Capacity Limitations in Human Information Processing: Theory and Applications

Two factors that are critical aspects of complex system performance are system design and operator training. The contribution of each of these factors becomes paramount as increases in system complexity demand more sophisticated operator timesharing skills to monitor and control system operations safely and efficiently. In order to increase human operator skill levels, improvements in system design must be achieved to make aspects of monitoring and controlling tasks more commensurate with human abilities. Secondly, more effective and efficient training programs must be developed to allow human operators to acquire and maintain appropriate skill levels. Before these improvements can be accomplished, however, a greater understanding of the capabilities and limitations of the human information processing system must be obtained.

In a typical modern system (e.g., aircraft cockpit, centralized control room of a power plant or battle management system) the human may perform many tasks concurrently, including visual search, memory search, retention and recall, comprehension, reasoning, judgement and decision making, and executing fine motor movements. Although some combinations of these kinds of tasks may be compatible and non-interfering, other task combinations may interfere and compete for the human's limited information processing capacity, creating overload conditions. The consequence of the human operator's low threshold for overload leads to increased probability of error, with subsequent deteriorations in system performance.

There are two theoretical approaches to human attention and information processing that have implications for system design and operator training issues in the context of timesharing and high workload situations. Multiple resource theory and automatic/controlled processing theory have each stimulated much empirical work that provided useful data on human timesharing abilities. Such data have provided the basis for predicting task combinations and training requirements that allow high levels of performance under timesharing and high workload situations.

The purpose of this symposium is to describe recent empirical developments that may further our understanding of human information processing capabilities and limitations, particularly under timesharing and high workload conditions. The set of papers includes theoretical and applied treatments of multiple resource and automaticity theories. The issues discussed include the advantages and disadvantages of spreading information input over different sensory modalities (e.g., visual and auditory), development of training methods to acquire sophisticated high level cognitive skills quickly and efficiently, measurement of information processing capacity required by specific task combinations, and a delineation of the characteristics and limitations of working memory.