control levels/function areas as well as how to handle new alter-
native means in different types of situations. The emphasis lies
therefore, as before, on knowledge and an understanding of the
effects of different types of measures.
Control and decisions
Control is also tied to decision making through the cognitive pro-
cessing of information. According to Klein (1998) expertise and
competence are extremely important for decision making in na-
turalistic environments. Important aspects of decision making in
such environments are an understanding of the dynamics and
characteristics of the situation (Orasanu et al. 1992a). Tengblad
(2000) writes that decision making at a higher system level exerci-
ses control through influence and that this is related to an ability
to reach consensus on a particular plan. At lower system levels
control is often based on a more direct form of influence over the
system to be controlled.
Here we can relate to what is known as cognitive control, which is
a type of intellectual control, and how control is maintained through
creating mental images of a situation and how to deal with it. As dis-
cussed above emergency response tactics are patterns of thought and
action. Cognitive control is then part of the thought process.
Cognitive control can, irrespective of the system level from which
the control problem is considered, be seen as having three levels:
experience based, regulation based and knowledge based control
(Rasmussen, 1983 and 1992). Experience based control is characte-
rized by the ability to act unconsciously under familiar circumstan-
ces through an inner dynamic model of the outside world. This is
typical for an expert, who has the capacity to draw conclusions and
act on the basis of his or her experience. This experience does not
necessarily need to be based on similar situations. Regulation based
control entails a conscious use of regulations in familiar situations.
These can be empirical, based on previous, similar situations. But
they can also be formal, taken from or based on the culture that
applies within the system at a certain level (known as company cul-
ture). This type of activity can be taken as a form of feedforward
control. Knowledge based control entails the transformation or
conversion of knowledge, in this case of the effects of various me-
asures, especially in relation to the course of events at an incident
site. Here a practical plan is developed based on the explicit goal
which is in turn based on an analysis of the current situation.