Diagrams and illustrations as aids to problem solving

The psychological literature relating to factors which should be taken into account in the design of illustrations and pictorial instructions as aids to problem solving is reviewed. The problem solver can invoke a wide range of strategies for using pictorial materials to achieve his goal, although pictorial instructions which indicate how to perform actions place a tighter constraint on the choice of strategy than illustrations showing only states to be attained. The designer must make his graphics compatible with as wide a range of strategies for using them as possible while building on the knowledge the problem solver already possesses.The author now works for the Post Office Telecommunications Systems Strategy Department, 88 Hills Road, Cambridge.