Perceiving

Perceiving is the acquisition of relevant and irrelevant conditions of the domain and of the behaviour of the interactive worksystem with respect to domain changes.

Examples of perceiving occur when:

a) a handler appraises the initial conditions, state of the object, for example, how heavy the patient is, what is a patient's likely ability and/or willingness to cooperate and/or help with the manoeuvre, the amount of space available to

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move in.

b) a handler detects a patient's state, changes in state throughout execution of the

task, for example is a patient heavier or more awkward than anticipated, does

his/her state change, e.g. is (s)he about to faint or lose balance.

c) a handler appraises his/her own state, e.g. his/her own position, level of risk.

4. Executing

Executing is the transformation of domain objects via implementation of the behaviours

specified by the plan

Examples of execution are:

he//

Q

a) verbal communication with patient asking him how4ie is, explaining what is

going to happen and how (s)he is required to assist.

b) positioning self to enable initiation of handling manoeuvre.

c) adjusting hand position to get a better grip on a patient.

d) lifting a patient

The M MAC-PH model for patient-handling is shown in Figure 5.2 and the relationship

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F igure 5.2 M MAC-PH

K n o w le d g e o f patient and environm ent

P erceivin g patient handling * D om ain o f patient handling C ontrolling patient handling * P lanning patient handling *

E xecu tin g patient handling * Plans P H B S * Key: Read Arrow Write Arrow P H B S P H G S

Patient H andling B ehavioural Structures Patient H andling G oal Structures Indicates M M A C E xtension

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Figure 5.3

Relationship between Goal structures and Behavioural structures in plans in MMAC-PH model

G3_____________ (achieve positioned upper limb)

G2

(ach ieve positioned

low er limb) m ove foot

Proc remove slippers check skin condition B3 B5 B2 B4 Behavioural structures Goal structures G1 bend knee B6 BN

Figure 5.3 show s an exam ple o f the relationship between achievem ent o f a certain part o f the goal structure and the recruitment o f behaviours. For exam ple, in the diagram, the goal 'A chieve lifted patient' can be decom posed into 'A chieve positioned lower limbs' G2, 'A chieve positioned upper limb G3. In satisfying G2, a procedure Proc 1 may be recruited. Proc I com prises three behaviours: B l , m ove foot; B 2, m ove slippers; B3, check skin condition. A s indicated satisfying G2 may also necessitate recruitment o f an atom ic behaviour, e.g. B 5, bend knee.

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5.4.1 The MMAC-PH model and teaching effectiveness

The training programme appears to support the acquisition of: a) goal states; Gi_„ (e.g. achieve hfted patient) and b) procedures; ProCi.^ (e.g. different ways of lifting) and c) atomic behaviours; Bi_„ (e.g. move shppers)

In each case n is an indefinite number specified by the variety of goal states or behaviours possible. The high level goal states are those concerned with specifying in a fairly general way what is to be achieved. The lecture components of the training programme can be presumed to support the acquisition of generic goals, procedures and behaviours. In Study

1, the lecture parts of the training programme were reported to be adequate, suggesting that novices have few problems acquiring the generic knowledge

The training programme also supports, by the practice elements of the programme, the translation of high level generic knowledge into a few specific instances. The specific training programme can be viewed as offering support to the formulation of a set of generic plans. The rules governing this formulation can be considered to be the default structure. This structure is presumed to be recruited when a trainee is required to perform in a novel situation.

Performance of a task occurs by the execution process implementing procedures and behaviours which have been selected fi*om the available repertoire, to satisfy the specified goal structure. Each level of the goal structure may be served by a different permutation

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of behaviours. The research problem can be expressed as one of how to make the generic knowledge to be conveyed in training programmes more generalisable, i.e. so that it supports a wider range of specific instances. This presumes, of course, that the training programme has not left the trainee deficient with respect to particular atomic behaviours.

Planning and control behaviours are concerned either with specifying and sequencing behaviours, procedures, and goals, or else with the translation of knowledge from high to low states. It seems reasonable to suggest that a solution which offers support to planning and control behaviours should support the formulation of appropriate goal structures, which are able to recruit appropriate behaviours in non-taught situations. In other words, supporting planning and control behaviours should facilitate the application of the generic knowledge.

5.5 Knowledge structures

By comparing novices' knowledge structures with the structure of knowledge intended by the training programme, some indication should be acquired of the need for support for more effective training. Further indications should be obtained from comparison of the presumed knowledge structures of novices with those of experts. This section considers the structure of knowledge which the training programme aims to dehver. It then places this in the context of the specific data from Study 1. This allows consideration of the differences between experts and novices in terms of their presumed knowledge

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representation structures (plans and knowledge-of-tasks) and their behaviours.

5.5.1 Structure of knowledge training progranune aims to deliver

In general terms, given that the research problem is one of poor transfer of learned skills, the criteria for postulating the structure of the knowledge which the training programme aims to deliver are, that it is able to encapsulate the structure of:

1. training programmes in general, i.e. the structure postulated is not idiosyncratic to the specific training programme

2. the presumed knowledge of novices including deficiencies and non-deficiencies 3. the presumed knowledge of experts including deficiencies and non-deficiencies

By distinguishing the presumed knowledge of novices and experts, a foundation is laid for subsequent prescription of relevant interventions to enhance the training programme.

The knowledge required to perform a task is commonly assumed to be represented as multiple hierarchies with knowledge at different levels of generality. Each level of the hierarchy can be viewed as being potentially complete, in terms of its abihty to describe its application without reliance on any other level. Within training programmes generally, a similar hierarchy of knowledge representation can be suggested and indeed hierarchical task analysis (Annett and Duncan, 1967) was developed for training. The nature of the relationships between different levels of different hierarchies can vary. For example, a

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'shoulder' lift has a 'TYPE' relationship to the higher level description, 'Types of patient lift'. In comparison, the bones of the spine exist in a 'PART OF' relationship to the 'anatomy of the spine'. In summary, the knowledge contained within the training programme aims to be appropriately structured such that it may be appropriately acquired by the student.

Cognitive neuroscientists concerned with movement often describe three inter-related levels of computation. Following this view, if a simple three level hierarchy is assumed, it seems feasible that aspects of a programme may support the acquisition of predominantly generic, high level representations. Only if converted to lower level representations and instantiated will these high level representations offer support to overt behaviour. Similarly, aspects of a training programme may support the acquisition of predominantly low level representations. Only if converted to higher level representations and generalised will these low level representations offer support to overt behaviour, other than that previously instantiated in the classroom.

The three levels of representation may be considered to be acted upon by a single process of implementation, whereby the high level representation is converted into a lower level, more easily applied form of knowledge. Alternatively, the low level representations are converted into a higher level, more generalisable form of knowledge. In both cases, the student has to generate the missing levels of representation.

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A low level representation is always necessary for physical behavioural instantiation. However, if a training programme only supports the acquisition of low level representations, then a student is unlikely to be able to generalise the knowledge and subsequently transfer it to support the performance of non-taught tasks. Conversely, a representation that is too high in level, would not be predicted to be readily able to generate representations at a sufficiently low level to support appropriate behaviours. Interestingly, Pheasant (1991p2g9) alludes to this type of situation when he compares the development of lifting skills to the development of a tennis serve. He points out that such skills can be taught procedurally using a, 'doing it by numbers' approach but explains that the levels of skill acquired in this manner are somewhat limited.

The next section aims to test this view and attempt to answer the question: 'What is the structure of knowledge in patient-handling training programmes?' Given that the patient- handling tasks analysed in the first study were believed to be representative of those carried out in health workplaces, sections 5.5.2 and 5.5.3 considers the findings of that study in the context of the MMAC model.

5.5.2 Presumed knowledge structures/specific model experts

In contrast to novices, experts perform adequately, if not ideally in the workplace, and their performances are significantly better than those of novices. Experts do, in general, select appropriate manoeuvres to reduce the load on the spine. Thus, they exhibit behaviours which are, at least partially, compatible with the training programme's aims of

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producing a set of trainee behaviours which wül reduce the likelihood of back pain.

The presumed knowledge structures of experts, are likely to be similar to those intended by the training programme, and are the knowledge structures it is hoped the novices would acquire. Unlike the novices, the experts' high level representations appear to support the formulation of multiple, appropriate, low level representations. In turn, these can support behaviour in different contexts. In other words, the quality of experts' high level representations is either better than that of the novices, i.e. there is better specification of the desired end state of domain, or else the translation process is better supported, or both.

In terms of the model, the experts seemed to show greater reliance on proceduralised knowledge with good heuristics, and were more able to adapt their behaviours to the workplace. For example, when performing a patient transfer, constraints imposed by additional objects attached to the patient did not seem to markedly impair the experts' performance whereas the novices' performance was very sensitive to these added complexities (see for example. Behaviour B14, Table 3.2).

The experts appeared to demonstrate adequate high level plans and adequate planning. For example, they spent time initially deciding what to do and were more able to respond to unexpected events, and to accommodate objects which do not appear in the training programme, e.g. drains, orthoses (see section 3.4.6 and Table 3.2). Behaviours such as

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preparing the destination area (Behaviour B5, Table 3.2) suggested that the experts had thought through their whole plan.

In comparison to novices, the experts also appeared to evidence more adequate domain knowledge indicating that their perceiving process was more effective. There seemed to be a suggestion that there was less and differently formatted information in the experts' plans conçared to the plans of novices. This may indicate that the translation process in novices may be in^aired. For example, the tendency appeared to be for experts to create a crude plan expressed in terms of the sub-goals to be achieved but omitting irrelevant detail. In comparison, novices tend to focus on low level details so that their plans

his/

included some of the details of where the handler was to position her feet, where to position the patient's limbs, and what to say to the patient, all transposed more or less directly from the training programme.

Apart from demonstrating only partially elaborated initial plans, the experts also seemed to demonstrate more updating of their plans as they moved. For example, if it became apparent during the manoeuvre that it would be easier for a patient to be moved in a different direction, the experts were more likely than the novices to change their plans. The apparent updating of plans indicates that experts may have better control behaviours such that they are more able to interleave planning behaviours with perceiving ones.

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by better perception. Because of this the experts were better able to generate low level representations to support behaviour in non-taught tasks.

5.5.3 Presumed knowledge structures/specific model novices

The specific data fi*om the first study showed that novice performance of patient-handling tasks was adequate and appropriate in the classroom, but was inadequate and/or inappropriate in the workplace. Thus performance in the workplace was, at best, equal to that in the classroom, and was often inferior to classroom performance. Although two subjects achieved the same performance score in the classroom and the workplace, no subject actually achieved a higher score in the workplace. The difference in performance in the two situations, is attributable to the requirement for knowledge support being different. The nature of the difference can be atttributed either to lack of knowledge or to a failure of implementation. Thus, firom the training programme, trainees have acquired knowledge which is appropriate to support behaviour in the classroom, but inappropriate to support behaviour in the workplace.

To summarise, two theoretical possibilities exist regarding the deficient workplace knowledge:

a) Classroom knowledge is appropriate for the classroom but not for the workplace even if it is remembered

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b) Classroom knowledge is appropriate for the classroom and for the workplace only if it is remembered and generalised

It has already been suggested that the training programme supports the acquisition of a range o f high to low level representations. Despite controversy over the, 'best' way of handling (e.g. Venning, 1988) the biomechanical principles on which the specific training programme is based are reasonably well established, making it unlikely that the knowledge is inappropriate to support behaviour in the workplace. This is not intended to imply that the knowledge provided by the training programme can always be instantiated at a high level of performance in the workplace. Clearly this is not the case, as often the physical constraints of the workplace preclude the use of a specific patient-handling manoeuvre, or the application of a specific behaviour, in precisely the manner taught. However, the actual knowledge provided by the programme, at the level which it is provided, is, in general, reasonably well founded.

Novices were able to produce the desired behaviours in the classroom but were, in the main, unable to do so in the workplace. Presumably, the training programme supports the acquisition of a set of low level representations which support behaviour in the classroom, but which cannot be generahsed to support behaviour in the workplace. For example, novices are able to perform a shoulder hft/shde (which entails them facing a patient and positioning their shoulders in the patient's axilla) adequately in the classroom situation but are unable to do so in the workplace. This failure is usually a function of novices' inabihty

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to configure either themselves or the patient appropriately, once the situation becomes more complex, as additional cues impact.

In terms of the three level hierarchical system of knowledge representation, it appears that the quality of the high level representations or of their translation to lower forms, may be presumed to be deficient with respect to supporting the formulation of low level representations, which in turn support behaviour.

Thus, the novices' behaviours showed reliance on predominantly declarative knowledge as they reverted either to what they knew before being trained, or else implemented the low level representations acquired during the training period. For example, novices may revert to dragging a patient, as they would have done before being trained. In other words, the novices failed to bridge the gap between their abstract knowledge and their physical behaviours.

In terms of the model, novices appeared to demonstrate a lack of high level plans and a lack of planning. Hence, they had difficulty in deciding what behaviours were necessary in order to achieve their goal so, for example, if a patient had a catheter or a sphnt attached, novices found it difficult to fit this into their overall goal of a moved patient (see section 3.4.6 and Table 3.2). Consequently, they tended to either become preoccupied with the catheter/splint, or else to ignore it (Behaviour B14, Table 3.2), suggesting an inabihty to use their knowledge to work out how to reconfigure their approach to the

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task. Unlike the experts, the novices were unable to create appropriate sub-goals to reduce the difference between the existing state of the domain and the desired state. By failing to create appropriate sub-goals, it may be presumed that the novices fail to set up the right conditions to then select appropriate behaviours.

Novices also appeared to evidence poorly constructed plans, with poorly formatted domain knowledge. Hence, the amount of domain information which appeared to influence novices' planning seemed to be greater than that referred to by the experts, probably because it included much irrelevant information. For example, furniture and its arrangement within the workspace was often adjusted even when the patient was not to be moved out of the bed and the workspace arrangements did not influence the novices' abihty to work. In the context of evidence which suggests that the structural properties of objects constrain the way in which actions (behaviours) are planned and controlled