A person may have an incorrect or incomplete representation of the device they are using. For example, the person may not know the correct causalities or interactions, or may not be able to represent correctly the development of events over time. Or someone may use an inappropriate category in recognition-primed decisions or case in case-based reasoning.
Knowledge about probabilities may be incorrect, or used wrongly. People may be under- or overconfident. They may have a "halo effect," attributing the same probabilities to unrelated aspects. They may give inappropriate credence to information or instructions from people of higher status. Different social groups--for example, unions, management, and the general public--may have different views on the risks and payoffs of particular scenarios.
This list of human weaknesses should not distract from two important points. One is that people can be good at detecting their errors and recovering from them, if they are given an interface and training that enable them to do this. Therefore design to support recovery should be included in cognitive task analysis.
The second point is that care is needed with the attribution of responsibility for faults. Although it may be a given individual who makes an error, the responsibility for that error may be attributed elsewhere, to poor equipment or system design (training, workload, allocation of function, teamwork, organizational culture).
There are several integrative concepts in this chapter.
Cognitive Goals. In complex tasks people use cognitive goals when implementing task goals. A person's cognitive goals are important in organizing the person's behavior, in directing attention to parts of the task, in choosing the best method for meeting a given goal, and in developing new working methods. The cognitive goals might be met in different ways in different circumstances, so the goals and the processes for meeting them can be independent. For example, flying an aircraft involves predicting the weather, and this may be done in different ways before and during the flight.
Contextual Overview. People build up an overview of understanding and planning, which then acts as the context for later activity. The overview provides data, expectations and values, and the criteria for deciding what would be the next best thing to do and how to do it.
Goal-Means Independence and Meta-Knowledge. Meta-knowledge is knowledge about knowledge, such as the likelihood of alternative explanations of what is happening, or the difficulty of carrying out a particular action. Alternative working methods have associated with them meta-knowledge about their properties. Decisions about how best to meet a particular aim are based on meta-knowledge, and are involved in adapting behavior to particular circumstances and in the control of multitasking and mental workload and in learning.
Modes of Processing. As well as using different working methods, people may use different modes of processing, such as knowing the answer by association or thinking out a new working method. The mode of processing used varies from moment to moment, depending on the task and the person's experience.