Two Levels of Supervision

All this work on adequacy converges towards a cognitive model of the individual, who is said to manage two types of supervision in parallel to ensure that he remains in control of the situation management of the physical process and the situation (referred to as external control or supervision) and management of himself as a cognitive actor in the process (referred to as internal control or supervision). These two forms of supervision, whose interests often conflict, explain the fundamental need for compromise mechanisms and adequacy. 

Supervision of the external process [44] permits intensive use of routines while relying on planning and guidance obtained from the affordance within the environment. It is only in situations where problems arise and routine processes are blocked that cognitive processes are invoked in that case cognition has to be used more intensively and that intensity must also be controlled so that it produces results that are useful before the deadline for the process, which continues to evolve [45]. 

Orientation of roundsmen in the corridors of nuclear power stations. 

A study using a realistic simulation [45] showed that roundsmen in a nuclear power station only check their own progress as they move around against a small number of key points and that they are not really aware of these checks. Sixty percent of those key points correspond to places where confusion between corridors is at a maximum (same colours, various similarities), creating an obvious source of errors. These checks are relatively common to aU the roundsmen, as if they were triggered simply by contact 

When these roundsmen are exposed to a change in time pressure (having to work more quickly), the external checks remain identical but the personal checks are organised differently, are closer together in time, probably in order to offer better monitoring of the automatically increased risk of errors and overload. 

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