Archive for April, 2011

Picture: Incognito. I thought David Eagleman’s book SUM was excellent – it’s a series of short accounts of the afterlife in which each version turns out to be surprising and disappointing in a variety of imaginative ways. So I looked forward to Incognito, his serious account of the conscious mind. The dazzling striped lettering on the dustjacket suggests we’re in for a lively read, and it does not mislead.

The first part of the book – the bulk of it in fact – is a highly readable account of many of the interesting and counter-intuitive discoveries of modern research about how the brain in general, and perception in particular, works.  There are many old friends here – blindsight, split brains, and synaesthesia, and so on – but also some stuff that was new to me. If you want to know what Japanese chicken-sexers and WWII British plane spotters have in common, this is the book for you.  In places I felt Eagleman’s account could have benefited from a few caveats and qualifications, and at times the breeziness of his explanation seems to carry him away. Is the tendency to talk freely about your life to anonymous strangers – people you might meet on a train journey for example – the ‘explanation’ for the continuance of confession in the Catholic church?  Er, no: back to the drawing board on that one, I think.  But in fairness this is essentially a popular account, not a scientific paper.

As the book progresses it becomes clear that Eagleman’s purpose is not merely to summarise interesting research: in fact, he’s been softening us up for some points of his own.  He speaks warmly of Minsky’s Society of Mind, but suggests that to complete the picture we need to assume that there is an ongoing competition for control among the various agents running our minds. I don’t think this idea is quite as novel as Eagleman seems to suppose, and he goes on to make a very traditional use of it by drawing a distinction between a rational controller, able to defer gratification, and a short-term pleasure seeker. This sort of echoes Freud, and for that matter Plato’s charioteer.

In fact Eagleman’s main purpose is to change our view of moral responsibility and legal responses to crime.  He spends some time quoting examples of people who committed crimes under the influence of drugs or brain tumours, and recounts the well-known story of Phineas Gage, whose behaviour was changed for the worse when a tamping iron was accidentally fired through his brain. This last example perhaps needs to be handled with a little more care than Eagleman gives it, as there are reasons for a degree of scepticism about how changed or how bad Gage’s behaviour became.  Eagleman foresees a day when neuroscience will make it impossible to hang on to the idea that free will means anything or that anyone is ultimately responsible for anything – or as puts it blameworthy. I think Eagleman is giving up too quickly: without re-fighting the Free Will issue, aren’t there special faculties of planning and decision-making which conscious humans have and other creatures lack? If so, isn’t it worth appealing to them, and isn’t blame a tool for doing so?

Eagleman seems to have a bit of a campaign going against blame. His base is at Baylor College of Medicine in Houston where he directs the College’s Initiative on Neuroscience and Law (as well as the Eagleman Laboratory for Perception and Action). He approvingly quotes Lord Bingham:

In the past, the law has tended to base its approach… on a series of rather crude working assumptions: adults of competent mental capacity are free to choose whether they will act in one way or another; they are presumed to act rationally, and in what they conceive to be their own best interests; they are credited with such foresight of the consequences of their actions as reasonable people in their position could ordinarily be expected to have; they are generally taken to mean what they say. Whatever the merits or demerits of working assumptions such as these in the ordinary range of cases, it is evident that they do not provide a uniformly accurate guide to human behaviour.

At first sight it’s possible to read this as a liberal, even  humane point of view: isn’t it ridiculous the way we blame and punish all these people for things they couldn’t really help?  But a moment’s reflection shows that the noble lord is letting these common folk off their punishment only because he’s demoting them into a sub-human category.  You know, he says, for some reason our legal system bends over backwards to treat people as if they were dignified creatures of some moral standing: it goes on treating them as worthy of admonition, worthy indeed of the honour of punishment, long after they have proved themselves to be pond life. You would almost think the law considered these people in some sense the equal of their judges!

The more I read the quote the less I like it.

Eagleman certainly has no truck with equality, and devotes a section to denouncing it. The question of whether equality of income is in itself a moral desideratum or an economic advantage, or the reverse, is of course politically contentious: but I had thought that no-one anywhere on the spectrum denied moral equality. Can Eagleman possibly mean that we don’t all equally deserve a fair hearing, natural justice, and to be judged by our actions alone?  Reader, I fear he does.

In fact what Eagleman is advocating in practice is not clear to me in any detail, but a couple of points are well established. People will still go to jail, he is keen to emphasise: not in order to be punished, but in order to protect society. It follows, though Eagleman does not dwell on this, that they might stay in jail forever, if they continue to be deemed dangerous. Indeed, if neurolaw (it seems to be as much a matter of genetics and other factors as genuine neuroscience) gives them the thumbs down as high-risk future perps, it seems to follow that they might find themselves locked up before they’ve done anything.

The other point, a little more appealing, is that Eagleman believes people can be trained out of their vicious propensities. Crime, he suggests, occurs when the struggle between the different agents in our mind goes the wrong way: when the rational self loses out to the weak-willed glutton. He mentions experiments conducted by his colleagues, which use neural feedback to try to help people overcome their desire for chocolate cake: he thinks a similar ‘prefrontal workout’ might help criminals get ready to re-enter society. So perhaps they won’t be in jail long, after all?

But does crime really arise from weakness of will? Is it that everyone wants to be good, but sometimes some people give way to an immediate temptation? Isn’t that a rather minor part of the problem? I can’t help thinking what a sunlit, untroubled life Eagleman must have led – never having experienced in himself or having reason to suspect in others any of the deep dark recesses of the soul – if he thinks evil is more or less the same as finding it hard to stop eating chocolate cake.

Another instance of naivety seems embodied in the idea that in the pandemonic struggle of our minds one side is always good and the other bad. Suppose we train our criminals to overcome their temptations and enthrone the rational, long-term part of their brain – will that make them model citizens, or will they become psychopaths who’ve learnt to rein in the empathy and repugnance which would otherwise have prevented their crimes? Terrible things have been done on grounds that seemed entirely cold and rational to their perpetrators. Sometimes it’s better to leave Falstaff in charge: there may be a glut of chocolate cake, but the Battle of Shrewsbury gets cancelled.

Eagleman is aware of the poor precedents for science-driven justice, but he has a curious way of immunising his own mind against them. He describes the failure of psychologists to predict the rate of re-offending: he describes lobotomy with distaste, yet somehow he manages to construe both as relics of the traditional way of doing things rather than early attempts at the kind of science-driven crime management he too is advocating (of course, they got it wrong while he will get it right). He describes the plot of One Flew Over the Cuckoo’s Nest without seeming to realise how much the predicament of McMurphy resembles that of an inmate in a new Eaglemanic detention facility. When McMurphy was in jail, under the benighted old system, his punishment was limited to match his crime and when his term was up a system like that deplored by Lord Bingham persisted in trying to make a free moral agent of him again. In the asylum, as in Eagleman’s jail, you don’t get out till the men in white coats are pleased with you.

At the end of the day, I think there’s a fundamental concept missing from Eagleman’s analysis: justice. He’s not the only one in recent times to overlook it or mistake it for revenge, but I’ll go out on a limb and say that it’s fundamental. There is a moral imperative that we should ensure good behaviour leads to good things and bad behaviour to bad regardless of other considerations, and this is what lies at the root of all punishment. Deterrence and rehabilitation are additional benefits we should strive to secure, but justice is what it’s about. Only justice permits, in theory and often in practice, the exercise of governmental or judicial power: to put it aside, however beguiling the reason, is tyranny.

Coming off that high horse, I suppose we can thank Eagleman for stating explicitly conclusions which others have avoided or fudged, and thereby promoting the clarity of debate. He could go a bit further in setting out the implications of his theses and proposing what they might really mean in practice. There’s no doubting that our current judicial systems are far from perfect, and even if we reject Eagleman’s prescriptions, they might in the end help things move on.

Picture: Astrocyte. Alfredo Perreira Jnr has kindly let me see an ambitious paper he and Leonardo Ferreira Almada have produced: Conceptual Spaces and Consciousness: Integrating Cognitive and Affective Processes (forthcoming in the International Journal of Machine Consciousness).

The unifying theme of the paper is indeed the integration of emotional and neutral cognitive processes, but it falls into two distinct parts.

The first, drawing on the work of Peter Gärdenfors, sets out the heady vision of a universal state space of consciousness.  Such a state space, as I understand it, would be an imaginary space constructed from a large number of dimensions each corresponding to one of the continuously variable aspects of consciousness. In principle this would provide a model of all possible states of consciousness, such that anyone’s life experience would form a path through some area of the space.

The challenges involved in actually populating such a theoretical construct with real data are naturally daunting. Perreira and Almada suggest that it could be approached on the basis of reported states of consciousness. An immediate problem is that qualia, the essence of subjective experience, are widely considered to be unreportable: Perreira and Almada meet this head on by adopting the heterophenomenology of Daniel Dennett: this approach (which I think implies scepticism about ineffable qualia) is based on studying phenomenal experience indirectly, through what subjects say about their own: the third-person perspective. Perreira and Almada note that Dennett adopted this stance mainly as a means of refuting first-person approaches, but I’m sure he would (or will) be delighted to hear of its being adopted as the explicit basis of serious research.  It’s implicit in this approach that we’re dealing with states that are capable of ‘inter-subjective validation’, that is, that they’re states which are accessible to all conscious entities.  This rules out objections on the grounds that, say, Andy having experience X is not the same as Bill having experience X, though in so doing it may appreciably impoverish the scope of the exercise. It could be that the set of experiences common to all conscious beings is actually a significantly restricted sub-set of the whole realm of conscious experience.  For that matter, can we afford to ignore the unconscious or the subconscious?  At times the borderline between conscious states and their near relations may be blurry.

I think two other worries are worth a mention. The state space model suggests that all trajectories are equally valid, but it seems unlikely that this is the case here. Consciousness is a stream, both emotionally and cognitively: certain kinds of state naturally follow other kinds of state. In fact, it doesn’t seem too much to claim that some states refer to previous states: we can’t repent our anger intelligibly without having first been angry. The business of reference, moreover, is a problem in itself.  We’ve already excluded the possibility of Andy’s anger being different from Bill’s, but we can also be in the same state of anger about different things, which seems a material difference. Me being angry about my tax return is not really the same state of consciousness as me being angry about receiving a parking ticket, though in principle the anger itself could be identical. Because, thanks to the miracle of intentionality, we can be angry about anything, including imaginary and logically absurd entities, this is a large problem. Either we exclude these intentional factors – and put up with a further substantial impoverishment of our state space – or the size of our state space balloons out infinitely in all directions.

The practical problems are not necessarily fatal, of course: it’s not as if Perreira and Almada were actually proposing a fully-documented description of the universal state space. What they do suggest is that if we assume another state space (wow!) corresponding to all the possible biophysical states of the brain, we can then hypothesise a mapping of points in one space to points in the other, which would give us the prize of a reduction of conscious experience to physical brain function.  Now I think a biophysical state space of the brain faces formidable difficulties of its own: for one thing we really don’t know exactly which biophysical features of the brain are functionally relevant; for another different brains are not wired the same way – and of course the sheer complexity of the thing is mind-boggling. The biophysical state space of a single neuron is a non-trivial proposition.

However, at a purely theoretical level, this is a nice rigorous statement of what the much-sought Neural Correlates of Consciousness might actually be. If we merely claim that there is a mapping between the two state spaces, we have a sort of rock-bottom version of NCCs, a possible statement of the minimum claim.  We would expect there to be some more general correspondences and matches between regions and trajectories in the two spaces – though I think it would be optimistic to expect these to be simple (and constructing the two state spaces and then observing the regularities would be a remarkably long way round to discovering correspondences between brain and mind activity). Still, the fact that these pesky NCCs turn out to be more abstract and problematic than we might have hoped is in itself a conclusion worthy of note.

All these heroic speculations are in any case just the hors d’oeuvres for Perreira and Almada: the state space of consciousness would have to represent emotional affect as well as rational cognition: how would that work?  They proceed to review a series of proposals for integration emotion and cognition. Damasio’s Somatic Marker Hypothesis, which has emotional affect deriving from states of the body is favourably considered, though criticised for elements of circularity. The alternative view that emotions come first avoids such problems but is ciriticised for not squaring with empirical evidence. Perreira and Almada suggest a better third alternative might be based on mapping the complex inter-relations of cognition and effect, and give a friendly mention to the oft-quoted Global Workspace theory of Bernard Baars. Now we can begin to see where the discussion is going, but first the paper brings in a new element.

This is a discussion of what actually makes mental states conscious – embodiment, higher order states, or what? Perreira and Almada look at a number of proposals, including Arnold Trehub’s retinoid system and Tononi’s concept of Phi, a measure of integrated information. Briefly, they conclude that something beyond all these approaches is needed, and something which puts the integration of affect and cognition at the heart of the system.

Now we come to the second major part of the paper, where Perreira and Almada introduce their own proposal: step forward the astrocytes.

Astrocytes are the most common form of glial cell, which are ‘the other brain cells’. Neurons have generally had all the glory in the past; historically it was assumed that the role of glia was essentially as packing for the neurons – in fact ‘glia’ is the Greek word for ‘glue’.  In recent years, however, it has become gradually clearer that glia, and astrocytes in particular, are more important than that. They form a second network of their own, across which ‘calcium waves’ are propagated.  I think it would be true to say that the standard view now sees astrocytes as important in supporting and modulating neural function, while still reserving the main functional signficance for all those showy synaptic fireworks that neurons engage in. Perreira and Almada want to give the neural and glial networks something like parity of esteem. The proposal, in essence, is that plain cognition is done by the neurons, while feelings are carried by large astrocytic calcium waves: only when the two come together does consciousness arise. Consciousness is the “astroglial integration of information contents carried by neurons”.

What about that?  It’s a bold and novel hypothesis (something we certainly need); it’s at least superficially plausible and has a definite intuitive appeal.  But there are objections.  First, there seem to be other established candidates for the role of feeling-provider.  We know that certain parts of the brain are required for certain kinds of affect – the role of the amygdala in producing ‘fear and loathing’ (or perhaps we should say ‘reasonable distrust and aversion’) has been much discussed. Certain emotions are almost proverbially (which of course is not to say accurately) associated with hormones and the action of certain glands. This needs to be addressed, but I don’t think Perreira and Almada would have too much difficulty in setting out a picture which accomodated these other systems.

More difficult I think are two more fundamental questions. Why would astrocytic calcium waves cause, or amount to, feelings?  And why would those feelings, when associated with cognitive information, constitute consciousness? Damasio’s and other theories can offer a clearer answer on the first point because it’s at least plausible that emotional states can be reduced to the pounding heart, the watering eyes, the churning stomach: calcium waves rippling across the brain somehow don’t seem as obviously relevant. And then, is it really the case that all conscious states have emotional affect? Perreira and Almada suggest that if neurons alone are involved (or astrocytes alone) all you get is proto-consciousness: but intuitively there doesn’t seem anything difficult about completely dispassionate but fully conscious thought.

One strength of the theory is that it seems likely to be more open to direct scientific testing than most theories of consciousness: a few solid experiments would probably relegate the kind of objection I’ve mentioned to secondary status. So perhaps we’ll see…