. A TMS pulse applied to a motor area of the brain can trigger muscle movements—causing a finger to twitch, for example. A strong pulse produces movement and a slightly weaker pulse no movement. Experiments by Lisa Aziz-Zadeh showed that a TMS pulse which was too weak to cause a finger twitch on its own would do so if accompanied by the sound of typing. When paired with a sound not associated with finger movement (thunder, or footsteps), the motor response was much weaker. Hearing a typewriter reinforced the subject’s TMS-induced impulse to move his fingers. Rizzolatti’s colleague Christian Keysers concluded that the auditory signal of the typing sound and the motor signal triggered by the TMS pulse must converge somewhere in the brain. The fMRI scans showed elevated activity in the pre-motor cortex, pointing to it as the likely spot for convergence. And the pre-motor cortex is where mirror neurons were positively identified in macaques. Taken together, these results support the view that the human motor cortex, like that of the monkeys, contains mirror neurons. [Keysers, 2011, p 43] Although the evidence is indirect, in the absence of a competing explanation it becomes compelling.
The word “emotion” has the same Latin root as “motivation,” and “motor”: all are concerned with movement. The use of “emotion” to refer to mental feelings of desire, hope, etc. is recent; the Oxford English Dictionary gives an earlier meaning as “a moving, stirring, agitation, perturbation (in physical sense).” We tend to think of inner feelings as causing the corporal and behavioural signs of emotion—the sweating palms, elevated heart rate, blushing cheeks, and muscular tension—but some renowned thinkers on the subject say that gets it backwards; in fact, the physiological and motor responses cause the feelings. William James maintained that when we become aware of some arousing event, the motor response comes first, the feeling later. We do not cry because we feel sorry; we feel sorry because we cry. Antonio Damasio also distinguishes emotions from feelings, describing the latter as “composite perceptions of what happens in our body and mind when we are emoting.” [Damasio, 2010, p 109] Damasio tempers James’ account of the emotions, describing a more complex interaction of cognitive, physiological, and behavioural responses to an emotion-arousing stimulus. But he holds to James’ idea that “feelings of emotion are primarily perceptions of our body state.”
If emotions are largely motor responses, it is plausible that the mirror neuron mechanism involved in action understanding also helps us understand other people’s emotions. Evidence is mounting that this is so.
Human emotions, by common knowledge, are contagious. A friendly smile is catching, and being around a sad person can bring us down. Keysers points out that the ways in which we are affected by the emotions of others seem contrary to ‘rational’ self-interest:
…this emotional contagion appears to occur outside the sphere of our rational thinking. If we witness the sorrow of our wife, chances are that her bad news affects us directly and emotional contagion is rational. If we enter a meeting room and find a stranger crying, our mood is affected despite the fact that the stranger’s bad news is highly unlikely to affect us directly. [Keysers, 2011, p 91]
Keysers’ account of mirroring explains why. Witnessing emotion in another person activates a subconscious mirror response which simulates the other’s emotional state. “A dynamic system that causes the feelings, bodily posture and facial expressions of the observer to converge with those of the sender without the necessary intervention of conscious thinking is created.” [Keysers, 2011, p 94]
One mechanism of simulation, facial mimicry, lets us experience the emotions of another person by first mirroring his or her facial expression. If I see joy in my child’s face, my own face lights up, giving rise to feelings of joy in me. Significantly, the emotional expressions of the face involve muscles which are not under direct conscious control. Hence a forced smile appears forced, and we are able to tell ‘crocodile tears’ from the real thing. Actors portray emotions convincingly by inducing their characters’ emotions in themselves; only when they feel contentment, or passion, or terror do they really look the part.
Keysers used fMRI to find the brain regions that light up when the emotion of disgust was induced in a human subject, and when the same subject witnessed disgust in others. He picked disgust because, unlike many other emotions, it can be triggered reliably and repeatably within the confined and artificial environment of an fMRI scanner. The test subject was exposed to a nauseating smell, delivered by a ‘smell dispenser.’ At other times, the dispenser delivered pleasant smells like sun-warmed strawberry and mint to the subject’s nose, as a control. The subject was also shown videos of actors sniffing the contents of a glass and then reacting, either with a neutral response, with an appreciative smile, or with an expression of violent disgust, wrinkling their noses and pushing the glass away.
In a dozen test subjects, smelling the foul odor triggered activity in the anterior insula, which is responsible for processing flavours sensed by the nose and tongue, and which also monitors the state of the stomach and other internal organs. Artificial stimulation of the insula can cause nausea and retching.
When the subjects watched movies of disgust reactions, not only did they show activity in the parts of the premotor cortex associated with the facial muscles, but their insulas also lit up. This was what Keysers predicted on the hypothesis that there is a mirror neuron system for emotions.
Since correlation is not causation, it remained to be shown that the mirrored neuronal activity has a functional role in understanding the emotions of others. The causal evidence came from brain-damage cases. Keysers cites a clinical report by Andy Calder showing that stroke damage in the left insula of the patient NK impaired both his own experience of disgust and his ability to recognize a disgusted face. The impairment was specific, not affecting NK’s experience or recognition of other emotions such as happiness, sadness, anger and surprise.
Although NK could neither experience disgust nor recognize a disgusted expression after his stroke, he retained an intellectual grasp of the emotion. When asked what kinds of situations most people would find disgusting, he “effortlessly produced plausible scenarios.” [Keysers, 2011, p 100] The cases of NK and others indicate that a cognitive understanding of emotion cannot generate the visceral, empathic perception of emotions that informs and facilitates our everyday social interactions. Our ability to understand emotion depends on our ability to feel it.
And feeling an emotion, as already noted, is feeling a bodily state. Like Damasio, Keysers stresses the “body-mindedness” of our brains. We are not ghosts that inhabit machines; rather, body and brain form a tightly-integrated system which, as a whole, is the physical basis of our mental life. This bodes poorly for the aspirations of trans-humanists, who dream of achieving immortality by uploading the informational content of their organic brains to more durable hardware. Uploading into a body that is quite unlike our animal bodies should be expected to result in profound changes in experience and abilities. Possibly future technology could be used to preserve some semblance of a mind in this way; but the changes following this transition would likely be so great that neither the mind itself, nor others who knew it in human form, would be tempted to call it the same person.
Some Objections to the Mirror Neuron Theory
In a 2009 paper titled, “Eight Problems for the Mirror Neuron Theory of Action Understanding in Monkeys and Humans,” Gregory Hickok expressed skepticism towards the claims of Rizzolatti and his colleagues. Some of Hickok’s skepticism stemmed from lack of direct evidence that humans even have mirror neurons; but I think that concern has been substantially addressed by later work of Keysers and Gazzola, and I will ignore it here. Other arguments seem directed against a straw man. According to Hickok, the mirror neuron theory predicts that observation of the same action always activates the same “motor program” in the observer, producing an inflexible, ‘knee-jerk’ response.
Indeed, most sports would be impossible to play, as the observation of an object-directed action (throwing a ball) would result in the activation of the same action in the observer when a very different action is required (catching or blocking). [Hickok, 2009 ]
But no defender of the mirror neuron theory has proposed a rigid ‘monkey see, monkey do’ model. The claim is that mirror neurons facilitate action understanding, and if they also facilitate action reproduction, they do not do so inflexibly. Only a subset of the neurons in the pre-motor cortex exhibit the mirror response, and those are not sufficient to generate actions on their own (except in pathological cases).
Rizzolatti advanced the hypothesis that one person understands another’s intention by simulating his actions in mirror neurons at the premotor level, then attributing to the other the intention the observer would have if he were to move in that way. Hickok’s paper rightly points out that mirror neuron activity in the premotor cortex is not closely associated with the higher-level goals which motivate specific actions.
The motor act of pouring liquid from a bottle into a glass could be understood as pouring, filling, emptying, tipping, rotating, inverting, spilling (if the liquid missed its mark), defying/ignoring/rebelling (if the pourer was instructed not to pour) and so on. [Hickok, 2009 ]
Mirror neurons are too closely tied to specific motor responses to represent actions at these higher levels of description. A higher-level goal such as filling a glass with water can be accomplished by any one of a variety of motor programs including “pouring from a pitcher, turning a spigot, dipping the glass in a lake” etc. Goals can be arranged in a hierarchy, with the most general, over-arching goals at the top and the most specific ones at the bottom. I would expect a goal that is represented by premotor mirror neuron activity to be quite low in the hierarchy (pouring from a jug rather than filling a glass) and yet, not at the very bottom (pouring from a jug rather than flexing a specific combination of finger and arm muscles in a prescribed sequence). This narrow band in the hierarchy of goals fits the location of the mirror neurons being studied—the premotor cortex, not the primary motor cortex which controls individual muscle movements, nor the ‘higher’ cortical areas which are presumed to represent higher-level goals. Although Hickok rejects the mirror-neuron theory of action understanding, his objections could be taken as constructive suggestions for the theory’s refinement.
Patricia Churchland also cautions that some interpretations of the mirror neuron findings may be overblown.
The idea that an explanation for “mind reading” all but falls out of the discovery of mirror neurons was surprisingly popular among cognitive scientists almost immediately. People took up mirror neurons as though the connection to menatal attributions was essentially self-explanatory, or very nearly so. [Churchland, 2011, p 137]
Like Hickok, Churchland takes issue with Rizzolatti’s account on grounds that a single movement may be caused by any one of many different higher-level intentions.
I may raise my arm, motivated by any number of completely different intentions: to ask the teacher a question or signal the soldiers to charge or reveal my position to my hunting group or to stretch out my shoulder muscles or to vote for building a school, and so on and on. …. Merely mirroring a movement will not tap into the range of higher-order intentions, or select the right one, for which a lot of background understanding, probably including a theory of mind, is needed. [Churchland 2011, p 140]
Understanding that someone has raised her arm is not sufficient for understanding her action. It is improbable that the intention to vote for building a school would be represented by, or even uniquely correlated with, activation of one or more specific premotor neurons. The mirror neuron hypothesis only works if the intention coded by the mirror neuron is the low-level one of raising the arm, not the high-level one of voting for a school. But if that’s so, then we understand other people’s higher-level intentions by some mechanism other than mirror neurons. And if there is another such mechanism, why wouldn’t it also serve for understanding low-level intentions like raising an arm?
Churchland also objects that humans often understand the purpose of observed actions which they do not know how to perform themselves, such as milking a cow or executing a back-flip on the balance bar. If understanding another’s intention depended on first simulating his action, then recognizing the intention one would have oneself if one were performing the action, one’s understanding should be impaired if one had never performed, and could not perform, the action. Premotor mirror neuron activity cannot be necessary for action understanding in these cases.
In discussing the mirror neuron interpretation of emotional response, Churchland points out that recognizing emotions in others does not always induce empathy.
If I see a colleague look disgusted when I make a proposal in a department meeting, I am apt to feel either annoyed or amused, but not disgusted. These sorts of difficulties with the simulation theory of mental attribution have long been appreciated, and the current excitement over mirror neurons does nothing to put them to rest. [Churchland, 2011, p 152]
Churchland’s example of recognizing her colleague’s expression of disgust without feeling at all disgusted herself is hard to reconcile with the model advanced by Keysers in this passage:
Interestingly, activations in the premotor cortex predicted those in the insula more than the other way around, suggesting that our brain first simulates what the other person’s face is doing in the premotor cortex, and once you share the facial expression in your premotor cortex, your insula kicks in, making you share the feelings of that person. [Keysers, 2011, p 114]
Churchland’s objections seem to pose serious challenges to the mirror neuron hypothesis.
What Does It Mean? An Emerging Interpretation
And yet, to abandon the mirror neuron hypothesis outright would be to leave much unexplained: the ease and sophistication of human beings’ intuitive understanding of one another, the direct evidence of mirror neurons in macaques, and the less direct, but still compelling evidence of it in human studies. It also would deprive us of the most promising clinical explanation of so-called “touch synesthesia.” Unlike most of us, touch synesthetes report actually feeling sensations of touch when they see another person being touched, or in some cases, actually feeling pain when they witness another’s pain. It would be hard to account for this phenomenon without positing a subcognitive mechanism like mirror neurons.
Touch synesthesia, particularly the kind that causes pain, is moderately maladaptive. If I were the parent of a child who broke its leg, I would be of little help if I literally felt the agony of the fracture. This suggests the intriguing hypothesis that, although touch synesthesia may be the ‘natural consequence’ of mirror neuron activity, humans have evolved defences against it, allowing most people to effectively insulate themselves from other people’s pain. In addition to mirror neurons, we have some kind of inhibition mechanism which kicks in when too much empathy would be dysfunctional.
Ramachandran proposes such a mechanism as an explanation of why most of us don’t copy every action we see, and don’t literally feel the pain of other people:
…there may be frontal inhibitory circuits that suppress the automatic mimicry when it is appropriate. … When these frontal inhibitory circuits are damaged, as in frontal lobe syndrome, the patient sometimes mimic gestures uncontrollably, a symptom called echopraxia. (Ramachandran, 2011, pp 124-125]
Instead of “touch synesthesia,” Ramachandran prefers the term “hyper-empathy.” He suspected that the mechanism which prevents most of us from feeling touch and pain witnessed in others is linked to the “null signal,” from skin and joint receptors in our own body, that tells us that we are not being touched. Ramachandran confirmed his suspicion experimentally by anaesthetizing the arm of a normal subject, who was not hyper-empathic, thereby suppressing the “null signal.” When the subject saw another person’s hand being touched, she reported feeling touch sensations in her own hand! Ramachandran describes amputees who feel touch in their phantom limbs when they see another person being touched, and who even feel relief from phantom limb cramps and pain when they watch someone else being massaged. [Ramachandran, 2011, pp 125-126]
If the mirror neuron hypothesis is roughly true, the existence of inhibition mechanisms should come as no surprise. In a world in which tragedy and treachery are commonplace, the ability to draw a clear line between self and other has adaptive value. But it also complicates the picture, making interpretation of such mixed evidence much harder than it otherwise would be.
Science is far from consensus on mirror neurons. But the evidence from all sides—experimental, clinical, anecdotal, and intuitive—is building at an impressive pace in support of a theory which, though not yet fully formed, is visible in broad outlines. Although skepticism and hard questions are always appropriate, and are needed in order to shape this proto-theory into something solid, I will be very surprised if they prevail, and mirror neurons are revealed to be a cold-fusion-like chimera.
What about the Hickok/Churchland objection that premotor mirror neurons are at too low a level—too close to the motor level—to represent even mid-level intentions like filling a glass with water? My guess is that these examples show, not that the mirror neuron theory is wrong, but that premotor mirror neurons are only a small part of the neural apparatus we use to model ourselves and other people. If premotor neurons represent low-level goal-directed actions, then actions and goals further up the hierarchy may be represented elsewhere in the brain. That is what I would expect, if we use our self-models, which undoubtedly involve cognitive as well as subcognitive capacities, to model other people. Premotor mirror neurons don’t do it all by themselves.
Keysers, who sees the term “mirror neuron” as suggestive of action, avoids using it for the mechanisms underlying emotional response. He coined the term “shared circuit” as a more general description of both phenomena. I don’t like “shared circuit,” because it suggests a misleading model of how mirroring works—as though mirror neurons were wires connecting the brains of two people, allowing them to share internal states. In fact, as Keysers makes clear, the communication between individuals which mirror neurons facilitate is not immediate, but mediated through the ordinary sensory channels of sight, sound, touch and smell. There is some hyperbole in Ramachandran’s statement that mirror neurons “dissolve the boundary between self and other.” Although mirror neurons reduce misunderstandings between people, they do not eliminate them. What’s revolutionary about the discovery of mirror neurons is that they reveal our understanding of other people to be largely subcognitive, and broadband. Our brains support models of other people as well as of ourselves, and the models of self and other are supported by a common circuitry. The architecture is one of simulation. The mirror neuron system causes our ordinary sensory perceptions of other people to update the mental models by which we represent them, using fast, subconscious pattern recognition based on floods of data obtained from all sensory modalities. Thus we intuit the intentions and emotions of the people we encounter. If we relied only on the cognitive hypothesis and test approach by which we diagnose our machines, we would be socially crippled.
But mirror neurons, Keysers emphasizes, are not magic. Their efficacy depends on the accuracy of our mental models of others. Being based on our self-models, they are likely to be most accurate when the people we seek to understand are like ourselves. Keysers makes this point with a personal anecdote about a misunderstanding between himself and a girlfriend. As they drove to a friend’s wedding on a glorious summer day, he thought she shared his feeling of euphoria, until, out of the blue, she started a fight.
My happiness transformed into a painful sense of distance. I was reminded of how much of what was going on inside her failed to be intuitively accessible to me. … What I suspect went wrong that day, and all the other times I had this same feeling, is the fact that the shared circuits that are the backbones of my social intuition and sense of attunement used my own way of feeling and acting to read Antonella’s mind. My shared circuits intepreted her reactions in the light of my own sense of happiness in the car…. My mistake was to trust this intuitive feeling of shared happiness even though her smile may have been just a courtesy to me. … Shared circuits are not magic; they make us interpret other individuals in the light of our own actions, sensations, and emotions. If your inner life fundamentally differs from that of the person in front of you, shared circuits will make you feel something the other person is not feeling. In these cases, the mirror of shared circuits lies to us. [Keysers, 2011, pp 173-174]
Because the channel of communications facilitated by mirror neurons is not a hard-wired “shared circuit,” because it is mediated through ordinary sensory perception of behaviour, the simulation can go wrong.
Bodies of Information
Mirror neurons appear to facilitate the flow of information between individuals of our ‘exquisitely social’ human species. They are part of a broadband communications network that supports modeling and real-time simulation of other people. Far from being ‘marooned on the island of our self,’ condemned to ‘live and die there alone,’ we are swimming in a river of connections. We are connected to each other in more ways than we can count. Our ordinary senses, sight and hearing and touch, open unconscious channels through which other people touch and alter us, and we them.
I have put forward the theory that persons are best understood as bundles of attributes, or bodies of information. What mirror neurons add to this picture is that our bundles are not discrete, our informational bodies not at all self-contained. Just to be around other people is to promiscuously share their attributes. Our inhibition mechanisms may stop much of this flow from reaching consciousness, saving us from drowning in the flood of information that pours in from other people. But it pours in nonetheless, provoking sympathetic premotor and insular responses. However self-contained we may believe ourselves to be, our bodies and feelings are affected,
Living as most of us do now, in densely populated centres, the barrage of information we receive from others far exceeds what our hunter-gatherer ancestors had to cope with. If our mirror neurons are automatically activated by other people, it would not be surprising if we felt discomfort when confronted too often by too many others. Perhaps our current fondness for texting and email is a way of protecting our integrity by reducing the bandwidth, choking off the communications channels. In the past two or three years, phone calls have been stigmatized as ‘intrusive,’ and many of us have attended parties in which people interact more with their smart phones than with each other. This may be yet another shred of evidence for the mirror neuron hypothesis.
Blakemore, Bristow, Bird, Frith, and Ward (2005), “Somatosensory activations during the observation of touch and a case of vision–touch synaesthesia,” Brain, 2005, 128
Churchland, Patricia (2011), Braintrust, Princeton University Press (Kindle edition)
Damasio, Antonio (2010), Self Comes to Mind, Random House.
Gallese, Keysers and Rizzolatti (2004), “A unifying view of the basis of social cognition,” Trends in Cognitive Sciences, Sept. 2004
Hickok, Gregory (2009), “Eight Problems for the Mirror Neuron Theory of Action Understanding in Monkeys and Humans,” J. Cogn. Neurosci., July 2009
Keysers, Christian (2011), The Empathic Brain, Kindle Edition
Ramachandran, VS (2011), The Tell-Tale Brain, W.W.Norton
Tags: mirror neuron