Classifications

From time to time I post about classifications, with the large CODOT classification of occupation being one favourite, a classification which tries to strike a sensible balance between the industry in which one works – usually classified by product – coal, television programs, fast food or whatever – and what one actually does. So a secretary is a secretary whether she works for the manager of a coal mine or the owner of a newspaper. Well, up to a point. A classification which perhaps reflects its origins in a time when there were still huge numbers of highly skilled manual workers, highly skilled in some very particular way. But the aim of the classification was clear enough, to improve the workings of the labour market, to, for example, help with the matching of unemployed people to vacant jobs.

I also like classifications of animals and evolutionary trees. See, for example, reference 1. Here the aim is not so clear, although the old way of grouping animals together which look like each other has been largely swept away by the new way of grouping animals together which evolved together. So elephants get put in the same part of the (new) tree as the extinct sea cow, while seals get put in a quite different part of the tree from whales – with the hippopotami getting the slot next to the whales. So how you make up the classification, how you draw the tree, depends on what you want them for, what you want them to predict.

Psychologists like classifications too, going in for the classification of the various kinds of behaviours, the various feelings and emotions and the various kinds of mental disease which humans are prone to – with these last generating a great deal of debate, heat, controversy and worse. Is ‘multiple personality’ a phrase fit for inclusion in the ‘Diagnostic and Statistical Manual of Mental Disorders’, issued from time to time by the American Psychiatric Association, a work intended for the use of scholars the world over? Not to mention physicians and insurance companies in the US. I even went so far as to read a book about DSM 5, for which see reference 2.

All this was sparked by György Buzsáki’s inference from the failure to agree on a behavioural correlate for the hippocampal theta rhythm, after more than half a century of dedicated work by lots of dedicated people, that maybe ‘behavioural-cognitive terms are simply working hypothetical constructs that do not necessarily correspond to any particular brain mechanism’ (see page 21, reference 3 and reference 4).

My first thought was that there was a box full of these behavioural-cognitive terms, with each of these terms describing some kind of behaviour, and the idea had been to find which one of these behaviours pressed the theta button. Examples of behaviour might be blinking, touching one’s toes or thinking about Christmas. But none of them fitted, so perhaps the theta rhythm was not the product of some single behaviour of that sort at all. Going back to CODOT, it was if we were trying to infer industry from an occupation – which can’t always be done.

Nevertheless, it still seems plausible that the theta rhythm could be related to, could be the result of some underlying feature of some of those behaviours. But was it the sort of feature which, at the present time, depends on its reporting by the subject – something that rats – with whom a lot of the work has been done – cannot do?

Perhaps one could do brain scans which captured the state of brains exhibiting theta rhythms, do some fancy statistics and come up with some other features of brain activity which predicted those rhythms? Then perhaps one could hunt around for behaviours which generated those features?

My second thought was an analogy from computers. Suppose we have a computer which is mainly used for email and word processing. A computer which carries Windows and Microsoft Office in order that it may be used for these purposes. We think of behaviours as being all the things a user might want to do and we might well have a lengthy list, a classification of such behaviours, perhaps to support the organisation of the entry screens, the ribbons and toolbars at the top of screens, the production of user manuals and the delivery of training courses. Now this computer is a complicated piece of machinery, including all kinds of internal processes for keeping it in good working order, as well as the external processes which do the stuff which you know about.

One of them is the process which refreshes the indexes of the contents of the disc, the indexes which mean that when you ask the computer for documents containing the words ‘cabbage’ and ‘crab’ it does not have to spend all morning looking through all the documents. Another is the process which tidies up the disc. Over time, with files coming and going, growing and shrinking, the mapping of files onto the disc can get terribly complicated – which makes accessing those files slow and error prone. It is a good idea, from time to time, to tidy things up, to try and map most files onto nice clean segments of disc. Windows runs these processes when it thinks that the user does not want to do anything, or at least does not want to do anything resource intensive.

Now when the first process is busy it generates a signal which we call the alpha wave and when the second process is busy we get the beta wave.

One fine morning, some bright spark with nothing better to do notices the alpha wave. He assumes that the alpha wave must stand for something. It must mean something. And being rather ego-centric, the bright spark assumes that it must be the sort of something that he knows about, one of the behaviours on the aforementioned list. If he is very lucky, he might chance on the fact that there tend to be alpha waves when he is not using the computer for anything and when searching has got rather slow. Or more tricky still, when certain kinds of search have got rather slow.

We suppose that he has been so lucky and this builds his confidence up even more. And the next fine morning, he notices the beta wave. Bouyed up by his success with the alpha wave, he assumes that he can crack the beta wave in the same sort of way. He might find out fairly quickly that the computer only does beta waves when he is not doing anything much. But it does not do them very often. So what behaviours increase the chances of getting beta waves later? My guess is that he would have to be very lucky indeed to stumble upon the right answer.

So, by analogy, it could take us some while to come up with behaviours which result, perhaps some time later, in theta rhythms. It is not that the task is impossible, just rather difficult. Perhaps to the point of chaos, to the point where, despite the theory being well understood, it is more or less impossible to predict the theta rhythm. Just like it is more or less impossible to forecast when exactly there is going to be a short, sharp shower over Epsom.

That said, getting the right classification of external behaviours is one way into the problem – while getting a grip on internal behaviours would be a better way. The catch is, that in the case of the brain, our knowledge of those internal behaviours is very sketchy indeed, at least at the level or scale which would help the present enquiry.

At which point I retire from the fray to organise my second cup of tea of the day; a quite reasonable substitute for the second fag of the day of my youth.

PS: in the course of learning where hippopotami lived in the tree of life, I also learned that their lower canines might grow to as much as five feet in length and that when hippopotami fight the idea is to break one of the front legs of one’s opponent, an injury which is invariably fatal in the wild.

Reference 1: http://psmv2.blogspot.co.uk/2015/08/aryans.html.

Reference 2: http://psmv2.blogspot.co.uk/2013/06/dsm-5.html.

Reference 3: Rhythms of the Brain – György Buzsáki – 2006 – Oxford Paperback.

Reference 4: https://en.wikipedia.org/wiki/Theta_wave.