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

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СКАЧАТЬ influences that might disturb the fun. On the other side, the leeward, are the Bottle Squad, whose job it is, if tickled in various ways, to stuff messages in bottles asking for help, or more music tapes, or whatever. In the middle are those who simply pass the tickles around.

      The combined effect of this curious collection of stimulating and tranquillizing influences is to ensure that only a small proportion of the assembled company is awake at any moment. And it also ensures that the group of awake octopuses keeps changing. A couple of tentacles start tickling you, you wake up and start swishing your own tentacle-tips; but soon you start to get tired and drowsy, or to succumb to the relaxing massage. So if an observer were hovering over the island on a clear night, she would see these patterns of pink octopus bodies continually shifting around; and she would see a general increase in activity if the wind got up, or if a boat was sighted; and sometimes she would see a flurry of activity on the leeward shore as a bunch of messages were scribbled, stuffed into their bottles, and hurled out to sea. And the observer would notice that the pattern of activity at any moment was likely to be quite widespread throughout the network, not bunched up. She would be more likely to see an irregular pink ring extending across the whole island, rather than a concentrated pink blob.

      The observer would also see, if she hovered long enough, gradual changes in the way the patterns of activity moved through the total octopus population, and this is because each time one of octopus A’s tentacles is successfully involved in waking up octopus B, the spot on B’s head where A’s tentacle is resting develops a little bit of extra long-term sensitivity. Now the next time A tickles B, the net effect on B is greater, and fewer other contributing tickles are needed to make B wake up. So the more often A and B are awake at the same time, the better A becomes at wakening B on its own. And the more likely it is, when A is awake and tickling, that it will be B that is roused, as opposed to Z, who A is also tickling, but with whom it has a less successful track record. What is more, if a number of octopuses are regularly involved in each others’ awakenings, then they will develop into a ‘gang’ – what Hebb called a ‘cell assembly’ – who will tend to turn on or turn off as a unit.²⁵

      Priming

      One very important feature of the octopus colony is that, even though an individual or a gang may be asleep, they may be sleeping more lightly or more heavily as a result of stimulation which is not yet strong enough to wake them up fully. So if an octopus or a gang of octopuses, A, can sometimes awaken gang B and sometimes gang C, which one actually wakes up – i.e. which direction within the octopus colony the flow of ‘wakefulness’, or activity takes – will depend on the relative level of this ‘priming’ of B and C, as well as on the long-term state of their connections to A.

      In fact this phenomenon of priming can operate more generally than between single octopuses, or individual gangs. We could suppose that buried in the tangled heap are groups of octopuses with different musical tastes. For one group Miles Davis tends to make them sleep more lightly, while Madonna lulls them into an even deeper slumber; for another group, Madonna gingers them up, while Mozart makes them insensitive to almost anything. Thus the ‘path’ that the area of wakefulness takes through the colony depends on what music happens to be playing. The difference might be sufficient to make A wake up B when the background music is jazz, but C when it is Country and Western. In other words the behaviour of the whole community is highly context-dependent and situation-specific. The effect of any particular stimulus depends on the state of the whole system – its priming, its state of sedation, its tiredness – as well as on its whole idiosyncratic history of who has woken up whom in the past. And conversely an individual input can ‘set’ whole areas of the community to be either more or less sensitive to what happens next.

      Resources and Attention

      Another important feature of this model is that the total wakefulness of the community – the overall ‘amount’ of activation available to the system at any moment – is finite. If there were no sources of inhibition as well as activation, the octopuses could wake each other up until they were all wide awake at once. Clearly such an eventuality has to be prevented: it would put us in a state of cortical meltdown – a condition of total perceptual and behavioural freak-out. Everything would be ‘On’, but we would be incapable of being appropriate. The beauty of the system of checks and balances built in to the fabric of the octopus colony is that it becomes, of its very nature, selective and integrative. The colony as a whole has to choose and moderate amongst what is going on.

      This is not to say that the total level of activation is always fixed. If you looked down from your helicopter and counted the pink bodies, there would not always be exactly the same number. Sometimes the total might be a bit greater, sometimes a bit less, but the important point is that the total is relatively fixed, and is certainly finite. It cannot explode, though it may vary somewhat as a reflection of the overall state of ‘alertness’ of the system.

      In fact, though, there is a very important source of variability in the effective amount of energy that the system has at its disposal, independent of variations in the total energy available. Imagine that, when a particular gang of octopuses, A, is awake, one of its ‘jobs’ is to send a constant low-level tickle (or massage) to a variety of other gangs or individuals, B, C and so on. In addition, suppose that A is able to stay awake for long periods of time. These continuous ‘trickles’ of excitation and inhibition will make a network with one set of connections respond as if it were a network with a different pattern of strengths. The crucial difference, however, between the effect of priming, and the long-term change in the strengths of the connections, is that, in the former case, it is possible for the priming overlay to be removed. If A were turned off, even for just a few moments, there would be an instantaneous, apparently ‘magical’ reorganization, perhaps a re-prioritization, of the brain system as a whole. What had always been ‘at the back of one’s mind’, or ‘on the tip of one’s tongue’, now would no longer be there, or would stand out with unfamiliar clarity.

      And in this hypothetical situation there would be another interesting effect as well. While unit A has been ‘on’, it has not only been keeping particular other units or groups of units on a hair trigger; it has in so doing been keeping tied up some proportion, perhaps a significant proportion, of the total activation permitted in the brain. If there is only so much energy available at any time, then if 10 per cent of it has to be dedicated to certain locations to keep them primed, there is less available – less ‘free energy’, we might say – to underwrite the activity of the rest of the system. And the less free energy there is, the more crude or stereotyped we might imagine the response of the system to be. Only those octopuses with the lowest thresholds, and the biggest and most numerous inputs, get woken up. (This option, for the brain to change its way of operating by tying up some of its total pool of activity, will become very important later when we try to explain the phenomena of mystical experience.)

      The Brain with No Self

      In the octopus colony there is no privileged group with special status or special powers. Just as the brain as a whole has to be seen as a subsystem of the whole body, so each octopus gang must be seen as a member of a participative democracy. What happens in the brain, and the momentary conjunction of priorities, interpretations and actions that it is involved in computing, arise naturally and uniquely from the state of the system as a whole – brain, body and world.

      Many of those who have been working in the area of neuroscience have made it very clear that their object is to see just how much of human functioning can be accounted for without recourse to any ‘ghost in the machine’. How far can we get before we have to call upon ‘the self? Could it be that we can even get all the way: that the hypothetical ring-master or engine-driver, the personal ‘I’, is not actually in control; that the biology, when it comes down СКАЧАТЬ