Moral neuropolitics and ideology

An interesting paper was recently brought to my attention. It's all worth reading, but I want to focus on one specific passage, because I think it spotlights a very important question, and provides a springboard for discussion of a number of significant issues in political psychology.

This is the paper:

We Empathize, Therefore We Are: Toward a Moral Neuropolitics

It's by Gary Olson, who is currently Chair of the Political Science Department at Moravian College, Bethlehem, PA.

Olson begins by pointing out the important human characteristic of being able to empathize with the experienced injustice and suffering of others. Citing the empathy felt by people who viewed art depicting victims of the transatlantic slave trade, Olson connects this with recent neuroscience having to do with mirror neurons:

The abolitionist's most potent weapon was the dissemination of drawings of the slave ship Brooks. Rediker asserts that these images were "to be among the most effective propaganda any social movement has ever created" (p. 308).

Based on recent findings from neuroscience we can plausibly deduce that the mirror neurons of the viewer were engaged by these images of others suffering. The appeal was to the public's awakened sense of compassion and revulsion toward graphic depictions of the wholesale violence, barbarity, and torture routinely practiced on these Atlantic voyages. Rediker notes that the images would instantaneously "make the viewer identify and sympathize with the 'injured Africans' on the lower deck of the ship . . ." while also producing a sense of moral outrage (p. 315, Olson, 2008).

In our own day, the nonprofit Edge Foundation recently asked some of the world's most eminent scientists, "What are you optimistic about? Why?" In response, the prominent neuroscientist Marco Iacoboni cited the proliferating experimental work into the neural mechanisms that reveal how humans are "wired for empathy." This is the aforementioned discovery of the mirror neuron system or MNS. The work shows that the same affective brain circuits are automatically mobilized upon feeling one's own pain and the pain of others.

Iacoboni's optimism is grounded in his belief that with the popularization of scientific insights, these findings in neuroscience will seep into public awareness and " . . . this explicit level of understanding of our empathic nature will at some point dissolve the massive belief systems that dominate our societies and that threaten to destroy us" (Iacoboni, 2007, p. 14).

Given that background, the crucial passage in Olson's paper seems to me to be this:

That said, one of the most vexing problems that remains to be explained is why so little progress has been made in extending this empathic orientation to distant lives, to those outside certain in-group moral circles. That is, given a world rife with overt and structural violence, one is forced to explain why our deep-seated moral intuition doesn't produce a more ameliorating effect, a more peaceful world. Iacoboni suggests this disjuncture is explained by massive belief systems, including political and religious ones, operating on the reflective and deliberate level. As de Waal reminds us, evolutionarily, empathy is the original starting point out of which sprang culture and language. But over time, the culture filters and influences how empathy evolves and is expressed (de Waal, 2007, p. 50). These belief systems tend to override the automatic, pre-reflective, neurobiological traits that should bring people together.

Right off the bat, of course, we have a problem. As I've just been writing about (here, here), there may be serious scientific difficulties with the whole concept of a "mirror neuron system" in humans.

Olson says "we can plausibly deduce that the mirror neurons of the viewer were engaged by these images of others suffering." He does mention fairly recent (2007-8) studies that seemed to indicate the existence of mirror neurons in humans, but the skeptical opinions of neuroscientists like Gregory Hickok, whose very recent paper I wrote about, suggest that this whole issue is still up in the air.

But perhaps the issue of mirror neurons isn't all that important. While it can be questioned whether humans have mirror neurons, and whether such mirror neurons (if they do exist) actually account for empathy in humans, surely it would be hard to dispute the existence of empathy in humans.

Or would it? One does have to question how often empathy, even if it exists, plays a dominant role in humans affairs. Sometimes it does, as the ending of the transatlantic slave trade and the final ending of slavery in the U. S. attest. On the other hand, different forms of slavery still persist in the world, as well as all manner of other ills, such as crime, genocide, war, territorial occupations, and economic exploitation.

Nevertheless, let's leave that whole question aside. Human empathy does exist in many circumstances (even if we don't have an adequate neurobiological explanation of it), yet even so, there seem to be social and cultural forces that all too often are able to override empathy. Olson evidently agrees with Iacoboni in identifying the responsible factor as "massive belief systems, including political and religious ones, operating on the reflective and deliberate level."

Let's refer to those political and religious belief systems as "ideology".

The key question, then, is how to explain the substantial power that ideology has over human social behavior – not just behavior that is culturally conditioned, but even behavior that has evolutionary, biological roots, such as the empathy that derives (perhaps) from mirror neurons. That is, we have to explain how "belief systems tend to override the automatic, pre-reflective, neurobiological traits that should bring people together."

It seems to me that this is a rather important open question that political science ought to be addressing.

Because we are dealing with phenomena that can override neurobiological traits, I think we have to look at explanations that also refer to neurobiology. It just makes the most sense to consider the problem as a whole at that level.

How is it that ideology has such a compelling influence over people? What is it that ideology has to offer? How does it fit with underlying psychological factors?

We need some frame of reference to consider these issues. For the sake of concreteness, I'm going to proceed here using a circle of ideas championed by Jonathan Haidt as a convenient reference frame.

What Haidt has proposed is a "moral foundations theory" that claims to identify five "fundamental moral values" that are held by a large number of people, to greater or lesser extents, in a wide variety of cultures around the world (and in history). I think his list is incomplete as a comprehensive foundation for "morality" in general, and there are valid questions about whether some aspects of the "values" he describes even merit consideration as part of a fundamental set. Nevertheless, each of the "values" does have its devoted adherents, and so ipso facto plays a role in social behavior in those cultures where the "value" is recognized.

Here, according to Wikipedia, are the five "fundamental moral values":

1. Care for others, protecting them from harm. (He also referred to this dimension as Harm.)
   
2. Fairness, Justice, treating others equally.
   
3. Loyalty to your group, family, nation. (He also referred to this dimension as Ingroup.)
   
4. Respect for tradition and legitimate authority. (He also referred to this dimension as Authority.)
   
5. Purity, avoiding disgusting things, foods, actions.

Further references (listed at the end of this article): [1], [2], [3], [4].

I'm not ready to make an overall evaluation of Haidt's ideas, but let's look at them and see where they might lead.

On the basis of cross-cultural research Haidt came up with these five distinguishable biological bases of morality. If nothing else, they should be factors that would give significant force and impact to ideologies that are leveraged from them.

The first two factors are (quoting from [1]) "(i) harm, care, and altruism (people are vulnerable and often need protection) or (ii) fairness, reciprocity, and justice (people have rights to certain resources or kinds of treatment)."

Haidt sees these as having evolutionary origins in kin selection and the mechanism of reciprocal altruism.

I think they could have other evolutionary origins as well. In addition, I find it a little difficult to distinguish these two factors. Both encode an obvious "golden rule" sort of morality. However that may be, it seems that mirror neurons, or something equivalent, might play a role in the neurobiology of these factors, which both relate to "empathy".

So another important question we can ask is: what are the evolutionary origins of mirror neurons (or equivalents)? Since other primates, and indeed other animals (e. g. dogs), seem to have something functionally like mirror neurons, and also notions of fairness and justice that resemble human notions, we probably need to look back further in time than the origins of hominids.

It seems to me that something like mirror neurons should be useful equipment for a member of any species that engages in intra-species combat, which is probably a large percentage of species. That certainly doesn't mean many species necessarily have mirror neurons. But, at least, the evolution of mirror neurons certainly could be a useful adaptation for many species. So something like mirror neurons could well be a primary evolutionary development, not a mere side effect of something else. And if empathy, altruism, etc. have roots in such a mechanism, they too are at least useful side effects of evolution, even if they were not directly adaptive in themselves. (Though there are plenty of reasons to think they are adaptive in themselves, especially if you believe in group selection.)

But perhaps the more interesting aspect of Haidt's ideas comprises the three other factors he regards as basic to many human moral codes.

Quoting again from [1], "In addition to the harm and fairness foundations, there are also widespread intuitions about ingroup-outgroup dynamics and the importance of loyalty; there are intuitions about authority and the importance of respect and obedience; and there are intuitions about bodily and spiritual purity and the importance of living in a sanctified rather than a carnal way."

Let's look at these separately. First up is group loyalty, preference for the ingroup, and fear/aversion towards the outgroup. This is pretty clearly, at least in part, a kin selection sort of thing.

There is also another clever evolutionary argument for this factor. It's spelled out by Choi and Bowles in [5]. They call the idea "parochial altruism". The authors present computer simulation evidence for their idea. It has the interesing property of being able to explain the otherwise paradoxical fact that humans are a fairly warlike species, in spite of countervailing empathetic tendencies. I wrote about it here at some length. See also [6].

There are, of course, other evolutionary arguments for group loyalty, such as basic considerations of group selection – successful groups should tend to be cohesive and behave something like kin groups, even in the absence of near kinship. And this would be especially true in time of resource scarcity (which probably was not infrequent).

Among the neurobiological bases of group loyalty would be any neural capabilities that enable the detection of cheating and disloyalty. These need not be discrete neural systems or brain modules. They might be just general capabilities that enable individuals to remember the past behavior of others and reason about it in such a way as to recognize signs of loyalty or disloyalty to the group. Capability for cheater detection might be a general learning ability, like the ability to learn language. Individuals need not be born being good cheater detectors. They just need to be able to learn how to be good at it.

I'm not aware of neurobiological research into cheater detection mechanisms, or other mechanisms that could support group loyalty. Studies of loyalty and cheater detection and conditions for extending trust to others should also connect up easily with the importance of "patriotism" and "solidarity" in various ideologies. This would seem to be a great area for future research.

The bottom line here is that there are very good reasons to expect ingroup/outgroup dynamics to have neurobiological underpinnings, and that these factors would strongly influence ideology. ("Deutschland uber alles." "Defend the fatherland." Etc.)

Turning to the next factor Haidt mentions: authority and the importance of respect and obedience. The psychological power of authority is quite well established. Including the Milgram experiment, which provides a glaring example of how social psychology can override any innate sense of empathy for others. Zimbardo's prison experiment is also relevant.

Respect for and obedience to authority pretty clearly have evolutionary roots in any social species that has a hierarchically organized social life – which is many species, even insects. (Some very recent research shows that even ants will attack other ants that don't follow the rules.)

Interestingly, though, degree of respect for authority varies a lot in humans. (But then, so to does a propensity to cheat.) Political scientists have known for a long time of Theodor Adorno's concept of an "authoritarian personality".

Again, respect for and obedience to authority are key features of many powerful ideologies – features that easily override empathy-based respect for peers.

This is another area that calls for much more neurobiological research. What characteristics of our neurobiology equip us to recognize and defer to authority? Is is just fear based on the consequences of disobedience to actors with substantial social/physical power? Are obedient personalities just a result of a kind of "Stockholm syndrome"?

Haidt's last factor is "intuitions about bodily and spiritual purity." This is, to my mind, the murkiest of the factors. Clearly, humans have evolved good instincts for avoiding contaminated or corrupt food, or other gathering places of pathogenic things. Exactly how that bootstraps into elaborate ideologies featuring supernatural beings is a whole bigger question.

I think there are quite a few additional factors that go into the social psychology of religion and its ideologies, including group loyalty and obedience to authority. And research into such factors seems to be pretty active these days, though not primarily into neurobiological factors. This is a large area of research all by itself. So I don't have clear ideas about how important "purity" is as a factor, by itself, that influences ideology.

Pascal Boyer has an interesting recent essay in Nature ([7]). He writes, "So is religion an adaptation or a by-product of our evolution? Perhaps one day we will find compelling evidence that a capacity for religious thoughts, rather than 'religion' in the modern form of socio-political institutions, contributed to fitness in ancestral times. For the time being, the data support a more modest conclusion: religious thoughts seem to be an emergent property of our standard cognitive capacities."

As an aside, this suggests that what we may find is that political behavior in general, and specific ideologies, are also emergent properties of our standard cognitive capacities. And that's a disquieting thought. Our cognitive capacities were shaped in a time when humans were far fewer in number, and had much less ability to cause large-scale problems for themselves and the rest of the world. Our inherited cognitive traits may result in less sanguine outcomes today than they did in the past. In particular, religion as a common sort of ideology, and Haidt's other moral predispositions, may be less beneficial for humans now than they may have been in the past.

One token of this may be seen in moral principles that do not seem to have deep roots in evolution and neurobiology. For example: aversion to war, faithful attention to truthfulness and honesty in dealing with others, sensitivity to and aversion towards manipulative behavior on the part of social elites, and respect and concern for the natural environment. Such principles don't even appear in Haidt's scheme.

Alternative reference frame: fear and emotions in general

All that said, Haidt's ideas are not the only way to approach the question of neurobiological bases of ideology. Another distinct approach involving neurobiology would center on the importance of the emotion of fear. There is, of course, a voluminous amount of research on the underpinnings of fear and its opposite (trust), as mediated by anatomical features like the amygdala and the limbic system in general.

I've just summarized a number of previous comments on this topic here. Since we're concerned with ideology in this note, it seems especially worth observing the similarities between beliefs about government and about religion, in particular the significant role that fear plays in both (see here).

Fear obviously plays a role in practical politics. How it interacts with organized ideologies is less clear. Certainly, fear of death or great harm is enough to motivate ideologies that feature institutions of authority that "protect" the populace. In any case, fear in some form or other is a strong motivator, another factor that can easily override an individual's healthier empathetic instincts.

Alternative reference frame: personality theory

Yet another direction of possible research involves trying to relate specific personality traits to ideological preferences. Perhaps the best supported of such findings could provide clues as to underlying mechanisms that link psychological tendencies to ideological features.

However, I'm skeptical. Personality traits, in fact, have been defined empirically by looking at the way people tend to use labels to describe other people. The most widely accepted type scheme, the "Big Five", is based on studies of language usage, in which factor analysis is employed to group certain behaviors using labels given to people who exhibit those behaviors. So it's entirely driven by data of a particular type, rather than theory.

That raises two problems. Firstly, there is little logical relationship between either the traits or the behavioral characteristics associated with them and specific ideologies. This is in contrast with Haidt's morality types that do connect reasonably well with ideologies. While empirical correlations between personality traits and ideologies have been found, they usually aren't very strong.

The second problem is that there's little apparent connection between personality traits and neurobiology. Perhaps that will change as more laboratory work is done that investigates the underpinnings of emotions and behavior, but I don't have the sense that clarity is close at hand.

The net result is that personality traits aren't an obvious way to make connections with either ideology or neurobiology.

Conclusion

All in all, it certainly looks like there's a huge need for research to explore how neurobiology interacts with social behavior, politics, and ideology. Understanding the potential role of something like mirror neurons is certainly important. But I think there's a whole lot more we need to understand, especially concerning the darker sides of human nature.

References and further reading:

[1] The New Synthesis in Moral Psychology – 5/18/07 Science review article by Jonathan Haidt

[2] The Roots of Morality – 5/9/08 Science News Focus article by Greg Miller

[3] Is ‘Do Unto Others’ Written Into Our Genes? – 9/18/07 New York Times article by Nicholas Wade

[4] The Moral Instinct – 1/13/08 New York Times Magazine article by Steven Pinker

[5] The Coevolution of Parochial Altruism and War – 10/26/07 research paper in Science by Jung-Kyoo Choi and Samuel Bowles

[6] The Sharp End of Altruism – 10/26/07 Perspectives article in Science by Holly Arrow

[7] Being human: Religion: Bound to believe? – 10/23/08 essay in Nature by Pascal Boyer

Tags: political science, political psychology, ideology

What are mirror neurons good for?

Last week I noted that there have been some serious questions raised in a paper by Gregory Hickok about the "mirror neuron theory of action understanding".

I've now read the paper, and there's a lot that could be said on the topic.

But first, what's the discussion about to begin with?

"Mirror neurons" have received a lot of speculative attention in the popular science media. I've done some of that myself. (See here, here, here, here.)

So what is a "mirror neuron"? According to Wikipedia (which is as good a source as any for popular usage of a term), "A mirror neuron is a neuron which fires both when an animal acts and when the animal observes the same action performed by another (especially conspecific) animal. Thus, the neuron "mirrors" the behavior of another animal, as though the observer were itself acting."

That definition needs to be unpacked a little, for the sake of being specific about what's under discussion, even if we have to deviate from what is popularly understood. So, more specifically, a mirror neuron is one that's found in a motor control area of an animal's brain. It's not the only type of neuron there, but it does activate when the animal performs specific motor actions (different ones for different neurons).

The other characteristic that a mirror neuron is presumed to have is that it also activates when the animal perceives another animal performing the same action that causes activation of the neuron in the observing animal.

Notice what's not being defined as a mirror neuron. We aren't talking about just any neuron which activates when an animal perceives another animal performing some action. If that were the definition, it would be somewhat tautologous to assert that such a neuron helps the observing animal to "understand" the actions of another animal. Clearly, any animal that is capable of "understanding" the actions of other animals (of the same or even different species) must have some action-specific neurons that activate when observing actions of other animals.

It would not be pointless to discuss such things, but we would be more into the area of what it means for an animal to "understand" actions of another and how that might happen. That's a much broader issue, even applied to particular species, especially humans.

However, as soon as we agree that we're talking about certain neurons only in the limited sense mentioned above, the question arises of whether such neurons exist at all. And the interesting thing is that there are generally accepted research findings that such neurons do exist – in one particular species: macaque monkeys. These are one particular species of old world monkeys that happen to be used frequently in neurobiological research, because (being primates) they're a lot closer to humans than, say, rats, but also a lot more convenient and less expensive to work with than humans.

But note that, again according to Wikipedia, "The only animal in which mirror neurons have been studied individually is the macaque monkey. In these monkeys, mirror neurons are found in the inferior frontal gyrus (region F5) and the inferior parietal lobule." Apparently, evidence that mirror neurons even exist in other species, especially humans, is sparse to non-existent.

That's one of the main points made in the Hickok paper I've been referring to (Eight Problems for the Mirror Neuron Theory of Action Understanding in Monkeys and Humans). Specifically:

there have been a host of studies aimed at investigating the ‘‘mirror system’’ in humans, but much of this work has investigated behaviors that mirror neurons could not possibly support given their response properties in monkeys, and therefore, the connection between these behaviors and mirror neurons is tenuously based on a chain of assumptions: Mirror neurons exist in humans (there are individual cells that respond both during action execution and action perception), mirror neurons have evolved to support functions in humans that they do not support in monkeys, this evolution has conserved the functional properties found in monkeys, and mirror neurons are responsible for the behavior in question.

Unfortunately, the existence of mirror neurons in humans is still just an assumption. And further, assumptions about what aspects of human cognition mirror neurons (if they exist) might take part in significantly exceed what is known about the function of mirror neurons in monkeys. Hickok provides a partial list of human capabilities sometimes assumed to involve mirror neurons: "speech perception, music perception, empathy, altruism, emotion, theory of mind, imitation, autism spectrum disorder, among others".

Clearly, that list far surpasses merely "action understanding". And it goes far beyond the data, because macaque monkeys are not known to exhibit most of those capabilities. Indeed, they are known not to have (e. g.) much ability for imitation. So to assume that mirror neurons can be used to explain all of those things requires the assumptions that humans have analogues of macaque mirror neurons, and that such analogues play a significant role in those varied capabilities.

Such assumptions may well provide fruitful hypotheses for future research. But the research to adequately justify such ideas has scarcely begun.

On top of all that, it's not clear how important mirror neurons are for "action understanding" even in macaques. I find two main points in Hickok's paper, and this is one of them. The other is to call into question the importance of a "mirror system" (of neurons in motor-related brain areas) in humans, should such even exist, for "action understanding". Unfortunately, I don't have time in this note to go into more detail on his arguments regarding these points.

I think one has to question what exactly is meant by "action understanding" in the first place. It's certainly a valid question for macaques. We can't even be sure of what it means for a macaque to "understand" anything – since we have no introspective knowledge of the macaque mind. But here's a possible way to operationalize the notion. We might say that "understanding" means an ability to predict what might follow the observation of a specific action in another individual. For example, certain facial expressions might predict further actions, such as overt aggression or attempts at mating behavior.

Many animals certainly have such abilities. Dogs, for instance, obviously know what it means when another dog is seen baring its teeth. But does that mean dogs have analogues of mirror neurons that contribute to this understanding? Do we know whether mirror neurons, even in macaques, assist in predicting future behavior of other individuals? Since I'm hardly an expert in animal behavior, I can't answer those questions.

What all of these questions mean to me is not that we have to give up hope of understanding human characteristics, such as empathy, altruism, imitation, theory of mind, and so forth. Instead, the take-away is that a vast amount of further research work needs to be done in order to establish a sound scientific understanding of the neurobiology of such abilities. The hypothesis that humans have some sort of "mirror system" of neurons that plays a role in empathy, altruism, imitation, etc. is at least a plausible one, inspired by a rough analogy with macaque mirror neurons.

But almost all the research remains to be done that would (1) identify parts of the human brain that comprise a "mirror system", and (2) show that such subsystems underlie each specific case of what we might call "empathetic behavior" in humans. This would appear to be a task similar in difficulty to that of achieving a neurobiological understanding of almost any type of "higher-level" human capability, from abstraction to complex language to long-range planning.

And yet there are good evolutionary reasons for expecting that one or more "mirror systems", in some broader sense, may exist in humans. Very generally, humans have highly developed capabilities for social organization. Such capabilities are needed to enable specific aspects of human social behavior, e. g. the ability to construct elaborate social hierarchies, build complex, enduring social coalitions, and detect covert violators of important social norms. Such capabilities would be evolutionarily favored in selecting for groups that are more cohesive and unified in competition with rivals. (At least if one thinks that group selection is possible.)

If you don't happen to believe in group selection, there are other reasons that individuals possessing good "empathic skills" would have an adaptive advantage and higher fitness compared to other individuals.

For example, consider hand-to-hand combat. Humans have always fought bloodily against others of their species, especially members of unrelated tribes. The ability to rapidly and accurately predict the next hostile moves of an opponent bent on one's destruction would have to be ranked as very valuable. Obviously, some individuals are able to become very skilled in "martial arts", which rely on highly sensitive observance of the detailed behavior of others.

More generally, beyond the level of physical combat, the admonition to "know your enemy" has always been excellent advice. Sensitive understanding of the subtleties of body language is an extremely useful skill in many competitive situations, as good poker players and canny negotiators will attest. Being able to understand the goals and intentions of an opponent certainly has evolutionary survival value. And the same ability regarding others in general is just as useful for achieving cooperation.

Understanding the neurobiology of such skills is an excellent, albeit very long-range, research goal. I'm not necessarily skeptical of the possibility of such a reductionistic goal, but I don't expect it to be achieved very soon, either....

One may reasonably ask why, if the actual evidence for a mirror neuron system in humans is so questionable, the idea is also so popular and widely discussed. The answer seems to be that, if valid, the idea provides important support for the philosophy of "embodied cognition", which holds that the nature of human thinking and emotion is closely tied to the physical body. But that's far too large of an issue to start addressing here.

Tags: mirror neurons, neurobiology, embodied cognition

Problems for the mirror neuron theory of action understanding

This is a heads-up for people who have been assuming that mirror neurons – which have been most thoroughly studied in monkeys rather than humans – play an important role in the ability of humans to "understand" the actions of others. (It's kind of hard to determine whether monkeys understand, in the human sense, the actions of other monkeys.)

There is increasing skepticism from some in the neuroscience community that mirror neurons – if they even exist in humans in a form analogous to those in monkeys – live up to the high expectations.

Greg Hickok, Professor of Cognitive Sciences, and Director of the Center for Cognitive Neuroscience at UC Irvine, has been expressing concerns in this area at his blog, Talking Brains. Now a paper of his that discusses these concerns has been published at the Journal of Cognitive Neuroscience.

Here's the announcement from his blog:

Eight problems for the mirror neuron theory of action understanding (2/10/09)

The basic conclusion is that there is little or no evidence to support the mirror neuron=action understanding hypothesis and instead there is substantial evidence against it.

The announcement is also here.

Unfortunately, the journal isn't open access, and I haven't yet seen the paper. If and when I have a chance to read it, I'll very likely try to report a lot more. I've already written about the subject of mirror neurons, based on various earlier accounts, e. g. here, here, here, here.

Pending more information, Hickok has some posts on his blog that provide a few details. Especially this from last August:

Eight Problems for the Mirror Neuron Theory of Action Understanding (8/6/08)

Regular readers (and perhaps even occasional readers) of Talking Brains are well aware that I have been rather critical of the interpretation of mirror neurons that dominates the literature, namely, that they are the basis of action understanding. I've finally synthesized all of these critical comments into a critical review titled "Eight Problems for the Mirror Neuron Theory of Action Understanding in Monkeys and Humans."

Here are other posts by Hickok since that one that discuss mirror neurons:

• Mirror neurons, hubs, and puppet masters (8/21/08)
• How much can a motor representation contribute to action word meaning? (8/26/08)
• Mirror neurons in the inferior parietal lobe: Are they really "goal" selective? (10/24/08)
• Rock-Paper-Scissors and mirror neurons: Executed and observed movements have different distributed representations in human aIPS (10/31/08)
• Ventral premotor cortex and action processing: Urgesi, et al. (11/3/08)
• Mirror neurons in humans revealed by fMRI adaptation (11/4/08)

There are many earlier posts. Just search the blog for "mirror neuron".

One last piece of information – the PubMed abstract for Hickok's paper:

Eight Problems for the Mirror Neuron Theory of Action Understanding in Monkeys and Humans

The discovery of mirror neurons in macaque frontal cortex has sparked a resurgence of interest in motor/embodied theories of cognition. This critical review examines the evidence in support of one of these theories, namely, that the mirror neurons provide the basis of action understanding. It is argued that there is no evidence from monkey data that directly tests this theory, and evidence from humans makes a strong case against the position.

Stay tuned.

Tags: mirror neurons

Mirror neurons control erection response to porn

Does anyone find this surprising? Isn't it exactly the effect one would expect mirror neurons to have? (Past discussion here.) However, it is welcome to note basic research that has practical applications...

Mirror neurons control erection response to porn (6/16/08)

You don't have to be a scientist to observe that pornographic images lead to erections in men. But you would have to be one to show those images to volunteers while meticulously measuring the volume of response in the brain and penis.

Harold Mouras, at University of Picardie Jules Verne in Amiens, France, and his colleagues wanted to understand the cerebral underpinnings of visually-induced erections.

They suspected there might be a role for mirror neurons, a special class of brain cell that fires both when people perform an action and when they observe it being performed.

Not a terribly difficult guess to make. So what did they find?

While the volunteers watched the movies, the researchers watched their brains using functional magnetic resonance imaging (fMRI).

They also kept tabs on the tumescence of the other target organ, using a hand-crafted "penile plethysmograph" – essentially an airtight tube in which the enlarging penis causes measurable pressure changes.

As expected, all the subjects got erections and many parts of the brain lit up.

Interestingly, the volume of the erections correlated with the strength of activation in a part of the brain called the pars opercularis, which is known to display mirror neuron activity. Even more intriguing, the brain activation, say the researchers, precedes the penile response.

Tags: mirror neurons

Update on mirror neurons

I had a piece about mirror neurons here a year and a half ago. It seems to have been popular. There was a shorter piece here.

There's been a bit of recent news on the subject:

Culture Influences Brain Cells: Brain's Mirror Neurons Swayed By Ethnicity And Culture

In their study, the researchers wanted to investigate the imprint of culture on the so-called mirror neuron network. Mirror neurons fire when an individual performs an action, but they also fire when someone watches another individual perform that same action. Neuroscientists believe this "mirroring" is the neural mechanism by which we can read the minds of other people and empathize with them.

When it comes to the influence of culture, they found that indeed, the mirror neuron network responds differently depending on whether we are looking at someone who shares our culture, or someone who doesn't.

A special case of this culture specificity is language, and almost a year ago there was some research reported that linked written language with mirror neurons:

First Evidence Found of Mirror Neurons Role in Language

What do we find so gripping about a good book, the kind that makes us stay up later than we should to find out what happens to hero or heroine?

A new brain imaging study from UCLA may provide an answer, and further, shed light on the language problems common to autistic children. In a study published in the Sept. 19 issue of Current Biology, UCLA researchers show that specialized brain cells known as mirror neurons activate both when we observe the actions of others and when we simply read sentences describing the same action. When we read a book, these specialized cells respond as if we are actually doing what the book character was doing.

Another article on this research: here.

In fact, a similar relation seems to exist between spoken language and mirror neurons:

Strong Mental Link Between Actions And Words

The brain's premotor cortex shows the same activity pattern when subjects observe an action as when they hear words describing the same action, the study's authors said.

Concurrently with those reports, there were others linking mirror neurons with (non-linguistic) auditory stimuli: here, here, here.

Further research appeared this January relating (musical) sounds and mirror neurons:

New Study Shows Brain Rapidly Forms Link Between Sounds And Actions That Produce Them

The researchers taught nine subjects with no previous musical training to play a five-note, 24-second song on a keyboard. Then they ran functional magnetic resonance imaging (fMRI) scans while the subjects listened to the song they had just learned, a different song using the same five notes, and a third song made up of additional notes.

When the subjects listened to the familiar music, their brains showed activity in a network of areas in the frontal and parietal lobes that are involved in the control of movements. The authors note that Broca's area, the human equivalent of the area in the brain where mirror neurons were found in monkeys, was particularly active when subjects listened to music they knew how to play compared with equally familiar music they did not know how to play.

Update: Here's an article on the subject that references this note: How Your Brain Allows You to Walk in Another's Shoes.

Background:

The mind's mirror

What Do Mirror Neurons Mean?

Reflecting on Another's Mind

The Origin of Speech

Tags: mirror neurons, neuroscience

Mirror neurons

We had a pretty detailed article on mirror neurons back in March (here).

The research discussed there is hardly the last word, of course. Now it is reported that infants less than a year old begin to anticipate the actions of others at just about the point where they are capable of the actions themselves -- probably courtesy of mirror neurons.

Toddlers Anticipate Actions As Well As Adults

Terje Falck-Ytter and his colleagues at Uppsala University in Sweden tested the responses of 11 babies, 11 toddlers and 11 adults when watching nine identical videos of an actor's hand placing three toys into a bucket. Both adults and toddlers moved their eyes to the bucket before the hand finished its motion and did so in roughly the same amount of time. The babies, however, did not shift their eyes until the hand had reached the bucket.

Similar trials with mechanical motion or toys moving without a hand did not result in either adults, infants or babies looking ahead, leading the team to speculate that the mirror neuron system might be responsible for the ability. This system, first discovered in macaque monkeys, allows primates to map the actions of others in the same areas of the brain that would be activated if they undertook the action themselves.

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Additional references:

Predicting actions starts young - UPI

Mind Reading Is Child's Play - ScienceNow (subscription rqd)

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Tags: mirror neurons, neuroscience

Mirror neurons

Here's an extremely interesting and well-written article by Sandra Blakeslee in the New York Times. It's a lot better than most newspaper science articles. Although it does not go into technical details, its virtue is how it describes so many interrelated aspects of the subject, while still remaining comprehensible.

Cells That Read Minds (January 10, 2006)

The cells in question are "mirror neurons". They were discovered around 1990 in the laboratory of Giacomo Rizzolatti, a neuroscientist at the University of Parma, Italy. Researchers in the laboratory had been studying brain activity in macaque monkeys.

The monkey brain contains a special class of cells, called mirror neurons, that fire when the animal sees or hears an action and when the animal carries out the same action on its own.

But if the findings, published in 1996, surprised most scientists, recent research has left them flabbergasted. Humans, it turns out, have mirror neurons that are far smarter, more flexible and more highly evolved than any of those found in monkeys, a fact that scientists say reflects the evolution of humans' sophisticated social abilities.

The human brain has multiple mirror neuron systems that specialize in carrying out and understanding not just the actions of others but their intentions, the social meaning of their behavior and their emotions.

"We are exquisitely social creatures," Dr. Rizzolatti said. "Our survival depends on understanding the actions, intentions and emotions of others."

He continued, "Mirror neurons allow us to grasp the minds of others not through conceptual reasoning but through direct simulation. By feeling, not by thinking."

The discovery is shaking up numerous scientific disciplines, shifting the understanding of culture, empathy, philosophy, language, imitation, autism and psychotherapy.

Everyday experiences are also being viewed in a new light. Mirror neurons reveal how children learn, why people respond to certain types of sports, dance, music and art, why watching media violence may be harmful and why many men like pornography.

I highly recommend you go read the whole article yourself at the link given above. It's well worth your time.

I'd like to write a whole book on this set of interrelated issues connected with mirror neurons -- but that would be an investment of a lot more time than I have available at the moment, so I'll just set down a few notes about some of the topics touched upon in Blakeslee's article.

If you'd like a little more background on mirror neurons to begin with, you might try this Wikipedia article. Unfortunately it's rather sketchy and lacks references for most assertions.

However, it does refer to a longer article at Edge by V. S. Ramachandran that was written in early 2000. You might also want to look at the introductory material and especially a discussion of the article by several experts in related fields. You may find the critiques in this discussion to be a bit confusing, as they assume some acquaintance with fields like neuroscience, linguistics, anthropology, and so forth. But if that doesn't scare you off, the discussion is worth reading. You may even wish you could jump in yourself to reply to some of the arguments, especially with an individual like Rafael Nuñez (a rather ideological anti-reductionist).

Also, keep in mind that many of the remarks in the Ramachandran paper are conjectural or speculative. There are many hypotheses about the role that mirror neurons may play in the workings of the human brain. A great deal of work remains for scientific research to confirm or disprove many of these speculations -- probably enough to keep researchers busy for decades. Ramachandran himself has recently been working on some of these questions, as we will see.

Anyhow, let's get back to Blakeslee's article. She summarizes the key property of mirror neurons as follows:

Studies show that some mirror neurons fire when a person reaches for a glass or watches someone else reach for a glass; others fire when the person puts the glass down and still others fire when the person reaches for a toothbrush and so on. They respond when someone kicks a ball, sees a ball being kicked, hears a ball being kicked and says or hears the word "kick."

So mirror neurons are associated with a wide variety of fairly complex actions, where many muscles have to be activated in order to accomplish some intended goal. This idea of "intention" is very important. Blakeslee quotes neuroscientist Marco Iacoboni:

"When you see me pull my arm back, as if to throw the ball, you also have in your brain a copy of what I am doing and it helps you understand my goal. Because of mirror neurons, you can read my intentions. You know what I am going to do next."

This is the sense in which mirror neurons can "read minds" -- some of your mirror neurons respond to seeing another person do something in the same way as the neurons would if you were doing the action yourself. And you are able to detect this neural activity and correlate it with the particular action.

For example, in February 2005 Iacoboni and colleagues published a paper that described research demonstrating that the firing patterns of mirror neurons discriminated between moving a teacup to drink from it or to remove it from the table. See UCLA Neuroscientists Pinpoint New Function For Mirror Neurons. (Here's an earlier study from the same laboratory: UCLA Imaging Study Reveals How Active Empathy Charges Emotions; Physical Mimicry Of Others Jump-starts Key Brain Activity (4/8/03).)

Being able to infer the intentions of other people is an extremely important ability for humans in their social interactions with others. It's a large part of what makes humans such a social species. Think of the importance of being able to tell from the way someone else handles a rock whether he is just studying it or getting ready to throw it at you.

Psychologists describe this ability as being part of a "theory of mind". This is the idea that humans (and possibly a few other animals) recognize that others have minds like their own and that people can make accurate hypotheses about beliefs, desires, intentions, and mental states of others. As a scientific notion, the idea seems to have originated in the 1970s. It seems to have been suggested by various people. The discussion of Ramachandran's article exposes some of the controversy about who gets the credit. Some of the names offered are Nicholas Humphrey, Simon Baron-Cohen, David Premack, and Daniel Dennett. Ramachandran was onto the idea himself at an early stage.

Dennett is also known for extending the idea to his notion of the "intentional stance". As the Wikipedia article says, "To use the intentional stance in explanation one looks at a particular bit of behaviour and ask what beliefs and desires could give rise to that behaviour. One then assumes that those beliefs and desires are actually held by the creature." Clearly, mirror neurons could well be a basis for inferring beliefs and desires from observed behavior of others. Dennett's theorizing goes on to incorporate this intentional stance into his ideas about consciousness, as described in his book Consciousness Explained.

This is hardly the time to launch into an extended discussion of consciousness. But we can't help noting a slightly different way in which mirror neurons may play a part. Blakeslee has a further quote from Iacoboni:

"[I]f you see me choke up, in emotional distress from striking out at home plate, mirror neurons in your brain simulate my distress. You automatically have empathy for me. You know how I feel because you literally feel what I am feeling."

In other words, mirror neurons help us understand not only the intentions of other people, but their feelings and emotions as well. They enable us to empathize with others.

For instance, most people can easily read the emotions of others from facial expression, tone of voice, and other body language. It seems rather likely this is because our mirror neurons simulate the muscular activity that underlies these kinds of emotion-expressing behaviors. Further, if one tries to imitate facial expressions associated with emotional states (like fear, sadness, joy, etc.), one actually feels at least a little bit of the emotion itself.

Some neuroscientists have suggested that emotions originate, at least in part, from our perceptions of how our own bodies react when in situations that naturally evoke fear, pleasure, and so forth. This idea is propounded, for instance, in Antonio Damasio's book Descartes' Error. Damasio then goes on, in The Feeling of What Happens to construct from these ideas a more general theory of consciousness. So it's not too much of a stretch to think of mirror neurons as important parts of the neural basis for the phenomenon of consciousness.

But we're still not done. As if enabling consciousness were not enough, mirror neurons may also play a big role in the development of human culture, by enabling humans, from a very early age, to acquire complex behaviors (such as using tools, learning language, participating in group social activities, etc.) by a process of imitation. Blakeslee quotes psychologist Patricia Greenfield:

Until now, scholars have treated culture as fundamentally separate from biology, she said. "But now we see that mirror neurons absorb culture directly, with each generation teaching the next by social sharing, imitation and observation."

And adds

Other animals - monkeys, probably apes and possibly elephants, dolphins and dogs - have rudimentary mirror neurons, several mirror neuron experts said. But humans, with their huge working memory, carry out far more sophisticated imitations.

This isn't just speculation. There's already research that has implicated the mirror neuron system in imitation. For example, this from January 2005: Human See, Human Do: Ballet Dancers' Brains Reveal The Art Of Imitation

While previous studies have found that the system contains mirror neurons or brain cells which fire up both when we perform an action and when we observe it, the new study shows that this system is fine tuned to each person's 'motor repertoire' or range of physical skills. The mirror system was first discovered in animals and has now been identified in humans. It is thought to play a key role in helping us to understand other people's actions, and may also help in learning how to imitate them.

It's hard to overestimate the importance of learning by imitation in the transmission of human culture. Most things humans really need to learn how to do can only be learned by carefully observing someone who already has the skill. For early humans it was things like making stone tools, building a fire, or throwing a spear. For more modern humans it's painting a landscape scene, playing a violin, or making wooden furniture.

What else might mirror neurons be involved in? Well, how about learning language? Blakeslee mentions neuroscientist Michael Arbib's work. Some of this goes back to 1998. For instance, this: Monkey Do, Monkey See ... Pre-Human Say?

"This mechanism provides the neural prerequisite for development of inter-individual communication, and finally of speech," Dr. Arbib says.

"For communication to succeed, both the individual sending a message and the individual receiving it must recognize the significance of the sender's signal. Mirror neurons are thus the missing link in the evolution of language. They provide a mechanism for the sharing of meaning."

And the language involved need not be just literal statements of facts. It could extend to figurative language such as simile and metaphor. When we talk about "reaching for an understanding" we are using the physical act of reaching in a metaphor. Or Shakespeare's "Tomorrow, and tomorrow, and tomorrow, Creeps in this petty pace from day to day..." Ramachandran's Center for Brain and Cognition at the University of California, San Diego is investigating metaphors and slyly using them in their press releases (May 2005): Grasping Metaphors: UC San Diego Research Ties Brain Area To Figures Of Speech

Ramachandran's lab is continuing work on linking other brain areas, the supramarginal gyrus and human homologues of mirror neurons, for example, to other types of metaphoric abilities.

Recall that it's not only the act of observing another person doing something that activates mirror neurons. Just thinking about an action or hearing about one or (especially) reading about one can also cause activation. This may well account for a large amount of the pleasure we obtain from viewing photographs or reading literature depicting people engaged in all kinds of activities -- running a marathon race, climbing Mt. Everest, or having sex. (Reading or viewing pornography was bound to come up, no?) It's called vicarious experience. (I wrote here about a related, though different, way that literature seems to arise out of characteristic ways that human brains work.)

So there's plenty of evidence now about the great things that mirror neurons do. But what happens if there's a problem in the mirror neuron system? The answer appears to be simple: autism. Mirror neurons enable humans to understand the intentions of other people and have a "theory of mind", to have empathy with the emotions of others, and to learn cultural skills by imitation from watching others. A person who is lacking in those abilities, especially a child, is autistic. Actually, some autistic children can mimic facial expressions other actions of others, but they don't understand the corresponding emotions or intentions of others.

Research is accumulating that impairment of the mirror neuron system is implicated in autism. Here are reports of some of the studies: UCLA Imaging Study Of Children With Autism Finds Broken Mirror Neuron System (12/6/05), Abnormal Brain Activity During The Observation Of Others' Actions (2/18/05), Autism's Fogged-up Mirror (1/3/05).

Undoubtedly, there's still much more to learn about mirror neurons and other brain systems that may also be involved in such things as imitation and perceiving the emotions and intentions of others. But what we've figured out so far is pretty interesting.

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Here are reports of some other studies in the same general area --

Brain Patterns The Same Whether Doing Or Just Watching, Queen's Researcher Discovers (8/14/03)

Brain Senses The Pain Of Someone Else's 'Ouch!' (2/24/04)

Discovering That Denial of Paralysis Is Not Just a Problem of the Mind (8/2/05)

The First Laugh: New Study Posits Evolutionary Origins Of Two Distinct Types Of Laughter (11/22/05)

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Tags: mirror neurons, neuroscience, autism, empathy, imitation, theory of mind