Vilayanur S. Ramachandran has a short piece on Edge about the neurology of self-awareness – more specifically about the role played by mirror neurons. Ramachandran seems to have a special interest in mirrors, having used them in a famous series of experiments which succeeded in eliminating the pain from the ‘phantom limbs’ sometimes experienced by amputees. He certainly attaches considerable importance to mirror neurons.
We’ve known for some time the relatively unsurprising fact that certain groups of neurons fire whenever an experimental subject performs a certain action. More recently it has emerged that some of these neurons also fire when the subject sees someone else performing the same action. It’s as though when the brain sees an action performed, it goes through a small pantomime of triggering the same action; it mimics, or mirrors the presumed brain activity of the person being observed. Similarly, among the neurons that fire when a subject is poked, there are some which also fire when the subject sees someone else being poked.
These mirror neurons are clearly interesting in a number of ways, but perhaps the most striking is that they appear to provide a clear neurological basis for empathy, and perhaps for the ability humans (and a few other animals) have to reason successfully about other points of view. This capacity is often called a ‘theory of mind’, or ‘theory of other minds’ though I think that’s a misleading label which implies a much more explicit understanding than is actually at work. Being able to tell what your rivals know and don’t know, and how they are likely to behave as a result, clearly opens up a whole new field of opportunities for a cunning organism, but it involves a level of abstraction which few animals appear to have reached, and indeed it seems the ability does not become fully developed even in humans until they are well into early childhood.
The mirror neurons we know about to date are not, of course, enough by themselves to provide any very high-flown level of empathy, but they suggest that similar processes may be at work on a higher level, and they might well be part of the final answer. Ramachandran wants to go a bit further, however, and suggest that they help constitute our sense of self. I think it would be true to say that the traditional view here is that we begin as solipsists, with a natural sense of self but not really distinguishing other people from the inanimate objects around us. Then we go on to make the awesome conceptual leap into realising that there are other people like ourselves out there, and that they have thoughts and feelings similar to our own (with some psycopaths, perhaps, never making the leap and remaining permanently indifferent to other people’s pain).
Ramachandran’s proposal is that the process works the other way: we start by observing the behaviour of other people and come to have a basic understanding of them sufficient to attribute a kind of selfhood to each of them. It’s only then that the empathy supported by mirror neurons leads us to realise that we too have a self of the same kind. Ramachandran acknowledges that others have offered theories along roughly similar lines, but I think this is the first time the link with mirror neurons has been drawn in this way.
Are these ideas right? I think it’s important to be clear about what kind of selfhood we’re talking about here. In spite of the poking experiments, I don’t think it can be anything to do with our experiences, or feelings. Take pain: if we applied the theory here we should be saying that to begin with we may be aware of pain, but don’t really attribute it to ourselves: noticing how other people try to avoid it at all costs, we begin to think that the pian we experience actually belongs to us. I suppose it could be so, but knowing as we do what pain is actually like, and how one of its properties is a location in our body, it seems implausible to me. That in turn casts some doubt on whether this kind of explanation from others to ourselves can deal with important cases like our ability to tell that what other people can see is different from what we ourselves are aware of. It doesn’t seem very likely, in other words, that we come to know there are things hidden from our view because we have previously noticed that things may be hidden from other people.
I could be wrong about that, but perhaps we are really talking about the self as the origin of volition; the mysterious thing that makes the decisions and (at least when things are running normally) does the talking. We attribute the intentions and thoughts of other people to an essential core called the self, and through empathy we come to attribute our own to a similar self. This seems a much more appealing line of argument.
There is certainly something hard to pin down about our selfhood in this sense. Hume famously observed that when he tried to observe his inner self there didn’t seem to be anything there except a bundle of perceptions; Dennett has suggested that the self is a kind of explanatory abstraction akin to a centre of gravity. I think the problem is that the self in this sense is not so much a thing as a source – like the spring which provides the origin of a river. Hume says all he can see is a lot of water; Dennett says the source is a geometrical abstraction, not a real physical thing: there’s something in both points of view but both also have an element of perversity.
I’ll make the bold claim here that Hume actually missed something, in that sometimes we actually experience the emergence of thoughts and intentions. I submit that we sometimes know, in an inexplicit way, what we are about to say, and even what we are about to think about, before the event actually occurs; we directly experience the emergence of intentional stuff, and hence have a direct handle on our own selfhood. I must admit that this claim, resting as it does on introspective evidence, is not very strongly supported, but if it is true, it contradicts Ramachandran’s view: we know about our selfhood from direct experience, not from observing others, and in a way quite different from the way we know about the selfhood of others.
It may be that Ramachandran is in fact thinking about yet another kind of selfhood; apart from the two I have touched on. But there is a further reason for doubting whether mirror neurons are as important as they seem. A lot depends here on the way the story unfolds. First we have neurons that fire as part of the neurological business of performing a task, or of experiencing a sensation. Then it turns out some of them fire when we merely see someone else performing the action, or having the experience. We draw the conclusion that these neurons are reflecting, or simulating, what’s going on in the other person’s brain; doing a subliminal imitation of what the other person is going through. But perhaps we ought to reinterpret our original view that the firing of these neurons is part of the business of performing the action. Perhaps these neurons were only ever part of a system for recognising actions. There was a perfect correlation between them firing and our performing the action, but that was because every time we did the action, we recognised it: the neurons were never part of the actual performance of the action. It’s then not surprising that the same neurons fire when we see the action performed by someone else. It remains interesting that a single set of neurons respond to the same action whether we are acting, or someone else; but once we shed the preconception that these neurons are part of our own control system, some of the wider implications fall away.