Human information processing, skill and performance
If the organism carries a 'small scale model' of external reality and of its possible actions within its head it is able to try out various alternatives, conclude which is the best of them, react to future situations before they arise, utilise the knowledge of past events in dealing with present and the future, and in every way to react in a much fuller, safer and more competent manner to the emergencies which face it.
(Craik, K. 1943)
Human-machine interaction depends on a two-way exchange of information between the operator and the system. Designers usually have detailed, explicit models of machines
and machine behaviour
that can be used to improve human-machine interaction. According to Preece (1993), a general model of the user's cognitive processes and cognitive behaviour
is also needed to
|• Provide knowledge about what can and cannot be expected of users |
|• Identify and explain the nature and causes of problems |
|• Supply modelling tools to help build more compatible interfaces |
A general information processing model of the user
According to Reason (1990), in broad terms, the human information processing system (HIP) can be thought of as
|• A general-purpose pattern recogniser |
|• With limited information processing capacity |
|• Using heuristics (rules of thumb) to simplify the information processing load |
|• And acting as a 'satisficer' rather than an optimiser |
Satisficing refers to the tendency to seek pragmatic, rather than optimal, solutions to problems by trading-off the costs and benefits of alternative actions.
In the information processing approach, flow diagrams are used to represent how the brain processes information. It seems to be the case that much of human information occurs without conscious effort. A great deal of pre-conscious (or 'pre-attentive') processing takes place. Velmans (1991) gives the following example:
'The forest ranger did not permit us to enter the reserve without a permit'.