Gordon Pask

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Gordon Pask

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Gordon Pask

Techniques

"Man" as a self-organizing system.

Let us take "man", whom most of us would agree is a self-organizing system. A man is any member of a well-specified set of men. But this set can be well-specified (that is, specified in a way that meets common approval) in a vast number of ways, according to an observer's objctive. Man, for example, may be specified anatomically (two legs, head, and so on), or alternatively as a decision maker which influences and is influenced by his circle of acquaintances. Each specification is equally valid and entails criteria of similarity. The point is, there are objectives for which neither the first specification (and the criteria it entails), nor the second (and the criteria it entails) are sufficient. In conversation, when trying to control a man, to persuade him to do something, how do I define him? Manifestly I do not, at least, I continually change my specification in such a way that he appears to me as a self-organizing system. (ATC 47)

A candy factory as an illustration of an adaptive control system.

The recently automated candy factory in Figure 15 (ii) illustrates an industrial application of adaptive control. An indication of sucessful activity -- a reward variable X, is derived from one of two sources (only one at once) namely -- (Mode I). An output meter (1) which measures quality and quantity of candy (according to a predetermined criterion), or (Mode II) a manager (2) who developes a preference for certain states of the plant upon a diversity of evidence, sampling the candy, watching his material bills, and altercating with customers who object to the sweetmeat.

In either case values of X are conveyed to clerk (3). The engineer (4) (having the status of overall controller) knows that the factory can be run by some possibly changing controller, because a limited number of taps used to be turned and a limited number of measures used to be made by men (5) before the place was automated. But the men (5) are disgrutled and will not disclose their arts. So (4) has to experiment by changing the parameters of a versatile sub-controller (which is equivalent to selecting different sub-controllers from a box) (6). For each setting of the parameters (7), the clerk records a value of X in a table (8) and these records are averaged and guide the engineer who wishes to maximize the average value of X. Finally (9) and (10) represent the imperfections which disturb any real control system. (ATC 63-64)

Experiments

Cooperative Externalization Technique: CET.

The first instrumentation of the CET took place in the context of learning experiments involving small groups of 3 subjects, held in adaptivelt stabilized conditions and maintaining communication through a mechanical but fairly rich language (capable of expressing descriptions of a universe, questions, obstensions, and proposals of a structural kind: for example, about communication or coalition structures). This is reported in Pask and Lewis, 1962, 1964, 1969, and Lewis obtained further data upon aberrant communication strategies, which will be published during the next year or so. The first serious application of the CET to individual learning slanted, in particular, to the empirical distinction of exclusive learning strategies and bearing witness to the (apparently ubiquitous) effect of cognitive fixity is summarized in Appendix B. In the main text it is only necessary to comment that strategy types, their invariance due to cognitive fixity, the existence of an individual competence to execute a learning strategy of a given type and the salutory effect upon learning of a conversational CET have been observed in the context of a complex perceptual motor skill (Pask and Scott 1971) and that the phenomena in question were predicted and modelled. As the same phenomena occur, reliably, in the context of intellectual skills and bodies of academic knowledge it is conjectured that the processes responsible permeate all facets of the psyche. (CCL 51)

Course Assembly System and Tutorial Environment: CASTE.

CASTE is an essential tool for studying conversations and is a clear embodiment of many parts of the theory. It operation is most readily described by reference to a specific series of experiments (reported in detail in Pask and Scott, 1972, 1973). The respondent in any of these experiments plays a student like role and is usually called "the student" or A. For the experiments of particular concern, A interacts with a heuristic, B, which, depending upon the conditions, is either designed to externalize normally private aspects of cognition as stretches of L dialogue (i.e. an "unbiased" conversational heuristic) or it is a modified form of this heuristic, designed to encourage faster or more effective learning (recall that A learns something if any conversation is maintained). Other experiments, briefly noted because they ass to data about strategies of learning, involved more rigid teaching operations. (CCL 78)

Real-life artifacts/Teaching machines

Special purpose computers (Eucrates).

Although developed independently, an automaton of my own called Eucrates, embodies a nmber of these ideas. Plate I. It is a collection of two kinds of element, namely, "motor" elements and "memory" elements, which can be connected in various ways. The name Eucrates relates to a series of special-purpose computers, the first of which was demonstrated by C. E. G. Bailey, T.R. McKinnon Wood, and myself and, whilst chiefly intended to simulate the behaviour of a trainee it is applicable also to industrial control. A motor element i Eucrates is functionally analogous to one of the "artificial neurones" used by other workers in this field (that is, an electrical cicuit or other artifact, which imitates certain carefully specified features of a real neurone but, except in this restricted sense, is not intended as a "neurone model". (ATC 67)

Teaching machines.

In 1952 I became interested in the interaction between men and "learning" machines, constructed some rather whimsical automata and managed to acheive a stable, in a certain sense, a "conversational", man/machine relationship. Since 1956 Bailey, McKinnon Wood, and I have applied similar methods to the synthesis of teaching systems which will act as private instructors. (ATC 89-90)

If teaching is the control of learning, then it might be mechanized. That is not to say that it must be mechanized or that mechanization is either economic or practically advantageous. But it might be mechanized insofar as a control procedure is a prescription for what to do at each step in a process; frequently, (in the cae of feedback control) a prescription that is contingent upon evidence regarding the current state of the process. The controller, which executes the prescriptive strategy, may be a human being who carries out some algorithm or it may be an artifact, made in the metal, which does the same thing. In other cases again, the function of executing the control strategy may be relegated to the student himself insofar as he adheres to certain rules and interprets the contents of a programmed book. The important thing, is that a strategy exists. (TM 1)

Having said all this, it is hardly necessary to stress that the hardware of a teraching machine is unimportant compared to the software (the teaching programme in a sequentially acting device or a programmatic organization in the case of a parallel acting training machine). As noted at the outset, the essential issue is whether or not teaching can be mechanized; not whether or not it is. Nevertheless, it is always convenient to have a machine and the administration of a programme may even be impractical without one. Apart from the teaching function as such, it is usually possible to connect up recording devices which provide the data needed for programme assessment, adaptation and revision. (TM 6-7)

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