Noises from the Darkroom: The Science and Mystery of the Mind. Guy Claxton

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СКАЧАТЬ precise. When an impulse was sent from A to B, it had to be sure of arriving at the right place and not being side-tracked. Marcel Kinsbourne has suggested that this problem of ‘functional insulation’ of higher level packages of capabilities, in the absence of any structural walls, is solved by the strategic use of the brain’s powers of inhibition.³⁴ Each area of the brain that is active may, almost as a matter of course, tend to create a halo of inhibition around itself. Members of an ‘awake’ octopus gang will be strongly activated enough, by mutual stimulation from each other, to resist the soporific effects of the inhibition. But other nearby units, even though they may have some connections with the active network (but which are not at the time being stimulated directly will have insufficient ‘strength’ to prevent themselves succumbing to the inhibition. As we know, this strategy for keeping the system ‘on the rails’ is by no means foolproof. There are many occasions when our minds slide off the point, and the train of thought finds itself chugging off down some apparently irrelevant siding. But no mechanism is perfect, not even in the brain.

      Mini-Worlds

      The evolution of predation, and especially of active stalking and hunting down of prey, would have acted as a stimulant for the evolution of minitheories. The hunter needs keen eyesight, hearing and sense of smell; powerful muscles for running, pouncing and killing; and greater abilities to predict the behaviour of its prey under various conditions. When the prey goes to ground, or disappears behind a clump of rocks, the more successful hunter will not immediately give up the chase and wander off, puzzled at the sudden dematerialization of its lunch.

      To keep concentrating on something you cannot see, but which you presume is still there, demands a brain that is able to keep active a representation of some bit of the world that is not, at that moment, being stimulated from outside. The minitheory for Hunting, the subroutine for Rabbit, and the running memory of The Story So Far, must be able to be stay activated, and the minitheories that relate to alternative goals must stay inhibited, at least until you have satisfied yourself that the rabbit has truly retreated to a safe place, or that it might just have been a few leaves stirred by the wind in the first place. The activity of the brain, in other words, has to become ever more capable of proceeding in an inner-directed, self-organized fashion, of ‘ignoring’ some environmental changes and fleeting body sensations, and of pursuing ‘plans’ and ‘intentions’.

      So each minitheory develops the capacity to represent one of the sub-worlds which the animal regularly inhabits. A minitheory is a functional map of the recurrent patterns which the sub-world has been found to contain. It provides a manual that enables you to ‘diagnose’ the different options that are likely (on past experience) to occur, and to know instinctively how to ‘treat’ them. The ideal minitheory is one that so comprehensively covers all the angles that it is no longer possible for this sub-world to surprise you.

      A minitheory keeps tabs on a domain – ‘mating’, ‘hunting’, ‘parenting’, whatever – in two senses. First it distils different experiences and encounters into a general set of expectations and capabilities. But secondly it also provides a continually updated record of how any particular encounter is going. As each episode unfolds, so the general expectations are continually being modified to take into account gambles that paid off and discrepancies from what was predicted. In brain-language, the levels of priming and inhibition are constantly being adjusted, on the basis of present experience, to shift the balance of priorities and dispositions that the network represents. Each bit of the brain-mind system is energized or sedated so that the system as a whole is ready to respond to whatever (on the basis of both long-term and recent influences) is the most likely and/or the most significant thing to happen next.

      Note again that, though I have used words like ‘plan’, ‘intention’ and ‘believe’, I have put them in quotes to mark the fact that these words refer to capabilities that we can infer from the way an animal behaves, without implying any role for consciousness whatsoever.

      Overcoming Internal Isolation

      Marvin Minsky has pointed out an additional benefit of a brain that is designed to keep some of its resources and processes separate. A knowledge store that is not subdivided is not capable of being very creative. The flow of activity in an undifferentiated brain-mind can only follow the grooves laid down by genetics and experience. Different areas of the colony that are functionally far apart are never going to be able to meet up. If such a network ‘tries’ to get two distant areas to be simultaneously alive by allowing its area of activation to get bigger and bigger, any possible benefit of having opposite edges ‘awake’ at the same time will be lost in the general clamour of activity. It would be like match-making by holding an enormous cocktail party in a confined space: even if the candidate lovers meet one another, the din will be so great they will not be able to hear what they are saying. But if two circumscribed, special-purpose areas can be activated side-by-side, then their tête-à-tête might well be more fruitful. A network that is divided up into sub-areas has the potential to put those areas in touch with one another more specifically.

      But how is this potential asset to be realized? In the octopus model there is no way of getting different gangs to ‘talk’ to each other, unless they have already been put in touch by direct experience. What is needed is some kind of alternative access system; a way of enabling cross-talk between these different little capsules of intelligence. It is this need to expand the flexibility of internal communication within the brain-mind, and thereby to enable speedier and more precise access, as well as greater creativity, that posed the next major evolutionary problem.

       SIX The Pressures of Society

      Individuals buy in to (their) community…by eternal psychological vigilance. They may spend time apparently doing nothing, passing time in idle gossip. But this time spent socialising is as crucial to their survival as any time spent hunting or gathering in the field. For it is round the campfire or lying out in the sun that the social backbone of…society is laid down and, if necessary, repaired: friendships are established, problems talked out, plans hatched, love affairs commented on.

      Nicholas Humphrey35

      It is hardly an exaggeration to say that a chimpanzee kept in solitude is not a real chimpanzee at all.

       Wolfgang Kohler

      The brain-mind’s retrieval problems obviously get more acute the more different scenarios you have to keep tabs on. A solitary animal has only a few different types of situation that it has to take part in. Sociable animals such as fish and birds may also have only a limited number of roles to play as they do not make many distinctions between other members of the group. Animals such as the large cats that hunt in packs have to be rather more concerned about their roles and relationships.

      But it is when we get to the social primates, and our own human ancestors, the early hominids, that the number of different scenarios which each individual has to keep track of begins to mushroom. The nature of each encounter becomes increasingly dependent on the particular individual you are dealing with. And if you have to have a separate minitheory for every member of your community, the larger and more complex that community becomes, the more the fragmentation of the brain-mind is likely to become a problem. (When we get on to the complexities of modern industrialized human society, the extent of the problem becomes staggering.) If each of our familiar scenarios were stored separately, there would be an enormous duplication of effort, and an incredible waste of usable information.

      The Mixed Blessing of Community

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