The work tasks of industrial process operators can have far reaching implications for both the safety of personnel and protection of the environment. The training of these operators to be competent in their work tasks, therefore, attains a high level of importance. The control of industrial processes often requires operators to undertake complex dynamic tasks. Cognitive science is attempting to explain the cognitive processes that underlie the behaviour of operators when carrying out these tasks. This paper will investigate the current theories concerning these cognitive processes and will discuss their implications toward the training of industrial process operators.