Noise in the brain, decision making, determinism, free will and consciousness
In the introduction to his chapter Rolls emphasises that decision making in the brain involves a mix of the reasoning system and the reward system, the latter to a large extent meaning the same thing as our emotional response. Rolls has made an extremely valuable contribution to the understanding emotional processing in the brain and especially in the orbitofrontal cortex. Unfortunately when it comes to consciousness, Rolls seems to put himself into the dubious hands of twentieth century philosophy rather the drawing on his own much more useful findings about the emotional system.
In this chapter he tends to argue that consciousness is the exclusive property of the reasoning system. This is at the very least counter-intuitive. We are all conscious of a good deal of emotional processing, whether or not this is considered to influence behaviour. On the other hand existing non-conscious computers have shown themselves more capable than humans in many areas of problem solving, which can be taken to equate to the reasoning system.
Rolls himself has shown in recent studies the strength of some activity in the orbitofrontal cortex calibrates to the strength of subjective experience rather than the strength of the signal itself. He and others have also shown how the orbitofrontal is an upstream influence on the dorsolateral prefrontal long-term planning region, and the basal ganglia and dopamine areas that govern actual actions and also give feedback to the cortex.
Rolls wants us to think in terms of error-checking a plan, with several steps where one step is suspected of being incorrect. He describes the error-checking as thoughts about thoughts. For some reason this level of thinking about other thoughts is considered to be the conscious level. Such thoughts are dignified with the term “higher order thoughts”, but there is really no logical basis for the idea. The spelling and grammar check on a computer could be viewed as ‘thought’ about a draft, but most do not attribute consciousness to their spelling and grammar check, and most are not sufficiently pessimistic or realistic to regard the checks as ‘higher order’ than their draft material.
Unfortunately neuroscientists have been discouraged from taking a stance on consciousness, and Rolls clearly feels to be in more of a comfort zone in drawing on a variety of twentieth century philosophers in preference to drawing on his own research. Ironically many of these philosophers tend to make remarkably little reference to advances on modern neuroscience, such as those made by Rolls.
Rolls seems to want to insist that all emotional processing and action resulting from it is unconscious and that the qualia or subjective experience only exists as part of the higher order thinking. This is at least a concession relative to the normal hard line of philosophy that qualia can have no influence on the reasoning system or subsequent action. However, it seems apparent that Rolls is not really happy with the functioning of qualia as part of the thought system, just as in other writings he does not really dwell on the links between the orbitofrontal (emotional) and the dorsolateral (planning) areas. This chapter mentions the role of qualia in the higher thoughts, but the whole emphasis is on ‘rational explicit consciousness’.
Where actions appear to flow from the emotional side without involvement of reasoning, Rolls falls back on the explanation that this is a ‘confabulation.’ The idea of confabulation is often a sleight of hand in modern consciousness studies. In ‘studies’ subjects are variously prompted to an apparently silly response, and when asked why they did that they ‘confabulate’ a rationalisation. The fact is the human brain did not evolve to deal with the type of circumstances that arise in these studies, but for survival in dangerous ancient African grass lands, and confabulation or rationalisation is the best they can do when the brain is effectively fooled in circumstances unlikely to have arisen in ancient Africa. But as in other areas of consciousness and freewill studies the bar is set much higher than many suppose. It is not sufficient to show that subjects sometimes confabulate a conscious reason for an unrelated unconscious emotion, to get rid of freewill, it is necessary to show that it is always so.
For instance on the basis of Rolls own studies, the reward system in the orbitofrontal provides a representation of the pleasures of eating chocolate cake and pretty soon the action of eating cake gets performed. Are we really expected to believe that pleasure of chocolate cake → eat chocolate cake is a confabulation, or alternatively should we think that this has to be processed through a long-term planning or error checking system. Nevertheless, Rolls would have it that the idea that we responded directly to the reward system is an illusion of freewill. It is not just that this is directly counter to experience, it cuts across the known brain systems that Rolls himself has helped to discover. The question which is not asked here, but should be asked is how the brain decides between competing emotions such as the choice between chocolate cake and cream gateaux. Hardly a job for the higher thought system, but similarly not a straight forward response to an automatic reward. There has to be some form of neural currency in which to compare these two subjectively valued rewards and it here we seem to experience the action of subjective consciousness and possibly a non-algorithmic decision process.