A study of mental procedures in electronic trouble shooting

The mental procedures used by skilled electronics repair men in their normal working environment have been studied by analysis of verbalized records. The aim of the experiment was to identify and isolate typical heuristic subroutines and their role in the search procedures. The procedures found are organized as a search through a system which is viewed as a hierarchy of subunits. The general structure of the search can be broken into a sequence of recurrent search routines. Basically different types of such routines are found with great differences in respect of the number of obervations needed and the complexity of the mental data processing involved. They also differ gratly with respect to the depth of knowledge of the internal functioning of the system used by the repair men. The records demonstrate a great ability in the men to conduct the search by general routines mostly depending upon their general professional background, and a preference for rapid streams of simple decisions as good/bad judgements regardless of whether observations ar informatinally redundant or not. Seen form the viewpoint of information economy, the procedures are inefficient, but if the men are supposed to minimize the time spent on the task and the mental load involved, the procedures are very rational.